The uncertain fate of the spent mixed-oxide (MOX) fuel removed from two nuclear power reactors in western Japan last month — for the first time since the commercial use of plutonium-uranium fuel in light water reactors began about a decade ago — is yet another sign of the stalemate over the government’s nuclear fuel cycle policy. While the government maintains that all spent nuclear fuel will be reprocessed for reuse as fuel for nuclear reactors, there are no facilities in this country that can reprocess spent MOX fuel so it will remain indefinitely in storage pools at the nuclear plants.
A reprocessing plant owned by Japan Nuclear Fuel Ltd. that is under construction in Rokkasho, Aomori Prefecture, can only handle spent uranium fuel. No concrete plans have been made for building a second plant capable of reprocessing spent MOX fuel. Completion of the Rokkasho plant itself has been delayed for years amid an endless series of technical glitches resulting in huge cost overruns since construction began in the early 1990s. When the plant is completed and begins operating it will likely only add to Japan’s plutonium stockpile. This is because the use of plutonium in MOX fuel remains sluggish due to the slow restart of reactors idled following the 2011 meltdowns at the Fukushima No. 1 nuclear power plant operated by Tokyo Electric Power Company Holdings Inc.
Instead of shelving hard decisions on the nuclear fuel cycle policy any further, the government and the power industry need to candidly assess the prospects of the policy and proceed with a long-overdue review.
Under the policy that touts efficient use of uranium resources, fuel assemblies spent at nuclear power plants will be removed from the reactors to extract plutonium, which will be blended with uranium to make the MOX fuel. What were removed from the reactors at Shikoku Electric Power Co.’s Ikata reactor in Ehime Prefecture and Kansai Electric Power Co.’s Takahama plant in Fukui Prefecture in January are the MOX fuel rods that were installed in 2010. The government maintains that it’s technologically feasible to reprocess spent MOX fuel, but experts are doubtful about the efficiency of this practice.
Initially, the policy assumed a transition to fast-breeder reactors in Japan’s nuclear power generation. Touted to produce more plutonium than it consumes as fuel, a fast-breeder reactor was deemed a dream technology in this resource-scarce country. However, Monju, the nation’s sole prototype fast-breeder reactor — on which more than ¥1 trillion was spent — was decommissioned in 2016 after sitting idle for much of the time since it first went online in 1994 due to a series of accidents and troubles. The government sought to continue research on next-generation fast reactors in a joint project with France, but that bid has been in limbo since Paris decided to substantially scale back the project in light of the abundance of uranium resources, which cast doubts over its economic feasibility.
As completion of the reprocessing plant in Rokkasho continues to be pushed back, some 15,000 tons of spent nuclear fuel is stored at nuclear power plants across Japan. Combined with 3,000 tons kept in the storage pool at the Rokkasho plant, the total comes to around 18,000 tons. The volume will only increase if more reactors are restarted without the launch of the reprocessing plant, and the capacity of storage pools at power plants is limited.
On the other hand, Japan is under pressure to utilize its 45-ton stockpile of plutonium as fuel due to proliferation concerns. As the Monju project went nowhere, the government and the power industry have pursued the use of MOX fuel in conventional light water reactors since around 2010. However, the use of MOX fuels has remained slow following the shuttering of most of the nation’s nuclear plants after the 2011 Fukushima disaster. Currently, MOX fuel is used in only four reactors across the country — far below the 16 to 18 planned prior to the Fukushima accident. There are also doubts about the economic viability of the use of MOX fuel, which is more costly than conventional nuclear fuel.
It seems clear that the nuclear fuel cycle policy is stuck in a stalemate, but neither the government nor the power industry will accept that — apparently because abandoning the program would seriously impact nuclear energy policy. An alternative to reprocessing is to bury the spent fuel deep underground — a method reportedly adopted in some countries. But then the spent fuel — which has so far been stored as a resource to be processed for reuse — will be turned into nuclear waste, raising the politically sensitive question of where to dispose of it. That, however, is a question that cannot be averted given Japan’s use of nuclear power. It should not be used as an excuse for maintaining the quest for the elusive nuclear fuel cycle. It’s time to review the policy.
The Japan Times Editorial Board
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