Rod Adams, Atomic Insights, reviews the situation at the spent fuel pool at reactor 4 and determines that NRC Chairman Jaczko was wrong and not fully informed when he declared them empty.
Getting the actual risk situation right is important - [Japanese] Officials have warned that the nuclear incident is hampering efforts to deliver aid to victims of last Friday's earthquake and tsunami, with reports that drivers are reluctant to travel to areas even outside the exclusion zone.
I have done a lot of fact checking and communicating. One of the nice things about being an old ring knocker (I graduated from the Naval Academy almost 30 years ago) is that you can have a pretty useful set of highly placed friends. Some of them gave me enough information to confirm what I suspected. I cannot think of any way to say this gently - Dr. Jaczko was wrong. It is possible someone in his staff provided bad information, but it should not be all that difficult to see the problem with some simple, back of the envelop calculations.
Based on those numbers, here is my analysis:
The spent (aka used) fuel pools are not generating much hydrogen. They are not boiling away. They are not empty. UO2 CANNOT burn, it is almost fully oxidized already. (That is what the O2 part of the compound equation is.) Between 90-95% of the material in a used fuel pool is UO2.
The water level in the pool at unit 4 is significantly lower than normal, which leads to higher radiation levels above the pools than normal.
The measured levels can be caused by a reduced amount of shielding above the still radioactive used fuel. Pools normally contain about 6M of water, the tenth thickness of water is .7 meters. You lose 70 cm of water, the dose rate above the water increases by a factor of 10.
As swimmers or hot tub lovers know, it is never surprising to see clouds of vapor rising from hot water on a cold day. However, even with an increased rate of evaporation, pools full of water take a long time to empty out.
The temperatures in the pool at unit 4 rose from about 40 C to 84 C during the first 4 days after the quake/tsunami. That should give you numerically inclined people the confidence to assert that boiling off of 6 meters of water could not have occurred during the 5th day. (Don't forget about the latent heat of vaporization.)
PopAtomic - indicates that now is the time to speak out in support of nuclear energy
* Focus on the successes of the Japanese efforts in exceedingly difficult circumstances, especially the intact containment structures.
* Compare the damage at oil, coal and natural gas facilities.
* Use this as an opportunity to highlight the safety features of Generation III+ technologies and Next Generation Nuclear Power
* Highlight the stellar safety record of America’s existing nuclear fleet.
* Reiterate that the true disasters are the earthquakes and tsunamis, not the complications at nuclear facilities.
* Integrate personal and positive imagery into outreach materials, and hold media accountable for misleading imagery such as natural gas plant fires in combination with nuclear related headlines.
Nuclear green points out that the term nuclear disaster should is not correct in describing the Fukushima situation
People are beginning to use the term "nuclear disaster," to describe the Japanese reactor problems which are actually a part of the aftermath to a real and huge disaster, the Japanese earthquake/tsunami. The word disaster is used in this case in a quite loose fashion. The normal characteristics of a disaster include loss of life, wide scale material damage to property, and undesirable changes to the environment. It is not clear that the problems at the Japanese reactors minimally qualify as a disaster. There has been no damage to property outside the reactors themselves, and no loss of life. The real disaster was the earthquake/tsunami event of which the reactor problems are consequences. Thus the use of the term 'nuclear disaster" seems inappropriate.
This site provided:
Lowering deaths per terawatt hour with air pollution mitigation and other methods
Deaths per terawatt hour by energy source
One of the Radiation chart articles
Radiation and risks article