Report: Nuclear Plants Should Focus On Risks Posed By External Events

mdsolar (1045926) writes "Engineers at American nuclear plants have been much better at calculating the risk of an internal problem that would lead to an accident than they have at figuring the probability and consequences of accidents caused by events outside a plant, a report released Thursday by the National Academy of Science said. Accidents that American reactors are designed to withstand, like a major pipe break, are "stylized" and do not reflect the bigger source of risk, which is external, according to the study. That conclusion is one of the major lessons from the Fukushima Daiichi nuclear accident in Japan in 2011, which began after an earthquake at sea caused a tsunami.

Comments

already done

[Mr D from 63]

External events are considered in US plant design already, this author seems to be a bit ignorant on how the safety case for plants is built. Who cares if we refine the probability of an event is if the plant is already designed to withstand it? More total stupidity disguised as a serious study. Even highly unlikely events are designed against in our plants.

Now, Post-Fukushima, plants are adding response capabilities for apocalyptic type scenarios even though three is nobody that can provide an example of how such an event may happen for the particular site short of some major war type event. Fukushima was simple...don't put reactors that were not design to operate underwater where they can find themselves underwater. Given the situation, the outcome was quite easily predictable.

Re:already done

[Mr D from 63]

Let me clarify; "more total stupidity" was aimed at the article author's interpretation of the study, not at the study itself. Poorly worded in my post. The study is what it is, the article author is clearly not qualified to interpret it.

Re:already done

[mdsolar]

Matthew Wald does his homework and reports pretty accurately. Perhaps you should give some examples where he has misread the report.

Re:already done

[mdsolar]

But isn't that what the National Academy of Sciences is saying in the report? Platts reports he same. http://www.platts.com/latest-n... "US nuclear regulators and industry officials must do more to protect reactors from extreme, but unlikely, events like the earthquake and tsunami that caused the accident at Japan's Fukushima nuclear plant, the National Academy of Sciences recommended in report issued Thursday."

Re:already done

[Mr D from 63]

Well, that isn't what the author said, is it? Thanks for helping prove my point.
And, the NRC and industry are already "doing more" so the report is a bit of a redundancy, and a little late on that conclusion.

Re:already done

[tp1024]

It gets better, all the way back in 1975, the Wash-1400 report listed tsunamis as one of the potential ways to knock out the safety systems of a nuclear power plant, leading to the exact same outcome we have seen. All the way to the point of having to evacuate a few thousand square kilometers, given the BWR Mark I containment. (Actually, it was just one thousand, but the rest was off-shore.)

The main problem was that just about ALL the tsunami protection in Japan (both for cities and nuclear power plants) was based on the 1960 tsunami, that came all the way across the Pacific from Chile. The result was quite a disaster, but the worst part was the completely unprotected population and certainly not the nuclear power plants. Contamination is quite reversible, 18500 dead people not so much.

Re:already done

[mdsolar]

OK, so they are right and Wald reported accurately. NRC already agrees with the report. It hardly seems late if it is a report requested by congress with a particular scope. NAS is usually pretty thorough. It hardly seems wrong for congress to want to know about this since the US shoulders nearly all the risk for an accident through the huge Price Anderson subsidy.

Re:already done

[JimSadler]

I find it hard to believe that a major earthquake would allow a reactor to remain intact.

Re:already done

[HangingChad]

Given the situation, the outcome was quite easily predictable.

If it was that easy FP&L would be making plans to close Turkey Point instead of expand it. That whole site is going to be underwater and, before that happens, there's going to be a storm surge high enough to swamp it. That's a guarantee which seems to fly in the face of your supposition.

I worked in the nuclear industry for nearly a decade. What I saw with my own eyes could best be described as straining out a gnat and swallowing a camel.

Re:already done

[Mr D from 63]

It will, in fact the reactors near Fukushima experienced major quakes beyond their design basis, remained intact and actually saw little or no structural damage. Only those plants that got flooded by the tsunami had problems, because they were not designed to be underwater.

If a major natural disaster hits, a nuclear plant is probably one of the safest places to be.

Re:already done

[Mr D from 63]

Can you please describe the event that suddenly places Turkey Point underwater without sufficient warning to take appropriate actions? Many hurricanes have come through, even those with the highest scale, and TP has been quite fine. If you can show there can be a surge will inundate the plant that is not accounted for, please specify the height and relative limits for the plant.

Re:already done

[brambus]

And yet we know how to engineer such systems. That having been said, Fukushima clearly demonstrated how poorly water performs as a coolant in nuclear power plants.

Re:already done

[multi io]

Now, Post-Fukushima, plants are adding response capabilities for apocalyptic type scenarios even though three is nobody that can provide an example of how such an event may happen for the particular site short of some major war type event. Fukushima was simple...don't put reactors that were not design to operate underwater where they can find themselves underwater. Given the situation, the outcome was quite easily predictable.

Can you cite any pre-Fukushima regulation that mandates this? Because if you can't, then that's a case of "hindsight is 20/20". I'm pretty sure the type of thing that happened at Fukushima has always been thought to be a "there is nobody that can provide an example of how such an event may happen for the particular site" type of scenario -- until it did happen.

Re:already done

[tp1024]

If your definition of "reasonable" is "one millionth" you'd be right, but also perfectly unreasonable. There is such a thing as natural radioactivity, it is everywhere. And if you demand that "artificial" radiation must be less than 1/10.000th of natural radioactivity in the worst contaminated areas to be "reasonable", then you suffer from a gross form hubris. Your claims about Iodine-129 neglect to mention that is has 1/1.000.000.000th of the activity of I-131. Even by your stupid definition, it's not a problem. This is further compounded by the fact that Iodine is highly mobile, most of all, it is water soluble. This means that it will be dispersed in the environment at a much greater rate than it will be concentrated in humans. In fact, it is not even detectable around Fukushima Daiichi.

You also neglect to say that the total radiotoxicity of all longlived fission isotopes is less than the radiotoxicity of the natural uranium before it went through the reactor. It is LESS than what was naturally there anyway. I know you don't care about such facts, lots of other people do.

Your body is full of potassium-40, carbon-14, thorium, uranium and their decay products. If you're so scared of radioactivity that you must demand Cs-137 to decay to one-millionth of the current concentrations before you feel safe, then go commit suicide. There is no place in the solar system that will satisfy your demands. You, sir, are a lunatic.

Re:already done

[Mr D from 63]

Plants do address what they call "beyond design basis" events with various coping scenarios over and above the prescribed design basis accidents and events. Post Fuku response is really an extension of that severe accident management element. But that is not in response to a specified event, rather the approach is to simply imagine the plant is left crippled badly in various ways and put mitigations in place to cope. Now, they simply imagine a more crippled starting point. That's all well and good and conservative, but it doesn't address an event, which was the failing at Fukushima.

Re:already done

[Rich0]

It will, in fact the reactors near Fukushima experienced major quakes beyond their design basis..

Is anybody else concerned that anything like a nuclear reactor could ever encounter a major quake beyond their design basis?

Shouldn't we be designing reactors to handle any quake that is reasonably likely to occur? Japan is highly prone to earthquakes - I'd expect any reactor design to account for a very strong one.

We're not talking about a freak incident like a comet impact that destroys all of Japan. We're talking about an earthquake in one of the most earthquake-prone regions on Earth. I'd expect a reactor in an inactive region to be designed to withstand a major quake just as a matter of course.

Re:already done

[Rich0]

What I saw with my own eyes could best be described as straining out a gnat and swallowing a camel.

I don't have any experience in the nuclear industry, but this sort of thing is common where satisfying inspectors/etc are concerned.

