Uranium Pebbles May Light the Way

kristy_christie writes "According to Wired News, South Africa's state-run utility giant Eskom and its international partners want to build the world's first commercial 'pebble bed' reactor, which, instead of using fuel rods, 'is packed with tennis ball-size graphite "pebbles," each containing thousands of tiny uranium dioxide particles'. To developers, the Pebble Bed Modular Reactor promises a rebirth of nuclear energy. Proponents insist that the reactor's design features make it 'meltdown-proof' and 'walk-away safe'."

Comments

Sweet

[__aavhli5779]

I applaud this kind of work.

Nuclear Power, despite the cries of environmentalists, is possibly the cleanest mass power source. On a scale of power generated per ton of input material it is incredibly efficient (bested only by those power sources which require no nonrenewable input, like wind/tidal/etc.), generates no effluent or air pollution, and needs only a competent staff (and, unfortunately, security), to stay running properly.

Nuclear plants may be prohibitively expensive to build these days, but if "pebble bed" reactors cost significantly less, then they may lead the way back towards what I view as our ideal energy source.

It's time to give nuclear a second chance.

Re:Sweet

[Anonymous Coward]

Nuclear power is definitely efficient. Nuclear waste, on the other hand, is not clean, and that's the problem environmentalists have with fission power.

Re:Sweet

[Anonymous Coward]

However, coal power plants release more radioactive waste into the enviroment than nuclear power plants and still provide most of the power in the US.

There's big money in keeping things the way they are. Nuclear power is so heavily regulated that it is too expensive. Thats the only reason we don't have more of it. If the other types of plants were regulated just as strictly we'd switch over as quickly as we could build them.

Re:Sweet

[SteveAstro]

On a scale of power generated per ton of input material it is incredibly efficient (bested only by those power sources which require no nonrenewable input, like wind/tidal/etc.) Possibly not true, because for the same energy output you need a lot more material and maintenance with the "renewable" systems - a gigawatt of wind power would be 100 10MW windturbines - and 10meg windturbines would be VERY big. Steve

Re:Sweet

[gl4ss]

the problem that most people have with nuclear power is tchernobyl(or similar catastrophy that would release radioactivity to a wide area).

'most people' don't know even the basics of how the energy is generated, all they know is that the place can explode and then there's going to be 3eyed fishes. the problem is that even if it's a 'failsafe'(won't explode) plant there's going to be hell explaining it to the people who are against nuclear power for mainly emonational reasons(and assume that people defend nuclear power for similar reasons because they hate the environment or something silly like that, or just for pure greed).

it's like that old joke... "what we need nuclear power for? i only need electricity"(dunno how the variation goes in english actually, but you get the idea).

around here there's a need for another reactor(industry needs the juice) but there's quite many people who are against it, yet they don't complain when we need to buy the same amount of electricity from russia(that is generated by nuclear reactor there, just over the border, at lower safety standards than what would be in place if the reactor were on our side of the border).

Re:Sweet

[Glock27]

Two words: Nuclear waste.

Two words: Lung Cancer.

That is the alternative, and pollution from traditional power generation plants is killing people every day, and sickening many more.

There is not a single permanent disposal site world-wide. no one can guarantee the safety. the U.S. government even has a website on _just this problem_. Ready-made dirty bombs are driven in trucks all over the country. GREAT IDEA.

If someone wants to kill a lot of civilians, all they need is a garage lab to produce chemical or bio agents. Much more effective, much easier to deal with, even more scary (1 gram of the right bio agent could kill millions). See the recent research on mouse pox for some really scary stuff (did that story make /.?). How 'bout a bio agent that'll only wipe out one ethnic group? The research is just about there. It is always hard to evaluate relative risk, but to me nuke power is way down the list.

BTW, as far as nuke disposal, there's a good reason for a lunar colony... =) Name another major energy source where the pollution could realistically be taken entirely off-planet.

Also BTW, I hope some of the recent solar energy developments lead (finally) to competitive photovoltaic power generation on a distributed basis (that'll tick off the power companies!). One of the more exciting developments is solar fabric, which can be used in curved building designs.

Re:Sweet

[quenda]

> It's spelled "Chernobyl".

Is it? Last time I checked, they still used the cyrillic alphabet in Ukraine. Yes, "Ch" is the dominant convention in the English speaking world, but that doesnt mean its the only one.

Re:Sweet

[Gordonjcp]

Sorry, no. Very little of them will be recyclable. Furthermore, the materials used in the construction of the wind turbines will turn out to be as nasty as the materials used for the nuclear power station.

There is a 30-turbine site proposed on the Isle of Skye. Each turbine will produce 10MW of electricity, and they are *huge*. Furthermore, the bases for each pylon will require 400 cubic metres of concrete - 2800 tonnes. Making this concrete will release 2800 tonnes of CO2 into the atmosphere - and that's for *one* turbine base, never mind the concrete pylon it will sit on.

Re:Sweet

[dreamchaser]

Nuclear power plants are required by law to have insurance. Do your research, rather than just loosely citing a couple of environmentalist texts. Here is just one of many links pointing out that these plants are indeed insured.

Re:Sweet

[joshv]

The problem with radioactive waste is that its half-life is in the tens of thousands of years.
We don't know who's going to be blowing who up even this time next year.

Very little of the waste produced by power plants has this sort of a half life. Even so, the less radioactive a substance, the longer the half-life. Those elements that do lasts tens of thousands of years simply aren't producing that much radiation.

Highly radioactive substances, on the other hand, have shorter half lives, and aren't much of a worry after a few decades.

-josh

Re:Sweet

[ckaminski]

I'm sorry, but with 600+ nuclear reactors in the world, it would seem to me that nuclear power has indeed turned out to be "safe enough". Minus a few notable events in Japan, the U.S. and the Ukraine, nuclear power has proven to be as safe as any other non-renewable power-generating industry.

I live next to 3 very large natural gas holding tanks that are a much more vulnerable terrorist target than any nuclear reactor.

Re:Sweet

[Aglassis]

You said: "The history of nuclear power so far, however, doesn't leave one optimistic."

What metric are you using to say that nuclear power has historically been unsafe? The number of deaths caused per MWh produced? Deaths or injuries per reactor-hour of operation? Average deaths per year at a given plant?

Really, compare these metrics to that of any other power distribution plant and you will see historically, even with the huge publicized disasters like Chernobyl and TMI, that no other large scale power producer even compares in safety to nuclear power.

But since we're on the topic of nuclear power safety history, the website The History of Nuclear Power Safety is an excellent resource.

Re:Sweet

[sql*kitten]

Even if you make it relatively "meltdown-safe", you still have huge issues as to what to do with the waste. The plutonium generated by the reactor described has to be stored for thousands of years, guarded against terrorist use. That is a massive hidden future cost, financial & risk-wise.

That is a myth spread by the anti-nuclear lobby, who are really anti-industry, as a side-effect of being anti-capitalist. Think about it logically for a minute. Why is spent fuel dangerous? Because it emits radiation. What is radiation? It is energy. What is the point of any fuel? That you can extract energy from it.

The problem of what to do with nuclear waste has already been solved: just loaded it into another type of reactor (called a "fast breeder reactor") and continue to use it. Nuclear waste simply is not a significant reason not to use nuclear power. The only problem is what to do with old, worn-out reactors.

Re:Sweet

[adeyadey]

Yeh, alternative energy is "anti-capitalist", Linux is "communist", etc..

Truth is that Wind power is a hard paying proposition - cheap energy, doable today, without all the headaches that comewith nuclear.. In what sense is that "anti-capitalist"?

Re:Sweet

[Eccles]

What metric are you using to say that nuclear power has historically been unsafe?

"Unsafe" was a poor choice of words, although not completely tangential. Clean-up is the big issue. Follow the Yucca Mountain issue much? Nobody wants nuclear waste. Until you can change that, there's no point in proposing ways to make more of it. And saying, "Well, people shouldn't be so frickin' uptight about it" is not a solution.

While the deaths from Chernobyl pale next to coal-mining and other "uninteresting" power-production deaths, 115,000 people were evacuated and the town of Pripyat was and still is abandoned, and nuclear material was spread all over Western Europe. (The initial discovery of the problem in the West was when Swedish nuclear techs started registering for radioactive dust, and a check of their plant didn't discover a leak there.)

Then there's the terrorism issue. Every time the alert level rises, the National Guard gets sent out to guard powerplants. That doesn't fill me with love for the things.

And what of Iran, North Korea, et al? Every time they start talking nuclear power, we get very nervous, and with good reason. One bomb in the hands of the wrong people would make 9/11 look like a fender-bender. Maybe these new tech reactors would provide power without needing the wrong type of nuclear expertise and fuel, but as-is, nuclear power plants have made the world less safe by giving totalitarian gov'ts a rationalization for working with nuclear fuels.

Re:Sweet

[adeyadey]

Nuclear waste is still *yet* to be dealt with fully - there is a lot of unprocessed waste being stored at various places. And if the companies cant afford to do it and go belly up, who do you thinks going to pay? Why the government..

The biggest argument is cost - these plants are proving very expensive to decommission, and the waste expensive to dispose of adequately. In the UK, its the poor taxpayer who is being left with this bill from the first generation of plants..

The biggest arguments against Nuclear are capitalist (cost) - not anti-capitalist. Although there are also Environmental issues..

Re:Sweet

[Waffle Iron]

The problem of what to do with nuclear waste has already been solved: just loaded it into another type of reactor (called a "fast breeder reactor") and continue to use it.

