The No. 1 reactor at Kyushu Electric Power Co.’s Sendai nuclear power plant in Kagoshima Prefecture came back online on Tuesday.
But the utility has not designated a site for relocating nuclear fuel in the event of a massive volcanic eruption, claiming that warning signs would give Kepco enough time to prepare and transfer the fuel.
The utility and the Nuclear Regulation Authority have also decided there is little chance of a major volcanic eruption in the next several decades.
In the event of a major eruption, however, pyroclastic flows could reach the plant and disable cooling functions for its reactors and spent fuel, which could trigger massive radioactive emissions.
There are five major calderas around the Sendai plant, suggesting that massive eruptions have occurred there.
The plant currently stores 1,946 fuel assemblies in spent fuel pools. The sheer volume makes it hard to find a relocation site big enough to take them.
A panel of volcano experts advising the NRA has compiled a report indicating that there are currently no technologies that can precisely predict the timing and scale of a major eruption.
Toshitsugu Fujii, a member of the panel and chairman of the Meteorological Agency’s Coordinating Committee for Prediction of Volcanic Eruptions, has said that the panel’s opinion is not necessarily consistent with that of the NRA.
According to experts, the commonly held view is that it is impossible to predict a major eruption from warning signs because such eruptions occur only once every 10,000 years in Japan, so the data are scant.
The panel has proposed launching an advisory organization to the NRA to help deal with volcanic eruption forecasting. Due to time constraints, however, the launch of the organization is expected to be in September at the earliest.
The panel has also pointed out that the NRA should set standards for judgments on whether an impending eruption would be huge, but the time-line for setting such criteria is undecided.
Evacuation-plan worriesTwo hospitals and 15 welfare facilities for elderly people within 10 km of the Sendai plant should have evacuation plans in the event that a serious nuclear accident occurs. However, concerns remain.
The prefectural government initially asked welfare facilities within 30 km of the plant to draw up evacuation plans in line with a central government policy. But it later changed course. Kagoshima Gov. Yuichiro Ito insisted that it would be enough if evacuation plans within 10 km are in place and that those beyond that would be unworkable.
The Otama-san no Ie elderly group home, the welfare facility closest to the nuclear plant — about 1 km south of the plant’s main gate — included an evacuation destination beyond 30 km of the plant and four routes to it in its plans.
“This is supplementary to local governments’ evacuation plans,” said Keiji Miyauchi, general manager of the group home.
Under the group home’s evacuation plans, residents will be first taken to a nearby shelter built by the Satsumasendai city government. The shelter, equipped with a filtered venting system that can block radioactive materials, has four days’ worth of water and food.
But Miyauchi said: “The group home has only a staff of two during the night shift. It would be difficult to take 18 elderly residents, some of whom are in wheelchairs, to the shelter.”
Miyauchi is also concerned about the evacuation routes. “Roads would be congested because they are narrow,” he said. “Some roads may be destroyed and made inaccessible if an earthquake occurs.”
Broad evacuation plans are available but details cannot be fixed, said an official at another elderly facility within 10 km of the nuclear plant. “Needs among elderly people change depending on the season,” the official said.
The facility has an evacuation agreement in place for an elderly home located beyond 30 km from the nuclear plant to accept its residents. But how to care for these evacuees remains uncertain.
“A facility alone can’t determine what to do after evacuations, and this is a matter that needs to be decided by the central or prefectural government,” the official said.
Source: Japan Times