Japan's nuclear crisis and Chernobyl: key differences

[Rhiannon12866]

Japan's nuclear crisis is spawning concerns about 'another Chernobyl,' but a number of American and European scientists are cautiously taking the edge off the worst fears.

<snip>

Key differences
The Chernobyl Soviet RBMK-1000 reactor exploded on April 26, 1986 after inexperienced handlers took the power down and then tried to power it up too quickly in an effort to discover whether a 40-second power gap in the cooling system could be bridged.

The Chernobyl reactor was new, it was undergoing tests, and it had very little structural containment measures to ward off a meltdown.

The Japanese reactors are a completely different design known as Boiling Water Reactors, which are old and tested, and have three quite elaborate systems of containment designed to constrain radioactive leakage, points out Josef Oehmen, a research scientist at the Massachusetts Institute of Technology (MIT) in Cambridge, Mass. “The third containment is designed, built, and tested for one single purpose: To contain, indefinitely, a complete core meltdown,” he writes.

More:
http://www.csmonitor.com/World/Global-News/2011/0313/Japan-s-nuclear-crisis-and-Chernobyl-key-differences

[SidDithers]

1. K&R. Facts are good...nt

Sid

[Rhiannon12866]

7. Thanks.

I was obviously concerned, so I looked it up and found this, agree that it's always less frightening to have the facts in the case. I've never been a huge fan of nuclear power, but I admit to having a bias, since I was in Russia the year that Chernobyl happened, and I was scared witless, even though we intentionally gave that area a very wide berth. :scared:

[meow mix]

2. another thing to conveniently leave out... japan has how many reactors melting down?

ive lost count myself. wtf people?

[Paradoxical]

4. Have you stopped for even a second to consider the possibility that you are wrong?

Wrong in your total damnation of nuclear power. Wrong in your "anger" towards anyone who supports nuclear power?

[kristopher]

34. How about you? The science says we DO NOT NEED NUCLEAR ENERGY

Renewable energy resources extracted with *existing technologies* are more than sufficient to meet all of modern societies energy needs.

The renewable path is less expensive.

The renewable energy path is completely sustainable.

The renewable path is safer in all ways.

The renewable path is faster to achieve.

And last but not least in the long run widescale reliance on nuclear power and its controling infrastructure "would" to quote an associate, "provide an irrevocable justification and impetus for the burgeoning surveillance/police state".

Those are ALL irrefutably true statements.

In light of that why do YOU support nuclear power?

[Sirveri]

10. doesn't matter if they don't release to the surrounding environs. n/t

[LAGC]

3. Finally some sanity injected into these debates.

So much fear-mongering in the other threads, its unbelievable...

I trust the people in the know to have a handle on what's going on.

[bbinacan]

5. Thanks for the info. n/t

[NutmegYankee]

6. While I support nuclear power - there is a reason all new designs are PWR

The boiling water reactor designs are inherently more risky and dangerous. Even GE eventually stopped making the Mark I design.

[Sirveri]

11. I always heard BWR was safer...

Operate further from thermal limits, and at a lower pressure (easier force feed injection).

[NutmegYankee]

16. The lower pressure makes things easier

But having a vessel completely filled with water makes it easier to prevent core damage. Boiling water designs always risk boiling the water off and exposing the core. The newest PWR designs, like the AP1000 are designed to keep water flowing by convection in the event of a pump failure.


This debate however has been going on for decades among engineers. Obviously I'm a PWR guy.

[Statistical]

31. Not exactly true. Older BWR are riskier (and this is a vary old design)

However newer designs are much safer.

For example the ABWR is fully passively safe. It can cool the reactor without any pumps or electricity. The ECCS contain 3 days worth of gravity fed coolant. It will operate without any human interaction in the event of a core overheat. As long as ECS water supply can be restored within 3 days the ECS can passive cool the reactor indefinitely.

The NRC rates the core damage frequency on the ABWR at significantly less than the most advanced PWR the AP1000.

Personally I favor PWR. They have many advantages and we have more experience with them but BWR can be done safely.

[denem]

8. Chernobyl was new. Fukushima is old.

(Fuck You Shima - I wish I had never heard the word, can't get the analogue out of my head)

The third containment is designed, built, and tested for one single purpose: To contain, indefinitely, a complete core meltdown

Indeed, if you say so.

