Why I am not worried about Japan’s nuclear reactors.

morgsatlarge.wordpress.com ^ | 12 March, 2011 | Dr Josef Oehmen

[Errant]

I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.

There was and will *not* be any significant release of radioactivity.

By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.

I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.

We will have to cover some fundamentals, before we get into what is going on.

[Errant]

I find the term destroyed a bit over the top and hard to believe.

I agree. It may be that the wave of water contaminated the fuel, lubricating oils or damaged supporting systems like cooling, supply lines, controls and etc.

If the engines were running at the time, they may have been damaged beyond repair. Certainly they must be in pretty bad shape, since they've not gotten them back into service by now.

Maybe at this site, they're located outside the buildings?

[Errant]

I just think it’s a good idea to be prepared.

Damn Right!

There seemed to be alot of outright mocking of people who simply had legitimate questions, and I don’t think that is very much in the spirit of FReepers helping FReepers.

Double Damn Right!!!

[sefarkas]

worst case

and why not try to get at least one of the other plants online to provide power to the others

Worst case: core is fused and will be difficult to remove from the reactor. Unit 1 was scheduled for permanent shutdown this month, March 2011. The decommissioning will be much more expensive than they planned.

It is simpler to reconnect the plant site to the off-site power source. Off-site power is inherently reliable because there are multiple generators that feed it. Running one plant to provide AC for the other is possible, but more trouble than re-connecting to the grid. The pictures of the environs leads to people using the word "destroyed" which is unlikely in the context of the grid-equipment. Cables need to be reattached. Breakers need to be reset. Transformers need to be energized. It is a bit more complicated than putting a neighboorhood back on-line after a storm. Note that TEPCO reported off-site power being restored to the site.

[theBuckwheat]

This points out the foolishness of having reactors that are inherently unstable when stable ones are available.

[bvw]

EXCELLENT article! Great work.

[Errant]

Worst case: core is fused and will be difficult to remove from the reactor.

So you don't see a possibility of a molten core melting through the containment vessel?

Makes sense on using offsite power as you say, if available, instead of trying to get one of the other units online.

[SteamShovel]

Sounds like this person knows just enough to be dangerous.

I'd be more worried if he were in control. But what difference does it make if he voices his opinion even if not entirely accurate.

There are big mouth pieces going around trying to stir up fear and panic. At least someone is trying to put some calm into the equation.

[djf]

Sounds like they will have alot of work to do for all those fake stewardess robots they keep coming up with!

[St_Thomas_Aquinas]

There was and will *not* be any significant release of radioactivity. By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight

Run for your lives! It's the end of the world!!!

The interesting question at this point is What will be the legacy of the media-generated disaster hysteria? Will the public reject it? Or will the nuclear power industry be set back another 25 years.

I'm hoping that people don't buy the hype, but when it comes to nuclear power, emotion usually overides intellect.

[Jusu]

He does sound like what he’s doing. And I’m not a physicist or a nuclear engineer, but when I see the ‘experts’ going on and on in the news sources, I have to take it with a grain of salt. To hyper-inflate and cast doom and gloom and advance the anti-nuclear agenda is to discredit your own credibility.

I hope we see actual people who can calmly explain like what this guy did instead of picking choice bits for a 1 minute interview.

[sefarkas]

possibility of a molten core melting through the containment vessel

What is possible is different than what is likely. What some are hypothesizing requires a complete melt of the core into one lump -- this is possible but unlikely given the shape of the various structures inside a BWR reactor vessel. Then, #2, the heat from the corium would have to work its way into a thick reactor vessel wall made of steel. Then, #3, instead of just deforming, a hole would actually have to form in the reactor vessel. Then, #4, the whole corium mess would have to get out of the hole and once again collect all in one place. Then, #5, the corium would have to work its way through the steel plate that is the drywell. Unlike the reactor vessel, there is rebarred concrete behind the steel plate -- so the steel plate could not deform/bubble out. Then, #5, these previous steps would have to happen before the fission products decayed away (removing the heat source). All items above are unlikely if at any time there is a pool of water above the corium. The probability of running out of sea water is pretty close to zero.

[Errant]

At least someone is trying to put some calm into the equation.

I'm shocked by the lack of credible information available on outcome of a total reactor core meltdown.

I don't know if its because no one knows, if the information is just not getting out, or no one wants to believe the assurances of the engineers and scientists that built these things. One would think, after all these years, that the human race would build these power plants in such a way that massive contamination would be physically impossible. But perhaps economics outweighs safety of design.

[texmexis best]

btt

[Mariner]

Problem is, he doesn't know the model of reactor in question.

The GE BWR-1 at Fukashima does not have a 3rd containment vessel like we had at TMI.

[SteamShovel]

no one wants to believe the assurances of the engineers and scientists that built these things

The reason is just as you said it. Irrational fear, phobia. No amount of reason can overcome it. Even if the worst happens, it isn't the end of the world. Atmospheric nuclear weapons testing didn't end the world. Besides, this is also a very very rare event.

It is physically impossible to make something 100% safe as everyone would like. There is always something else that could go wrong that isn't in the design. It's not so much economics as it is practicality that stops the design and begins the building.

Every now and then something entirely unprecedetented comes along, as this event has done, that will give us more information to put into the future designs and retrofit older designs where feasible. The future for nuclear power will be safer still.

Now is not the time to run away from nuclear power, there is too much energy available to ignore it. I'll take nuclear power over middle east thug oil any day.

[Errant]

Thanks, that's probably the best hypothesis I've seen concerning what's possible and what's likely.

In discussing additional possibilities, wouldn't the high heat of molten fuel rods vaporize any cooling water after some critical point.

Which brings to mind; why not build smaller reactor cores and containment vessels capable of handling complete meltdowns without the dependency on cooling?

[skeptoid]

Pah-ding

[Errant]

The GE BWR-1 at Fukashima does not have a 3rd containment vessel like we had at TMI.

I caught that from the diagrams shown.

Thanks,

[sefarkas]

wouldn't the high heat of molten fuel rods vaporize any cooling water after some critical point.

Imagine pouring the whole ocean on it. If you put enough liquid water on the corium, the liquid water will remain.

Which brings to mind; why not build smaller reactor cores and containment vessels capable of handling complete meltdowns

Read up on pebble-bed reactors -- they have beat you to it. What do you propose that we do with the several hundred light-water reactors we already have?

[sefarkas]

GE BWR-1 at Fukashima

BWRs come in flavors from BWR-2 (Nine Mile, Oyster Creek) to BWR-6 like Grand Gulf. Those BWR models are housed in containments that come in three flavors, Mark I (like Fukushima Daiichi No. 1), Mark II (like Limerick), and Mark III (like Grand Gulf). Containment is achieved via the fuel rods, the reactor vessel, and the containment vessel. The term "3rd containment" is not used in the industry.