Fukushima update: Not yet in the clear

Posted by Andrew Davies - 18 March 2011 at 6:05pm - Comments

One week after the earthquake and tsunami, humanitatian relief efforts continue while workers at the Fukushima power plant strive to bring the situation under control. Overall, with possible exception of the spent fuel pool of reactor 3, the status of all facilities is very similar to yesterday - which is a bad thing.

Major uncertainty relates to: the amount of radiation already being released to air and sea; risk of a violent fire in the cladding of the fuel rods as the spent fuel pools are exposed for hours; as well as to the behavior of the reactor cores as water levels remain low.

Good news is that the violent release of radioactivity, due to fire or explosion, feared yesterday has not happened yet. Power is still not restored to the facility, but some progress has made to bring off site power and more equipment. This means more effective cooling could be established in some days. But, at least until that happens, the situation remains critical and unpredictable.

 Our updates are based on the best information we have been able to collect from various sources. There is a lot of confusion in any crisis situation, and, in this case, several governments and official bodies have already questioned whether all the available information is being provided. 

Summary: Status of facilities

 

Reactors 1-3: water level in reactors low (about half of fuel rods exposed), no grid power, seawater injection apparently ongoing. Fuel rods have certainly damaged and are releasing radioactive substances.

 

 

Fire department has brought in 30 more trucks, at least one reported to be a 'super bomber' able to shoot to a distance of two kilometres. Yesterday, police trucks were unable to operate close to plant because of high radiation levels, only SDF (Self Defense Force) trucks that can be operated from inside the cabin were used.

Spent fuel pools of units 1 and 2: Water levels in unit 1 are decreasing. Steam was reported from unit 2, expected to be boiling.

Spent fuel pool of unit 3: Water in #3 almost depleted, but Tepco hopes some water is left. Fuel rods have certainly damaged, releasing radioactive substances. The reactor buildings are heavily damaged, allowing releases directly to outside air.

Spent fuel pool of unit 4: Water level very unclear.

Spent fuel pools of units 5 and 6: Temperatures still rising, water left but level unclear.

Worst case scenarios

  • The zirconium contained in the fuel rod cladding can react violently with air if exposed for hours. This fire would release and spread very large amounts of radioactivity high up in the air. There is however wide disagreement on the probability of this happening.
  • A large amount of molten fuel accumulates at the bottom and a nuclear reaction starts. Very low probability and can be prevented if there is any borated water in the pool.
  • Reactor boils dry, molten core breaches reactor pressure vessel and comes in contact with the water in the containment, which boils rapidly causing a steam explosion.
  • A major risk is an event (eg increased release of radioactivity from a spent fuel pool due to overheating) that raises local radiation levels to completely intolerable levels - preventing further work to restore cooling.

 

Tepco seemed to suggest that encasing the plant in concrete is an option if cooling efforts fail (according to Reuters live feed).

Wind

Local wind speed slowed down considerably in the morning but direction remained towards the sea. Winds towards Tokyo are still feared for Sunday.

See also

A day-by-day account of the nuclear accident from Reuters.

Our main Fukushima page and our Twitter updates.

Article tagged as: earthquake, energy, fukushima, japan, nuclear power, tsunami
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I have always been against nuclear power both for the danger it poses and the immoral burden of waste on future generations. I feel the British people have not been given the chance to be directly involved in the decision making process regarding the future development of nuclear power in the country. The level of awareness about the wind scale fire amongst the general public is not that great. If Germany can consider and plan for a future without Nuclear Power why it is the UK has to consider this dangerous technology. Corruption of the major political parties can be the only answer; they have done deals with big nuclear business. Whilst CHP has great potential to meet energy needs I feel the green movement should propose energy schemes that would trump government and the nuclear industry. The UK could easily replace the base load provided by nuclear with tidal power. The Seven, Mersey, Humber and Morecombe Bay alone have massive energy potentials. The focus is always on the Severn Estuary but there are many potential tidal sites around the UK where preliminary studies have been done.

By G Thraves - 18 March 2011 at 8:16pm

I've no doubt that cover ups and corruption can and do occur, but have you any idea how that sounds with regard to the nuclear industry and corruption?

My research has led me to the following conclusions:

1) Nuclear power was started in the UK principally to produce sufficient bomb making material; plutonium.

2) Nuclear power remained an attractive option to help insulate the economy against variable oil prices, plus infrastructure was already in place (which is one of the most costly things, fuel is cheap).

3) Nuclear waste is a massively misunderstood problem. The absolutely tiny volume of reprocessed waste produced is really quite insignificant. You need to remember that e=mc2! The mass of fuel in nuclear technology (and so the mass of waste too) is absolutely tiny for huge quantities of energy. It's what makes nuclear weapons so cataclysmic.

I can't help feeling that you're being incredibly naive with regard to extracting tidal energy. If it was so economically feasible, then someone would be making money off it already.

G Thraves, as a final point I would very much appreciate it if you could expand on how nuclear is dangerous. I will not deny that it is dangerous if you handle it improperly, much like cars, knives and electricity. Respectable UN bodies and scientific consensus is that deaths from nuclear power have been absolutely tiny in the 50 years or so of it's generation. I'm hopeful that none of the plant workers at Fukushima will get ill either and they're right at the heart of a 20km exclusion zone. I'm not saying I'd like to be exposed to 250 millisieverts at all, but if you go digging around for the Linear No Threshold radiation model that was based of Hiroshima survivors, you'll find that the increased risk of fatal cancer for 250mSv is about 1%. A lifetime's smoking will increase your risk of cancer by 900%.

I'm open to sound intelligent argument, but I just haven't heard anything terribly effective against nuclear yet. The worst thing I've heard so far is that the Fukushima plant was only designed to handle 8 on the Richter scale. This of course means somewhere along the line someone did a risk assessment and didn't think a 9 quake was sufficiently likely.

