April 5, 2011 U.S. Sees Array of New Threats at Japan’s Nuclear Plant By JAMES GLANZ and WILLIAM J. BROAD The New York Times http://www.nytimes.com/2011/04/06/world/asia/06nuclear.html?pagewanted=all&_r=0
[Excerpted] United States government engineers sent to help with the crisis in Japan are warning that the troubled nuclear plant there is facing a wide array of fresh threats that could persist indefinitely, and that in some cases are expected to increase as a result of the very measures being taken to keep the plant stable, according to a confidential assessment prepared by the Nuclear Regulatory Commission.
Among the new threats that were cited in the assessment, dated March 26, are the mounting stresses placed on the containment structures as they fill with radioactive cooling water, making them more vulnerable to rupture in one of the aftershocks rattling the site after the earthquake and tsunami of March 11. The document also cites the possibility of explosions inside the containment structures due to the release of hydrogen and oxygen from seawater pumped into the reactors, and offers new details on how semimolten fuel rods and salt buildup are impeding the flow of fresh water meant to cool the nuclear cores....
...the document raises new questions about whether pouring water on nuclear fuel in the absence of functioning cooling systems can be sustained indefinitely. Experts have said the Japanese need to continue to keep the fuel cool for many months until the plant can be stabilized, but there is growing awareness that the risks of pumping water on the fuel present a whole new category of challenges that the nuclear industry is only beginning to comprehend.
The document also suggests that fragments or particles of nuclear fuel from spent fuel pools above the reactors were blown “up to one mile from the units,” and that pieces of highly radioactive material fell between two units and had to be “bulldozed over,” presumably to protect workers at the site. The ejection of nuclear material, which may have occurred during one of the earlier hydrogen explosions, may indicate more extensive damage to the extremely radioactive pools than previously disclosed....
Thursday, Aug. 23, 2012 Plutonium traces detected at 10 locations in Fukushima
[Excerpted] Plutonium believed to be from the Fukushima No. 1 nuclear plant has been detected at 10 locations in four municipalities in Fukushima Prefecture, the science ministry said.
The highest reading was 11 becquerels of plutonium-238 per square meter, detected in the town of Namie, the ministry said Tuesday. That is about 1.4 times higher than the level that originated from fallout from nuclear weapons tests abroad.
The other municipalities are the town of Okuma, the village of Iitate and the city of Minamisoma.
The ministry said there was no health hazard, given the small quantities involved.
Majia here: Of course, the reality is that one atom of plutonium can give you cancer. And tragically people may already be dying from Fukushima radiation:
Posted by Mochizuki on January 13th, 2013 ·
On 1/11/2013, Fukushima Diary reported “Defense counsel of Fukushima group evacuation lawsuit, “3 police officers died of acute leukemia in 40~50km area” [Link] ”
Majia here: Read Bobby1 of Optimal Prediction's Statistical Analysis of the probability these deaths were naturally occurring and not caused by Fukushima radiation HERE