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The Fukushima accident was preventable

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Re: The Fukushima accident was preventable

#71

Post by pdkl95 »

Karunamon wrote: post #49
Avshalom wrote: post #45

Earlier quoted context omitted.

Yeah... the number of those deaths is estimated at somewhere between 0 and 100. Which is to say such a tiny number that it won't be empirically distinguishable from normal fluctuations.

I said diseases , not deaths. Cancer isn't always fatal, but they impact the quality of life for the sufferers as well as putting an economic burden on the healthcare system.

Ok. That's still only a handful of people in the worst cases.

Now what is the cost to the healthcare system of the coal power generation that replaced the nuclear power stations that were shutdown after the tsunami?

Re: The Fukushima accident was preventable

#72

Post by pdkl95 »

api wrote: post #66
bsder wrote: post #22

Of course it was, as were things like the explosions afterward. However, management always gets in the way--either up front, because there is profit pressure, or on the backend, because there is profit and/or political pressure. This paper covers the up front failures. However, backend failures, like spraying water on the core ( NOT one of the established procedures because calm engineers knew that the reactor could…

(9) solar+wind+storage is orders of magnitude simpler, can be incrementally financed, and is nearly on parity in many markets. The middle point -- ability to be incrementally financed -- cannot be overstated.

Where, exactly, are we storing power in the TWh-scale? The terrible availability[1] of wind and solar is going to require a heroic amount of storage, which isn't going to be "simple". It will probably have serious environmental impact as well.

[1] https://en.wikipedia.org/wiki/Capacity_factor#Real_world_cap...

Re: The Fukushima accident was preventable

#73

Post by guscost »

bsder wrote: post #54
Someone1234 wrote: post #48

Earlier quoted context omitted.

> However, backend failures, like spraying water on the core (NOT one of the established procedures because calm engineers knew that the reactor could dissociate the hydrogen and oxygen) I cannot find any other information on this claim and I just read the main Wikipedia article, this article, and the Wikipedia timeline. Didn't the hydrogen explosions start before they started spraying the reactor/building with fire…

It seems I stand corrected. It looks like the hydrogen was a result of the dissociation of the zircalloy.

According to a chart in this press release[0], fresh water was being pumped through Unit 1 for ~10 hours prior to the first explosion, during which time none of the "active fuel" was submerged. I'm not a professional but it seems like a lot of that water would have evaporated and could have been oxidizing the cladding the whole time, if it was hot enough. I wouldn't discount the rest of your theory too quickly.

[0]http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/im...

Re: The Fukushima accident was preventable

#74

Post by dalke »

thaumasiotes wrote: post #58
mikeyouse wrote: post #51

Earlier quoted context omitted.

> As nuclear "disasters" go, I honestly don't even think Fukushima should be among them. Considering what COULD have happened, very little actually happened. There are hundreds of square miles still in the exclusion zone and some 80,000 people haven't been able to return to their homes.. I'd say a nuclear meltdown that displaces tens of thousands of people and costs several hundred billion dollars to clean up qualifi…

Eh. A traditional disaster kills people.

Eh?

I don't think "a traditional disaster" means what you think it means.

The Cerro Grande Fire destroyed about 420 homes and caused ~$1 billion in damages but no one died. The Bel Air Fire destroyed 484 homes but again left no fatalities. Tropical Storm Fay hit Texas and nine counties in Texas were declared disaster areas, but again, no fatalities.

Re: The Fukushima accident was preventable

#75

Post by nickff »

PaulHoule wrote: post #68
nickff wrote: post #21

Earlier quoted context omitted.

I have read that many times, and it makes some sense. The issue with this line of reasoning is that the move would be a design change which is not required by the specification (as I have read and understood it), which would have been seen as unnecessary waste at the time. A study which I would find more important and useful than the one here would be a cost/benefit analysis of increasing all specifications relating…

When you consider that a nuclear plant costs billions of USD and that billions of USD of damage has been done, the $500,000 upgrade to the generators is a slam dunk. Also based on recent projections, the probability of a tsunami event of that severity was 80% for the next few decades, so it is a no brainer -- particularly when you consider that the nuclear industry worldwide has been set back 20 or 40 years at least…

You are still falling into the same trap.

cost of preventing low probability events in the future >> cost of preventing events in hindsight

The problem is that you do not know which events will occur, so you will inevitably spend not only on implementing that $300000 upgrade on one plant which will need it, but on many $500000 upgrades on many plants (most of which will never be necessary or related to tsunamis). The cost/benefit ratio of preventing low probability events in the future should be studied, and only after looking at such studies can we decide whether any one change should be made. For example, the US government rejects any highway improvement which costs more than $3MM per life saved, as there are many lower-cost measures that save lives, and spending on less cost-effective measures is "statistical murder".