The Third Steel Containment is 40 years old.

That Third Steel Containment that has had 40 years of high intensity neutrons to deal with.

Steel that has become a little brittle.

Not a problem, the temperature and pressure characteristics are much the same.

Not that much to worry about unless,maybe, if a huge jolt

produces a tiny crack.

[Sirveri]

12. neutron embrittlement affects the pressure vessel, not the third containment.

Any neutron escaping the pressure vessel and primary shield would be fully thermal.

[denem]

14. OK. I'm mixed up here.

The third containment vessel is steel. Yes? What happens over a 40 year operational period?

[Sirveri]

17. not neutron embrittlement, since there aren't any fast neutrons at the point.

Could have corrosion issues though. I think there is also concrete involved. My main experience was with the navy, so for us it would be steel, lead, and boropoly, but in this case it's probably a combination of steel, plastic, and concrete.

[Junkdrawer]

15. The pressure vessel in Unit 3 seems to be leaking....

Authorities were able to inject cooling water with a fire pump after reducing the containment pressure by a controlled venting of radioactive gas. As with Unit 1, they began pumping seawater into Unit 3. Seawater is highly corrosive and probably precludes any future use of the reactor, even if a crisis is averted.

However, Tokyo Electric recently reported that the water level in the Unit 3 reactor still remains more than 2 meters (6 feet) below the top of the fuel and company officials believe that water may be leaking from the reactor vessel. When the fuel is uncovered by water, it overheats and suffers damage. It is likely that the fuel has experienced significant damage at this point, and Japanese authorities have said they are proceeding on this assumption.


....

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=439x635409

So the neutron embrittlement concerns may be very real....

[Sirveri]

18. that's what I said... neutron embrittlement affects the pressure vessel

it could be a combination of things, that, sea water injection corrosive effects, thermal shock. That's what the containment building is for.

[Bonobo]

25. Do you have personal information about how the reaction chamber vessels are newly

electroplated every year?

I do.

I interpreted recently for a texas company that was working with Mitsubishi Heavy as part of electroplating of the insides of the nuclear chambers.

It is careful work and those things are made perfect regularly.

It's NOT like a 40 year old car or trailer, you know.

[Junkdrawer]

9. Re: "To contain, indefinitely, a complete core meltdown"...From the Union of Concerned Scientists:

...

While the authorities continue playing down the possibility of a breach of the primary containment at these reactors, I remain concerned. Fukushima Dai-Ichi reactor Units 1, 2, and 3 are boiling water reactors with Mark I containments. The Mark I is unusually vulnerable to containment failure in the event of a core-melt accident. A recent study by Sandia National Laboratories shows that the likelihood of containment failure in this case is nearly 42% (see Table 4-7 on page 97). The most likely failure scenario involves the molten fuel burning through the reactor vessel, spilling onto the containment floor, and spreading until it contacts and breeches the steel containment-vessel wall.

The Sandia report characterizes these probabilities as “quite high.” It’s not straightforward to interpret these results in the context of the very complicated and uncertain situation at Fukushima. But they are a clear indication of a worrisome vulnerability of the Mark I containment should the core completely melt and escape the reactor vessel.


...

http://allthingsnuclear.org/tagged/Japan_nuclear?utm_source=SP&utm_medium=head&utm_campaign=sp-nuke-head-3%2F13%2F2011-pm

[JCMach1]

22. +1, The Containment is vulnerable 42% of the time

Those odds are not too good.

[Chris_Texas]

13. Facts suck! Fear is way cooler!

[Overseas]

19. Watching TV in Japanese today

it has been really gratifying to see the TV stations completely turned over to the public interest. And I really appreciated the value of a solid science education as a national priority. Technical details could be given without dolling them up, and details about revised train schedules and rolling power outages were conveyed very efficiently.

During what would have been the wee hours in Japan, the TV was running lots of repetitions of the revised train schedules and electricity rationing schedules. I went out to do some chores while that was on, thinking it rather boring. But upon reflection, it was wonderful of their TV to do that. When a nervous populace is trying to sleep, they broadcast the dry news that the train schedule has been rearranged as follows, and power rationing plans had been composed... the engineers were still hard at work and in control.

