Recent statements by Shizuoka Gov. Heita Kawakatsu concerning the stalled plan to use plutonium-uranium mixed-oxide (MOX) fuel at Chubu Electric Power Co.’s Hamaoka nuclear power plant in Omaezaki, Shizuoka Prefecture, highlight various contradictions in the central government’s continuing pursuit of a nuclear fuel-cycle policy.
In an interview with Kyodo News and at a subsequent news conference in April, the governor said his prefecture’s approval of the utility’s plan to use MOX fuel at the Hamaoka No. 4 reactor — given before nuclear power safety was thrown into doubt by the March 2011 meltdowns at Tokyo Electric Power Co.’s Fukushima No. 1 plant — should be considered invalid.
Kawakatsu is suggesting that Chubu Electric will need to obtain the consent of the prefecture and host municipalities all over again if it plans to push ahead with using the plutonium-uranium fuel at Hamaoka.
Kawakatsu also urged Chubu Electric to shift from the practice of storing spent nuclear fuel in water pools at the power plant to the alternative “dry cask storage.”
He went on to say that the Hamaoka plant would be able to store spent fuel in dry casks on-site even if the used fuel currently kept at a reprocessing plant in Rokkasho, Aomori Prefecture, is returned to the plan in the event the reprocessing program goes nowhere.
For decades, the central government has pursued a policy of recycling fuel used at nuclear power plants by reprocessing it into MOX fuel, to be used again both at fast-breeder reactors — which are designed to produce more plutonium than they consume — and at light-water reactors. It was meant to be a dream program for resource-scarce Japan.
However, Monju, the nation’s sole prototype fast-breeder reactor in Tsuruga, Fukui Prefecture, has been inoperative for nearly two decades now because of a series of accidents and problems with its operator.
Use of MOX fuel began at several light-water reactors at nuclear power plants around the country, but all of them are offline today, and the tightened safety requirements on restarting nuclear power plants following the Fukushima disasters raise doubts about whether the prospect of having 16 to 18 reactors nationwide consume the nation’s plutonium stockpiles — already reaching 44 tons — is realistic.
Completion of the Rokkasho reprocessing plant has been delayed for years due to a raft of technical glitches, but starting the plant’s operation could end up producing more separated plutonium whose consumption is uncertain.
Nevertheless, the nation’s Basic Energy Plan, adopted by the Abe administration last month, keeps up the quest for a nuclear fuel-cycle policy — even though doubts about the validity of the program have become widespread because of the realities surrounding it.
One logic that proponents use in pushing the policy, despite all the doubts, is that a halt to the reprocessing plan could put the nation’s nuclear power generation itself in jeopardy. Spent fuel from nuclear power plants around the country that has been shipped to Rokkasho, waiting to be reprocessed, will need to be returned to each plant if the reprocessing program is canceled. This will lead eventually to the filling to capacity of spent nuclear fuel pools at the plants, effectively making it impossible for the utilities to operate their nuclear reactors.
This problem could be resolved if, as Kawakatsu says, the nuclear power plant operators kept their spent nuclear fuel — including fuel that might be returned from Rokkasho — on the premises of their plants in dry cask storage.
With this method, spent fuel already cooled in the pool for at least one year would be surrounded by inert gas inside a container called a cask — typically steel cylinders that provide leak-tight confinement of spent fuel — and further surrounded by additional materials including steel and concrete for radiation shielding.
While dry cask storage is becoming more common at American and European nuclear power plants, it has so far been used at only a few Japanese plants. The method is believed to be technically more stable than storage in pools, where temperatures can rise if the cooling system fails because of the loss of water or power.
Spent fuel today occupies about 70 percent of the total storage pool capacity at the nation’s nuclear power plants and the Rokkasho facility combined, raising alarms that the capacity would be used up within years if power plants are restarted without the reprocessing of used fuel at the Rokkasho plant.
Kawakatsu said that typical nuclear power plant sites should have enough surplus space for dry cask storage of spent fuel, noting that at least the Hamaoka plant does.
Dry cask storage does not provide a permanent solution to the problem of what to do with spent nuclear fuel. Still, it could provide some leeway for reviewing the government’s rigid pursuit of the nuclear fuel cycle policy.
The Hamaoka plant has five reactors, including two aging ones that Chubu Electric decided in 2008 to decommission. In 2011, the utility shut down two operating reactors and held off restarting another that was down for maintenance at the urging of the government following the Fukushima meltdowns.
In February, Chubu Electric applied to the Nuclear Regulation Authority for safety screening of its plan to restart the No. 4 reactor, hoping to resume operations upon the completion of the extra anti-earthquake and tsunami measures by the end of September 2015.
Kawakatsu said he would seek to hold a plebiscite to get local residents’s views if the government and the utility decide to restart the Hamaoka plant. His retraction of Shizuoka’s go-ahead for the MOX fuel use at the plant may also influence other prefectures and municipalities that had had MOX plans approved for the nuclear power plants they host — before the Fukushima nuclear crisis.
The governor’s remark that it is rational for nuclear waste to be kept where it has been produced speaks volumes about another problem with nuclear power generation in Japan — the imbalance between the direct beneficiaries of nuclear power and those who bear the biggest burdens of it.
Tokyo, for example, is the nation’s largest consumer of electricity, but nuclear power plants that serve its needs are built hundreds of kilometers away. Shizuoka, however, happens to be both a producer and consumer of nuclear power.
The government has been unable for years to find candidate sites for the final storage of high-level radioactive waste from power generation. The lack of clear answers to this question is symbolic of the shaky nature of nuclear power in Japan.