Re: The Fukushima accident was preventable

#76

Post by guscost »

jakeogh wrote: post #46
bsder wrote: post #22

Of course it was, as were things like the explosions afterward. However, management always gets in the way--either up front, because there is profit pressure, or on the backend, because there is profit and/or political pressure. This paper covers the up front failures. However, backend failures, like spraying water on the core ( NOT one of the established procedures because calm engineers knew that the reactor could…

"sat on their hands, done nothing" That's how it should be, but in this case not doing anything was not an option. The passive (gravity fed) cooling system on the first reactor to melt had it's valve's almost closed when they lost power. Seems like a bad design to even have valves on it but I'm not a Nuclear Engineer. And people at Daini were able to prevent meltdowns by hand-laying miles of high current cable. Reaso…

This is repeating points from other replies, but it has to be said again that much of the passive-safe design in a BWR/PWR has to do with the fact that it will melt down (rather than go prompt-critical and explode) even when every cooling system fails, since the coolant itself is what allows the reaction to continue.

Re: The Fukushima accident was preventable

#77

Post by btilly »

logicallee wrote: post #43
makomk wrote: post #39

Earlier quoted context omitted.

Engineers at TEPCO did tell them what they were doing wrong at Fukushima Daiichi. They were ignored: "In 2008, TEPCO did two sets of calculations, one based on the Headquarters for Earthquake Research Promotion (HERP) fault models which suggested tsunami height estimates of 8.4–10.2 m relative to the reference sea level. Another one based on Satake et al. [47] produced 8.7–9.2 m tsunami height estimates which were al…

if our title read "Nuclear power plants are still being run recklessly, and the next Fukushima-like accident is likely 100% preventable today" it would get my attention, and I would read what the claims that we need to be doing are. small statistical disagreements about experts on the other hand, are hard to take as seriously.

The thing is that those are not small statistical disagreements.

The maximum tsunami+tide they designed for was 5m. Design parameters said that you should have a wall 2x what you think you need so they built a 10m (about 30 foot) wall.

Two independent teams came up with realistic tsunamis near that 10m wall (one over and one under), so they should have changed their wall requirement up substantially. But they argued themselves into believing that 6m was a realistic maximum then did nothing.

Their estimates were also out of line with actual tsunamis experienced elsewhere. Tsunamis in recent decades from earthquakes similar to the ones that they knew could hit the area have ranged from 3-30m. Even a 7.0 earthquake managed to create a 12m tsunami in New Guinea.

The actual tsunami was 13m.

The most telling point is how the response afterwards has shown lessons not learned. For example The United States National Research Council of the National Academies had a 21 person panel conduct 18 months of interviews with a wide variety of technical experts on how the disaster could be prevented here. NOT ONE of the members of the panel or the people interviewed was an expert on tsunamis. The author's of the paper clearly believe that if you're studying the aftermath of a tsunami, you should at least talk to someone who studies tsunamis...

If the paper is correct, it is a question of time until somewhere in the world we have another entirely preventable major disaster because local officials underestimate tsunami threats that current knowledge is more than sufficient to predict. Of course enough things can go wrong that the next big disaster won't be that. But that preventable disaster is coming...

Re: The Fukushima accident was preventable

#78

Post by walshemj »

WalterBright wrote: post #12
Johnny555 wrote: post #7

Isn't every accident preventable in hindsight since you know exactly what the failure mode was? If they'd built the generators on a hillside that was washed away in a mudslide the article would read "Critical backup generators were built on unstable hillside despite warnings from scientists".

The idea with building safe systems is not to imagine what could cause subsystem X to fail, but to figure out how to cope when subsystem X fails. The most obvious design failure at Fukushima was not "how big a tsunami we should protect against" but not asking "how will we cope when the seawall fails". If the critical backup generators had been in a bunker designed to protect them from a seawall breach, the disaster w…

Or have plans to have backup power airlifted into place.

Re: The Fukushima accident was preventable

#79

Post by [deleted] »

dredmorbius wrote: post #62
maxerickson wrote: post #33

Earlier quoted context omitted.

Those quote marks are in the report to indicate sarcasm.

Useage elsewhere doesn't support your comment. E.g., in the introduction: Interestingly, while the Onagawa NPP was also hit by a tsunami of approximately the same height as Dai-ichi, it survived the event ‘remarkably undamaged’.

[deleted]

Re: The Fukushima accident was preventable

#80

Post by paulmd »

guscost wrote: post #73
bsder wrote: post #54

Earlier quoted context omitted.

It seems I stand corrected. It looks like the hydrogen was a result of the dissociation of the zircalloy.

According to a chart in this press release[0], fresh water was being pumped through Unit 1 for ~10 hours prior to the first explosion, during which time none of the "active fuel" was submerged. I'm not a professional but it seems like a lot of that water would have evaporated and could have been oxidizing the cladding the whole time, if it was hot enough. I wouldn't discount the rest of your theory too quickly. [0] h…

Not that Zircalloy won't dissociate, but you're correct, don't discount the water either.

At one point during the Windscale fire they tried to pump down liquid CO2, but the reactor face was so hot it was ripping the O2 off the molecule. They next tried to pump down water - there was a very real risk that it would rip the water apart as well, feeding the fire and potentially forming a hydrogen bubble and exploding. However they were able to deliver it in greater quantity than the CO2, and succeeded in cooling the fire.

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