Explosion at Fukushima Nuclear power station

[Bob Palin]

I don't know much about this source but it seems sensible

 

The Worst Case: What If the Water Ran Dry in the Japanese Reactors?

http://news.sciencemag.org/scienceinsider/2011/03/the-worst-case-what-if-the-water.html?ref=hp

[John Ranalletta]

The full list of top 10 riskiest NPPs in the US:

 

1. Indian Point 3, Buchanan, N.Y.: 1 in 10,000 chance each year. Old estimate: 1 in 17,241. Increase in risk: 72 percent.

2. Pilgrim 1, Plymouth, Mass.: 1 in 14,493. Old estimate: 1 in 125,000. Increase in risk: 763 percent.

3. Limerick 1 and 2, Limerick, Pa.: 1 in 18,868. Old estimate: 1 in 45,455. Increase in risk: 141 percent.

4. Sequoyah 1 and 2, Soddy-Daisy, Tenn.: 1 in 19,608. Old estimate: 1 in 102,041. Increase in risk: 420 percent.

5. Beaver Valley 1, Shippingport, Pa.: 1 in 20,833. Old estimate: 1 in 76,923. Increase in risk: 269 percent.

6. Saint Lucie 1 and 2, Jensen Beach, Fla.: 1 in 21,739. Old estimate: N/A.

7. North Anna 1 and 2, Louisa, Va.: 1 in 22,727. Old estimate: 1 in 31,250. Increase in risk: 38 percent.

8. Oconee 1, 2 and 3, Seneca, S.C.: 1 in 23,256. Old estimate: 1 in 100,000. Increase in risk: 330 percent.

9. Diablo Canyon 1 and 2, Avila Beach, Calif.: 1 in 23,810. Old estimate: N/A.

10. Three Mile Island, Middletown, Pa.: 1 in 25,000. Old estimate: 1 in 45,455. Increase in risk: 82 percent.

[Twisties]

I'll repeat myself:

 

1:74000 average risk per civilian power reactor per year. 104 civilian power reactors. 50 year operating life. 74000/104/50 = 14 If anyone knows statistics and con confirm or correct the calculation, I'd appreciate it. But as far as I can see, that's 1:14 overall program risk of core damage to an existing US plant from earthquake.

 

Now add in specialty, research and military reactors, and add in other risks such as operator error, terrorism, tsunami, flood, fire, and risks from short to mid-term on site spent fuel storage.

 

So far as I can see, we better start getting used to these incidents. They are part of the new normal. And look, after all, so far the hoopla has been more damaging than the damage.

 

Oh, yeah, and then there are the mining problems that we still live with here in the west, and the long-term waste storage problems. But we don't need to worry about those, they are the same as all the other deficits we are handing off to the future: Use the energy now, and hand the problems off to them. Problem solved.

[John Ranalletta]

Too little, too late...spin didn't put out the fire

 

 

 

[John Ranalletta]

Imagine this coming emanating from Indian Point. Bye, bye NYC, Philadelphia, New Jersey, Boston, and most of the big blue states.

 

 

[yabadabapal]

Here is a headline from Google news. Notice the misprint as they say 2 opposite things in the short text.

US Experts Assure Nervous West Coast Residents: No Radiation Risk

Voice of America - Mike O'Sullivan - ‎1 hour ago‎

Photo: AP American public health officials are reassuring West Coast residents that radiation from Japan's troubled Fukushima Daiichi nuclear plant does pose a threat to the United States.

 

[DavidEBSmith]

Just to clarify, John - those animations are projections, based on weather conditions and estimates (guesses) and incomplete data on the radiation releases. The scale is, the red color is 100 milliSievert per hour, the purple is 100 nanoSievert per hour (the latter, as the ZAMG site points out, being a rate less than that of the average person's annual exposure). For comparison, radiation levels around Chernobyl were 10,000 to 300,000 milliSievert per hour. The average annual radiation dose just from walking around is in the range of 1.5 to 6 milliSievert per year. The banana equivalent dose - the radiation you get from eating one banana chock full o' potassium, some of which is naturally radioactive, is 0.1 microSievert. So being in the purple area gives you the radiation of eating one banana per hour.

