Two nuclear reactors shut for maintenance in southern Japan will not be allowed to restart until Tokyo officials answer questions on safety policy, Saga prefecture's governor Yasushi Furukawa said on Monday.
Furukawa said he was not confident that new safety steps the central government ordered at nuclear operators after the Fukushima disaster go far enough to ensure safety at the 36-year-old Genkai nuclear plant, operated in the prefecture by Kyushu Electric Power Co.
"We don't think that we have to restart the reactors unless we can be persuaded that safety is secured," Furukawa told reporters in Tokyo.
A delayed restart for the Genkai plant's two idled reactors, which supply about 15 percent of the utility's power, increases the risk of electricity shortages this summer on the southern island of Kyushu, home to major auto and semiconductor plants.
The reactors had been considered among the likeliest candidates for the first idled reactors in Japan to restart after the Fukushima disaster.
Kyushu Electric had the No.2 Genkai reactor ready for restart in March while No.3 was ready in April, but it kept them shut pending approvals by local authorities.
Furukawa said it was not clear to him why Japanese Prime Minister Naoto Kan had ordered the shutdown of the Hamaoka reactor, 200 km (120 miles) southwest of Tokyo, while saying other reactors such as Genkai could be cleared for operation.
Furukawa said he had asked the central government to clarify whether the use of fuel containing plutonium at one of the reactors at the crippled Fukushima plant worsened the environmental damage. The No. 3 Genkai reactor also uses so-called MOX fuel containing plutonium.
The debate over the Genkai nuclear plant's restart has been seen as a test case for how Japanese officials will address safety concerns after the worst nuclear crisis since Chernobyl.
Japan has ordered new safety steps for nuclear power plants focused on protection against a tsunami, which the central government has said was the main cause of the Fukushima disaster. All of Japan's reactors have since complied with the order.
But the magnitude-9.0 earthquake on March 11 may also have damaged one of the reactors, officials have said. The 15-metre tsunami wiped out cooling functions at the Fukushima Daiichi complex, causing meltdowns at three out of its six reactors. Although there is no legal requirement to obtain the consent of local officials for nuclear plant operations, in practice Japanese utilities have always won their consent.
Local authorities' newfound caution could prevent restarts after maintenance at the 39 reactors in Japan that were unaffected by the March 11 quake.
Twenty of those reactors are already down for maintenance or other reasons, while the remainder will have to be taken offline for checks and repairs within the next year or so, since they are not allowed to run for more than 13 months without maintenance.That raises the possibility that all of Japan's reactors would be shut down if restart delays become prolonged.
Before the quake and tsunami, nuclear power supplied about 30 percent of electricity in Japan.
In an unprecedented step, in early May Kan urged the Hamaoka nuclear plant operator, Chubu Electric Power Co , to shut the facility until it could be better defended against a tsunami, citing the region's particular susceptibility to large earthquakes and its proximity to major population centres. The utility complied.
Furukawa complained that Saga prefecture, like Fukushima and Hamaoka, faces the risk of a major earthquake and must ensure the safety of its population.