There is a lot more emphasis on looking busy than being safe. If you try to introduce a product in a regulated space and your testing is documented on two pages of paper an inspector would laugh at you and deny your application to market the product. On the other hand, if you produced 10k pages of documentation, but ignored testing some likely failure mode, chances are it would get rubber-stamped. If one of those 10k pages of documentation were missing an initial/date or signature, they (or an internal auditor) would probably catch it.

It is just the bikeshedding problem in another guise. The people charged with oversight can't possibly properly supervise the work - they just are woefully understaffed to do that. So, they just get a sense for how impressive the documentation looks and assume that if there are problems they'd be apparent. That is why anybody about to be inspected by a regulator doubles-down on the housekeeping - a tidy shop is more likely to get less poking-around.

Re:already done

[Mr D from 63]

Shouldn't we be designing reactors to handle any quake that is reasonably likely to occur? Japan is highly prone to earthquakes - I'd expect any reactor design to account for a very strong one.

They do, but you have to prescribe a specific requirement in the license and that is on the regulator. The actual designs handle quite a bit more than the licensed design specification, because a reactor designer will typically consider the worst site where a reactor is expected to be built, and the site specific design can be augmented if necessary. US plants have conservative earthquake requirements to start with as prescribed by the NRC, and they do consider the location. Designing a facility to withstand an earthquake is really not that big of a technical challenge.

Withstanding a tsunami is a whole different ball game... there is no margin for something like that, you either place the plant where it won't get hit, or you design it to operate underwater with destroyed surroundings... that latter is not practical.

Re:already done

[tp1024]

Go read WASH-1400, that one said 36 years before Fukushima Daiichi what would happen when a tsunami hits a nuclear power plant. The predicted result is easily comparable to what we have seen, because Japan (just like the USA) didn't bother to implement major upgrades that were demanded by law in France, Germany and Sweden. Among those are hydrogen recombiners that the Japanese demanded by law in 2012 and were bought in France where they have been implemented for decades. You may remember the hydrogen explosions? Those were predicted. The same countries also installed filtered containment vents. Which would, by themselves, have prevented uncontrolled venting into the reactor buildings, they would have filtered out 99.99% of the Cs and they also have hydrogen recombines by default. In Germany those were required in 1988, Japan followed in 2013. Japan managed to require all reactors to have at least 2 emergency generators for each reactor in 2002 (before that 3 emergency generators were sufficient for 2 reactors). By comparison, at the same time, Germany required at least 2 WORKING emergency generators for each reactor, even if one generator is out for maintenance and another breaks down due to some technical fault. In other words, they required at least 4 generators and even more, if some of them were put in a place were they might fail due to some other causes (like flooding or a plane crash).

There is no tsunami risk in Europe. But nuclear power plants must be protected against 10.000 year floods. Fukushima Daiichi (along with all the coastal cities) was protected against a rather small tsunami that hit Japan in 1960 and nobody bothered that there were larger tsunamis in 1933 and 1896 (and many more before that).

It's not about hindsight. It's a matter of a complete lack of disaster planning in Japan, which is why you had almost 20.000 dead and 400.000 lost homes (that latter figure is without the additional evacuations due to the reactor accident).

Re:already done

[Hussman32]

The reactors are fine during an earthquake because they are effectively bolted to bedrock, and the move with the earth. There was a serious earthquake a few years ago at the Kashiwaszaki-Kariwa site, and the primary systems didn't move at all. There was a lot of damage to the switchyard and non-safety systems, and there was some water sloshed out of the spent fuel pool, but the reactor started up fine after all systems were requalified.

Re:already done

[BitZtream]

Ironically, the longer the half life, the less dangerous the material is. The truly dangerous ones have relatively short half lives which will easily have them dissipate well within a human lifetime.

Re:already done

[budgenator]

Why would Turkey Point be underwater? If it's the sea-level rise due to Apocolyptic Global Warming then you should be pushing for as much non-CO2 emmiting generation capacity as possible, Solar and Wind are the icing on the cake, but nuclear is your cake.

Re:already done

[angel'o'sphere]

It won't.
The reactors at Fukushima did not feel anything from the earth quake.
They where 450 miles away from the epicenter. They suffered because surrounding pillars for electric wires collapsed ... they got damaged enough to be broken beyond repair and finally they got hit by a tsunami destroying the emergency cooling.
So an earthquake that was at the site certainly below 6 on the Richter Scale already did server damage.
The news that is survived a 9.x quake is a myth, the 9.x quake was as far away as the distance between New York and Cleveland Conneticut.
So you have a quake in Conneticut and a plant in New York fails (mainly because the plower lines around it got nocked down) and you claim: the plant survived a quake ...
Sorry it did not.
Even without the tsunami nocking out the emergency generators, the plant was doomed.
Even more important: Japans government failed to place there alternative diesel engines. Can't be so hard to drive them in with trucks, every military has such things. Even if we had needed to fly them in from Germany with Trans All's and using tanker air planes for refueling and parachuting them down would have been a no brainer and likely done in 36h if there had not been a catastrophic put your head into the sand no nothing happened in the end it will not be so bad ... stupid attitude.
With swift reaction the rest of the world had saved the plants from disaster (if not the cooling pipes are/where broken themselves)
Can't be so hard to bring a couple of ships to anchor and power the cooling or bring in trucks or really parachute down emergency equipment.
IMHO the plant manager and the managers of the company should be shot at a wall for not disclosing the severity of the situation in time.

Re:already done

[Mr D from 63]

^you can make stuff up all you want, but there are no such thing as safety related electrical pillars. Offsite power supply is not credited in a safety analysis of the plant, and failure of those systems is just fine, as the safety related systems could more than handle the earthquake. The plant was doomed when it was inundated by water and the safety related systems became inoperable.

You should learn more about how a plant safety design basis is developed, and in particular the difference between safety related and non-safety related systems and components.

Re:already done

[greg_barton]

Wish I had points to up vote you. :)

Re:already done

[Mr D from 63]

Outside power is not required to shut the plant down. There nearby plants, the ones right next door, the ones not hit by the tsunami, also lost power but shut down just fine. The Fukushima Daiichi plants were in the process of shutting down after the quake and before the tsunami, even though offsite power was lost. The emergency diesel generators had started and the units were just fine to shut down. Had the tsunami not hit, regardless of the quake, you would never have heard of Fukushima Daiichi, just like you probably can't name any of the units that survived the severe earthquake without googling.

Re:already done

[Mr D from 63]

You claimed the plant was not at all affected by the earthquake, which is wrong.

I never said the plant was not at all affected, that is another fabrication by you. The safety systems, those designed to operate after such an event, were quite capable of safety shutting down the plant after the quake. They were not capable after the tsunami hit.

Re:already done

[brambus]

Gah, the stupid, it burns!

Natural radioactivity is mainly something that hits you from the 'outside'... it hits your skin

Except for the ~5kBq of K-40 in your nerves. And the C-14 in all of your tissues. Also, cosmic radiation doesn't stop on your skin - it's comprised of extremely high energy particles at 1 GeV or more. Those sort of energies make the radiation from nuclear reactors seem like child's play. That is not to say that you'd rather be inside of a nuclear reactor - most definitely not, the flux there is many orders of magnitude larger - but it does show that cosmic rays don't just "hit your skin", but instead fire right through you and irradiate your internals quite easily.

First of all a healthy person has no Uranium or Thorium in his body.

I'd be careful with throwing around superlatives like "none", but it's probably fair to say that the abundance of actinides in most humans would be classed as "trace" at best.

you are again mixing up external radiation by natural sources with radioactive elements incorporated into the body

Except that both K-40 and C-14 are both natural and inside your body. In fact, we use C-14 abundance in tissues to date when organisms died. Whether something is or isn't natural has no bearing on where it is harmful.

The fallout is measurable every where in north Japan.