And generate all sorts of weapons-gradd material in the process. It's a major proliferation risk; that's why the U.S. has not chosen that option.

Nuclear waste simply is not a significant reason not to use nuclear power. The only problem is what to do with old, worn-out reactors.

There's another little reason: the risk of terrorist attacks on the plants. People argue all day about the technical safety and waste disposal issues. However, the security issues of proliferation and terrorist risks are by themselves enough to make avoiding nuclear power a no-brainer.

Our president has been running around hysterically shouting about WMDs for several years now. What's one of the most significant sources of material WMDs? It's when 2-bit countries convince people to let them have their own nuclear reactors. Again and again, we find out that they start producing weapons materials as soon as they crank up their plants. Part of the "war on terrorism" should be developing energy sources that allow us to totally eliminate nuclear power with its fuel cycle that has allowed several countries to hide their nuclear arms programs. Not to mention the problem that nuclear plants in your own country allow someone to turn a truck bomb or an airplane into a WMD (and don't bother bringing about the 3-foot thick shield around the reactor; I'm talking about attacking the unshielded spent fuel storage ponds).

Re:Sweet

[CharlieG]

As a poster above said, the really HOT nuke waste is fairly easy to get rid of - breader reactors. Carter banned them in the US for a few reasons

1)It was just post TMI

and

2)To do them right, you end up with NEAR weapons grade PU in the reactor and in the reproccessing plants. He thought there was too much of a security risk to have this much PU running around

A LOT of the initial assumptions on the cost of Nukes had to do with the fuel being reprocessed - aka, make your waste into fuel again - what is left is low level stuff - LONG half life, but also low radiation

One of the huge problems we have with storage is we keep trying to store "Mixed" waste - It's got high level waste (say, PU) mixed with low level waste.

Re:Sweet

[Mr. Slippery]

That is a myth spread by the anti-nuclear lobby, who are really anti-industry, as a side-effect of being anti-capitalist. Think about it logically for a minute. Why is spent fuel dangerous? Because it emits radiation. What is radiation? It is energy. What is the point of any fuel? That you can extract energy from it.

The chain of fallacies here is fascinating.

1. The photovoltaic and renewable energy industries may be anti-nulcear, but hardly anti-industry or anti-capitalist. (And being anti-capitalist doesn't mean being anti-industry.)
2. Spent fuel is not the only waste.
3. The fact that somethng emits radiation does not mean that said radiation can be harnessed as useful engergy.
4. Breeder reactors recycle uranium and trans-uranics, but still create non-recyclable fission products in their waste. (Yes, there are short-halflife products that "only" require hundreds of years of storage, rather than thousands.)
5. Breeder reactors produce plutonium. Nations tend to be awfuly cautious about letting their enemies or potential enemies build such plants (like Israel's attack on the Iraqi nuclear reactor in 1981.

Meltdown isn't the (whole) problem

[Tim C]

It's how to handle the waste. That represents a real engineering challenge - some of that stuff is going to remain toxic for tens of thousands of years. Not only does it have to be stored safely and securely, but you have to work out some way of marking it so that should anyone stumble across it in a couple of thousand years, they understand not to touch it. The amount languages and cultures change, you can't just write on it, and even things like skull pictures could be interpreted as meaning "burial chamber - archaelogists, get digging!".

That said, I'm not against nuclear power (from fusion) per se. Of the options we have, it's one of the best at the moment. "Alternative" power sources need a lot more work, and fusion, whilst extrememly promising, just isn't practicable yet (unless I've missed a major breakthrough in the last couple of years). I'm just pointing out that there are still other problems that need to be addressed.

Re:Meltdown isn't the (whole) problem

[AlecC]

"What, exactly, is the problem with encasing it in a block of concrete and burrying it somewhere? Am I missing something?"

I think you are. While stable on human lifetimes, concrete is not, I believe, stable on the necessary time perios. It is also water permeable on a long enough timescale. In the past, people were researching "glassification" - incorporating the wast into a kind of glass which is much more stable than concrete. Even then, I believe they found that the heat generates by radioactive decay increased the mobility of the waste through the glass so that it might be expected to start leaking out of the block in 250,000 years worst case.

Re:Meltdown isn't the (whole) problem

[Znork]

The solution to that is simple. You make new fuel of the waste. The technology to do it already exists, so instead of using a miniscule amount of the fuel and then considering it 'spent' and trying to store that highly radioactive material you can run it through a breeder reactor and use it again. And again. And again. And again.

That way you dont get a lot of waste, and you get many many times more use out of the fuel you have.

Nuclear waste is a problem that already has a solution, and a solution that is ecologically sound and very much in line with recycling and reuse.

Re:Meltdown isn't the (whole) problem

[NSash]

Indeed, reprocessing spent uranium is the best solution, both from a commercial and an environmental standpoint. However, re-enriching uranium is banned under international treaty, since the uranium could then be used to make nuclear weapons. Yet another example of why sometimes there are non-technical considerations in a seemingly technical problem.

Re:Meltdown isn't the (whole) problem

[chthonicdaemon]

That's kinda the point of these pebbles. I have seen a lot of work on this reactor technology, and waste is an important concern. The Fuel spere pebbles safely encase the nuclear material -- you can handle them and throw them around a bit. "The silicon carbide coatings that surround the uranium fuel particles within the pebble form a miniature pressure vessel. This pressure vessel provides a highly efficient barrier against the release of fission products during operation." - from the linked-to site

Re:Meltdown isn't the (whole) problem

[gl4ss]

burying it deep enough is the key(so that it's not too probable that anyone with brains will just accidentally stumble upon it while on a picnic, also at relatively not too deep there's natural radiation also so that anyone who would dwell there would need to have the brains to protect himself anyways), or wait till we can send it to the moon/sun/mars/alfa centauri(50-400years.. if there's not a huge nuclear ww3 before that and then i wouldn't worry about nuclear waste).

burying it deep in some stable part of the earth is the best way currently though(at least much better than the sometimes used method of just stacking it in a shack). and besides, ancient egyptians got their cursed tombs, WHY CAN'T WE HAVE THEM??!?!?-)

however, we have much bigger waste problems than just nuclear waste.

Re:Meltdown isn't the (whole) problem

[Znork]

As far as I know there are no international treaties banning breeder reactors; the bans that exists in the US for example, are internal to the country.

Maybe it's time to reconsider those bans, as it is becoming quite apparent that there is no near term solution to the energy problem apart from nuclear energy and there is no other good way to handle nuclear waste.

Re:Meltdown isn't the (whole) problem

[Afty0r]

However, re-enriching uranium is banned under international treaty

I would be very surprised if this is true, care to provide some links? I have had dealings with BNFL - British Nuclear Fuels Limited. They carry out this reprocessing of spent Uraniaum on facilities less than 50 miles from where my parents lived all their lives.

Re:Meltdown isn't the (whole) problem

[stevelinton]

The problem with reprocessing is that

a) it's quite messy, dangerous and difficult to do safely. Not impossible, but neither easy nor cheap.

b) You turn a lot of moderately radioactive waste into a smaller amount of highly radioactive waste (purified fission products) and some reusable fuel (some of which is plutonium, which raises certain accounting and security issues) and in the process create a whole lot of medium level waste (irradiated machinery and such).

Neither is insuperable, but recycling is not a panacea

I'm a fan of fusion. If you look at the whole solar system, there are really only two large pools of energy -- light elements that could be fused and gravitational and kinetic energy in the planets orbital motion. Using the latter on a really large scale runs into a few problems with conservation of angular momentum, and also involves dropping Jupiter into the Sun, which is a but destructive, so it seems that fusion must be the way. Whether it is better to have one big central fusion reactor (as at present) and broadcast the energy (surely rather wasteful) or to distribute the generation more widely, I'm not sure. Breaking up the Sun into local sunlets might also be seen as a bit radical.

Re:Meltdown isn't the (whole) problem

[Antity-H]

Why not have earth recycle the wastes for us ?
Burying it in subduction zones should do the trick. wouldn't it take the wastes even further down in the mantle where they won't bother anyone?
I know the process is slow, but even so it _is_ faster than waiting for the most dangerous wastes to be harmless.

Re:Meltdown isn't the (whole) problem

[p4k]

The solution to that is simple. You make new fuel of the waste.

Sorry, doesn't work like that. The fuel rods have to be removed from the reactor not when the U235 is exhausted, but when the fission products start to build up. These fission products are orders of magnitude more radioactive than the original fuel was, and when present in any quantity will poison the nuclear reactions. This will happen after only a small proportion of the U235 has fissioned. "Reprocessing" simply consists of seperating out the unused fuel from the fission products so you get a second chance to use the remaining fuel.

Fast breeder reactors are a solution to an entirely different problem, i.e. converting unusable U238 into fissionable Pu239. There is currently no way to deal with fission products except waiting a few thousand years for the worst of the radioactivity to die away. It's also difficult to handle because with the extreme levels of radioactivity it generates there is also a lot of heat, if you encased it in concrete and buried it, it would just burn it's way out and end up in the groundwater.

Nuclear waste is a problem that already has a solution, and a solution that is ecologically sound and very much in line with recycling and reuse.

You don't have a clue what you're talking about.

Re:Meltdown isn't the (whole) problem

[Suidae]

If you had RTFA you'd know that the pressure vessel is lined with a rather thick layer of graphite (and also has a large graphite column in the center). Besides that, I doubt a 5cm sphere of even the hardest substance would rub holes in a steel pressure vessel in even large multiples of the entire plant lifetime. And what vibration? These aren't Mexican Nuclear Jumping Beans, the don't move around on their own.

