by das monde
Thu Mar 31st, 2011 at 04:08:42 AM EST
Disheartening developments at the Fukushima Daiichi nuclear plants continue, as nuclear elements take on their own course. Is it getting too late for human responsibility?
IAEA Confirms Very High Levels of Contamination Far From Reactors
Today the IAEA has finally confirmed what some analysts have suspected for days: that the concentration per area of long-lived cesium-137 (Cs-137) is extremely high as far as tens of kilometers from the release site at Fukushima Dai-Ichi, and in fact would trigger compulsory evacuation under IAEA guidelines.
The IAEA is reporting that measured soil concentrations of Cs-137 as far away as Iitate Village, 40 kilometers northwest of Fukushima-Dai-Ichi, correspond to deposition levels of up to 3.7 megabecquerels per square meter (MBq/sq. m). This is far higher than previous IAEA reports of values of Cs-137 deposition, and comparable to the total beta-gamma measurements reported previously by IAEA and mentioned on this blog.
This should be compared with the deposition level that triggered compulsory relocation in the aftermath of the Chernobyl accident: the level set in 1990 by the Soviet Union was 1.48 MBq/sq. m.
Radiation levels in seawater off Japan plant spike to all-time highs
The amount of radioactive iodine-131 isotope in the samples, taken Wednesday some 330 meters (361 yards) into the Pacific Ocean, has surged to 4,385 times above the regulatory limit. This tops the previous day's reading of 3,355 times above the standard -- and an exponential spike over the 104-times increase measured just last Friday.
Officials have downplayed the potential perils posed by this isotope, since it loses half of its radiation every eight days.
Yet amounts of the cesium-137 isotope -- which, by comparison, has a 30-year "half life" -- have also soared, with a Wednesday afternoon sample showing levels 527 times the standard.
Fukushima Workers Face Risk of Uncontrolled Reactions
The United Nations' nuclear watchdog agency warned that a potential uncontrolled chain reaction at Japan's crippled Fukushima atomic power plant could cause further radiation leaks and increase the risk to workers.
A partial meltdown of fuel in the No. 1 reactor building may be causing the isolated reactions, Denis Flory, nuclear safety director for the UN's International Atomic Energy Agency, said at a press conference in Vienna.
Nuclear experts call these reactions "localized criticality." They consist of a burst of heat, radiation and sometimes an "ethereal blue flash," according to the U.S. Energy Department's Los Alamos National Laboratory website. Twenty-one workers worldwide have been killed by "criticality accidents" since 1945, the site said.
"We share the view with the IAEA that various phenomena are possible," Chief Cabinet Secretary Yukio Edano said at a press conference today in Tokyo. "At the same time, the organization said they don't have clear signs that show such a phenomenon is happening."
Pumping Operation Stops at Plant
Workers stopped water-pumping operations near the Fukushima Daiichi nuclear-power plant's No. 1 reactor Wednesday after the container they were using filled up, part of the juggling act recovery workers are performing as they look for places to store increasing amounts of water.
Pumping operations at the No. 2 reactor facility--a much bigger concern because of the amount of radiation in the water there--faced continued delays, leaving toxic water in a nearby shaft still just three feet shy of spilling over into the ocean.
Meanwhile, officials recorded the highest radiation level yet in the ocean next to the damaged plant. The readings showed toxic water from an unknown part of the site was reaching the ocean, though government officials said they weren't sure from where, and marked a setback after ocean readings had fallen in recent days.
Workers Give Glimpse of Japan's Nuclear Crisis
Japanese Plant Had Barebones Risk Plan
Japan's nuclear nightmare set to run and run
Fukushima beyond point of no return as radioactive core melts through containment vessel
Japan nuclear crisis: evacuees turned away from shelters
Nuke crisis scares foreign buyers off seafood
Radiation Traces Found in U.S. Milk
The Nature: Concerns over nuclear energy are legitimate
Club Orlov: Nuclear Meltdowns 101
Youtube: Chris Busby Explains Why Uranium Is Bad For You
[editor's note, by Migeru] Japan threads: