FEPC has released another update.
This statements includes an announcement that Japan has increased the level of seriousness of the accident at Units 1,2 and 3 to 5 on the INES scale. A lot of folks thought a 6 was more appropriate (it seems worse than Three Mile Island after all), but I’ve spent a couple of days reading and am pleased to pronounce myself unfit to pass INES judgments. The scale baffles me.
Full text after the jump.
Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 11:00AM (EST), March 18, 2011
- Radiation Levels
o At 7:30PM on March 18, radiation level outside main office building (approximately 1,640 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 3,699 micro Sv/h.
o Measurement results of ambient dose rate around Fukushima Nuclear Power Station at 4:00PM and 7:00PM on March 18 are shown in the attached two PDF files respectively. [pdf1|pdf2]
o At 1:00PM on March 18, MEXT decided to carry out thorough radiation monitoring nationwide.
o For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
- Fukushima Daiichi Unit 1 reactor
o Since 10:30AM on March 14, the pressure within the primary containment vessel cannot be measured.
o At 4:00PM on March 18, pressure inside the reactor core: 0.191MPa.
o At 4:00PM on March 18, water level inside the reactor core: 1.7 meters below the top of the fuel rods.
o As of 3:00PM on March 18, the injection of seawater continues into the reactor core.
o Activities for connecting the commercial electricity grid are underway.
- Fukushima Daiichi Unit 2 reactor
o At 4:00PM on March 18, pressure inside the primary containment vessel: 0.139MPaabs.
o At 4:00PM on March 18, pressure inside the reactor core: -0.002MPa.
o At 4:00PM on March 18, water level inside the reactor core: 1.4 meters below the top of the fuel rods.
o As of 3:00PM on March 18, the injection of seawater continues into the reactor core.
o Activities for connecting the commercial electricity grid are underway.
- Fukushima Daiichi Unit 3 reactor
o At 2:00PM on March 18, six Self Defense emergency fire vehicles began to shoot water aimed at the spent fuel pool, until 2:38PM (39 tones of water in total).
o At 2:42PM on March 18, TEPCO began to shoot water aimed at the spent fuel pool, until 2:45PM, by one US Army high pressure water cannon.
o At 3:55PM on March 18, pressure inside the primary containment vessel: 0.160MPaabs.
o At 3:55PM on March 18, pressure inside the reactor core: -0.016MPa.
o At 3:55PM on March 18, water level inside the reactor core: 2.0 meters below the top of the fuel rods.
o As of 3:00PM on March 18, the injection of seawater continues into the reactor core.
- Fukushima Daiichi Unit 4 reactor
o No official updates to the information in our March 18 update have been provided.
- Fukushima Daiichi Unit 5 reactor
o At 4:00PM on March 18, the temperature of the spent fuel pool was measured at 152.4 degrees Fahrenheit.
- Fukushima Daiichi Unit 6 reactor
o At 4:00PM on March 18, the temperature of the spent fuel pool was measured at 148.1 degrees Fahrenheit.
- Fukushima Daiichi Common Spent Fuel Pool
o At 10:00AM on March 18, it was confirmed that water level in the pool was secured.
- Fukushima Daiichi Dry Cask Storage Building
o At 10:00AM on March 18, it was confirmed that there was no damage by visual checking of external appearance.
At 5:50PM on March 18, Japanese Safety Authority (NISA: Nuclear and Industrial Safety Agency) announced provisional INES (International Nuclear and Radiological Event Scale) rating to the incidents due to the earthquake.
Fukushima Daiichi Unit 1, 2 and 3 Unit = 5 (Accident with wider consequences)
Fukushima Daiichi Unit 4 = 3 (Serious incident)
Fukushima Daini Unit 1, 2 and 4 Unit = 3 (Serious incident)
(No official provisional rating for Fukushima Daini Unit 3 has been provided.)
Any chance of posting “the attached PDFs”?
So it seems the only success (mild) with the seawater is in reactor #2 – there does not appear to be any change in levels in #1 or #3
I’m sorry, but could you link the two PDFs or the original site?
Done.
A question: based on what I read, is it too early to say this will end with a whimper, and not a bang, of radiation?
please discuss
Assuming they restore power, I think it’s too soon to assume that cooling will be restored and the plant will be saved. Take into consideration the varying pressure levels in each reactor core; seems to indicate that there are leaks, that means it’s not over yet. Also, take a look at this:
http://www.solarstorms.org/FAAAirlines.html
The FAA appears to indicate that for every 1 mSv exposure, 6.3 out of 100,000 can expect to die an early death from cancer. In Fukushima City, they are seeing rates of around 150 uSv/hr, and have for at least the last two days. This translates to 7.2 millisievert exposure over two days, and with a population of roughly 300,000 they can expect to see 7.2*6.3*3 = 136 early deaths from cancer, and in Fukushima City alone. These are of course rough estimations, as there are countless variables that we simply don’t know (how many have left, how many are heeding guidance to stay indoors, if staying indoors will reduce exposure, if the levels being reported are accurate or if there have been spikes, if there are people remaining within the evacuation zone, etc.).
Further, the plant workers, while not yet reported to have been exposed to radiation sickness-causing doses, have excessively high risk because of the radiation readings where they are working. I estimate that for each day there is 1/3 chance that one of the 50 people being exposed will die from radiation-caused cancer. Also, levels at the plant are frequently spiking at higher levels, and it’s possible that one of these spikes (possibly from a fire or another explosion) could release doses that might cause moderate radiation poisoning without warning.