This statement, while true, is misleading, or at the very least oversimplified. We have extremely sensitive measurement equipment, but the mere detection of the presence of a radionuclide does not in itself imply any danger from it. What needs to be assessed is the particular type of radionuclide, its abundance and sample distribution, in order to be able to at least roughly assess the potential biological impacts. In pretty much any scoop e.g. topsoil you'd be able to find all manner of toxic stuff, from mercury through arsenic, lead and even to uranium - this is simply a consequence of the magnitude of Avogadro's number.

I'll leave you with just one tiny factiod: long-haul flights are associated with elevated exposure to cosmic rays, easily 20-30x sea-level background and comparable to some of the hotter parts of the Fukushima exclusion zone. This has been repeatedly assessed and demonstrated. As such, one would expect to find radiation-related cancer clusters among airline crew, who spend a sizable amount of their lives in this elevated radiation environment. And yet, no reliable evidence for this has been found so far.

Re:already done

[AmiMoJo]

When someone has to rely on an ad-hominem you can take it as read that they don't have any specific criticisms. I somehow knew the first comment would be an hominem.

Re:already done

[AmiMoJo]

Contamination is quite reversible

Yes, but the effects of short term contamination are not. The evacuated towns in Japan are pretty much being abandoned now, because even when they do manage to fully decontaminate them there will be no-one to live there. All the former residents have had to move on with their lives, find homes and jobs elsewhere, go to other schools and try to start some kind of new life.

Those communities, those businesses are all gone for good.

Re:already done

[AmiMoJo]

Actually the earthquake did damage the plant in a very critical way. The emergency cooling system was broken, so that even when they started pumping in water from fire engines it didn't cool the cores and they went into meltdown.

I suggest you try watching this documentary: http://youtu.be/ldki2ji5-gU

Re:already done

[Mr D from 63]

First, there were more than one unit that all met essentially the same fate from the tsunami, it was not just one unit, and each unit has multiple safety systems that are designed to complete their mission even if one fails, as the assumption is always that something will go wrong. There were plenty of operable cooling components in place to shut down the plant after the earthquake. Not so after the tsunami.

Re:already done

[Solandri]

External events are considered in US plant design already, this author seems to be a bit ignorant on how the safety case for plants is built. Who cares if we refine the probability of an event is if the plant is already designed to withstand it?

Technically, the Fukushima plant was also already designed to withstand this type of event. It had sufficient backup power systems necessary to continue operating the cooling pumps in the event of a catastrophic disaster of this type.

Where they screwed up was in the redundancy of the backups. This is unfortunately a fairly common failure mode in engineering designs. Say a single diesel generator has a 10% chance of failing to start up if you try to run it during an emergency. People then naively think that if you just put 6 diesel generators into the design, then that reduces the statistical probability of failure to 1 in a million. The chance of all six generators failing is (10%)^6 = 1 in a million.

That's the correct math for generator failures due to independent internal causes. But everything changes when you talk about external causes. Suddenly you have a cause like, oh, say, a tsunmai, which can affect all the generators simultaneously. The failure mode for each generator is no longer independent, and your redundancy does nothing to decrease the odds of a failure. All they had to avoid this effect was put the generators and diesel fuel tanks in different places. But no, the typical Japanese obsession with order and symmetry* mandated that they put all their generators in a row in the same place. And the tsunami took them out and contaminated their fuel all at once. Indeed the two newer Fukushima reactors where the generators and fuel were stored in a different location got through the earthquake and tsunami just fine.

* I rag on the Japanese, but the same thing happened with the Space Shuttle Challenger. They were having problems with poor O-ring seals in the solid rocket boosters. So to reduce the probability of a failure, they just added more O-rings. That worked to stop the independent failures (burn-through due to improper seating of an O-ring in one spot). But when an external factor popped up which caused all O-rings to fail simultaneously (cold weather), the safety of the redundant O-rings was negated.

Re:already done

[Mr D from 63]

The plant was not designed to operate when inundated by water, it was not designed to withstand a tsunami of this magnitude, it was assumed a tsunami would never breach the protective wall and reach the plant, therefore, simple things like protecting the structures from the forces of the tsunami, and waterproofing all of the ducts, vents, doors, etc with controls over when and how long they can be open, were never in place.

Even with diesel failures at a unit, it could still have been safely shut down had the tsunami not hit. One option could have been borrowing power from another unit, but that would not necessarily be required. Diesels are very reliable machines that are tested on a regular basis. Adding a third does not improve the situation as much as you may think, because if two fail at the same time, its more likely a common cause than a different one, and the third diesel would stand a good chance of suffering that common cause as well. That is where testing, maintenance and reliability programs become very important. Also, having diverse means to achieve a safe state is also key.

The key is not placing a plant that cannot withstand a tsunami where it can be hit by one, because designing to withstand a tsunami suddenly inundating the site it really not practical.

Re:already done

[tp1024]

But
a) Nobody died. (Unlike due to the direct effects of the tsunami.)
b) In places like Ishinomaki, Kesenuma, Rikuzentakata or Ofunato the people are essentially in the same situation. People can't just go back, because they now realized that those places are too darn dangerous to live in, because of the tsunami hazard. If history provides any pattern there, the towns will be abandonned for several decades upon which people will start ignoring the danger again, rebuild former settlements and then suffer the next big tsunami. All very much on the same time-scale as for the evacuation zone around Fukushima Daiichi. With the difference that the next tsunami WILL come and WILL NOT be prevented, while nuclear power plants can simply be build properly to modern standards (i.e. designed to contain a meltdown, which General Electric said this containment wasn't designed to do all the way back to 1966, as you can read in the CR-6042 manual).

c) The number of people evacuated because of radiation is a fraction (10-20%) of the total number of people who lost their homes. Most of those will be free to return in the next few years. (There is no statistic that I'm aware of saying how many people's homes were destroyed in the area that was later declared off-limits. Extrapolating from the number of dead people in the area it ought to be about 10% or 50,000, but that could be wrong.)

Re:already done

[angel'o'sphere]

You said: the plant survived an earthquake undamaged ... should I click ten times parent/parent/parent to quote you?

Re:already done

[Mr D from 63]

yes, please find that quote.

Re:already done

[angel'o'sphere]

Either you are a moron or you should not let other people use your /. account:
http://slashdot.org/comments.p...

if I did not miscount, just 5 posts 'back' .... hm, where is the 'that was easy' button?

Re:already done

[Mr D from 63]

I think you did not read it, because it does not say "the plant survived an earthquake undamaged". So, you are resorting to changing my words so you can play a game of "gotcha", and you have gone down that path because your arguments were failing.

Please just stop now while you are behind.

Re:already done

[Rich0]

Shouldn't we be designing reactors to handle any quake that is reasonably likely to occur? Japan is highly prone to earthquakes - I'd expect any reactor design to account for a very strong one.

They do, but you have to prescribe a specific requirement in the license and that is on the regulator.

My issue is with the statement, "the reactors near Fukushima experienced major quakes beyond their design basis." That suggests to me that regulators set a design basis requirement smaller than earthquakes that have subsequently hit the region.

Obviously they have to set some kind of design threshold, since no machine can withstand an earthquake of such magnitude that it destroys the earth and half the solar system with it. I'd just expect them to take the largest earthquake in known history in that area, and add a safety factor to it. I wouldn't expect the plant to ever actually experience such an event within our lifetimes.

Re:already done

[Mr D from 63]

Agreed. Japan is a high seismic activity area and should have set higher requirements to start with, just as they should have never assumed a massive tsunami would not happen when its clear that it could based on the geology of the area and the type of coastline. Raising the minimum requires going back and re-analyzing to see if the design is still adequate and making modifications where it isn't, costly to do after the fact.

Re:already done

[brambus]

Comparing the 'natural' intake of C14 and other elements 'in a normal' amount with the levels in Fukushima makes you a moron. Not C14 or other minimal intake.