I'm a proponent of nuclear energy

[Dancin_Santa]

I think it is important to move away from the current reliance on fossil fuels as quickly as possible and move towards nuclear power generation as the only realistic sustainable alternative power generation scheme.

Many of the world's problems exist because of the small patch of oil-soaked land out in the Middle East and the lack of trustworthy stewards of those fields. With Gulf War II over and those oil fields finally in the hands of Western democracies we may see some improvement in global stability vis a vis the opening of OPEC to its main customers. However, because we continue to rely on oil as our primary power source we will likely continue to have problems as the oil fields run drier and drier.

It is good to see Africa (of all nations!) take the lead in this new system of nuclear power generation. Older systems like the ones in Canada and France are fine, however it would be a stretch to say that they are perfect. There is plenty of room for improvement in those power plants. This usage of uranium pebbles is one such improvement, but there are more.

It is a problem that people would be willing to block the development of Africa because they object to the usage of these newer power systems. Especially so because for the most part the same protesters unwittingly reap the benefits of their own country's nuclear power generation systems.

Re:I'm a proponent of nuclear energy

[spankalee]

Are you saying that the US is a "trustworthy steward"? Maybe from the point of view of a Patriotic American, since it's a bit like trusting yourself.

Global instability over the past, oh... how about all of recorded history, has been about power struggles (that usually have very little to do with oil). Imperialism, world wars, revolutions, slave revolts, coups, violent protests, terrorism - all these examples of instability are caused by struggles for power (freedom being a power). Oil may seem like the cause of recent problems, but really it's just a weapon in the war. We fight for oil because without it we couldn't fight for power.

And what western democracies are the oil fields in the hands of? Iraq certainly doesn't constitute "those oil fields", and after we're out of there we may very well see Iraq run by a government unfriendly to the US. What other western democracy is over there? Not Kuwait. Calling them a democracy is a joke.

OPEC is probably doing the world a favor by controlling the oil production. If we pumped the oil out as fast as possible to reduce prices we'd only exagerate the problems of polution and a limited supply of oil.

It is good to see Africa (of all nations!) investigate cheap and clean power since they need it so very badly, but I worry about how the waste will be handled. The environmental and saftey issues of nuclear energy has caused us to spend millions and possibly billions on researching and implementing advanced waste disposal. Will cash strapped nations in Africa be as diligent?

Waste disposal

[Space cowboy]

The perennial question is one of waste disposal. It's all very well having a realtively clean source of energy right now, but if you have to guard against people getting hurt for X years, where X is a very large number...

They claim the graphite and silicon carbide around the pebbles will keep it sealed for ~ 1 million years, which is impressive. It'll be interesting to see if humanity is around in ~1 million years ...

It also produces about 19 tons of radioactive waste (in the form of these coated pebbles) every year. That's going to be some landfill site, if the technology takes off...

Simon.

Re:Waste disposal

[netwiz]

19 tons of heavy metal radioisotope doesn't take up much space. These elements are quite dense.

I remember seeing a demo of this stuff in school.. It's so safe to use in a reactor it's crazy; they referred to it as "walk-away" safe. Lose _all_ cooling in the core, leave it over the weekend, fix it on Monday. It was going to bring about a revolution in safety WRT nuclear power generation. It's nice to see this finally coming to fruition.

Re:Waste disposal

[LaCosaNostradamus]

People blather on and on about long-term storage of waste, and how it's got to be out of everyone's hands.

The key error in this thinking is the assumption that the site has to be stable.

I propose a deep sea trench, like the Marianas.

1) The depth of the trench will provide more security than can ever be achieved on land, given the pressures of miles of ocean water.

2) The waste will have to be packaged in non-water-soluable form. These ceramic pebbles seem to be just the thing.

3) Any waste release in the trench will have to penetrate miles of ocean water to harm anyone, surface sea life included.

4) The waste will slowly be covered in silt, and even more slowly will flow with the ocean bed into the subduction zone under the opposing continental plate, ending up many, many miles beneath the surface in the mantle itself.

5) After millions of years, subduction heat will melt the waste and mix it with magma, and some will eventually appear in volcanoes beyond the trench zone, right above the subduction melt point.

Well, after millions of years, the waste will probably be no more significantly radioactive than magma normally is.

-1 Flamebait

[Dancin_Santa]

Reading some of the comments in this article, I have to wonder when 'Geek' and 'Nerd' transformed into 'Reactionary Luddite'.

Africa? A continent not a country

[Anonymous Coward]

"Africa's state-run utility giant"... WTF?
Africa is not a state or a single country for that matter, it's a continent made up of many states. Please be specific, ppl are very ignorant about this, just like many think that all africans speak the same langauge (there are over 200 langauges in Nigeria alone for example).

I hate ignorance!

[Rico_za]

Africa's state-run utility giant Eskom
I'm going to pop a vein! Afirca is not a country, it's a continent . South Africa, the country where Eskom resides, is a country in Africa (easily confused with South America by Americans. South America is a continent south of North America, the continent with three different countries on it, including the USA). There are 54 independent, different countries in Africa, each with their own government. Africa is not simply a big ol' jungle where everyone speaks Swahili (only 50 million of the more than 700 million people in Africa speak Swahili). /rant
OK, now that I got that off my chest: Eskom has been talking about this for a while now, and they are facing some resistance to the idea. The problem being the general conception that "nuclear is evil".

Re:I hate ignorance!

[cascadingstylesheet]

South Africa, the country where Eskom resides, is a country in Africa (easily confused with South America by Americans. South America is a continent south of North America, the continent with three different countries on it, including the USA).

Er, so it isn't ignorant to confuse a Slashdot story poster with "Americans"?

I've never confused South America with South Africa, nor has anybody I know.

Environment/North Korea

[lostnihilist]

We (USA in the 90s) promised two of these (or very simiar to these) to North Korea so that they a) could have plenty of power and thus might spend money on economic growth/feeding their people and b) couldn't develop nuclear weapons from the material. but oops, congress wouldn't approve it. Now look where we are with them. big mistake

though many popular activists site environmental reasons as opposition to nuclear energy, disposing of nuclear waste really isn't that difficult. Most scientists (at least those in the field) object to nuclear power because of the potential of the spread and proliferation of weapons. while environmental issues ARE a concern (there's always some governmental dweeb that screws things up), it is something that can fairly easily be isolated given the proper precautions. Part of the reason that these reactors get so much attention is that these same experts have much fewer qualms with them precisely because they are so much more difficult to make weapons-grade uranium/plutonium from. (i cite Howard Margolis, Dealing with Risk as a decent summary of this topic).

Re:Environment/North Korea

[AbbyNormal]

disposing of nuclear waste really isn't that difficult.

Landfill or that Mountain Place? What if it seeps? Breaks/chips/breaksdown and leeches into the soil substrate? Three eye fish, as cool as they are, will not be the worst of our concerns.

Re:Environment/North Korea

[adeyadey]

How about funding an extensive renewable program in North Korea, in return for no nukes? In the UK we will be getting off-shore wind farms generating power for as little as $0.03/kw/hr.. (British Wind Enrgy Association page )

Africa isn't a state

[Bozovision]

For you geographically challenged people. Africa is a whole continent. Like North America, South America and Australia.

South Africa is a country. It's at the tip of Africa. You'll never guess where it is in Africa.

It was a British Colony, but gained independence about 55 or so years ago, and promptly began to institutionalise pernicious racially-based discrimination. It was called Apartheid. After a long struggle (40 years) the white people agreed to share power and democratic elections took place. Nelson Mandela (you may have heard of him) was elected president.

The economy of South Africa is split - there's a strong first world component, and a large third world component. The first world component rivals the economies of Europe and the USA in sophistication - though it's much smaller. The third world component - i.e. subsistence farming, and subsistence trading - involves many more people. Unemployment rate is high - a few years ago it was 40%. Not sure what it is now. HIV/Aids rate is probably the highest in the world - hitting around 10% of population. Some places have rates as high as 40%. The current government until recently has ignored the problem.

Eskom is a world-class power utility. They have existing nuclear reactors, which were learning grounds for the Apartheid state in their quest for nuclear weapons. (Ten or so years ago South Africa admitted that they had nukes, and then destroyed them. Thank you Nelson Mandela and South Africa for making the world a safer place.)

It's questionable whether South Africa needs more nuclear power plants but Eskom has traditionally had a strong technocratic streak. (I was an employee a long time ago.) SA is rich in coal and natural gas.

I personally think that the money could be better spent given South Africa's problems - the only justification would be to export the technology. And maybe greater access to nuclear expertise is not what the world needs.

Jeff Veit

Re:Africa isn't a state

[RefriedBean]

It wasnt mandela who dismantled the nukes. It was the last white president (DeKlerk).

http://www.globalsecurity.org/wmd/world/rsa/miss il e.htm

Re:Clean nuclear power

[October_30th]

Your glow-in-the-dark wristwatch is more likely to cause cancer than walking near a piece of depleted uranium

The difference, of course, is that you're breathing in the radioactive depleted uranium dust. Radioactivitiy is much more dangerous inside your body. Human skin pretty much blocks weak alpha radiation, but such an emitter in lungs is highly dangerous.