 

As someone who once upon a time actually worked on software that projected radiation release plumes from nuclear power plants, I take the accuracy of these projections with a grain of potassium iodide. An equally good projection method is:

 

(1) are you close to the plant?

(2) is it leaking?

(3) wet your finger and stick it in the air. Is there wind?

(4) if 1, 2 & 3 are Yes: run away.

[hootowl]

The LA Times reports that:

The reactor at Diablo Canyon nuclear power plant in San Luis Obispo operated for a year and a half with some emergency systems disabled, according to a 2010 safety review by the federal Nuclear Regulatory Commission.

 

 

The incident was one of 14 "near-misses" the NRC uncovered in its inspections of nuclear power plants where problems had been occurring. An analysis by the group Union of Concerned Scientists concluded that "many of these significant events occurred because reactor owners, and often the NRC, tolerated known safety problems."

[Joe Frickin' Friday]

A chart showing various radiation exposure levels in context. This may be helpful when trying to understand the raw numbers sometimes presented by the media without any context at all.

 

a time-lapse computer animation showing actual local earth displacements (vertical and lateral) over the course of an hour of time, encompassing the earthquake in Sendai. Data came from a dense network of GPS stations throughout the country. Of note:

 

• Quake happens at 0:08 into the video.
  
• A compressive P-wave can be seen traveling through the country twice as fast as the S-wave. It's smaller in magnitude, and it reaches the southernmost part of Japan (at 0:10) just as the larger S-wave reaches the Osaka/Kobe area. One second of video is 2 minutes real-time, so the P-wave took about 4 minutes to get from Sendai all the way south to Kyushu (and the slower S-wave took a full 8 minutes).
  
• Parts of Japan near Sendai were permanently displaced by as much as 8 feet lateral. This is shown by the large blue vectors. Note that the rest of Japan mostly snapped back to its original position after the quake ended.

[Twisties]

On the other hand, the plant has been evacuated again after the spent fuel storage pond at unit 3 (the mox reactor with highly toxic plutonium) began "smoking."

 

While I don't see the world economy collapsing, or anything even close to that, this is nowhere near over yet. It remains for the moment a local/near regional problem, although obviously with global economic consequences.

 

I think, in the absence of information, we are left to speculate why two days after restoration of power to the plant, spent fuel storage pools have not been refilled: Damage so severe after the explosions that no way to do it? High radiation keeping workers too far away? Uncertainty as to the effect of adding water to already heated material without any confinement?

 

I'm thinking the last is most likely. Water hitting that hot material could cause a severe reaction that causes a major release of radioactive material. I think they are contemplating sand or concrete, but really just don't know what to do about it. Of course, I am just guessing. In the meantime, if it's emitting "smoke" I'm guessing that is going to force their hands here pretty quick.

 

I would suggest that permanent burial is not a desirable outcome. The location is too unstable, and the sea is right there. No way that spot is stable for a million years. Better to remove it, but then the question is, at what expense (not $$$, lives, further releases)?

[Bob Palin]

Uncertainty as to the effect of adding water to already heated material without any confinement?

I don't think that is it because they have fire trucks continuously pumping water in there. Haven't read a definitive answer but the hint in one article I read yesterday was that the pumps didn't work when poweer was restored - why would the plumbing be intact anyway if the power supply was destroyed by the quake/tsunami.

[Twisties]

Uncertainty as to the effect of adding water to already heated material without any confinement?

I don't think that is it because they have fire trucks continuously pumping water in there. Haven't read a definitive answer but the hint in one article I read yesterday was that the pumps didn't work when poweer was restored - why would the plumbing be intact anyway if the power supply was destroyed by the quake/tsunami.

 

Could be.

[ESokoloff]

..... - why would the plumbing be intact anyway if the power supply was destroyed by the quake/tsunami.

 

If you go back to one of the links I posted, there was a time line & the generators ran for about 1hr after the quake before the tsunami took them out presumably by flooding/ingestion of water.

If that were the case the plumbing should be fine. However I suppose it's a possibility that electric motors & controls may have suffered damage from water.

[Twisties]

..... - why would the plumbing be intact anyway if the power supply was destroyed by the quake/tsunami.

