UK Scientists Designing Cement To Safely Store Nuclear Waste For 100,000 Years (ibtimes.co.uk)

An anonymous reader writes: A team of British scientists are working on designing a form of cement which could safely withstand the harmful effects of nuclear waste for thousands of years. The team at the UK's synchrotron science facility, Diamond Light Source, said the project will be vital as Britain looks to expand on its nuclear industry.

The team believe the new material is 50% better at reducing the impact of radiation than current storage solutions. The government is set to choose a location of where to store the estimated 300,000 cubic metres of radioactive waste which is estimated to have been accumulated by the UK by 2030.

Comments

Keep it close

[slashping]

As long as they keep it close, because the stuff that we call "spent fuel" still has 99% of the original energy locked inside. At some point, we'll want to dig it back up and actually use it.

Re: Keep it close

[WarJolt]

The Pyramids of Giza are like 4.5k years old. With some tech we should be able to make tens of thousands of years.

Re:Keep it close

[AJWM]

Er, assuming that was a serious question...

100,000 years is ten half-lives (for a 10,000 half life). The amount of the original material left would be (1/2)^10, or a mere 1/1024th the amount of material.

As far as the amount of (useful) energy left, that depends on what the original material decays into, vs what it was originally.

Re:Keep it close

[slashping]

The waste is composed of a mix of radioactive materials with widely varying half lives. Some half lives, such as Strontium-94 are only 75 seconds, which means that it'll be completely gone in a few months, and radiation/heat produced by the waste will drop. Another common waste product Sr-90 has a half life of 30 years, but there are also waste products with half lives of millions of years. Most of the danger comes from the parts with intermediate half lives, as they produce lots of radiation, and will do so for years.

Re: Keep it close

[naughtynaughty]

All you need to know about Robert Schoch is that he believes in telekinesis and the paranormal.

Re:Keep it close

[Anonymous Coward]

Actually nuclear energy without reprocessing spent fuel; is bad proposition, because it is not sustainable.
Assuming that we use standard uranium/plutonium pallets; we will run out of fuel in 30-50 years, if we do reprocess it will last us few million years (it is a very energy dense).
That is why countries like France, Russia and etc; which are serious about nuclear energy do have reprocessing plants.
The technology is there it is well understood, but there is no political will to commit to it; that is why we are burring nuclear waste.

The only real concern is that most of the older reactor designs allow to generate enriched uranium/plutonium that is suitable for WMDs.
This is actually remedied in the new designs like thorium reactors.

Re:Keep it close

[Firethorn]

What comes out will be, without any processing really, be valuable reactor fuel. With some processing it can be made into a lot of valuable things, including the reactor fuel.

You're still going to have to process it to get reactor fuel. The important thing is that it's the radioactivity that makes reprocessing used fuel rods expensive, because said radioactivity tends to contaminate things.

If you store the used rods in a reactor pool for ~30 years, then in an above ground cask for another 30-60, as you say, the radioactivity is a tiny fraction of what it used to be. That means that it doesn't contaminate things nearly as much, thus will be something like an order of magnitude easier/cheaper to reprocess. You stuff the non-useful radioactives, and other materials you can't be bothered to separate, into another cask.

Utter Stupidity

[Anonymous Coward]

Why don't these idiots use that "waste" as fuel for breeder reactors? They are throwing away 98% of their fissile material and worse, trying to make 100,000 year plans for it.

Re:Utter Stupidity

[JoeMerchant]

Because: politics.

Re:Utter Stupidity

[careysub]

Cue the knee-jerk fuel-reprocessing-and-fast-reactor-is-the-complete-solution-to-all-nuclear-waste-problems-everywhere nutter comment.

Pointing out the problems with this comment is a bit of a problem in itself knowing what I should start with.

First, the 200,000 cubic meters of high-level waste already exists and is the product of the British nuclear weapons program, and possibly some of the high-level waste already created by fuel reprocessing. This stuff is a radiological and chemical witches brew that cannot be easily treated in any way. Some means of reducing this stuff to a stable state for long term storage is essential.

Second, there are only three operating (or soon to be operating) commercial scale breeder reactors in the world, two in Russia (operating) and one in India (not yet operating). A non-existent world fleet of breeder reactors cannot solve any real existing problems. Building a world-wide industrial deployment of breeder reactors is an exercise orders of magnitude more costly than waste disposal problems.

Third, breeder reactors do not make fission products go away. These must still be disposed of once the actinides are burned.

Fourth, fuel reprocessing systems currently operating produce larger volumes of high-level waste in physical terms than they take in. This must be converted to some form that be stored long term (see point one, above).