Contrary to your quite uneducated assertion that background radiation in a "normal" amount is somehow inconsequential compared with the radiation levels at Fukushima, they are rather comparable. We have quantified these things quite accurately. Terrestrial background is anywhere from 0.1 uSv/h (Japan) to 0.3 uSv/h (USA) in most places on the planet, ignoring outliers. By comparison, the Fukushima exclusion zone typically ranges from 0.1 uSv/h to ~15 uSv/h with the median being somewhere close to 3 uSv/h or about 10-30x background. This is comparable to radiation exposure on a long-haul flight, as I've shown you, and that has so far not been shown to result in any increased risk, even in people who work for the airline industry and spend a sizable amount of their lives in this environment.

Cosmic Ray != radioactive iod or caesium

From a radiotoxicity standpoint, they are in fact not really distinct. You may recall that Sievert is a unit of committed dose, so it expresses biological effects, not just raw counts, and is capable of accounting for the differences between internal and external emitters. Now you could argue that whole-body exposure numbers are too simplistic to accurately asses ionizing radiation impact, and I'd agree (for certain radionuclides), but this has been considered and more accurate models are available, they're just not used very often in discussions, because they're too complex to easily wrap your mind around. For a first-degree approximation, though, whole-body exposure numbers seem to be quite a good rule of thumb.

Re:already done

[Boronx]

The earth quake was a millennial quake, so they figured they only had a five percent chance of seeing one in the life span of the plants. In other words, they cut corners. They also cut corners on personnel. Competent management could have prevented the meltdown even post tsunami. For instance, they could have vented the Hydrogen gas, and they should have moved mountains to get the generators running (or get new generators flown in) and keep them fueled.

Re:already done

[AmiMoJo]

People did die during the evacuation, mostly the elderly. They can't go back because there are still spots of significant contamination where radiation levels are above the legal limit. The towns near Fukushima survived the tsunami unscathed, they are perfectly safe from even the largest waves.

Re:already done

[tp1024]

If all those cities were "fine", 'unscathed" and "perfectly safe from even the largest waves" then how come there were 182 deaths in Namie, 85 deaths in Okuma and 35 deaths in Futaba? And why have all the coastal communities of Namie essentially been scrubbed from the coast? Why has the mayor of Futaba (previous population 7406) said, that 90% of its houses have been destroyed?

As for people dieing during the evacuation. Yes, there have been such reports. But those people died because the evacuation was botched beyond belief. Who would have thought that evacuating a hospital with lots of people who are severely ill, without providing food, drink or medical support could result in dead people? Well, the lancet says there are "lessons to be learnt". I'd say the only lesson to be learnt here is that radiation is completely harmless compared with the gross neglect of even basic human needs as soon as somebody screams "radiation everybody will die!".

Re:already done

[Rich0]

Good point. You'd think that after the fact this could have been escalated so that the military could have heavy-lifted whatever they could into the area.

I'm not surprised about the lack of venting though. You're talking about somebody having to make the call about deliberately venting what was probably contaminated air into the environment. For whatever reason society tends to favor allowing a huge disaster over causing a smaller one - just the trolley problem in another form.

Re:already done

[angel'o'sphere]

If something is a magnitude higher (factor 10x - 30x, as you pointed out), it is not 'comparable' in its effect to the 'original' thing.

It is quite a difference whether I drink *one* beer or 10 - 30.

The exclusion zone is not what we are talking about ... or where. The article and our discussion is about the plant side.

From a radiotoxicity standpoint, they are in fact not really distinct. You may recall that Sievert is a unit of committed dose,
You try to compare stuff that can't be compared. A cosmic ray, a high energy ion, is crossing my body. Along its path it destroys a DNA strand here and there and kills some cells completely.
Incorporating a radioactive element into your body is a bit different. Yes the 'Sievert modeling guys' try to 'compensate' the different effects to get a 'uniform' threat indicator.
Makes no sense IMHO, as all those slightly different forms of radiation have completely different effects.
Plutonium e.g. settles in the bone marrow ... the deadly dose for a human is something like 50 nano grams, perhaps 100, don't remember.
Iodine accumulates mainly in the thyroid, causing cancer there. It seems you can prevent that with high doses of Iodine intake, and Thyroid cancer seems relatively easy to treat and surviving rates are high.
Cesium accumulates in bones and sinew ... I assume in muscles as well.

So, your 10x - 30x increase of radiation versus 'normal' background level still simply measures what you can count with a geiger counter. It does not take into account what happens if you inhale some dust on a dry summer day ... perhaps working in a field with your shirt of covert with sweat when the dust accumulates on your skin.

It does not take into account what you get if you eat something that 'accumulates' the radioactive material, like a chicken or its eggs, or a fish, that have 100x higher level of radioactive Cesium than the measurement you make.

So suddenly we jump from your '10x - 30x' to the more realistic '10000x - 30000x' because a human living there eats an egg or an apple or a fish that was harvested/caught there.

Do you really think the exclusive zones exist because some idiots who have no clue overreact? In THE country that has the MOST experience with radiation victims?

You do know that according to normal regulations the whole coast north east of Fukushima beyond Tokyo, roughly 10 - 20 million people ought to be evacuated?

Re:already done

[angel'o'sphere]

Well, if you want I quote your exact words and debunk your exact words.
Fact is: the quake was elsewhere. Claiming Fukushima survived a quake is just nonsense. Because: there was no quake.

Re:already done

[Mr D from 63]

If those are your final words of wisdom for this particular exchange... well, I'll just let you rest with them. I did chuckle a bit.

Re:already done

[angel'o'sphere]

Oh, I half chuckled on your first post.

Re:already done

[brambus]

If something is a magnitude higher (factor 10x - 30x, as you pointed out), it is not 'comparable' in its effect to the 'original' thing. It is quite a difference whether I drink *one* beer or 10 - 30.

Except that here we're talking about far smaller effects, more in line with 1 drop vs 10-30 drops of beer. Stick to facts and not analogies.

You try to compare stuff that can't be compared. A cosmic ray, a high energy ion, is crossing my body. Along its path it destroys a DNA strand here and there and kills some cells completely. Incorporating a radioactive element into your body is a bit different.

In what significant capacity? Radioactive element decay produces exactly the same kind of particles (high-energy electrons & gammas; high-energy ions being notably absent in fission product decay and mind you, high-energy ions are much more dangerous, so cosmic rays might even win from a danger perspective particle-by-particle).

Yes the 'Sievert modeling guys' try to 'compensate' the different effects to get a 'uniform' threat indicator. Makes no sense IMHO, as all those slightly different forms of radiation have completely different effects.

Your humble opinion on the matter is your right to have, but dismissing the work of researchers and professionals in the field without evidence would at best net you a label of science denier. Unless you can produce good research to substantiate your opinion, it'll remain just that - opinion.

Plutonium e.g. settles in the bone marrow ... the deadly dose for a human is something like 50 nano grams, perhaps 100, don't remember.

This is the problem when you listen to non-scientists like Ralph Nader and even a cursory read of the Wikipedia article on Plutonium's toxicity would have given you tons of references to studies, research and experiments done which essentially debunks this. Plutonium is toxic for sure, but it's nowhere near the levels you assume it is.

Iodine accumulates mainly in the thyroid, causing cancer there. It seems you can prevent that with high doses of Iodine intake, and Thyroid cancer seems relatively easy to treat and surviving rates are high.

I-131 is the primary problem child in inadvertent radiation releases, since there's plenty of it (~3% fission yield), it's highly mobile, it's intensely radioactive and easily bioaccumulates as you describe. After a few weeks, though, it decays away completely into stable Xe-131. There is also I-129, however its radiotoxicity is billions of times lower than I-131, so it's not really much of a problem once diluted.

Cesium accumulates in bones and sinew ... I assume in muscles as well.

Correct. Add Sr-90 to that.

