TOKYO -- Water containing radioactive substances may have leaked into the ocean from the Fukushima Daiichi nuclear plant on Thursday, the plant operator said, the latest example of continued problems at the stricken plant more than three months after the government declared conditions there stabilized.

The leakage was at a pipeline carrying concentrated radioactive water from a desalination device to a storage tank early in the day, plant operator Tokyo Electric Power Co. 9501.TO +4.29% said
in a news release. The leak was contained after 30 minutes when valves were closed.
The company estimates roughly 12 tons of contaminated water may have escaped into the ocean. High levels of cesium 134 and 137 were confirmed at the point of the leak roughly 300 yards from the ocean, but no detectable amounts of radioactive contamination have been found in the sea water.
The company will further investigate the possible spread of contamination and its potential impact in the ocean, including the existence of beta radiation that could contain harmful strontium, company spokesman Yoshikazu Nagai said.
The amount of water reportedly released was tiny compared with the amount Tepco dumped into the ocean during the early weeks of the accident. The Japanese government alarmed neighboring countries in April last year when it approved the discharge of 10,000 tons of low-level radioactive water from the plant as Tepco ran out of space to store the water used to cool reactors.
Thursday's leak came on the heels of several other problems at the plant.
In late March, Tepco said readings of airborne radiation inside the containment vessel at the No. 2 reactor had surged to a deadly 79 sieverts, the highest level since the crisis began March 11 last year. That came alongside news that the volume of the reactor's cooling water had declined sharply.
A leakage incident near the desalination facility similar to Thursday's was also reported March 26.
Such problems have cast doubts about the plant's stability long after the government declared in late December the reactors had been brought under control.
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by staff report via stan 2012-04-09 07:53:35
"Based on U.S. Energy Department data, assuming a total of 11,138 spent fuel assemblies are being stored at the Dai-Ichi site, nearly all, which is in pools. They contain roughly 336 million curies (~1.2 E+19 Bq) of long-lived radioactivity. About 134 million curies is Cesium-137 — roughly 85 times the amount of Cs-137 released at the Chernobyl accident as estimated by the U.S. National Council on Radiation Protection (NCRP). The total spent reactor fuel inventory at the Fukushima-Daichi site contains nearly half of the total amount of Cs-137 estimated by the NCRP to have been released by all atmospheric nuclear weapons testing, Chernobyl, and world-wide reprocessing plants (~270 million curies or ~9.9 E+18 Becquerel). It is important for the public to understand that reactors that have been operating for decades, such as those at the Fukushima-Dai-Ichi site have generated some of the largest concentrations of radioactivity on the planet." (Robert Alvarez, former Senior Policy Adviser to the Secretary and Deputy Assistant Secretary for National Security and the Environment at the U.S. Department of Energy)
The Greatest Single Threat to Humanity: Fuel Pool Number 4
We noted days after the Japanese earthquake that the biggest threat was from the spent fuel rods in the fuel pool at Fukushima unit number 4, and not from the reactors themselves. See this and this.We noted in February:
Germany’s ZDF tv quotes nuclear engineer Yukitero Naka as saying:
(Unit 4 contains plutonium as well as other radioactive wastes.)
Mainchi reported on Monday:
Kevin Kamps said last month:
Fukushima...radiation so high - even robots not safe
Former U.N. adviser Akio Matsumura – whose praises have been sung by Mikhail Gorbachev, U.S. Ambassadors Stephen Bosworth and Glenn Olds, and former U.S. Deputy Secretary of State and Goldman Sachs co-chair John C. Whitehead – notes:
Matsumura was told that if the fuel pool at unit 4 collapses or the water spills out, so much radiation will spew out for 50 years that no one will be able to approach Fukushima:
Fukushima Reactor 4
Even more dramatically, Matsumura writes:
Japan’s former Ambassador to Switzerland, Mr. Mitsuhei Murata, was invited to speak at the Public Hearing of the Budgetary Committee of the House of Councilors on March 22, 2012, on the Fukushima nuclear power plants accident. Before the Committee, Ambassador Murata strongly stated that if the crippled building of reactor unit 4—with 1,535 fuel rods in the spent fuel pool 100 feet (30 meters) above the ground—collapses, not only will it cause a shutdown of all six reactors but will also affect the common spent fuel pool containing 6,375 fuel rods, located some 50 meters from reactor 4. In both cases the radioactive rods are not protected by a containment vessel; dangerously, they are open to the air. This would certainly cause a global catastrophe like we have never before experienced. He stressed that the responsibility of Japan to the rest of the world is immeasurable. Such a catastrophe would affect us all for centuries. Ambassador Murata informed us that the total numbers of the spent fuel rods at the Fukushima Daiichi site excluding the rods in the pressure vessel is 11,421 (396+615+566+1,535+994+940+6375).
I asked top spent-fuel pools expert Mr. Robert Alvarez, former Senior Policy Adviser to the Secretary and Deputy Assistant Secretary for National Security and the Environment at the U.S. Department of Energy, for an explanation of the potential impact of the 11,421 rods.
I received an astounding response from Mr. Alvarez [updated 4/5/12]:
Many of our readers might find it difficult to appreciate the actual meaning of the figure, yet we can grasp what 85 times more Cesium-137 than the Chernobyl would mean. It would destroy the world environment and our civilization. This is not rocket science, nor does it connect to the pugilistic debate over nuclear power plants. This is an issue of human survival.
There was a Nuclear Security Summit Conference in Seoul on March 26 and 27, and Ambassador Murata and I made a concerted effort to find someone to inform the participants from 54 nations of the potential global catastrophe of reactor unit 4. We asked several participants to share the idea of an Independent Assessment team comprised of a broad group of international experts to deal with this urgent issue.
I would like to introduce Ambassador Murata’s letter to the UN Secretary General Ban Ki-moon to convey this urgent message and also his letter to Japan’s Prime Minister Yoshihiko Noda for Japanese readers. He emphasized in the statement that we should bring human wisdom to tackle this unprecedented challenge.
Ambassador Murata’s letter says:
Anti-nuclear physician Dr. Helen Caldicott says that if fuel pool 4 collapses, she will evacuate her family from Boston and move them to the Southern Hemisphere. This is an especially dramatic statement given that the West Coast is much more directly in the path of Fukushima radiation than the East Coast.
Will humanity rise to the occasion, and figure out how to stabilize fuel pool number 4 before catastrophe strikes?
Or will modern civilization win a Darwin award for failing to pay attention to the real threats?
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