Waste is less of a problem in this setup too

[fruey]

Check out this page

It would seem, critically, that the waste can be stored on site for 40 years, does not need to be transported elsewhere, and is inherently more stable than the waste in a typical water reactor.

Ever heard of Hamm-Uentrop? No? Read this...

[Savage-Rabbit]

This technology has been around for at least 30 years. The Germans even built an example pebble bed reactor at Hamm-Uentrop which has led to the technology being heavily criticized by enviromentalists. Normally I would be hesitant to swallow raw what enviromentalists feed onto the internet, especially the religiously fanatical German anti nuclear lobby, but in this case their claims are reenforced by the fact that their opinions of pebble bed reactors are shared by the German state who shut the Hamm-Uentrop plant down in 1989 after the management covered up serious problems with the reactor. The whole affair has led the People of Hamm-Uentrop to start a citizens group which among other things aims to start an Information exchange with the people of South so that the Africans can take into account the German experiences before one of these things gets built in their back yard. Feel free to call this a troll but with so many people singing the "See!! I told you nuclear is safe" psalm here I figured the other side of the coin deserved a mention.

Re:Ever heard of Hamm-Uentrop? No? Read this...

[Savage-Rabbit]

No not really, the parties behind the S-African reactor are the same ones as were behind the Hamm-Uentrop fiasco, which by the way is only 13 years old. And the Germans at least have significantly scaled down their interest in the technology. By the time construction started Hamm-Uentrop drew on 20+ years of research and testing. Even so took 3 times as long to build as planned, it went way ahead of budget and due to amont other things fuel handling problems never functioned 100% reliably. So if the S-African reactor is based on German PB-reactor technology which has not evolved much since Hamm Uentrop due to lack of funding I rather think these people are trying to restart development of a troubled technology in a place where they think resistance will be weaker. They are betting the S-Africans will allow them to do something that would have the Europeans picketing by the thousands at the construction site faster that you can say "pebble bed".

Re:Ever heard of Hamm-Uentrop? No? Read this...

[Twylite]

The basis for this technology has been around for at least 30 years, as you would know if you read the background on the site. The PBMR is not the same technology as the AVR or THTR at Hamm-Uentrop.

The THTR reactor was not closed due to technical problems. The problems it experienced were related to the loading of fuel, an issue addressed by the PBMR. Even Greenpeace admits regarding the THTR "In 1989 the reactor was permanently closed due to both economic and political reasons."

Whenever the issue of pebble-bed reactors has been discussed there has been allusion to "problems" in all reactors produced so far (in Germany, Japan and the US) -- without indicating that none of these reactors have been closed down for safety reasons! The biggest problem with these reactors so far has been getting them to reliably and economically perform their purpose.

As for information exchange so that South Africans know whats getting build "in their back yard" - we have a strong anti-nuclear lobby already. Unfortunately we also live in a country where 16% of the populate are illiterate and only 25% have completed secondary education -- so just how do you think it is possible for the public to make an educated decision on how long our coal reserves are going to last, whether a particular incarnation of nuclear technology is better or worse than pumping out greenhouse gasses, and what our electricity requirements are going to be in 2010?

Come on, its ancient...

[Anonymous Coward]

Such reactors are not new, e.g. there was/is one in Hamm-Uentrop, Germany called "THTR 300".

Building started 1970, reaction started 1983, shut down 1988, disassembling started 1991.

Its output was 308MWe, so I assume it was not just a toy.

AFAIK they had problems with the moderation and breaking of the balls.

Nothin' new, actually.

I want this technology for my car

[Powercntrl]

Seriously. I hate buying gas. Would be nice not to have to buy gas again - ever.

Oh sure, what happens if I get into an accident? Well, that's why you build the reactor compartment the same way as an airplane's black box, if that can survive a plane crash, a car crash should be a walk in the park.

There's a problem with terroists getting uranium and making dirty bombs you say? Not a problem either! Just outlaw radiation suits so anyone that opens the reactor is instantly nuked like a frozen chicken pot pie. Of course, that means no more tinkering with your car, but would you really miss it if you never had to buy gas again?

I want my nuclear car, damnit.

Re:I want this technology for my car

[Pompatus]

Well, since the reactor compartment will be built out of the same material as an airplane's black box, I demand that my nuclear car can fly.

Re:Money

[StrawberryFrog]

Why do they invest more money in such technologies. They have the Sahra desert.

No thay don't. This article is about a company in South Africa, which is nowhere near the Sahara Desert. It's a bit like responding to an article on Canada by mentioning the desert in Mexico because hey, both are in North America.

Been there, buil that, dircarded it

[phooka.de]

It's been done before. In Germany. It was called "schneller Brueter". It never went operational.

The rationale was that it would be vatsly more efficient. In practice, those "balls" were harder to control than the normal rods. In testruns they would jam as they were processed in the facility.

So it's neither the first time this is being built, nor is it the answer to all energy-questions in the world.

Uranium Pebbles

[lateralus]

"Uranium Pebbles" Sounds like a great name for a breakfast cereal. Makes your teeth glow!

Re:Decomissioning and waste management?

[WegianWarrior]

Yeah, disposal is a problem.. but it's not like it wasn't just lying around to begin with.

Oh please.. that old, tired argument again. YES, uranium occurs in most rocks in concentrations of 2 to 4 parts per million and is as common in the earth's crust as tin, tungsten and molybdenum. HOWEVER, uranium in the natural state is a mix of two isotopes; 99.3% U-238 and 0.7% U-235. And guess what? U-238 is barely radioactive, with a halflife of about 4500 million years. U-235 on the other hand is way more radioactive, and thus the part they are interested in using for reactorcores.

Guess what? The enriched uranium they use in reactors contains in the region of 3% to 4% U-235 - making it litterary too hot to handle. Even 'spendt' reacorfuel contains more U-235 than ordinary oranium-ore, as well as more than a bit of Pu-239 and Pu-240 (the longer the fuel stays in the reacor, the more Pu-240). And Pu-239 and Pu-240 is two isotopes of an element better known as plutonium... granted, it's not weapongrade plutonium, but it's still something I wouldn't have scattered about.

Fact: There is little or no pollution from an operative reacor.

Fact: Spent fuelrods from reactors are a major enviromental problem.

You might find this and this webpage interesting.

Southa African lobby against Pebble reactor

[Anonymous Coward]

Just a rather pedantic point but something that I do find irritating: Eskom is not a state run utility it privatised many years ago and is listed on the Johannesburg Stock Exchange (JSE).

It has been mentioned above that there is some opposition locally to the idea. Based on some of the comments in support of the idea it would be great if those interested could inform Earthlife Africa of your opinion.

Rational thinking.

[Palinor]

People are going to have to start to do some sensible and unemotional re-evaluation of nuclear power generation pretty damn soon.

Yep, some people will die from an increased incidence of cancer and yes, some people will die from nuclear mishaps and/or terrorism.

However, global climate change will kill billions of people unless fossil fuel utilisation is vastly reduced over the next century.

Renewable energy supplies may solve some of the problem. USAians forgoing their gas guzzling trucks and starting to think some about energy efficiency willl solve some more. However, the only current economically viable non CO2-producing technology is nuclear fission and adopting it on a wider scale will save lives and help to protect the environment.

You'll never convince the lumpenproletariat of the fact, though.

Re:Rational thinking.

[Anonymous Coward]

Can you prove this link betwen global warming and "fossil" fuel use? Seems to me that a lot of climactic change has happened already in Earth's history, and strangely enough, there weren't any SUVs around at the time...
How about the Sun? Didja know it's a variable star?

Re:Rational thinking.

[Doc Ruby]

Nuclear power is not renewable. We are using up some of the rarest resources in the world, in the Universe, in an extremely ineffecient 1st generation reactor. A century from now, we'll have technology to more safely process the waste. When they're mining the basements of the poorest ghettoes in the world for those last remaining fissionable materials, they'll curse us for wasting the cheaply available high-quality uranium and plutonium, just like we're just burning the oil, the best source of plastic and organic building blocks. Think ahead, the future will be your home for a long time.

Re:Rational thinking.

[TamMan2000]

Yep, some people will die from an increased incidence of cancer...

I don't know if that is the case... Coal, the major alternative to nuclear, has numerous carcinogens among it's combustion byproducts. These carcinogens are not tightly controled like the nuclear ones are, they are simply dumped into the environment surrounding the plant. I would much rather have a nuke in my back yard, than a coal burner...

Re:Decomissioning and waste management?

[mlyle]

Guess what? The enriched uranium they use in reactors contains in the region of 3% to 4% U-235 - making it litterary too hot to handle. Even 'spendt' reacorfuel contains more U-235 than ordinary oranium-ore, as well as more than a bit of Pu-239 and Pu-240 (the longer the fuel stays in the reacor, the more Pu-240). And Pu-239 and Pu-240 is two isotopes of an element better known as plutonium... granted, it's not weapongrade plutonium, but it's still something I wouldn't have scattered about.


Sure, we "enrich" the uranium-- largely by sorting isotopes. There's no reason why you couldn't choose to de-enrich/deplete the uranium back down for storage, if you thought this was beneficial. This is why it's entombed in glass in many storage proposals, and why it's often reprocessed-- so you can sort the "useful fuel to reuse" and "spent fuel/waste".

There are intermediate-term (80-500 year) storage problems involved with the high level wastes produced in fission reactors. The thing is, these wastes inherently have short half lives and decay to more harmless stuff very quickly.

Re:Clean nuclear power

[quenda]

> what happens to the depleted uranium?