Fifth, spent fuel from power reactors does not contain "98% of their fissile material". Real nuclear fuel today is enriched to about 4% U-235 for loading (96% U-238), plutonium is bred and burned in place so that 5% of the actinide content is consumed, and the discharged fuel is about 0.8% U-235, 1.2% plutonium and 0.2% other actinides, for a "fissile content" of 2.2%. Reprocessing can only recover about 44% more usable energy content that the fuel already has provided. If you are thinking of the U-238, it is not fissile, but must be bred further to make it fissile. We can obtain U-238 far more cheaply and easily, if we need it, by simply converting the millions of tons of depleted uranium currently in storage into breeding fuel element.

Sixth, reprocessing is very expensive. Make that "VERY expensive". The cost of the fissile material produced is much higher than enriching natural uranium, and every aspect of fuel fabrication and handling is much more expensive due to it being "hot" from the beginning. The value of mixed oxide fuel on the market is less than zero. Utilities must be paid a subsidy to take it for free.

Seventh, a breeder reactor power economy cost much more than a conventional power reactor economy. As things now stand the high capital cost of conventional power reactors make them economically unattractive without some sort of construction mandate, or special economic support. A system that is much more expensive is a non-starter if the conventional power reactor problem is not solved in practice (see point two, above).

Eighth+ (yes, I have more points), but I am tired of typing.

Re:Utter Stupidity

[nojayuk]

Gas and coal are cheap and the waste from burning them can be dumped into the atmosphere and nobody cares enough to stop burning them since that would increase the price of electricity and cost jobs (see "War on Coal"). Nuclear reactors, including breeders are expensive to build and everyone is petrified of spent fuel from reactors because they've been fed bullshit and crappy movies about the effects of radiation ever since 1945.

Using up spent fuel in new-design reactors by reprocessing and other means will cost money and new uranium fuel is really cheap at the moment (current spot price for U3O8 yellowcake is $34.15 per lb) and it will remain cheap for another 50 years and more as more mining sources are developed and brought into production.

The Russian BN-800 reactor is designed to burn spent fuel and also plutonium from decommissioned nuclear weapons but it's quite experimental and it will be a while before more reactors like it are built. The fuel for it still needs to be processed and specially fabricated, it can't just take used fuel pellets and this adds to the expected cost of operations.

Some countries such as Russia do reprocess spent fuel but that only concentrates the unusable isotopes that are actually waste and they still need to be dealt with, probably by deep geological burial. There doesn't seem to be any real problem with this idea but it gets a lot of attention from the panic merchants with the 100,000 year figure being thrown about a lot although that's quite arbitrary considering the environmental radiation sources already present around us naturally which do not emanate from the nuclear power industry.

Re:Utter Stupidity

[blindseer]

Let's take this point by point.

First, the 200,000 cubic meters of high-level waste already exists and is the product of the British nuclear weapons program, and possibly some of the high-level waste already created by fuel reprocessing. This stuff is a radiological and chemical witches brew that cannot be easily treated in any way. Some means of reducing this stuff to a stable state for long term storage is essential.

That may be true but we have ways to reduce the mass of what needs to be stored if we use some preprocessing to separate out some of the valuable materials.

Second,...Building a world-wide industrial deployment of breeder reactors is an exercise orders of magnitude more costly than waste disposal problems.

Breeder reactors may be an expensive and difficult task but we can make energy from the "waste" that it burns. It is quite possible that by investing billions of dollars/euros/rupees in this we could get a net gain on our investment. Basically we can make money from burning this waste.

Third, breeder reactors do not make fission products go away. These must still be disposed of once the actinides are burned.

Many of those fission products are very valuable. Either because they are very useful radioactive isotopes or rare minerals. Much of the rest is not in fact radioactive, a fission produces two nuclei, with only one of them radioactive. If we just separate the non-radioactive elements from the radioactive elements then we'd cut the mass needed for storage in half. Then by separating the useful isotopes from the less than useful isotopes we could cut the mass needed to store by more than half again. With smart processing we could turn 10 tons of waste we'd have to bury into 4 tons. I think that alone is worth something.

Fourth, fuel reprocessing systems currently operating produce larger volumes of high-level waste in physical terms than they take in. This must be converted to some form that be stored long term (see point one, above).

If that is the case then you are doing it wrong.

Fifth, spent fuel from power reactors does not contain "98% of their fissile material". ...
We can obtain U-238 far more cheaply and easily, if we need it, by simply converting the millions of tons of depleted uranium currently in storage into breeding fuel element.

U-238 is only one of the many elements that can be obtained by properly processing spent fuel and other radioactive wastes. There are many other valuable elements in this radioactive wastes and if we process it out we reduce the mass of waste we need to store considerably and we can make money doing it.

