Fukushima Daiichi Site : Cesium-137 is 85 times greater than Chernobyl .
By Akio Matsumura
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 assemblies 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 assemblies, located some 50 meters from reactor 4.
In both cases the radioactive assemblies 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 assemblies at the Fukushima Daiichi site excluding the assemblies 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 assemblies.
I received an astounding response from Mr. Alvarez [updated 4/5/12]:
This then leaves 1,231 irradiated spent fuel rods in pool No. 4, which contain roughly 37 million curies (~1.4E+18 Becquerel) of long-lived radioactivity. The No. 4 pool is about 100 feet above ground, is structurally damaged and is exposed to the open elements. If an earthquake or other event were to cause this pool to drain this could result in a catastrophic radiological fire involving nearly 10 times the amount of Cs-137 released by the Chernobyl accident.
The infrastructure to safely remove this material was destroyed as it was at the other three reactors. Spent reactor fuel cannot be simply lifted into the air by a crane as if it were routine cargo. In order to prevent severe radiation exposures, fires and possible explosions, it must be transferred at all times in water and heavily shielded structures into dry casks. As this has never been done before, the removal of the spent fuel from the pools at the damaged Fukushima-Dai-Ichi reactors will require a major and time-consuming re-construction effort and will be charting in unknown waters. Despite the enormous destruction cased at the Da–Ichi site, dry casks holding a smaller amount of spent fuel appear to be unscathed.
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.
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.
It seems to us that the Nuclear Security Summit was focused on the North Korea nuclear issue and on the issue of common security from a terrorist attack. Our appeal on the need for the independent assessment at Reactor 4 was regarded as less urgent. We predicted this outcome in light of the nature of the Summit.
I suppose most participants fully understood the potential disaster, which will affect their countries. Nevertheless, they decided not to raise the delicate issue, perhaps in order to not ruffle their diplomatic relationship with Japan.
If Japanese government leaders do not recognize the risk their nation faces, how could the rest of us be persuaded of the looming disaster? And if the rest of us do not acknowledge the catastrophe we collectively face, who will be the one to act?
I wish to express my heartfelt gratitude for your considerate letter dated 2 March 2012. Your moral support for a United Nations Ethics Summit will remain a constant source of encouragement for my activities.