Depleted Uranium is barely radioactive - totally different from nuclear waste. It does NOT comes from reactors. I think you need to do a little reading.
"The longer the half-life, the lower the radiation" may seem obvious, but escapes many.

Sadly, you got your facts all wrong...

[Moraelin]

... yet that doesn't keep you from judging and condemning something.

First of all, as was already said, the waste produced by fission plants is _not_ depleted uranium. It's not like "new batteries" and "used batteries", you know. When a uranium nucleus splits, it splits into much smaller nuclei. Ones which aren't uranium at all.

Second, I get this feeling that you don't understand how depleted uranium weaponry even works. I keep reading all sorts of SF (read: stupid) posts about how it explodes inside the tank, or how some shell's explosion spreads uranium dust and debris all over, and whatnot.

The only quality of depleted uranium is that it's an extremely hard material. Much harder than steel or even than tungsten penetrators. Its only quality is that a sharp tip made of depleted uranium, can go straight through armour made of steel. That's all.

It's also _not_ used in high explosive ammo. And APHE ammo (i.e., ammo which is both armour piercing and explosive) was last used by the Soviets in WW2. They discarded it as being useless.

The shells that tanks shoot at each other today are _not_ explosive. (Regardless of how it looks otherwise in computer games.) The preferred large caliber anti-tank ammo nowadays is APFSDS: Armour Piercing Fin Stabilized Discarding Sabot. It basically shoots a thin sharp metal rod with fins. Much like a crossbow bolt, if you will.

This goes through armour by sheer kinetic energy, and by being sharp. Again, just like a medieval crossbow bolt would.

Why is it important that it's very hard? So it doesn't deform while going through armour. Think a crossbow bolt with a steel bodkin tip, and now think one with a rubber tip. The rubber one will deform and spread the impact over a larger surface, whereas the steel one might stay sharp as it goes through armour. (Thus keeping the impact concentrated on the small surface of the tip.)

Re:Sadly, you got your facts all wrong...

[TheLink]

Actually DU does kinda explode inside the tank. Uranium is "pyrophoric".

More info:
http://www.guardian.co.uk/print/0,3858,4019 520-107 286,00.html

Some spin:
http://www.heritage.org/Research/NationalSe curity/ EM721.cfm

Quote: "FACT: The health risks posed by the military's use of depleted uranium are extremely low."

Such bullshit. He already admits "Like lead, depleted uranium is a heavy metal that can be toxic if it enters the body". Breathe in some DU dust (should be plenty around after that pyrophoric thing) and bad things happen to you.

Maybe someone should shoot him with a DU bullet if he still thinks the health risks are that low.

Re:Sadly, you got your facts all wrong...

[Silburn_Luke]

You misread the previous poster. He said (its in the section you quoted) that *APHE* ammo was last used in WW2. IIRC that ammo used tungsten for a penetrator rather than DU. APHE has nothing to do with DU anti-tank shells other than both technologies are intended to destroy tanks.

As others have said modern anti-tank rounds are basically very fast, very dense crossbow bolts and achieve their killing effect via kinetic energy. By contrast APHE get to the same end-point (breaching a tank's hull) by creating an explosion on the outer surface of the tank - there are various different wrinkles regarding how this explosion translates into a hole through the armour, but the basic operating principal of APHE is fundamentally different to that governing kinetic rounds.

As others have also said DU is not nuclear waste, the 'depleted' part of DU refers to the fact that the more radioactive isotope (U238) has been removed leaving the less radioactive isotope (U235) behind. DU is the natural consequence of the enrichment process - you start with natural uranium (NU) and after running it through an enrichment process you are left with a small quantity of enriched uranium (EU) and a larger quantity of depleted uranium (DU).

Now EU is used as feedstock for nuclear reactors or to make the warheads for certain types of nuclear weapons, so DU is certainly a byproduct of the nuclear industry but it is not 'nuclear waste' as the term is generally used. It should also be pretty obvious that DU is actually less radioactive than either EU or NU - its still a bit radioactive (because U235 is an alpha emitter) and its still chemically toxic (as all heavy metals are). These attributes make the post-battle effects of DU munitions problematic, but the same can be said of pretty much any kind of war materiel. People still get hurt in northern France by munitions dating from the 1914-18 war for example.

Regards
Luke

The Three Real Issues

[salesgeek]

Nuclear power is a subject that is near and dear to my heart having spent a part of my life working in the industry for Uncle Sam. There are three real issues with Nuclear power that keep it a hot button issue:

* Proliferation of WMD. Widespread use of nuclear power creates huge opportunites for people to get their hands on fissile material or highly radioactive material. A "dirty bomb" consisting of a few hundred pounds of waste and a few hundred pounds of explosives could do incalcuable damage. Nuclear power and nuclear weapons are NOT high tech. It's technology from the era of propeller airplanes, black and white movies, radio and vaccum tube electronics.

* Economics: widespread use of nuclear power would render a large sector of the global economy useless. There is a substantial interest in keeping the world dependent on our dwindling supplies of fossil fuel -- remember suply and demand? What happens when the supply decreases and demand increases? Many nations, corporations, and ultimately individuals stand to get very, very rich by monopolizing the resource (OPEC is a benign example compared to what we'll see in the future)

* Finally, there is a more practical issue: much of today's power challenges are demand side issues. Most people are blissfully unaware of what it takes to supply a couple of killowatt hours to their homes and especially businesses.

meltdown proof??? possibly, but NOT fireproof...

[advocate_one]

If I'm not mistaken, hot Graphite burns when exposed in air (and this stuff is at 900 deg Celcius plus and under pressure, 8.4 Mega Pascals)...... and we've already had one too many of those "burning Graphite" disasters already... Windscale back in 1957, and they changed the name to get around the public memory of the original disaster.
Sorry, but I have no faith in any process which combines a combustible material run at high temperatures and relying on keeping air out...

Chernobyl was stupid

[cr0z01d]

Chernobyl had a lot of things that were just wrong.

The reactor increased in efficiency as temperature increased. This is a nice little feedback loop. Most reactors lose efficiency as temperature increases, meaning that it is difficult to try and overload the reactor, even on purpose.

The reactor was designed to be cheap, and it did not have a dome. Domes contain radioactive material very well. Tests have shown that an aircraft hitting a dome would hardly scratch it.

As another cost-cutting measure, the reactor didn't have any good backup power. It may seem silly to have a power plant that needs power, but nuclear power plants do need power to start up and in case of emergencies. Western plants have batteries and generators.

As if these technological blunders weren't enough, some bonehead transfered control of the power plants from the ministry that designed and built them, where all the trained personnel are employed, to the ministry of energy. There are reports of operators sitting on the control board and people showing up to work drunk.

Basically, in 1986, the Chernobyl reactor demonstrated a bunch of "don'ts" to a world that should have already known.

There will always be technology out there that can be misused. The amount of that technology will only increase. Do we ban knives because people get stabbed? Do we ban nuclear power because a couple of Russians cut costs?

The 'ball' nuclear reactors are basically foolproof. You put a bunch of balls next to each other and you get heat. This is not weapons grade Uranium.

I only see one problem with nuclear -- the small amount of waste that is generated needs to be handled properly. It can be done, but it just has to be done right.

Re:Chernobyl was stupid

[16K Ram Pack]

Another problem, it was also a totalitarian state with no press freedom.

The press is essential to things like safety. In the UK, someone blew the whistle on results being falsified at Sellafield. BNFL immediately sacked 5 staff.

Let's say hypothetically BNFL hadn't, and just decided to cover it up, and then the press had found out about it - the uproar against the power industry would have been massive. Then, if government did nothing that would have damaged them.

The totalitarian equivalent is - nuclear agency fakes results, but because the public don't have a free press, no-one can tell them. And even if they do find out, they can't kick out the government.

IIRC the worst nuclear accident was Three Mile Island. AFAIK, no-one was directly killed in this, although there is some debate over indirect effects.

And comparing possible nuclear power deaths in say UK and US with car deaths each year, it looks pretty small.

BTW Anyone know why France has a huge nuclear industry and the UK doesn't?

Re:Chernobyl was stupid

[pyros]

In my opinion, anything that might kill thousands of people while handled by a drunk should be illegal.

Yeah, I mean who really needs to travel by plane anyway? While we're at it, lets do away with recreational cruise ships, all military aircraft, naval vessels, missle silos, etc.

P.S. - if you want to debate the need for military equipment please start a new thread, they were just examples of things "that might kill thousands of people while handled by a drunk."

Re:Chernobyl was stupid

[FredGray]

The worst nuclear accident, by far, was Chernobyl, 1986. There were a couple of other accidents of the same magnitude as Three Mile Island (1979); IIRC, one in Britain, and one in the American south.

Don't forget about the one at the Tokaimura fuel processing plant in Japan in 1999. It was an inadvertent criticality in which two workers were killed by radiation exposure and dose rates in the surrounding area were significantly elevated. As usual for nuclear accidents, it involved a lot of gross stupidity (unapproved modifications of procedures, bypassing safety systems).

Re:Chernobyl was stupid

[Pii]

Ice cubes in beer?

Philistine.

Re:Chernobyl was stupid

[Registered Coward v2]

Same story - silly russians cutting costs, but costs get cut and things are mismanaged on a spectacular scale in the USA too. Three Mile Island is the textbook example of why you have to have enough staff to watch the contractors when they try to rip you off. The same weld joint was x-rayed several hundred times, with only the numbers changed on the print to pretend that other more inaccessable joints were checked. When the accident occured and people looked at the x-rays to see if there had been any pre-existing flaws they found that the area where the problem occured had never been checked.