Sixth, reprocessing is very expensive. ...
The value of mixed oxide fuel on the market is less than zero. Utilities must be paid a subsidy to take it for free.

Again, that is because you are doing it wrong. People are experimenting with a pyro-processing system that can melt down this waste and with some very creative chemistry they can separate out all the valuable stuff from the not so valuable stuff. Basically it's heated until melting, what becomes gasses at those temperatures is collected and separated by masses and chemical properties. Gasses like iodine can be made into medicines, noble gasses collected for welding, and so forth. Noble metals tend to just sink to the bottom and can be sold for jewelery or coinage. Zirconium, hafnium, beryllium, and many other non-radioactive elements can be separated out and reused in nuclear facilities because of their unique properties when exposed to radiation.

Reprocessing is expensive partly because we haven't figured out all the chemistry yet. It's also expensive partly because government regulations throughout the world make it expensive. The first country that creates sane regulations on the processing of nuclear

Re:Utter Stupidity

[Firethorn]

No: you want a design that stop instantly the moment you stop pressing the plug, not the other way around (in other words: a dead-man's switch).

I like the liquid thorium design - in the prototype plant they shut the reactor off for the night by turning the cooling system off.

How that worked is that the reactor vessel had a drain in it. The drain had a fan/cooler such that when they pumped the reaction mass into it(using a different heating system to melt it), the drain was cold enough to solidify the mass, plugging the drain. Turn the cooling system off, the drain plug heats up and liquifies(the vessel itself might heat up a little, but well within design tolerances). With the drain clear, the reaction mass drains out of the reactor into a sort of ice cube tray array that separated the mass into sub-critical amounts, where not enough heat is generated to keep the mass liquid, so the whole kit solidifies.

When the researchers came back in the morning, they'd fire up the heating system to re-melt the cubes and pump the mass back into the reactor. A cooling fan pointed at the drain would solidify the mass wanting to drain back to the trays. Once plugged, a critical mass could be built in the reactor vessel, and the operation of the reactor would resume.

Re:Utter Stupidity

[blindseer]

No, I do get it. The only reason nuclear reprocessing, or nuclear ANYTHING really, is expensive is because of nonsensical rules governing the handling of anything deemed "nuclear".

If the rules were such that we treated these materials based on the real and actual hazards they pose then we'd see more nuclear power plants. That's because we'd be shutting down all the coal plants based on how much radioactive material they spread to the environment alone.

The expense lies solely with government regulation. I'm not saying we need to do away with the regulation, I say the regulations need to make sense.

Clarification

[PuddleBoy]

I believe what they mean is "concrete" rather than "cement".

Cement is a powder that is one component of concrete;

https://en.wikipedia.org/wiki/Cement

Together with sand, water, and aggregate (rock) they undergo a chemical reaction (when mixed) to form concrete. Changing the quality, component ratio and admixtures of concrete can dramatically change various characteristics like strength, set time, resistance to water pressure, etc. I can remember seeing concrete that was very dark (almost black-ish) in color. I was told it contained a lot of lead for use in radioactivity shielding.

Just sayin'

Re:Clarification

[wbr1]

Thanks for the concrete example. It really cemented things in my mind.

Re:Clarification

[PuddleBoy]

... No, they mean cement. You add aggregate to provide structural properties and reduce the cost of the mix when used for construction. This is for waste disposal.

FTA: "...the plan for a Geological Disposal Facility (GDF) where highly radioactive waste, immobilised in cement, would be interred deep underground"

I'm pretty sure they mean concrete. Cement is a dry powder (think of those bags at the home improvement store - "Portland Cement") - it would be tough to immobilise anything in a loose powder for 100,000 years.

It is quite common for people to use the words cement and concrete interchangeably, though they are two different things.

Cement (in this context) is a dry, loose powder. It is one component of concrete.
Concrete is a hard 'finished product' that they make (some) roads and buildings out of. Concrete is a mixture of ingredients that, after going thru a chemical transformation, "sets" or hardens into something with tremendous compressive strength.

Re:Clarification

[thisisauniqueid]

In the UK, concrete is frequently referred to as simply "cement", e.g. "the cement building", "it's made of cement".

100,000 years?