So, your 10x - 30x increase of radiation versus 'normal' background level still simply measures what you can count with a geiger counter. It does not take into account what happens if you inhale some dust on a dry summer day ... perhaps working in a field with your shirt of covert with sweat when the dust accumulates on your skin.

Not correct. Sieverts are units of committed dose and all of the factors you mention have been considered in its calculation. Geiger counters just measure counts - disintegrations per second. To get a Sievert measurement what we do is we measure counts, then we take samples and employ systems such as mass spectrometry and gamma ray spectrometry to measure the exact radionuclides present and their proportions. These are then combined wit

Re:already done

[MrKaos]

it was assumed a tsunami would never breach the protective wall and reach the plant

Tepco ignored geological evidence and relied on historical data when evaluating the height the sea wall *should* have been.

The key is not placing a plant that cannot withstand a tsunami where it can be hit by one, because designing to withstand a tsunami suddenly inundating the site it really not practical.

Another key issue is not grouping all of the backup generators on the sea facing side of the reactor with an inadequate sea wall was a disaster waiting to happen. Tepco had ample time to prepare but colluded with the regulator to prevent such changes in regulations which, according to the official report into the accident, was caused by an inherent belief that nuclear power was safe.

While your hindsight is all well and good now, this was all predicted and ignored. Worse still the report to the Diet highlights that these external events were human nonfeasance and "Wholly man made" - to quote the report. Criminal negligence through nonfeasance is an external threat the modelling is trying to predict.

Even with diesel failures at a unit, it could still have been safely shut down had the tsunami not hit.

You are incorrect, it could not have been safely shutdown with diesel failures. Design basis issues with the Generation 1 reactor mean that it must *always* have access to electricity. Specifically S and B class facilities in the installation must always be powered otherwise they are exposed to these design issues. Exposure to these issues are why the Fukushima plant exploded, as predicted by the American Society of Mechanical Engineers.

Re:already done

[Mr D from 63]

On that last DG failure item, the point was that with multiple units right next to each other, each with multiple DGs, if the DGs for a unit failed, they could, in a reasonably short time, use supply from another unit's DG (that assumes the site was not destroyed by a tsunami, of course). You are correct, a source of power beyond the batteries is required to be available within a certain period of time. That period of time ranges from several hours to a few days, depending on the specific plant design.

Re:already done

[Mr D from 63]

Another key issue is not grouping all of the backup generators on the sea facing side of the reactor with an inadequate sea wall was a disaster waiting to happen.

Exactly my point, the plant should never have been placed where it could get hit by a tsunami, because it was not designed to withstand one. Had it been designed to withstand one, you would see a lot of differences, including layout of DGs and alternate sources above tsunami level. Improperly assessing the potential event was a failure of the regulator, and the constructor/owner as well.

Re:already done

[MrKaos]

Exactly my point, the plant should never have been placed where it could get hit by a tsunami, because it was not designed to withstand one.

I agree with the premise, though I'm not certain that is something you can do with any degree of certainty, certainly not in Japan where earthquake activity is more frequent. The driver of placing them is the availability of cooling water, so this generally means they will be located next to large bodies of water.

I'm satisfied with the approach of making sea walls, and the like, however the external risk we are talking about is if the operator actually complies with the rules, as is the case with Tepco.

Re:already done

[Boronx]

I get the attitude, but the nuclear engineers I work with were sure the thing was going to explode.

Re:already done

[multi io]

That was quite interesting, thank you.

Re:already done

[angel'o'sphere]

"so cosmic rays might even win from a danger perspective particle-by-particle"

That is what I pointed out: they kill most cells they "touch" right away. So for what they hit they are more dangerous, but for the whole body they are less dangerous as they don't "accumulate" in the body and don't continiously bombard the DNA.

A cosmic ray is like a bullet, it goes in and goes out ...

Regarding the rest, I'm not an expert regarding Sieverts ... most publications are in Becquerel anyway.

notably zero of which became a radioactive wasteland but they where for years ... seems you forgot that.

Why people ask for "Sources" when someone points out public knowledge is beyond me :D

Re:already done

[MrKaos]

If your definition of "reasonable" is "one millionth" you'd be right, but also perfectly unreasonable. There is such a thing as natural radioactivity, it is everywhere. And if you demand that "artificial" radiation must be less than 1/10.000th of natural radioactivity in the worst contaminated areas to be "reasonable", then you suffer from a gross form hubris. Your claims about Iodine-129 neglect to mention that is has 1/1.000.000.000th of the activity of I-131.

This statement is confusing. Regardless of the activity of the radioisotope, the issue is not radioactivity in the environment it is the release of radioisotopes *into* the environment. They didn't exist naturally, they are mutagenic to life and cause cancers to gestate when they are inside a living being.

This is further compounded by the fact that Iodine is highly mobile, most of all, it is water soluble. This means that it will be dispersed in the environment at a much greater rate than it will be concentrated in humans. In fact, it is not even detectable around Fukushima Daiichi.

That's not right. The water solubility and the fact that it is a micronutrient analogue will mean it actually concentrates in the foodchain. This is called bio-concentration because the radioisotope presents to a metabolism as something it can use. On uptake it is incorporated into the biological systems in the body and becomes organically bound. It's alpha, beta or gamma emissions are absorbed into the surrounding tissue and depending on the energetic levels of the radio isotope causes a cancer to gestate. In humans this process takes about 6 years.

You also neglect to say that the total radiotoxicity of all longlived fission isotopes is less than the radiotoxicity of the natural uranium before it went through the reactor. It is LESS than what was naturally there anyway. I know you don't care about such facts, lots of other people do.

Which longlived fission isotopes? pu-239 is a long lived fission isotope and it is highly toxic. It presents as an iron micronutrient so it also bioconcentrates readily, it's chloride is highly soluble and it's oxide is toxic when inhaled. Oppenheimer's research found it was toxic to humans in concentrations of 1-10 micrograms.

So yes, other people care about such facts. Can you clarify what you mean?

Your body is full of potassium-40, carbon-14, thorium, uranium and their decay products. If you're so scared of radioactivity that you must demand Cs-137 to decay to one-millionth of the current concentrations before you feel safe, then go commit suicide. There is no place in the solar system that will satisfy your demands. You, sir, are a lunatic.

That is not relevant. At issue is radioisotopes, not radiation and it is completely valid to try to prevent Nuclear Industry effluents into the environment because they are toxic and mutagenic. I'm not so afraid of radiation however I think it is completely sane and rational, to be concerned about radio isotopes acting as nutrient analogues in the foodchain as they a factor that affects human health.

At the same time, your original point re WASH-1400 is interesting. I'm not sure if it is one I've read and I commend you for highlighting it. So whilst I don't agree with what you have said here, on points of fact, I think the polarization of this debate has been destructive and hasn't really led to an increased level of understanding of the issues that matter.

Re:already done

[brambus]

That is what I pointed out: they kill most cells they "touch" right away.

That is not how radiotoxicity works. Quantum particles aren't really like bullets and targets (even though in the popular media it's often simplified to that). They don't "shoot the cell dead". Instead what happens is they transfer energy to the particles that make up the cells and do so rather sporadically (not every particle in the path gets this energy contribution and not always in equal proportions). This can lead to particles ejecting from their molecular structures and changing their chemical properties. In ~30% of the time we observe this radiotoxicity manifesting in mechanical damage to DNA and ~70% of the time the particles never hit the DNA itself, but instead cause the creation of OH- radicals in the water inside cells (by essentially ejecting one of the hydrogen atoms from an H2O molecule), which then increase the oxidative stress on the cells.