TMI is a textbook case, but for other reasons:

a) Had the operators not shut down the safety systems (because they thought it was going to overpressurize the reactor), the event would have been a non-event. Lesson - be sure you know what's happening before you stop safety systems, and is why emergency procedures are designed to make operators diagnose and respond to symptoms, not events.

b) Steam cools as it expands - which is why the downstream temp after the leaking valve was much lower than the operators expected - and caused them to think the valve on the presurizer was shut, not open. Had they checked a p - t diagram, they would have discovered their error. Lesson - double check assumptions,especially when anomlies can be explained by a different conclusion than you reached.

c) A similar event occured at Davis-Besse, but the operators reacted correctly and no damage was done. Unfortunately, no one bothered to tell other plants about the events. Lesson learned - share information (which was why INPO - the Institute of Nuclear Power Operations was founded)so you don't make the same mistakes as someone else - something the aviation industry learned the hard way a long time ago.

Let the Navy do it...

[craenor]

I would like to see the Department of Naval Reactors, in conjuction with the Department of Energy and the U.S. Navy be contracted to design, build, man and run nuclear power plants for commercial power consumption. Then turn around and sell that power to the utilities companies.

They already buy power from one another on a regular basis and the more importantly the track record of the U.S. Navy in Nuclear Power useage is impeccable. The training program, security, design protocols, safety record and tradition of excellence make them the only people in the world I would trust 100% to run a nuclear power plant.

Fires?

[RayBender]

I have a question about these reactors: what happens when air gets into the reactor vessel? Don't you get a pretty big fire? It's notable that both Sellafield and Chernobyl were graphite-moderated reactors that ended up with graphite fires. Graphite is actually a difficult material to use in a reactor, it stores up energy in the lattice that can then be released at unpredicatble times. "Wigner energy". The link provides some interesting information, but take the nuclear-phobic tone with a grain of salt.

Another problem with pebble-beds is that they use natural or low-enriched uranium in a cycle where the fuel passes through the reactor relatively quickly and continuously (no big refueling outages). This makes them ideal Plutonium factories, which is obviously a matter of concern. Most of the graphite-moderated reactors ever built were designed primarily to produce Plutonium, including the Soviet RBMK's and the piles at Sellafield.

Don't get me wrong - I'm all for nuclear power for many reasons, but I'm not sure the pebble bed is that much of a breakthrough, and I don't think graphite is the best choice of material. And any operator of a plant in trouble that went home for the weekend should be shot. "Walk-away safe" my ass.

Re:Decomissioning and waste management?

[TamMan2000]

Fact: There is little or no pollution from an operative reacor.

Fact: Spent fuelrods from reactors are a major enviromental problem.

Fact: The byproducts of all other currently viable forms of energy production are major environmental problems.

I can't think of anyone who would say that nuclear waste is not bad. But I for one, and many others who have researched the topic, believe it is less bad than the alternatives.

I would rather have a small amount of really bad stuff being controled, than a huge amount of pretty bad stuff being spewed into the air I breath every day.

Is this new form of nuclear power renewable?

[seniorcoder]

Is any form of nuclear power renewable? Can we recycle any waste? No? Let's skip this one then. We already have plenty of non-renewable, non-recyclable power generators. Maybe we should ask the politicians to stop taking bribes from people whose hands are filthy with oil and politely request more effort in the area of renewable energy. How about not using so much energy in the first place? I remember my last visit to Vegas, seeing a casino front wide open to the outside with a veritable wall of air-conditioning blasting from the ceiling above the opening. Never have I seen such wasteful energy consumption. Without doubt, nuclear power has a major waste management problem. I don't think the same thing applies to PhotoVoltaics or wind turbines. If this really is news for nerds about stuff that matters, well this matters and yet I have read far too much from some nerds who are willing to endanger their chilrens-childrens-childrens-childrens... lives to the half-life of stuff that anti-matters. http://www.homepower.com Get on the right track.

Half-errors on half-lives in parent post

[G4from128k]

U-238 is barely radioactive, with a halflife of about 4500 million years. U-235 on the other hand is way more radioactive, and thus the part they are interested in using for reactorcores.

Not true. The half-life of U-235 is 710 million years -- enriched uranium is NOT too hot to handle.

Pu-239 (half-life 24400 years) and Pu-240 (half-life 6580 years) are hotter and are the reason spent fuel needs to be sequestered for so long. But the really nasty, ultra-hot radioisotopes are all the neutron-rich fission byproducts from splitting U-235 or Pu-239. Byproducts like barium-140, cesium-134, cesium-137, and iodine-131 have half-lives in the days to only a few years that make them intensely radioactive (thousands of times more radioactive than Plutonium and millions of times more radioative than U-235). Worse, these byproduct elements will chemically react with ordinary matter, form water-soluable compounds, and lodge in living tissue if injested.

Fact: Spent fuelrods from reactors are a major enviromental problem.

Extremely true, but not because of U-235.

Re:Half-errors on half-lives in parent post

[guybarr]

Byproducts like barium-140, cesium-134, cesium-137, and iodine-131 have half-lives in the days to only a few years

AFAICR, a short lifetime is actually a good thing when considering
environmental concerns: with a HL of, say, 10 days, in less than a year
there'll be practically nothing to worry about.

It's the mid-range isotopes that are problematic.

Re:Decomissioning and waste management?

[Aglassis]

You said: "U-238 is barely radioactive, with a halflife of about 4500 million years. U-235 on the other hand is way more radioactive"

Nuclear types like to measure radioactivity in what is known as activity:
A=(lambda)*N,
(lambda)= (ln 2)/ t1/2,
where is the decay constant, N is the concentration, and t1/2 is the half-life.

What this means is that activity is inversely proportional to half-life. So in order to have a highly radioactive sample with a long half-life you must have a high concentration of it. It doesn't work this way with U-235. It has a 713,000,000 year half-life. Doing a quick calculation you will find that even a pure large sample of U-235 (subcritical of course) would have very low activity.

So what not a modern design like IFR/ALMR/AFR?

[vovin]

The Advanced Fast Reactor, an improved Integral Fast Reactor/Advanced Liquid Metal Reactor is a modern design that:
- burns it's own waste as fuel.
- is safe (The reactor core will cease to function when it gets to hot).
- could be use current 'nuclear waste' as fuel.
- could use current weapons grade plutonium (think decomissioned warheads).
- the final by products 'nuclear waste' will be as radio-active as normal uranium ore.

I really with the nuclear energy phobic would learn a little bit about modern reactor technology.

IFR - http://www.nationalcenter.org/NPA378.html
AFR - http://www.rae.anl.gov/research/ardt/afr/

Re:So what not a modern design like IFR/ALMR/AFR?

[JSBiff]

I think a lot of us fall into a 'middle-ground.' I'm fearfull of the long term effects that plant melt-downs have. . . but at the same time I realize that there potentially are safe(r) designs. If someone can truly come up with a 'disaster proof' reactor design that doesn't produce highly dangerous waste (it sounds like the design you mentioned is a likely candidate) then I'm willing to at least consider them.

Safe designs for nuclear reactors actually kind of excite me, because we clearly need to get away from fossil fuel energy.

Although, ultimately, I'm most excited about bio-mass energy (if it can ever be made to be practical at a large scale), because while burning bio-mass derivative fuels produces CO2 - at least the next generation of fuel will re-fixate that CO2 as it grows. . . it's a stable system where we are at least not increasing the amount of CO2.

Xtra useage

[WindBourne]

While I do think that nuclear power will make up more energy in the future, I also think that with a bit of inginutity we can lessen the need for plants. Basically, by storing excess power, we can add 33% to 100% power to the plant. This would also allow for alternative energy input. One approach is via 2 water resoivors with hydro power and simply use excess power to pump the water back.
Perhaps a better way is for us to spend money on high thermal storage with salts. Ideally, we would do small units and spread them out to provide emergency power in local areas (think hospitals, anywhere on the coast esp, Florida, Texas, and California).

Partly true...

[pdhenry]

However, coal power plants release more radioactive waste into the enviroment than nuclear power plants and still provide most of the power in the US.

True, if you only consider what is legally released into the environment while the nuclear plant is operating. If you consider the fission byproducts and their "disposal" (e.g. long term storage) then this isn't true. Yucca Mountain nonwithstanding, the problems associated with nuclear waste may not be worth the benefit (and I'm a nuclear-trained engineer).

Re:Partly true...

[mwood]

Whatever happened to vitrification? Mix the stuff into glass, cast into handy-sized lumps, bury in moist earth, post a guard to keep the bad guys from digging it up. As deep as they want to bury it, any post-catastrophe society capable of reaching the stuff should be developed enough to figure out that it is dangerous, particularly since, unlike natural ores (which are also dangerous), the stuff will be *marked*.

Also, we've done well with Reduce and Recycle, but how are we doing with Re-use? It seems to me that much rad"waste" is just a resource for which nobody has tried hard enough to find a use. Medicine, nondestructive testing, long-term preservation of organic matter, etc. all have uses for long-lasting sources of radiation. (I tell my kids to remember where the landfills are, because their grandchildren will want to mine them.)

Re:Partly true...