[Anonymous Coward]

Hello scientists, the unsinkable Titanic would like to have a word with you

Depends on the radio element

[aepervius]

Firstly not radioactivity is equal. Alpha unless ingested is not a problem. Beta or gamma is another matter. But even then highly radioactive one are not a "problem" (e.g. half life of 100 years, by 1000 years you get less than 1/1024 of the radioactivity and the very short half lived one are even mostly gone during temporary storage). Weakly radioactive material with extremely long life are not a problem either (they don't emit much per second because long half life). The problem at worst is the one with medium half life, radioactive enough to be dangerous, beta or gamma emitter, but also around the half life you cite , and in sizeable quantity. IMHO this is anyway not a big problem, because the quantity involved are minuscule. 300000 cubic meter is barely a cube of 66 meter side. For the whole country over 15 years nearly. Let us not hide the fac that this is a problem but let us be realist and not make a mountain out of it. Basically the 100K years is not a scam. It is just a little bit exaggerated as problem & consequence. Compare to CO2 emission and radioactive emission of coal for example.

Re:Why 100,000 years

[careysub]

The 100,000 years thing is a scam meant to make the nuclear waste problem look intractable. LONG before that, the "waste" will be no more radioactive than natural rocks laying out in the desert in the U.S.

Not quite. Unless the actinides have been removed by reprocessing the spent fuel does not return to the same level as ore for a few hundred thousand years. The period chosen: 100,000 years is about right - not quite long enough to reach that point, but pretty good. The legacy waste they are dealing with contains actinides and is a nightmare to try reprocess due to its non-standard composition.

Imagining that all waste problems are really that of disposing of nearly non-existent reprocessed fuel waste with all actinides removed is silly. They are dealing with real waste that really needs disposal, not hypothetical types of waste.

BTW: the (quasi*) natural rocks laying out in the desert (tailings) are a significant waste problem since they have been removed from their stable geological context.

*They have been physically and chemically altered.

Re:Why 100,000 years

[sjames]

Removing the actinides is the easiest part if you don't care about separating the U and Pu from them. IIRC, a CANDU reactor can use mixed actinide fuel.

Also BTW, the natural rocks I mentioned are NATURAL ROCKS, not tailings. If I meant tailings, I'd have called them that.

I doubt this will ever work

[Sax Russell 5449D29A]

Looking at the pyramids, I doubt we can ever build something that lasts for a hundred thousand years. There will always be somebody who wants to take a peek inside for one reason or another.

Pyramids

[Smiddi]

The Egyptian Pyramids are about 5,000yrs old we still don't know a lot about them, even after we went in there and took almost all the items out. Imaging the mess in 10,000yrs time when mankind opens up these storage containers because they also want to know what's in them?

100,000 years!

[blindseer]

If it takes 100,000 years for something to decay then it is no more radioactive than the concrete in my driveway.

Us humans separate radioactive elements into "short", "medium", and "long" lived isotopes. We separate them like that because compared to our life span these isotopes are short, medium, or long. The short lived stuff is gone in less than a couple months. These isotopes are effectively gone even before the spent fuel leaves the nuclear power plant. Fuel rods taken from the reactor core is placed in a cooling pool for at least two years so that all of these isotopes decay away. When they come out the radiation is so strong that even seconds of exposure means death. After they come out of that pool it's just the long and medium lived products that remain. The most dangerous of them are elements like cesium and selenium which can collect in bones and irradiate people for the rest of their natural life, however shortened that might be.

The long lived isotopes have half lives on the order of thousands of years or more. Elements with half lives this long is not any real radiation hazard since a person is more likely to die of old age before it decays. These elements should still be handled with care since they are still likely to pose hazards like heavy metal poisoning but that basically means don't eat it, breath in the dust, or handle it with bare skin.

We don't need to bury radioactive anything for more than perhaps 300 years, and we know how to do that. We've built plenty of structures that can last that long. After 300 years all the short and medium lived products are gone, only the long lived stuff remains. At that point the waste can be handled much like we'd handle anything containing lead, mercury, or arsenic. That means rubber suits, gloves, goggles, and masks. Then we can reprocess this material to separate out what are valuable metals, fissile reactor fuel, and other elements for medical and industrial uses.

I can remember reading as a kid about how scientists were trying to develop a "language" to communicate to future civilizations where we've stored our dangerous radioactive wastes. That way we don't contaminate future generations with all that nasty radioactive waste us evil people in the here and now are producing. Then I learned some real science from people that actually knew what they were talking about and learned that we don't need to store the waste for hundreds of thousands of years. If we store it for just a couple hundred years we can make it safe

We already do something like this now. Forestry people with watch over a forest for forty years so that we can harvest that for wood. People will build and maintain structures that they intend to make last for centuries. Libraries and museums will keep valuable items from history for as long as we can imagine. Keeping an eye on radioactive material, for the purpose of mining it again for it's valuable elements in a century or three, seems like a trivial problem really.

whatever happened to glass?

[ihtoit]

Has it suddenly become incapable of containing LLNW? Should I return my almost-antique radioluminescent bowls? And to whom should I return them?