Now each of these interactions causes the high-energy particle to lose a bit of energy, but in most cases it doesn't stop right away. It keeps going, plowing through cell after cell until all of its energy is depleted or it comes out the other end. The distance it travels is described as the mean free path, which depends on a product of its energy and strength of interaction with surrounding atoms. Electrons interact a lot more than photons, hence why photons of the same energy can shoot straight through tissue without losing much energy and so causing much less harm, while an electron will deposit its energy much faster in a shorter distance. Now consider cosmic rays - they consist of mostly similar stuff (electrons, protons, gammas), but at much, much higher energies (on order of >1000x). Thus an electron from Cs-137 (~500 KeV) has the capability of breaking ~100000 covalent atomic bonds (~5 eV each). By comparison, a cosmic ray photon, even though it interacts 1000x less strongly, has >1000x the energy (1 GeV or more), so it acts mostly similarly, if not worse. And let's not get into cosmic ray electrons and protons, those are real beasts.

So I hope you see that it's not that easy.

[Cosmic rays] are less dangerous as they don't "accumulate" in the body and don't continiously bombard the DNA.

I think you misunderstand the difference between radiation and radioactivity. A radioactive nucleus doesn't "keep intoxicating you" by its mere presence. It's like a grenade, it goes "pop" once or twice, emitting one or two particles of radiation (which really aren't that distinct from cosmic rays - high-energy particles either way) and it's done - no more danger from that one guy. Meanwhile cosmic rays keep on coming non-stop at a more-or-less constant rate. You can imagine it like being surrounded by radioactive nuclei, day in, day out, with the notable distinction that these guys never stop giving off radiation. They keep going forever.

A cosmic ray is like a bullet, it goes in and goes out ...

And then the next one comes, and the next one, etc. forever. It never stops. Moreover the mean free path of 500 KeV electrons (most of the "dangerous" emissions from fission products) is a few milimeters at best. A cosmic ray, however, at >1 GeV (i.e. 2000x the energy of the electron) doesn't stop after a few milimeters, it keeps going, irradiating many more cells and potentially breaking many more bonds.

but they where for years ... seems you forgot that

They weren't, people lived there continuously since the dropping of the bombs until today. Yeah, lots of people got sick in the initial aftermath and some sizable portion died (though by far nowhere near the amount that died from the initial blast and searing heat), but that effect subsided rather quickly. While terrible, we mustn't forget that it was war back then and fire bombings of Tokyo killed comparable numbers of people to Hiroshima and Nagasa

Re:already done

[angel'o'sphere]

Perhaps you should try not to switch or twist always what I say.
We talked about cosmic rays. Cosmic rays come in 3 ways, X-Rays, gamma rays and heavy ions (basically the reason for the x-rays). Well, you mention protons, ofc those come as well :) light ions then, hehe.
I pointed out that they kill the cells more or less right away ... does not matter if it takes a few minutes due to OH- radicals or even hours or what ever. Point is: they don't really cause a genetic defect that is spread due to multiplication, in contrast to radioactive elements that get incorporated into the body and may damage surrounding cells DNA for/over a long time.
Cosmic rays basically work in the same way as a neutron bomb, or intensive gamma radiation, they just come in a much lower density.
Hence IMHO external radiation is not comparable with metabolized radioactive elements, even if the 'Sievert norming groups' try hard to find 'equivalent' formulas.

Re:already done

[brambus]

Perhaps you should try not to switch or twist always what I say.

Where did I do that?

I pointed out that they kill the cells more or less right away

Can you demonstrate that? Additional oxidative stress and/or DNA single and double strand breaks are not necessarily fatal - cells are capable of withstanding a certain amount of both.

Point is: they don't really cause a genetic defect that is spread due to multiplication, in contrast to radioactive elements that get incorporated into the body and may damage surrounding cells DNA for/over a long time.

And that's exactly where you are wrong. Cosmic rays can cause DNA defects and, as best as we know, can cause cancers (assuming LNT). It really doesn't matter if the source of a high-energy particle sits right next to the cell, or is billions of miles away. Also once a radioactive nucleus has decayed, it's done, no more danger from it for that particular cell, assuming there aren't many more nearby (this can happen with concentration, but not everything concentrates - that's what the tissue and radionuclide weighting factors in calculating risk values is used for). In short, from a biological perspective, the source of the high-energy particles is more or less irrelevant as to their effects on living cells. If you claim there to be a fundamental distinction, you must have access to information that the medical and health physics societies don't have and I'd appreciate if you could cite sources for your claims.

Hence IMHO

Again, your humble opinion doesn't equal research.

even if the 'Sievert norming groups' try hard to find 'equivalent' formulas.

I trust the experts in the field more than your unsubstantiated opinion. You can claim "common knowledge" all day long, but things asserted without evidence can be dismissed without evidence.

Re:already done

[angel'o'sphere]

You did again twist,what I said and you don't even realize it?
I did not say cosmic rays can't cause DNA defects, I said "usually" they kill the cell.
So bringing up 3 links confirming that they indeed can cause DNA defects is pointless.

Re:already done

[brambus]

I did not say cosmic rays can't cause DNA defects

And that's not what I claimed. Here, read again what I said:

Cosmic rays can cause DNA defects and, as best as we know, can cause cancers

Which was in response to your statement of:

Point is: they don't really cause a genetic defect that is spread due to multiplication

I challenged you to provide evidence of this, as I can't find any research supporting this in the scientific literature. You're essentially claiming that Linear Energy Transfer works in the opposite way that it does, depositing more energy per unit distance travelled as particle energy increases, which presumably should lead to more damage per unit of distance travelled and hence a higher proportion of cells killed right away. Unfortunately for you, however, LET works in the opposite way. LET quite neatly explains why cosmic rays have deeper penetration and irradiate more cells in their path. We're not coming at this blind, you know, we use this for targeting tumors during radiation therapy. However, this is just an argument from physical theories that, although they may work well in most areas of ionizing radiation, may for some inexplicable reason be inaccurate when applied to cosmic rays. The real meat is in the health effects studies and I've yet to see any epidemiological studies that can differentiate between the ionizing effects of cosmic rays vs. fission product radionuclides at similar dose levels and seeing as you don't seem to be able to produce any either, I'm going to have to dismiss your claim of a difference between them as pure unsubstantiated speculation.

Re:How would that be even helpful?

[Mr D from 63]

Earthquake probability and characterization is a 'continuously improving' science. Knowledge improvement is factored in by the regulator. Fortunately, plants are designed to withstand very large quakes with a large design margin added on top. In reality they will withstand quakes much larger than their stated design capacity.

Stylized

[mdsolar]

It really harms the credibility of the NRC when their risk calculation come to a accident every ten thousand years while the real world rate is one every 18 years. There are ten or more near misses each year http://www.ucsusa.org/news/pre... so nuclear plants are operating far outside the claimed safety envelope.

Re:Stylized

[khallow]

while the real world rate is one every 18 years

Over 400+ nuclear reactors in the world.

Re:Stylized

[mdsolar]

Accounted for that.

Re:Stylized

[khallow]

No, otherwise you wouldn't have written:

It really harms the credibility of the NRC when their risk calculation come to a accident every ten thousand years while the real world rate is one every 18 years.

Re:Stylized

[mdsolar]

What?

Re:Stylized

[Mr D from 63]

khallow, he just doesn't understand about application of statistical data, and repeats what he reads from nuclear FUD websites. You won't get a logical response to this obvious point.

Re:Stylized

[Anonymous Coward]

If the 1 in 10.000 years is per reactor, 18 years between accidents is "reasonable". With 400 reactors worldwide, that would mean approximately 25 years (~10000/400) between accidents.* Accounting for older designs, improving risk estimation, worse safety/quality standards in some parts of the world, etc. 18 years is close and not "far outside the claimed safety envelope".

Also, one "near miss" per year suggests luck, ten or more per year implies that there are enough safeties and checks in the systems to catch trouble before a catastrophe happens.