After the day had gotten going, we saw how people were cooperating at major train stations, lining up way outside just to get into the station. The anchors were explaining alternatives people had mentioned in interviews and messages to the station.

When discussing the different categories of electricity consumers and how power would be rationed in the weeks to come, they also showed a short clip of a mom tending to the life support machines for her child, and how she adjusts them to battery power during the outage periods. That quietly helps put things in perspective.

They brought on engineers with charts of the reactors to explain the partial melting and the plan in action to cool them down in a calm, professorial manner.

They even showed and explained the process of people being tested for radiation exposure and what the various levels mean.

The information is not delivered in a flashy style. It is like a classroom lecture. Very reassuring to a traumatized public.

They also demonstrated a way to make 3 little Bunsen burners at home, with 3 soda cans, kitchen scissors, aluminum foil, and I'm not sure what the wick material was, and salad oil. They cut the cans and rolled the wicks into aluminum foil rings into the 1/3 cans into which oil was poured, and showed that a pot of water could rest on those, and one cup would boil in about ten minutes.

They also discussed how to handle various material that might be contaminated.

Soon after that there was an aftershock alert. A red box in the middle lower screen, the anchors stopped their current story for the announcement. We have just been informed that there will be a fairly strong aftershock in the following areas very soon. Please remain calm but prepare yourselves and move away from any objects that may fall. And within a minute the aftershocks occurred and the map was up with 3s and 4s on it. The offshore quake was around a 5.

Then back to regular continuous programming about safety and clean up measures, and more discussions about nuclear power.

I've also really loved the way the Prime Minister and his cabinet have all been wearing workers' uniforms. They look like technical engineers as they are asking very respectfully for public cooperation with conserving electricity and the rationing plans.

There's also a tsunami watch in place. You hear a distinctive sound and the broadcast is interrupted to announce the location and give details.

[Rhiannon12866]

20. Thanks so much for sharing this information with us.

As you can probably tell, we're struggling here to find timely and accurate news about exactly what the situation is, after this horrific tragedy. This first hand report deserves its own OP. :hi:

[Overseas]

26. Thank you.

[BlueCollar]

21. Obviously FOX "news" isn't allowed

to broadcast in Japan.

Thanks for the informative post.

[Overseas]

27. Thank you.

I liked all the unadorned facts Japanese news broadcast. Lots of technical details. Treating viewers like adults.

[Dennis Donovan]

23. Rec'd. I feel confident in this report because CSM isn't one to shill...

:thumbsup::hi:

[Rhiannon12866]

24. Thank you! I felt better after reading this account, too...

:thumbsup: :hi:

[PhillySane]

28. Unfortunately

It may take many months to determine what exactly has happened inside those reactors. As many as 7 could have been damaged to some extent or another.

[Peace Patriot]

29. Opening shot of the nuke industry's defense campaign, is what this is.

And it doesn't surprise me at all to see it in the CSM, a flabby-brained old "liberal" magazine gone corporate.

There is absolutely no way to tell, at this point, whether we are looking at merely a humongous mess for decades to come, or armageddon-like, out-of-control, multiple meltdowns. And that's why these CSM-selected experts hedge their bets. Notice the iffy language (this is supposed to be reassuring?)...

----

"After it's all cooled down, it may well still be possible to simply remove the fuel and dispose of it in a relatively normal procedure," said Mr. Grimes. "What's clear, because of the incidental radiation being released at the moment, which is significant but not overwhelming, is that the structure of the core is probably still intact. So it's not as bad as Three Mile Island."

-----

There is no way to know that the "structure of the core" is intact. Reports have been consistent that they can't get to it. There is too much radiation. It's too "hot." But then he concludes with, "So it's not as bad as Three Mile Island." He can't know that. He doesn't know that. The whole article (which is rather short) is like this--a couple of experts speculating on the basis of conflicting and confusing reports. Another says, "he doubted a complete meltdown is possible." Doubted.