[Martin Blank]

Most of the re-use part of nuclear fuel is, as I understand it, prohibited by government regulation, something having to do with plutonium generation. My understanding of a possible use involving breeder reactors, though, involves using the plutonium's natural decay to enrich uranium fuel, allowing the plutonium to break down into less harmful byproducts while the uranium is enriched for fuel in the near future. This seems a more complete use of the fuel to me, and could result in less hazardous waste.

However, use of plutonium is rather taboo for some reason -- witness the furor over Cassini's radioisotope generator, which some environmentalists claimed could kill thousands in the event of an accident on launch in 1997 or during the flyby of Earth in 1999, with one site suggesting a 10-micron particle could result in the exposure of a person inhaling it to thousands of REMs. Their argument was that the release of the 72 pounds of plutonium would be catastrophic over centuries.

An article in a 1993 Oak Ridge National Laboratories Review states, "according to NCRP Reports No. 92 and No. 95, population exposure from operation of 1000-MWe nuclear and coal-fired power plants amounts to 490 person-rem/year for coal plants and 4.8 person-rem/year for nuclear plants. ... For the complete nuclear fuel cycle, from mining to reactor operation to waste disposal, the radiation dose is cited as 136 person-rem/year; the equivalent dose for coal use, from mining to power plant operation to waste disposal, is not listed in this report and is probably unknown."

Even factoring in mining -- where radioactive dust presumably goes into the air -- and disposal -- where various bits of radioactive dust and water are released -- nuclear plants produced only about a quarter of the average radiation dosage that coal plants do over their lives. I've seen the strip mines that are used to get at uranium, and while it's not pretty, it's not nearly as bad as the destruction of entire mountains in the Appalachians. There is also research going into extracting uranium from seawater for about $120 per pound, which, although about 10 times the current rate, could be more environmentally safe and could provide thousands of years of power, presuming we operated on nuclear power for that length of time.

I'm all for nuclear energy. While I am also a proponent of renewable sources, I don't like the environmental damage caused by hydroelectric. Solar has issues of night-time electricity use, and it is reportedly a messy thing to make, with some pretty dangerous chemicals involved, not including any batteries that would be needed for cloudy days and night use. Wind has issues of reliability, and tidal generators have a range issue, not to mention that I wonder how it would affect the beaches to have thousands of them operating.

I recognize the dangers of nuclear energy. I know that it's hard to clean up, and that there are significant security risks; I'd much rather be in a room with an exposed piece of coal than an exposed piece of reactor-grade uranium. But that piece of uranium will be useful long after the ash from the coal has been carted off and buried. It will have given off no CO2 or nitrogen or sulfur oxides during its use (save whatever transportation is used for it), and less radioactivity.

In balance, I believe that nuclear reactors are a far better source of energy than anything else we have at the moment.

Re:Partly true...

[Rorschach1]

For what it's worth, you can get your piece of reactor-grade uranium at United Nuclear. The interesting part is that it's slightly LESS radioactive than the natural chunk of uranium ore I've got in my bedroom. That's about 30,000 counts/minute on my Geiger counter in direct contact, but three feet away it's almost undetectable against the background radiation. I keep it in a small tin that blocks a large portion of the radiation, and helps keep it from getting lost in the clutter of my desk.

I don't think I'd want to carry it around as a good luck charm, though.

Re:Partly true...

[mwood]

Well, reprocessing "spent" fuel to get the unconsumed U back was what I meant by "recycling". It's a good idea and, if we can do it right, we ought to do it.

By "reuse" I meant take the stuff that's no good for large-scale power reactor fuel and use it for something else. Like sterilization or probing metal castings for flaws. And if all else fails, someone else pointed out that the gunk still produces quite a bit of heat -- not enough for a commercial electric plant, but maybe enough for something that has to sit in an inaccessible place for decades without resupply.

Hydro...yeah, come to Indianapolis and ask the old-timers where Dandy Trail is. (It's at the bottom of a reservoir now, not such a fun place to go anymore.)

Stuff like solar, wind, tides, etc. can be stored as compressed air, used to extract hydrogen from water, pushed into high-performance flywheels, etc. so batteries are not necessarily needed.

Tidal generation might actually be a good thing for e.g. the barrier island systems of the North American east coast. Hmmm.

Oh, and coal mines are hard to clean up too. Ask about all the acid runoff. Ditto the mines that produce whatever materials go into your favorite alternative energy source.

We could boil all this down pretty compactly: energy production is messy and dangerous. So's millions dying of cold or fighting the wolves off with sharp sticks, though.

Re:Partly true...

[Anonymous Coward]

You are mistaken.

A nuke plant produces about 6.5 ounces of waste per minute, or about 20 tons per year for a typical thousand megawatt plant. A single coal plant produces about 10 tons of waste per minute, or about 300,000 tons of waste per year. Since the radioactives don't burn, they get concentrated in the ash. That thousand-megawatt coal plant releases about 20 tons of uranium and thorium (alone) from the 4 million tons of coal it burns.

All waste is an "emission", whether it literally goes up in smoke, is stored on site, or gets bundled into bricks and hauled away by truck. The only question is in what form, and where and how you transport it and store it.

Where do you think all that coal ash goes? They retain most of it at the power plant and bury it -- just like nuclear waste. Some of it gets made into building materials. The FAS estimates there are 2000 additional cancer deaths per year from radioactivity from the 5% of coal ash incorporated into building materials; it would be 40,000 if all the ash were used.

You can imagine the panicked public reaction if nuke plant waste were spread out by diluting it with a lot of neutral material and built into people's houses.

And, of course, the non-radioactive toxins from coal, like lead, cadmium, mercury, and C02, remain toxic forever, with a nearly infinite half-life.

There's no funny accounting going on here, with the coal emissions being counted while all the nuke emissions are ignored because they're stored at the plant, as you suggest. The radioactive emissions from a coal plant are indeed about the same as the total waste produced from a nuke plant. But then you have to pile on all the other waste from those fossil plants. Nuclear plants are cleaner, in total, and surprisingly not even any messier when it comes to radioactive waste alone.

Re:Partly true...

[mikerich]

For what it's worth, you can get your piece of reactor-grade uranium at United Nuclear. The interesting part is that it's slightly LESS radioactive than the natural chunk of uranium ore I've got in my bedroom.

That's because the chunk of ore will be far from pure uranium, it will contain traces of the decay products - such as polonium, radium and radon, all of which have shorter half lives (and are hence more radioactive).

Glad to hear that you're taking basic safety precautions though.

Best wishes,
Mike.

Re:Partly true...

[cheesybagel]

"The 72 pounds referred to would kill every human being on earth, if well distributed."

And I could kill every human being on Earth by choking them in the ocean. So?

Re:Partly true...

[dbIII]

Whatever happened to vitrification?

Even better than that was the synrock project - chemically incorporating all the elements found in radioactive waste (which can be anything really) into a synthetic rock which resists leaching of elements away by water (ie. make sure things are not soluble). When it appeared to have acheived success the funding was cut. I beleive the current solution is just to shove the stuff into drums so that some idiot on minimum wage can pack the drums tightly together so that you get increasing amounts of neutrons emitted until someone else notices it and gets the drums spread out again - or at least that's what was happening two years ago.

Mix the stuff into glass, cast into handy-sized lumps, bury in moist earth

There tends to be a bit of leaching of radioactive materials out of the glass over time from the moisture. Deserts are good places to put things like this, and putting the material in various glasses (not all glasses are silica based or transpanent) appeared to be the best solution available ten years ago (don't know about now).

It seems to me that much rad"waste" is just a resource for which nobody has tried hard enough to find a use

It doesn't look easy.

Medicine

Once you get stuff mixed up, you don't want to let it near a human body - so that makes it tricky. Re-cycling someone's barium meal has biohazard potential.

nondestructive testing

The radioactive source materials for this are already cheap so there isn't much incentive. I have heard of people in an Indonesian reactor using random lumps of radioactive material which were neutron sources (neutons do a lot more damage than X-rays or gamma radiation - and can make nearby materials radioactive as well) for general purpose radiography, which would have been really cheap, but I find this very scary, and it has definite shades of Homer Simpson.

long-term preservation of organic matter

Until the nuclear industry stops lying through it's teeth about how "clean" everything nuclear is we won't see much irradiation of food going on. People will not believe it is safe to eat, they'll just assume it's another lie, and that the irradiated chicken will be emitting gamma rays in their childrens stomach or something.

I tell my kids to remember where the landfills are, because their grandchildren will want to mine them

Power station ash dams are being mined - everything nicely seperated by gravity.

The economics don't make sense

[pvanheus]

I've done quite abit of research on this PBMR design, and specifically the economics of it.

The latest cost estimates for building a 'demo model' is about R10 billion, and will be completed in 2008. That's about 5 years over schedule, if my memory serves me. The PBMR company ltd., not Eskom directly, is building this thing. That company's shareholders are currently Eskom and BNFL. Since BNFL is currently being restructured, as the cleanup costs for Sellafield have forced it into bankruptcy, Eskom is the only real player. (US company Exelon was involved, but now they've pulled out)

R10 billion is way more than Eskom can afford. Therefore they are looking for external partners to invest in the project, and that depends on selling PBMRs being commercially viable. Now, nuclear electricity is very expensive - one of the reasons that the world nuclear industry is in the doldrums. There was a paper in the South African Journal of Science about this some time back, which examined the economic models Eskom was using for PBMR, and found them to be wildly optimistic.

