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Tokyo, Japan - Japan, which currently produces about 30 percent of its electricity from nuclear power, is turning to a plutonium-based fuel to supplement its existing energy programs. For the resource-poor country, recycling reprocessed plutonium – which can also be used to produce nuclear weapons – can help reduce dependence on foreign energy supplies.
There are still some issues to be resolved in implementing the program, however. The process involves burning a mixed plutonium-uranium oxide, or MOX fuel, in conventional light water reactors.
MOX fuel is made by mixing plutonium extracted from nuclear spent fuel with uranium. It has been used in 57 nuclear reactors in nine countries so far, and is currently fueling 35 reactors in France, Germany, Switzerland and Belgium. Only two plants, in France and Britain, are currently producing commercial quantities of the fuel.
Two tankers carrying fuel produced by French nuclear giant Areva are expected to arrive in Japan in late May. The Kyushu Electric Power Co. in southern Japan will be the first company to burn the fuel, replacing one-third of its uranium fuel with MOX in its Genkai power plant No.3 by late September or early October, after a safety review by the government. Later, the Shikoku Electric Power Co. and Chubu Electric Power Co. will also load the fuel.
One purpose in implementing the MOX program is to consume 35 tons of plutonium Japan had stockpiled in France and England. To avoid international suspicions that it might develop a nuclear weapon, Japan has promised it will not keep surplus plutonium. It has shipped 7,100 tons of nuclear spent fuel to those countries' reprocessing facilities. The MOX fuel on its way from France was made from this plutonium supply.
Another purpose is to conserve uranium fuel. "It is true that the program can save 15 to 20 percent of uranium fuel, but that is not the main purpose," said Hajimu Yamana, a nuclear energy professor at Kyoto University.Domestic sources provide only around 4 percent of Japan’s energy needs – considering that even its nuclear power depends on imported uranium. Oil still accounts for nearly 50 percent of Japan’s energy consumption, and it imports 90 percent of its crude oil from the Middle East, an area the government considers politically unstable.
A desire to reduce its foreign energy dependence was a driving force behind Japan’s decision to develop nuclear power, and the same goal drives its decision to reprocess plutonium for fuel.
After uranium is burned in a typical reactor, the spent nuclear fuel still holds 50 percent of its potential power – 20 percent as uranium and 30 percent as plutonium.
"Plutonium is semi-domestically produced energy for Japan. If we continue to use all usable resources in the electrical power generation system, it could link to a fast breeder reactor, a more energy-sufficient system," Yamana said.
The MOX program will also help reduce the volume of high-level nuclear waste, Yamana pointed out. Compared to the direct disposal option – burying spent nuclear fuel underground after decades of cooling – extracting plutonium before disposal could reduce the waste repository by one-half to two-thirds, he said.
Some citizen groups have raised concerns as to the safety of the technology, as high technical precision is required to handle plutonium. An accident involving MOX fuel could be far more damaging than one with uranium, experts agree, as it emits 200 times more radiation.
Storage and transport of the fuel also requires more care and cost to prevent its handlers’ exposure to radiation. Another difficulty is the handling of spent MOX fuel, as it is much more radioactive and generates twice the heat of spent uranium fuel.
Currently, only France and Japan are proactive in using MOX fuel; Germany and Belgium use it only to consume existing stores of reprocessed plutonium. The United States, Sweden, the Netherlands and Italy have withdrawn from the program over the past dozen years because of high costs and resistance to the use of plutonium in their countries.
The United States has designed a MOX fuel plant to consume high-grade plutonium taken from dismantled nuclear weapons, scheduled for operation in 2016. The government hoped to sell the fuel to commercial reactors, but the failure of a MOX fuel test in a South Caroline power plant last year caused the program’s only contractor to withdraw, leaving the program in question.
Japan was expected to start burning MOX fuel in 16 to 18 commercial reactors by 2010. However, that plan also went off course when a scandal exposed in 1999 that British Nuclear Fuels had fabricated quality assurance data for MOX fuel exported to Japan.
Tokyo Electric Power Co., which had planned to load MOX fuel into its commercial reactors, also spread distrust of nuclear energy among Japanese citizens in 2002 when it was discovered to have covered up a series of technical problems. So far, only seven reactors are ready to begin burning the fuel, including the Genkai plant.
A citizens’ group in Saga prefecture, where the first reactor to be loaded with MOX fuel is located, aims to collect 400,000 signatures to stop the project and plans a huge protest rally in May to coincide with the arrival of the fuel tankers.
The Rokkasho Reprocessing Plant in the northern region of Aomori, which was the first commercial plant in a nonnuclear-weapon state, has also experienced troubles. Last year scientists said the plant was located above an active geological fault, sparking fears that an earthquake could damage the plant and release radiation.
Such fears are not unfounded in an earthquake-prone country that has 54 nuclear reactors in all. In July 2007 a 6.8-magnitude earthquake shook the Kashiwazaki-Kariwa Nuclear Power Station north of Tokyo, which was the world's largest nuclear power plant in terms of electricity generation. The plant was damaged by the tremors and all seven of its reactors still remain inactive.
"It is very risky to rely excessively on nuclear power, which holds numerous safety concerns and is vulnerable to earthquakes," said Hideaki Takemura, a project manager at the Institute for sustainable energy policies. The institute is looking for the best energy source for Japan.
Uncertainties over the long-term effects of burying highly radioactive waste are also a matter of concern. Whether nuclear waste is reprocessed or disposed directly, a certain quantity of radioactive material ends up underground. The only country that has specified a repository site for spent nuclear fuel is Finland; its site is under construction.
The United States selected Yucca Mountain in Nevada in 1978 and began research to determine whether it would be a suitable site for a nuclear repository. Even though over US$10 billion has been invested in research since 1994, President Barack Obama announced in late February that construction would not go ahead on the site.
Nuclear power, which generates electricity without emitting carbon dioxide, holds promise from the viewpoint of preventing global warming and of responding to high oil prices. However, the many issues yet to be resolved suggest it will take time for its full potential to be tapped.