Doomsday Scenario 2.0
With the decision to entomb four Fukushima reactors in concrete, Tokyo Electric (TEPCO) is moving the disaster into uncharted waters. The heat producing fuel rods cannot be turned off. Concrete will insulate the heat from the fuel rods, and cause the internal temperatures to climb. The nuclear fuel will melt down and pass through the bottom of the reactor vessel and containment structure and enter the environment. The radionuclides, primarily cesium-137 and strontium-90, but also plutonium and others, will enter the sea. The human health and economic costs will be enormous.
TEPCO's choices were limited. The brave workers who were attempting to put a lid on atmospheric releases were fighting a valiant, but losing battle. Iodine was entering the air and the sea. Iodine concentrations in the sea were already over 4,300 times safe limits and in the plant, greater than 10,000 times safe limits for nuclear workers. Cesium, a semi-volatile metal, was also entering the sea through unknown pathways, likely leakage from below. Clearly the cladding around the nuclear fuel rods and the reactor vessel had been breached. So the choice was to continue to expose workers to extremely high radiation doses, while releasing cesium and iodine to the air and sea, or close it down, cover it with concrete and let the reactor cores and fuel pools melt into the ground and into the sea.
Assuming four reactors are coated with cement, and reactors 5 and 6 and the common ground level shared fuel pool can be saved, we can give a rough estimate of the radioactive inventory and compare it to two other nuclear disasters: Hiroshima and Chernobyl. Roughly, 2,100 Curies of cesium-137 were released at Hiroshima. At Chernobyl, according to the UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation, 2000), 2.3 million Curies of cesium-137 were released. The approximate inventory of reactors 1 through 4 is 100 million Curies cesium-137, or more than 40 times the Chernobyl release, and 48000 times the Hiroshima release of cesium-137. (spreadsheet available). Only a fraction of this Fukushima inventory has been released to-date. If a sizable release takes place, say 10% of the Fukushima inventory, this represents 8 times the Chernobyl release and 4,800 times the Hiroshima release. This would be a major catastrophe. Cesium would not just dissipate in the ocean or concentrate in fish; it will also wash back to shore. This will make it difficult for workers to service reactors 5 and 6.
The implications of cementing over reactors 1-4 are not clear. With the cesium-137 and iodine-131 releases from Fukushima, the evacuation zone is out to 30 miles, but a much larger coastal zone may ultimately be affected for many decades. The internal heat may explode the containment and cause additional cement cracking. The heat will certainly melt through the bottom of the reactor vessel and containment and into the underlying soil. The human health and cost implications of this accident could be enormous. Four hundred thousand Japanese have already been displaced by the tsunami and the forced evacuation. The present cost estimate of $300 billion, before the decision to cement over the four reactors, does not account for the long-term loss of the coast. Based on our cost estimates for potential nuclear transportation accident for the State of Nevada, we believe $300 billion is far too low. TEPCO may go into receivership and be taken over by the government. The Japanese economy, struggling before this accident, will take another hit.
For the United States, the Nuclear Regulatory Commission may take a harder look at the safety of the 23 or so Fukushima-type boiling water reactors. While the industry has fastened on the low probability of an earthquake and a tsunami, other factors may also be important. Reactors are complicated high tech machines run by humans, who, as TMI showed, make mistakes.
Vermont Yankee has had leaking and inoperable safety valves and a rundown cooling system. Entergy, the company that runs the plant, has little incentive to put money into the operation, since the State has refused to grant it a Certificate of Public Good to continue operation for an additional 20 years. Its decommissioning fund is half the needed amount. New York State is pushing Entergy to close down its Indian Point reactor. In case of a major accident, the evacuation zone includes New York City and its suburbs.
The Fukushima accident has heightened the tension between profits and safety. As the Fukushima accident plays itself out, the nuclear industry and GE in particular, must be vitally concerned. Unlike an oil or gas generating station, the heat at Fukushima cannot be turned off. Nuclear fuel is the gift that keeps on giving. GE, TEPCO and the Japanese economy will take a big hit, but the Japanese people, who have suffered through the earthquake and tsunami, will take the biggest hit, in terms of an expected increase in cancers caused by radiation from Fukushima.