 

If you go back to one of the links I posted, there was a time line & the generators ran for about 1hr after the quake before the tsunami took them out presumably by flooding/ingestion of water.

If that were the case the plumbing should be fine. However I suppose it's a possibility that electric motors & controls may have suffered damage from water.

 

Yes, I too had thought that the pumps had been running, first on generators for an hour, then on battery back-up for 8 hours. Obviously there is more to this story.

[DavidEBSmith]

I think, in the absence of information, we are left to speculate why two days after restoration of power to the plant, spent fuel storage pools have not been refilled: Damage so severe after the explosions that no way to do it? High radiation keeping workers too far away? Uncertainty as to the effect of adding water to already heated material without any confinement?

 

All that, plus another concern that I have seen expressed: if the fuel rods, either in a reactor or in a dry storage pool, have melted down, the molten metal can puddle into a compact mass. In the air the neutron flux from this mass just dissipates. Water, however, is a good neutron moderator, increasing the fission cross-section. Covering a mass of fissile material could bring the whole mess closer to criticality, and accelerate the fission reaction. It's unlikely it would go supercritical and cause a nuclear explosion, but you could perhaps have a fairly energetic, long-lasting and unconfined nuclear reaction.

 

As an aside, the unit of measurement of nuclear cross section is the barn, as in the big farm building you couldn't hit the broad side of.

 

Also as an aside, the stuff you get when nuclear fuel melts through the bottom of your reactor is called corium (not to be confused with the countertop material) and, in the very limited number of opportunities we've had to study it, has been shown to have some interesting properties.

 

It may well be that the best option is to let everything melt and bury itself into the earth in a solid mass.

[Dave McReynolds]

It may well be that the best option is to let everything melt and bury itself into the earth in a solid mass.

 

If I were living in an area as geologically unstable as Japan, I don't think I would like to have a lot of hot nuclear waste buried under me, but as you say, I suppose that could still be the best of a bunch of worse alternatives.

[Twisties]

71,862 tons spent fuel storage in the US

 

 

I guess that's 144 million pounds. Of course the real problems today are the government weapons sites, like Hanford and Savannah River. Their problems are much more complex.

 

I look forward to the day when we figure out what we are going to do with this stuff.

 

[SuperG]

 

I look forward to the day when we figure out what we are going to do with this stuff.

 

Send it out to space?

[OoPEZoO]

 

I look forward to the day when we figure out what we are going to do with this stuff.

 

Send it out to space?

 

Had that discussion with the co-workers yesterday. Sounds like a great idea until the next Challenger disaster

[Joe Frickin' Friday]

All that, plus another concern that I have seen expressed: if the fuel rods, either in a reactor or in a dry storage pool, have melted down, the molten metal can puddle into a compact mass. In the air the neutron flux from this mass just dissipates. Water, however, is a good neutron moderator, increasing the fission cross-section. Covering a mass of fissile material could bring the whole mess closer to criticality, and accelerate the fission reaction. It's unlikely it would go supercritical and cause a nuclear explosion, but you could perhaps have a fairly energetic, long-lasting and unconfined nuclear reaction.

 

If it gets warm, it'll boil off the water, removing the moderator and moving away from criticality. If it's important to keep the mass of fuel covered with water, you can add a neutron poison such as boric acid to absorb the thermal neutrons that are causing elevated fission activity.

[ESokoloff]

 

I look forward to the day when we figure out what we are going to do with this stuff.

 

Send it out to space?

 

Had that discussion with the co-workers yesterday. Sounds like a great idea until the next Challenger disaster

But from what I understand, the Challenger could have been (made to be) survivable.

Perhaps in the distant future the risks of taking on such an endeavorer will out weigh the risks of not.

[Joe Frickin' Friday]

Send it out to space?

 

Space shuttle can only put stuff in orbit, which is definitely not what we want for radioactive waste; we would need it to escape earth altogether.

 

Jan's cite says we've got 144 million pounds of the stuff. The Saturn 5 was capable of getting 100,000 pounds of payload to the moon; if you can get a payload there, you can get it pretty much anywhere. Great, now we just need to build 1440 Saturn 5's. Where nuclear accidents are concerned, we like really, really low probabilities of occurence. Given the less-than-stellar safety record of modern rocketry (the space shuttle program currently has a 1-in-50-launches failure rate), launching radioactive missiles into space seems a dicey and expensive proposition.