* I know this is not exact. It should be close enough. Fanatics can do the 1/(1 - ((10k-1)/10k)^400) stuff with a calculator.

Re:Stylized

[Mr D from 63]

Add that 'near miss' is not an official event defined event by the NRC , but rather that of the anti nuke group, so they decide what to call a near miss.

Re:Stylized

[JimSadler]

The contamination from a reactor spill might be so serious that one spill in ten thousand years might not be an acceptable risk. There is also a problem in that giving one nation the permission to build reactors really gives any regime the right to do the same. And we have no control over the safety or design standards applied in other nations. Nations like Iran and N. Korea act like mental patients who failed to take their meds. I'm not certain these nations should be allowed to chew gum much less have anything to do with nuclear power.

Re:Stylized

[mdsolar]

It is not per reactor, that is 1 in over in a million in the generic approach.

Re:Stylized

[dasunt]

Accounted for that.

Do you understand how this works?

18 * 400 = 7,200 reactor-years per accident.

Not too far away from the 10,000 figure.

Re:Stylized

[Rich0]

Nations like Iran and N. Korea act like mental patients who failed to take their meds. I'm not certain these nations should be allowed to chew gum much less have anything to do with nuclear power.

If my next door neighbor runs over a kid with their car because they don't look backwards when reversing, the solution isn't to remove the reverse gear from every car in the world.

You can't use the existence of N Korea as a rationale to constrain the behavior or legitimate governments.

Re:Stylized

[budgenator]

khallow, he just doesn't understand about application of statistical data, and repeats what he reads from nuclear FUD websites. You won't get a logical response to this obvious point.

I'm an astronomer who is also interested in music, especially sacred, and global warming. In astronomy, I've worked mainly on how intertellar dust can reveal the presence of super massive blackholes. ... For a number of years I've been involved in attempting to reverse global warming. I'm a member of the Green Party of the United States EcoAction committee and have helped to develop energy policy for the party. Very recently, I've gotten involved in a startup that plans to rent solar photovoltaic systems in the residential market. mdsolar (1045926)

Obviously he is more than capable of inderstanding the stats, whether he's willing to, due to conflicting vested interests and ideology is a different matter.

Re:Stylized

[khallow]

18 years*435 current reactors=7830 reactor years. Which is close to the claimed 10,000 reactor years of your original post.

Re:Stylized

[khallow]

So you're so concerned by my behavior that you post an unsubstantiated ad hominem attack anonymously? Do tell.

Re:Stylized

[khallow]

mdsolar stated that the NRC estimated the odds of a "nuclear accident" at 1 in 10,000 and then claimed that such accidents occurred at a frequency of 1 every 18 years. What I noted is that there are 435 reactors currently (according to Wikipedia) and that accident rate he claims corresponds to one such accident per 8,000 years of operation of the nuclear reactor. That is very much in line with the estimate.

This has nothing to do with "nuclear FUD websites". This is just rudimentary statistics.

Re:Stylized

[khallow]

Ok, where's the reference then?

I see when I googled, an estimate for "large" "loss of coolant accidents" around 5*10^-6 per year per plant. That sounds like your number. It's worth noting that the accident category in question hasn't happened yet since they're speaking of loss of coolant from pipe corrosion and mechanical failure in a plant with proper maintenance and the following of procedures, not the many other sorts of loss of coolant accidents that can happen to a nuclear plant (such as the real world examples caused by earthquakes, incompetence, and poor maintenance).

Re:Stylized

[Mr D from 63]

Thanks for the correction. I mis-read the statements and I was wrong on that one. I got thrown off by the sudden switch from a discussion of external events to this topic which really isn't external events. I admit when I am incorrect and appreciate your clarification.

Still, be careful with the terminology of 'accident' and 'near miss' and the statistics behind them, as they get applied and represented in a very inconsistent manner by the anti-nuke lobby.

Re:Stylized

[mdsolar]

Which is what makes it stylized and useless. Which is the point of the report.

Re:Stylized

[khallow]

mdsolar indicates that he is referring to some estimate rate of 1 such accident in several million. But that sounds like a theoretical rate for a limited class of failure modes under ideal maintenance and regulation conditions. Can't say any more about that until I find out what he's speaking of.

Re:Stylized

[MrKaos]

Still, be careful with the terminology of 'accident' and 'near miss' and the statistics behind them, as they get applied and represented in a very inconsistent manner by the anti-nuke lobby.

That is incorrect.

Specifically the term 'near miss' is referred to (in the report) when the NRC sends a special, augmented or incident investigation team, under the Reactor Oversight Process, to a reactor site because the risk of reactor core damage has exceeded a factor of 10. NRC classifies these as 'reactive inspections' as response to a Accident Sequence Precursor.

Accidents come under a different class which results in a formal written report (called a Licensee Event Report) to the NRC because a failed or degraded component caused a change in the operational characteristics of the reactor.

So the statistics are not inconsistent, nor are they misrepresented by calling them a 'near miss' or 'accident' any more than it is calling a 'spade' a 'Soil Moving Device' under the ROP.

Re:Stylized

[MrKaos]

But that sounds like a theoretical rate for a limited class of failure modes under ideal maintenance and regulation conditions. Can't say any more about that until I find out what he's speaking of.

The report in question actually refers to (something we've previously discussed) the metrics used to report on reactors by the NRC, specifically accident sequence precursors and licensee event reports. They are actual events that generated a reactive inspection by the NRC or a formal report to the NRC under the Reactor Oversight Process because the risk of damage to the reactor core exceeded a factor of 10, or there was an accident.

These are the metrics used by the NRC so they're not theoretical or limited failure modes, they are actual failures caused by an incident that could damage the core of the reactor.

Re:Stylized

[khallow]

The metrics don't include failures so infrequent that they aren't expected to happen in our lifetimes. That sort of infrequent failure was precisely what I was speaking of.

I think the thing that bugs me here, as usual with this topic is the adversarial and somewhat ignorant nature of the debate. The original research that mdsolar spoke of, may well be accurate. But I don't see his condemnation of that research (as undermining the credibility of the Nuclear Regulatory Commission) based on the actual content. That's more a problem with mdsolar's point of view than with the NRC.

As to your current arguments, I find them a lot better quality.

Re:Stylized

[MrKaos]

The metrics don't include failures so infrequent that they aren't expected to happen in our lifetimes. That sort of infrequent failure was precisely what I was speaking of.

That is because there are two things being discussed here. Metrics vs Modeling via Calculated Core Damage. The CCD places probability of failure on every piece of equipment and component of the installation to determine reliability.

The original research that mdsolar spoke of, may well be accurate. But I don't see his condemnation of that research (as undermining the credibility of the Nuclear Regulatory Commission) based on the actual content. That's more a problem with mdsolar's point of view than with the NRC.

This report refers to such content. I surmise that mdsolar's criticizm, and indeed the report's is valid. CCD has to be "a theoretical rate for a limited class of failure modes under ideal maintenance and regulation conditions" because it isn't real life that includes human related external factors. Indeed stylized in the very way you referred.

Further, the measure of 1 reactor accident per 10,000 years of reactor operation refers to a reactor *design* and Calculated Core Damage is not an industry or world wide measure of all reactors - just a coincidence. As each reactor is different it requires a completely new CCD for each reactor. Europeans use a Probabilistic Safety Analysis to determine possibility of core damage and the English use Failure Mode Effect Analysis.

At issue is human factors, that led to Chernobyl, TMI, FUkushima, that are not modeled and have meant 3 accidents in 14,500 years of civil reactor operation. The point here is that it's valid to critique the NRC's modelling when its metrics show a contradiction. I don't see this as undermining the process of approving reactor designs, but strengthening it because it standardizes human factors into the certification processes.

The concerning issue is that the NRC's own metrics show an increase in the frequency of 'reactive inspections' - these are the real numbers. CCD, PSA and FMEA only apply to the machine as a certification mechanism. Calculating human factors is a complex endeavor.