And this isn’t taking into consideration the estimated 200,000 people evacuated for the past week, unable to return home. The rolling blackouts from losing a few gigawatts of power generation in late winter. The economic damage caused by said blackouts. And the considerable damage that this incident (and the media’s response) has caused to our hopes of building a non-coal, non-oil based economy.
If your question, though, was whether the plants still have a chance to explode… They can’t go critical, as the control rods were inserted immediately upon plant shutdown, and if they’re leaking like I suspect, they won’t be able to build up enough pressure to explode. Data they’ve released indicates pressure within the cores reached over twice the maximum allowed by the design, then suddenly they dropped to nearly half (or less) of the nominal levels. Sounds like they’re leaking, and I wouldn’t be surprised if each core suddenly depressurizing into their containment caused each building to blow its lid. If right, this would mean that they’ve already done their exploding, which is a blessing in disguise…without an explosion or uncontrolled fire, any radioactive material will stay near the plant and contaminate a much, much, much smaller area than Chernobyl. The real risks now are from either a core melting through containment (which will put off crazy radiation and force workers to evacuate, probably dooming the other plants to meltdown as well) and possibly cause a fire as well, spreading radioactive material….and/or the spent fuel containment pools evaporating, causing the pools to ignite and/or melt and ultimately lead to the same situation.
Whatever happens, I don’t think we’ll see any more sudden changes in the situation.
Archjr,
My guess is that once cooling is restored the situation will slowly come under ever-improving control, and within five years we’re likely to see large parts of Fukushima surrounded by big lumps of concrete while they slowly remove the fuel robotically for bit-by-bit vitrification, disposal, or whatever.
tj,
I have to disagree with your comments on the likely number of deaths. The calculations you make are based on the Linear No Threshold model which, at doses below 100 – 200 mSv, is seriously lacking in evidence and used more for ease of calculation and lack of any alternative rather than because LNT produces demonstrably accurate predictions.
Many hundreds of thousands of people live in regions of the world (e.g. eastern Brazil, south-west India and parts of Iran) where the background radiation has comfortably exceeded 100 – 150 mSv per year ever since humans first moved in; if the LNT model were correct then in these areas we should expect a large and obvious excess of cancers. However, excesses do not exist in anything like the numbers that LNT would calculate them to be. Accordingly I suspect that if the situation at Fukushima does not now deteriorate again then in 50 years’ time we’d find no excess of cancers at all in the region except for those people exposed to more than just a rise in the general background radiation.
The rate Unit 4 as INES 3, yet the building is severely damaged and now…. on Friday, 18 March 2011 at 17:54
“Japanese authorities have informed the IAEA that, prior to the earthquake of 11 March, the entire fuel core of reactor Unit 4 of the Fukushima Daiichi nuclear power plant had been unloaded from the reactor and placed in the spent fuel pond located in the reactor’s building.”
…and they can not gauge the temperature?
I guess we’re good as nuclear boy? Let’s just hope he doesn’t poo or the diaper overflows with diarrhea.
I guess the key problem with INES is that too many judgement calls are involved and that there isn’t an “interpretation manual” or other normative sources to help the authorities of the accident country to pass such judgements.
Instead of “limited release” or “significant release” or even “large quantities of radioactive material” it would be much more helpful to define actual measurable or calculable limits (for example in total Bq of Cs137 released, or total estimated population dose in Sv). Sure, those would still require lots of estimation and possibly entail large errors depending on key assumptions, so perhaps there should be direct measurement radiological limits also with the highest measurement or estimate being the classification factor, such as there already are nationally for evacuation and sheltering in place (such as, “significant release is defined as any measurement of dose rate outside of plant premesis exceeding 100 uSv/h”).
I think the formulation where the local and differing radiation protection regulations and practices come to play in defining seriousness (such as limits of when a country goes from “planned countermeasures” to “extended countermeasures”) also unnecessarily complicates things.
Again, this amount of vagueness is probably intended for the descriptions of the scale to the general public, but surely there should be actual concrete numbers behind making judgements of how a certain accident should be classified while in progress. Now it appears sources tend to differ even for historical accidents, because the scale is so horribly unprecise and convoluted.
They need to find out if unit 4 spf has already melted down to its final state- a stable resolidified mass mixed with the concrete. If so, the safest thing to do is to pour 10 feet of concrete on top and call it a day. Pouring water on solidified corium only spreads radioactive particles in the steam.
“Corium” – I love it!! What a great description. I must remember this. Thanks!! You made my night!
But what happens to the several MWt of heat the Unit 4 SNF is generating, if you simply cover it with concrete? Wouldn’t the SNF fully melt, then crack the concrete, and partially escape? Or even cause a small explosion?
Both the NYT and David Wright of UCS say there were 1479 Assemblies in the Unit 4 SNF pool, 548 fresh from 30 November 2010 shutdown. So that is 2.7 reactor loads of SNF.
Assuming average heat production in the SNF now of 0.05% (anyone have a better estimate) of full reactor power (2381MWt), current heat output of the SNF would be:
2381 * 2.7 * 0.0005 = 3.2 MWt
Taking a different assumption of 10kw/tonne U, which I understand is the rough and ready estimate for one year old SNF, we get:
256 * 10 / 1000 = 2.6 MWt
Somegood news:
http://www.reuters.com/article/2011/03/19/japan-idUSL3E7EJ08F20110319
The status data is being updated here in easy to read tabular format:
http://en.wikipedia.org/wiki/Timeline_of_the_Fukushima_nuclear_accidents