 

FWIW, people were pretty up-in-arms over the 1997 launch of the Cassini-Huygens space probe because the power source for the space probe included about 60 pounds of plutonium.

[RonStewart]

Two weeks ago, NASA lost its second Taurus XL rocket in two years.

 

That's just an earth-orbit rocket.

 

I dimly recall a made-for-tv movie in the late 1970s called Earth II. It was about an earth orbiting space station. A well-intentioned character points a pod full of radioactive stuff at the sun, not realising that she had put it in an elliptical orbit that would cross earth's path a couple of times a year. Wasn't a great movie, but they tried to get the physics right.

[Bob_Minor]

Don't worry, the space elevator is right around the corner.

[4wheeldog]

We just need to get WWIII going. Then we could send it all to our enemies via cruise missiles, as nuetron bombs. (I am kidding, I hope).

[DavidEBSmith]

All that, plus another concern that I have seen expressed: if the fuel rods, either in a reactor or in a dry storage pool, have melted down, the molten metal can puddle into a compact mass. In the air the neutron flux from this mass just dissipates. Water, however, is a good neutron moderator, increasing the fission cross-section. Covering a mass of fissile material could bring the whole mess closer to criticality, and accelerate the fission reaction. It's unlikely it would go supercritical and cause a nuclear explosion, but you could perhaps have a fairly energetic, long-lasting and unconfined nuclear reaction.

 

If it gets warm, it'll boil off the water, removing the moderator and moving away from criticality. If it's important to keep the mass of fuel covered with water, you can add a neutron poison such as boric acid to absorb the thermal neutrons that are causing elevated fission activity.

 

Well, it depends on how much water you have on it, how fast it boils, what shape the hole is that it's sitting in, etc. Maybe it doesn't boil off fast enough, maybe it boils off too fast and you get a steam explosion that sends more bad stuff into the atmosphere. Maybe some hunks of steel from the reactor vessel fall into the hole and make a local neutron reflector. If you've gotten to the point of hoping to keep the thing under control by drowning it in boric acid, you're probably out of the realm of engineering and into gut feelings and best guesses.

[Twisties]

Well, today's news is not good. The first reliable estimates of the amount of releases, based on global measurements and modeling indicate releases are comparable to Chernobyl, less, but comparable.

 

Fallout Estimates

 

On top of this, there is now reason to suspect a containment breach at the mox reactor, #3. Although details I have seen so far leave more to the imagination than I would prefer:

 

Reactor Breach Feared

 

Neither of these is good news. While I still feel there is no (or not yet) EVIDENCE of impact beyond Japan's shores, I am never the less feeling a bit less sheepish about having bottled up some water when this first happened.

 

 

[ESokoloff]

It aint over till it's over.....

But it's looking more & more like Chernobyl vs Three Mile.

 

[Twisties]

...and the short version is that the geologic record shows that three times in the last 3000 years a major earthquake and tsunami like this one has hit the region near Fukushima. But the risk planners excluded the geologic record older than 1896 in their modeling, and then said nothing like this could ever happen. When it did happen, then they said they could never have imagined it.

 

Risk Downplayed

 

[John Ranalletta]

It aint over till it's over.....

But it's looking more & more like Chernobyl vs Three Mile.

the only possible outcome here is the Plan Z concrete entombment, which will guarantee an 80 km non-inhabitable radius around Fukushima in perpetuity, finally the "experts" are warming up to this idea: per Reuters: "Experts say there is still too much heat in the reactor cores and spent fuel at the Fukushima plant for a similar last-ditch solution to be considered yet."

 

[Twisties]

It aint over till it's over.....

But it's looking more & more like Chernobyl vs Three Mile.

the only possible outcome here is the Plan Z concrete entombment, which will guarantee an 80 km non-inhabitable radius around Fukushima in perpetuity, finally the "experts" are warming up to this idea: per Reuters: "Experts say there is still too much heat in the reactor cores and spent fuel at the Fukushima plant for a similar last-ditch solution to be considered yet."

 

 

John, who says that concrete entombment would cause an 80 km non-inhabitable zone and what is the basis for the statement?