The key to this corpo-fascist propaganda can often be found in the false set-up, in this case: Chernoybl vs the Japanese meltdowns. It is a false comparison. Causal factors are entirely different. Japan was hit with the worst earthquake in recorded history and a following tsunami, which, according to reports, knocked out the primary safety features in two nuke plants--the water pumping systems--causing partial meltdowns. The battery backup systems then either failed or ran out of power. In addition, one plant lost its outer containment structure to an explosion. (Report today, two plants lost outer containment structures.) In this situation, officials and workers have gone to a last resort measure to contain the meltdowns--pumping sea water and boron into the cores. But these systems are also having problems, including malfunctioning valves and gauges (so that they are having difficulty determining if sufficient sea water is being pumped in). And, finally, four other nuke plants have failing cooling systems.

On what basis does this CSM-selected expert "doubt" that "complete meltdown is possible." Clearly, from the facts that are known, from reports, a complete meltdown IS possible--or they wouldn't be pouring sea water onto the core to prevent it!

Will that last resort measure work? Unknown. What if there are additional complications? For instance, Takashi Yokota, director of Japan's Earthquake Prediction Information Division, just predicted another earthquake (of magnitude 7.0) in the next few days.

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=102x4768612

Or what if a third reactor goes critical? The CSM article is designed to minimize the danger that Japan is in, and the danger that the Pacific Ocean and Pacific Rim countries are in, in a "worst case scenario"--say, another earthquake that damages the sea water pumping operations, the two most critical reactors go to complete meltdown and the measures being taken at the other four reactors are hampered and they end up in the condition that the first two are in, now--critical. There are numerous scenarios in which measures now being taken don't succeed.

None of this may happen--God forbid that it does!--but it could well happen. Japan is in dire straits, with huge damage to parts of the country, hundreds of thousands of people being evacuated from the nuke plant areas, and at least 10,000 people already dead from the earthquake/tsunami. How well are the officials and workers doing, who are addressing this further dire danger? How much more can they take? What about human error--fear, stress, exhaustion?

Japan is reportedly the best country in the world on earthquake and tsunami preparedness, and look what has happened! They suffered the worst earthquake in history. Preparedness MAY enable them to contain this situation. It is by no means guaranteed.

Chernoybl isn't the fear. That was just ONE reactor. Japan has at least SIX reactors with cooling system problems, at least two of them critical (leaking radiation, probable partial meltdowns). Can they control this situation? How many reactors can they take last resort measures to contain?

This CSM article is hack journalism. Someone was told to call up a few experts and get them to make a few "state of the art" remarks that take the onus off the nuke industry.

What real journalism would look like in this situation would be, first of all, an effort to penetrate what are very likely lies by Japanese officialdom about the levels of radiation being leaked, the number of reactors in trouble, and the true state of things as to containment. Secondly, real journalism would seek out scientists who don't depend on the nuclear industry or its research grants for a living. And thirdly, real journalism would delve into the history of decision-making that produced this armageddon-like risk to millions of people and to sea life in the Pacific Ocean, as well as the risks from what has happened so far. (For instance, where is all that irradiated sea water and leaking sea water--one core said to be leaking it out--going?)

The article treats "Chernoybl" like a bogeyman, falsely compares it to this situation and tries to FOOL you that this situation is not critical and cannot become a catastrophe. That is a lie.

[Rhiannon12866]

30. Thanks for your perspective.

In a situation as serious as this, it's obviously important to get all the facts we can, and that's why I posted this. I was actually in Russia the year that Chernobyl happened, so this resonated with me. I was scared witless, even though I was nowhere the area, so the comparisons got my attention, and I was looking for facts. Thanks for adding yours. We need facts now, more than ever. :(

[kristopher]

32. Outstanding analysis of a piece of corporate "journalism"

I saw that CSM piece earlier today and just lumped it in with all the other crap that the Nuclear Energy Institute, the lobbying/PR wing of the U.S. nuclear industry has scrambled to get out.

[Zoeisright]

35. Yep. Exactly.

[nadinbrzezinski]

33. It is simpler than that

chernobyl was a pile reactor, this is a Light Water Reactor with a rod system.

After that... when all is said and done, this will be a L-6 disaster, ESPECIALLY if they lose primary containment ON ANY of the reactors.

so far three are critical at a single station, but nothing to see here. I see