By GNTC - 20 March 2011 at 3:39am
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Nuclear reactors should be built in nuclear bunkers. Keep the terrorists out and the accidents in. Choose a site suitable for waste storage, so you can leave the remains there at their end of life. In the case of a serious accident, fill the bunker with water. It will be expensive, but we are done with penny pinching nuclear power. We just need to solve the nuclear waste crisis.

By nuclear bunker for reactors. - 21 March 2011 at 7:18pm

"G Thraves, as a final point I would very much appreciate it if you could expand on how nuclear is dangerous. I will not deny that it is dangerous if you handle it improperly, much like cars, knives and electricity."
A nuclear bomb dropped on fukushima by a terrorist, liberating all the radioactivity on the site, would kill everyone in Japan and turn Japan into a nuclear wasteland. Its the scale of the worst case incident that separates nuclear from other risks.

By nuclear bunker for reactors. - 21 March 2011 at 7:23pm

'A nuclear bomb dropped on fukushima by a terrorist, liberating all the radioactivity on the site, would kill everyone in Japan and turn Japan into a nuclear wasteland.’ Err, no it wouldn't. On what sort of methodology are you basing that statment? Sure, potentially tens of thousands of people would die as a result of the blast (either as a direct result of the explosion, or as a result of early radiation effects), and perhaps thousands could die as a result of stochastic effects (i.e. cancer), but that’s way short of the 125 million people who live in Japan. And have Nagasaki and Hiroshima remained ‘nuclear wastelands’ following the attacks of 1945? Don’t get me wrong though, I’m not advocating the use of nuclear weapons! ‘Its the scale of the worst case incident that separates nuclear from other risks’ It’s not, it’s the perception issue which separates nuclear from other risks. Let’s expand your argument. Let’s assume (rather crudely) that the entire pre-tsunami population of Okuma, and immediately surrounding area, are wiped out as a result of your worst-case scenario. I think the pre-tsunami population of Okuma was approximately 10,000, and let’s assume that a total of 50,000 people are killed (either out-right, or as a result of a stochastic effect at some point in the future). I appreciate that there’s an underlying argument related to voluntary vs involuntary risk, but how do you reconcile that figure with the fact that approximately 6,000 people die in Japan EVERY YEAR as a result of road traffic accidents? This fatality rate is real, and people continue to drive their cars every day. In my (inexpert) opinion the deaths of 50,000 people as a result of terrorists detonating a nuclear device is highly improbable. Do you still consider driving as being less ‘risky’? Or do you advocate a ban on use of the motor car? Where do you draw the line between acceptable and unacceptable risk? In terms of the tsunami-related damage to the Fukushima plant and leaks of radioactive material, let’s assume that 1,000 people [highly unlikely, based on the information on radiological contamination available to date] die as a result. How does that sit, next to the road accident statistic? 6000 deaths every year, vs 1000 deaths as a result of a natural disaster which experts have said would occur with a frequency of one in every a thousand years. It’s time more people started to think in terms of relative risk, and move away from the usual knee-jerk response to nuclear issues, a response which in my opinion is founded in a combination of ignorance and fear. This fear is unfortunately being compounded by the world’s media at the moment, as a result of their inaccurate, sensationalist and disproportionate response to events in Fukushima.

By Nick Eustasy - 24 March 2011 at 10:28am

I would just like to reiterate that at present only one member of the workforce at the nuclear plant has been exposed to a dose of radiation where there is a measurable increase in cancer as a result, that measurable increase is around a 1% increased risk as I said earlier (with references).

You certainly wouldn't think that by watching the News.

The idea that 10 people might die from the nuclear accident so far is quite frankly absurd and unsupportable.

The most worrying thing about Fukushima is not the escaped radiation at all, but the fact that without the expert intervention that has occurred, we would be actually facing serious consequences.

I can accept that modern nuclear plants do not require intervention like Fukushima has done in order to fail safe, but it's worth bearing in mind there are a lot of older reactors out there.

I don't want to say old is bad, it's not, but culture has changed massively over the years and that change has been reflected in reactor design. When Fukushima was designed, no civil nuclear accidents had ever occurred.

Nuclear does have an astonishingly good safety record, being one of the safest power industries to work in, but now isn't the time to be complacent.

I think humanity would be insane to not use Nuclear to solve Climate change and to provide the energy needed to take the world out of Poverty (consequently stabilising population and helping to slow the expanding demand for world resources), but with great power comes great responsibility. We need passively safe, fail safe nuclear power. We need to be responsible.

I've seen a Greenpeace video on youtube saying "No more Chernobyls". There are still 3 power stations (Kursk, Leningrad & Smolensk Nuclear Power Plants), making up 11 reactors that use the same RBMK reactor design that caused the cataclysmic meltdown at Chernobyl (along with massive staff failure). They have had safety upgrades, but if anyone here feels the need to be anti nuclear, I'd like to direct their attention to perhaps getting something done about those, but not throwing the baby out with the bathwater.

By GNTC - 24 March 2011 at 2:08pm

On the front page of Metro last week was a heratbreaking article about the Fukushima 50 who were embarking on a suicide mission to prevent a nuclear disaster. Today I read on page 27 of Metro that two of them have recieved a180 millisievert dose and will not even require hospitalisation.

Such distorted reporting is understandably making the public unrealistically fearful of nuclear.

This whole topic is so open to bias - research the number of deaths from Chernobyl, and you'll find the number is between 50 (IAEA figure) and 900 000 (Greenpeace). The world health oranisation plump for 6000. Still less than the yearly number of deaths from traffic accidents.

By Grange - 25 March 2011 at 1:03pm

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