As to your current arguments, I find them a lot better quality.

Thank you, however I have always pointed to fact in our interactions, why are these any different?

Re:How would that be even helpful?

[mdsolar]

Not so for Humboldt Bay Reactor.

Asleep

[mdsolar]

An NRC inspector had a very hard time waking a guard up at Indian Point a few years back.

Re:How would that be even helpful?

[Mr D from 63]

Care to elaborate on how a small, long shuttered plant from the early 60s relates here, or are you just randomly copying stuff from your goggle search results trying to look like you have a point?

Re:How would that be even helpful?

[mdsolar]

It was shuttered because it was not built to withstand the earthquake risk. The margin was not there.

Re:How would that be even helpful?

[Mr D from 63]

Well, there you go, plants that are not designed to withstand an earthquake that is considered to be possible in an area are not allowed to operate. HB could not prove its safety case based on this EXTERNAL EVENT, and was shut down, many years ago.

Re:How would that be even helpful?

[mdsolar]

So, your claim that the margin is already there is false.

Re:How would that be even helpful?

[Mr D from 63]

Well, If we are talking about shuttered plants that are not operating, with no fuel, then they have plenty of margin, believe me. Anyone reading this thread to this point will clearly see how ridiculous your contention is, so I don't need to continue, but for your own edification, if HB were operating and were hit with a large quake, it would still likely withstand it due to the margin.

Most accident scenarios ...

[Ihlosi]

... unfortunately only regard one major failure (e.g. main coolant feeding line failure), with other failures (e.g. one emergency generator fails) covered by redundancies.

This might work for technical breakdowns, but not for external events. ("All coolant pumps and emergency generators fail - because the whole power plant compound is under three meters of water.").

Re:Most accident scenarios ...

[Fierlo]

There are probabilistic models that NPPs use to account for random failures, and human interactions (e.g., valve left in wrong position after test and undetected).

The issue that the OP is referring to is that most stations only use the internal events model which has an initiating event that starts with a NPP system failure (e.g., coolant line failure), instead of the external events models. They are called external, but includes fire, flood, seismic and high wind events.

Re:Most accident scenarios ...

[tp1024]

Read the NUREG-1150 or whatever more recent document (this one is from 1990 or so). You'll find that your claim is outdated by about half a century.

Re:How would that be even helpful?

[brambus]

Japan is a bunch of islands for crying out loud.

While true, it is quite an oversimplification. Japan is very mountainous even near the shores, in some places, and it would not have been impossible to place the plant a little further "uphill" to prevent this from happening. There are several reason they placed it right on the shore, one of them being construction purposes. LWRs consist of some very heavy single-piece components and it's much easier to ship them in via boat than it is to transport them over the road. In addition, you have a readily available source of large amounts of cooling water in the world's largest heatsink.

However, had TEPCO not been a bunch of colossal asshats and not skimped on the construction and piping costs, they could have just as easily placed the thing a few miles inland and at higher elevation and none of this would have happened. In fact, if Japan ever decides to build liquid-metal cooled fast breeder reactors, it is absolutely imperative they place it somewhere it can't ever get flooded. If OTOH they decide to go with molten-salt reactors (and they should!), they could place them pretty much where ever they want, because fluoride salts don't react with water, aren't water-soluble, don't operate under high pressure and their large liquid range allows for high temperature of operation, which in turn means that passive air cooling in the event of a plant blackout is far easier to do.

I think the key word is "focus"

[REden]

The headline says "focus". I take that to mean a lot of time has been spent on internal failures and external ones just need more study. That's not unreasonable. When I worked at one, I could imagine a movie plot military attack easily getting through security. I suspect that's the sort of thing they need to give more thought to.

Congress acts == too late

[raymorris]

> It hardly seems late if it is a report requested by congress

It's been said that one sure sign that an event is over is when Congress finally gets around to doing something about it.

eight days. Gunpowder dangerous, candles are not

[raymorris]

Iodine is most dangerous because it releases all of it's radiation quickly. With a half-Life of just eight days, it releases enough energy, quickly enough, to do real harm. After a few weeks, the radiation is pretty much gone. You can visualize that as being like gunpowder, it releases its energy quickly, and that's dangerous.

Other substances release energy very slowly, over the course of hundreds of years. That's like the heat energy released from from iron rusting - it takes a long time to release the energy, so it would take a LONG time to be affected by it. You wouldn't want to keep a piece of plutonium in your pocket for 800 years, because after 200 years or so you might start to notice some affects. Except of course you'll die of other causes in about 50 years, so you'd never notice any affects from plutonium.

Iodine and other isotopes with a short half-life ARE dangerous for a little while, until they "burn up".

Carbon dating is amazing. Look it up.

[raymorris]

Carbon dating is a very interesting technique. I think you'll be amazed at how it works. Or, you'll deny the existence of carbon dating in order to preserve your misconceptions.

Re:Carbon dating is amazing. Look it up.

[angel'o'sphere]

What has carbon dating to do with backround radiation?
Obviously nothing ... your comment is pointless.

stupid design

[slashmydots]

Internal, external, magical wizard attacks and gypsy curses, who cares? What they need is a generally less stupid design. 3 backup cooling systems or whatever is completely wrong regardless. Design it so that if nothing were to occur, as in all humans left and everything turned off, it won't melt down. Anything short of that will melt down eventually. At least nuclear fusion will spin itself down on its own. They really need to up the funding for that. It's virtually unlimited free energy. Add electric cars and boats and planes and the world has clean energy forever.

if you looked it up, you'd know

[raymorris]

> What has carbon dating to do with backround radiation?

If you looked up how carbon dating works, you'd know the answer to that.

Re:if you looked it up, you'd know

[angel'o'sphere]

I know how carbon dating works.
And rest asured the carnon dating of animals living around Fukushima womt be affected by the desaster.
In 10,000 years their remains look exactly the same regardless if the disaster had happend or not.

Hence: the one who knows nothing about carbon dating obviously is YOU.

Re:How would that be even helpful?

[AHuxley]

Re "plant from the early 60s relates here"
Plants often come form nuclear reactor designs and prototypes from the 1950's and 1960's.
We are now seeing the results of a very old sector trying to rebuild itself with new parts. Replacement steam generator plugging (failed pressure test and needed to be plugged). We have seen issues with air tightness of the reactor containments, issues in the re circulation pipe systems, cracks in the core shroud.
Then you have the complex costs of cleaning out a boiling water reactor and a pressurized water reactor ie radioactive steam moves via the entire plant system, tritium leaks, spent fuel storage costs vs limited decommissioning funds. Moving to dry storage and then moving all the regular waste from decommissioning and dismantlement (disposal license). The old plants waste size adds up and all you have a few Class A waste sites? Class B and C waste with more long-lived and short-lived radionuclides can just wait? Weld anomalies, through wall corrosion, corrosion of steel containments, walls of steel containments below the minimum design thickness. The old plants have containment degradation, metal pressure boundary corrosion incidents. Add in the fun of uprated license extensions to 2040+ with a power increase (Stretched Power Uprate).

Re:How would that be even helpful?

[MrKaos]

Well, If we are talking about shuttered plants that are not operating, with no fuel, then they have plenty of margin, believe me. Anyone reading this thread to this point will clearly see how ridiculous your contention is, so I don't need to continue, but for your own edification, if HB were operating and were hit with a large quake, it would still likely withstand it due to the margin.

Wow, you just can't concede that you are wrong. Plus all of your posts are upmodded so I wonder if you are using a sock-puppet

Re:How would that be even helpful?

[Mr D from 63]

typical response for those that can't make a valid point.

Re:How would that be even helpful?

[MrKaos]

typical response for those that can't make a valid point.

Typical response for those who can't understand a valid point.