So if the economics are so screwy, why is Eskom pursuing this project? No one really knows, but I'm sure the fact that the chairperson of Eskom, Reuel Khoza, effectively controls one of the main contractors (IST), through a holding company has got something to do with it. Even if the PBMR project fails, Khoza and buddies will end up much richer. IST got handed a R260 million (?) contract, which is about as much as its previous annual turnover. Their shareprice went through the roof, making Khoza and co's share options worth a lot more.

Besides the Reuel Khoza link, there is an argument to be made that difficult-to-manage technologies like PBMR will be an incentive for the government to keep a much more centralised and powerful Eskom around for much longer. Eskom is currently facing deregulation and restructuring, and this Apartheid-legacy parastatal needs to justify why it still needs to exist. Experience in other companies has shown that deregulating nuclear power is very hard, so PBMR might be a bargaining chip in the complicated game around Eskom's future.

Funnily enough, the Wired article and the Slashdot responses have all the hallmarks of engineers - in love with 'sexy technology' while pretty much ignoring the bigger political/economic picture.

Peter

Go nukes!

[mwood]

Sounds good so far. Maybe we can begin ignoring those for whom antinuclearity is a religion, when they point to _The China Syndrome_, and move on.

I *would* like to suggest that, in a setting with such grave consequences for error, engineers tell themselves daily that "meltdown-proof" really means "all failure modes are unknown." I think that would lead to a healthier attitued toward the whole thing.

Compare this against Three Mile Island.

[MtViewGuy]

When the Three Mile Island reactor had its partial core meltdown, note that there was still enough safety margins active that its radioactive release was very small indeed. It definitely helped that the reactor was inside a strongly-built containment building, which essentially confined the radioactive release.

Since Chernobyl had NO containment structure, when that reactor's fissile material pile exploded there was NOTHING to stop its release into the atmosphere.

There are other safe designs

[rbrander]

We should all welcome a new and (even safer?) design strategy, but all designs have trade-offs.

Canada is justly proud of its very safe CANDU design, some good links at:

http://www.nucleartourist.com/type/candu.htm ...but the tradeoff is all that heavy water runs up the price of the thing.

They've got a new design out that's, yes, even safer, and (they hope) cheaper to run. They've got a good business going overseas, but you can't sell the things in North America at all.

So far.

One can only hope the interest in reducing carbon emissions will bring people to their senses. I'm all for green renewable technologies, too, but hydro, wind, and solar are just not yet up to being more than 20% or so of the generation mix. The other 80% has to be fossil or nuclear. Nukes are way cleaner.

Salon magazine recently has some hair-raising stories about environmental devastation from coal; and that's what "greens" are guaranteeing to continue by opposing nuclear.

The Lessons of Chernobyl

[BigBlockMopar]

the problem that most people have with nuclear power is tchernobyl(or similar catastrophy that would release radioactivity to a wide area).

I'm glad you mentioned Chernobyl...

'is packed with tennis ball-size graphite "pebbles," each containing thousands of tiny uranium dioxide particles'... Proponents insist that the reactor's design features make it 'meltdown-proof' and 'walk-away safe'."

... because apparently these people haven't learned anything from it.

The most important lesson of Chernobyl is that graphite burns. So if you lose control of this thing, it will catch fire. And the fire will spread radioactive decay daughters all over the place.

I am a big proponent of nuclear power, but only of one design: CANDU (CANadian Deuterium-Uranium). It's inherently impossible for it to melt down. It uses U-238 (natural uranium, in the form of "ceramic" pellets of uranium dioxide) which is NOT capable of a chain reaction without a heavy water moderator. (Heavy water is just water where the hydrogens have neutrons. Non-radioactive, naturally occurring, and just slightly heavier than normal water.)

As a result, if you lose control of a CANDU reactor, the reactor will overheat. Pressure will build up in the heavy water system until something breaks. The moderator will escape as steam, and since the fuel is essentially non-water soluble, with only extraordinarily small trace amounts of radioactive materials. With no moderator, the chain reaction stops, and the reactor cools down. This process occurs as a result of the laws of physics; in other words, Chernobyl cannot happen at Pickering or Darlington even if all the control systems fail or someone goes to extraordinary lengths to circumvent them.

The other great lesson is not to let boobs run the reactor. All nuclear power programs have had problems with this in the past; a "walk away" approach simply encourages this.

Re:The Lessons of Chernobyl

[joib]

Incidentally, almost every power producing reactor in the western hemisphere is water moderated. And, discounting RBMK and their ilk, also in the rest of the world, for that matter. As you say, water moderation means that if the coolant boils off the chain reaction will stop. CANDU is in no way unique in this aspect. The problem is that the fuel will continue to generate a significant amount of heat even after the chain reaction is stopped, because of the radioactive decay of very short-lived fission products. This heat is enough to melt the reactor core if it's not cooled. This is essentially what happened at three mile island. That's why all nuclear power plants have all kinds of emergency power supplies etc. so that they can continue cooling the reactor after they shut it down.

Re:The Lessons of Chernobyl

[richard_willey]

The pebble reactors achieve the same effect using a different design principle.

Each pebble is a sphere.

A large number of spheres are arranged in a pile.

The density of the uranium is a function of the radius of the spheres.

Like most things, the pebbles expand as they get hot.

In turn, this creates a negative feedback loop which should prevent a catostrophic failure.

Ahh, so I must be against Capitalism

[Fighting.Cephalopod]

"...who are really anti-industry, as a side-effect of being anti-capitalist..." At what point does "Anti-industry" make you "anti-capitalist"? Generally, if someone does not like polluting, unclean industry it is largely because they a) like being able to breathe clean air, b) realize that there is nothing in history that should dictate trusting businesses to regulate themselves and c) understand that the only way you can get a & b is to enpower the state to regulate it as pollution prevention is inherently non-profitable. That being said, nuclear energy is probably our best hope for the future. Take a look at the Cold Fusion research program at CalTach & Cal Poly Pomona or at the UC Berkley Fusion research project. For that matter, there is nothing that says an anti-nuclear group is anti-industry. They are against what they see as an unsafe technology that has only been reinforced by events at home and abroad. Whether or not they are Luddites is another question... but they have as much right to their beliefs as anyone else. Thats what Democracy is about.

Anti nuclear tree huggers should be bombed

[eadint]

I am so sic of these ignorant tree hugging morons trying to stop nuclear power because they don't understand it or they watched one too many science fiction movies. thats the problem, the amount of waste produced by any chemical reactor ( gas, coal, oil) could fill a stadium the amount of nuclear waste that is created by a fusion reactor could fill the back of a Toyota truck. ooooo but radiation last a really long time, well no you primeval ignorant moron, if you recycle the rods you get even less radiation, but your inbred potbrained parents put a stop to that. if this world ever wants to solve its energy problems we need to take all of the green party and anti nuke moron's and shoot them, because they are the problem, they're worse than the so called evil corporation's they oppose. the way to introduce new formes of energy is not through dogma but through the pocket book. i agree that we did a really bad job of making reactors in the past, but this idea of ending fusion technowlogy is throwing the baby out with the bath water. the problem is that the green party and anti nuke FUD is even worst than Bill Gates could ever dream of. they lie, obstruct the truth and brow beat anyone who doesn't tow their party line. its time to fight their lies with the truth, such that any green party or anti nuke protester is laughed at like the village idiot that they are.

Re:Decomissioning and waste management?

[jlseagull]

Actually, the flyash produced is pretty useful. Allow me to explain. The pollution produced by a typical power plant falls within three categories: SOx (sulfur oxides), NOx (nitrogen oxides), and inert particulates. These are filtered out by spraying a high pressure fan of limestone (CaCO3) through the flue gas, causing the formation of CCP (coal combustion products) in a system called a "scrubber" - known also by its tongue-in-cheek name, "SOx NOx rocks box". Some uses include road agglutinates, cast concrete products, and drywall. See this page for more information.

Re:I hate ignorance! (but not enough to avoid it)

[Angst Badger]

North America, the continent with three different countries on it, including the USA).

When you're done correcting the original poster's grotesque ignorance of geography, you might spend a little time correcting your own. There are ten nations on the North American continent. The seven you forgot are: Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, and Panama.

Sounds like rice to me

[Xeger]

Direct quotes from the PBMR web page:

"This turbine forms part of the High-pressure Turbo...Next, the helium flows through the Low-pressure Turbine, which is part of the Low-pressure Turbo Unit...The helium is then cooled in the inter-cooler. "

In other words: they're going to build a twin-turbo nuclear reactor with an intercooler.

I didn't see any mention of chrome exhaust tips, cupholders, cruise control or racing stripes, but how far behind can these things possibly be? That's gonna be one decked out nuclear reactor...I wonder what kind of stereo system they'll put into it?

Perhaps for the opening ceremony I'll fly to Africa and plant a "Type R" decal on the side of the reactor building.

Just for your info

[Skuld-Chan]

Chernobyl is also a good example of a RBMK reactor which is a unique design in that it is graphite rod moderated. The less you cool it the more efficent it gets - what is called a "positive void coefficient" - after Chernobyl many of the same RBMK reactors were fitted with many safety systems including containment. They still don't meet western safety standards, but there are several still in operation today - some of them are even connected to Europe's grid and producing electricity continent wide as a write this. The biggest is one called "Ignalina" in Lithuania.

Chernobyl had a cap on it - in fact when Unit 4 exploded it blew off the 2000 ton shield off the top of the reactor. When it exploded they were doing a test and were impatient with the performance of the control system and had subsequently shut off the safety systems. Oops.

RBMK reactors are kinda cool in the sense they can be refueled while online, but other then that...