FUKUI – Kansai Electric Power Co. said Sunday it has put off preparatory work for restarting of the No. 4 reactor at its Takahama nuclear plant in Fukui Prefecture after a radioactive water leak was discovered a day earlier — a move that may delay plans to reboot the unit later this month.
Kepco officials said the utility is continuing to probe the cause of the leak.
Kepco had planned on Sunday to test the No. 4 reactor and pipes carrying coolant water by raising the pressures and temperatures to near normal operational levels. This work was tentatively put off until Monday or possibly even later, the officials said.
A delay in determining the cause of the leak and how to repair it could affect the reactivation timetable.
On Saturday, the utility announced it had found a puddle of radioactive water inside an auxiliary building at the No. 4 reactor.
The prefectural government’s nuclear safety division said the leak did not affect the environment.
“Resumption procedures have been suspended in light of the incident because we are still investigating the cause,” a Kepco spokesman said.
According to the company, an alarm went off after the utility injected water into a pipe connected to the No. 4 reactor’s first cooling system at around 3:40 p.m. Saturday. Water was found dripping from two valves on a coolant water filter in the auxiliary building, and the radioactivity of the resulting 8-liter puddle was 14,000 becquerels.
Judging from other traces on the floor, roughly 34 liters were leaked overall, amounting to about 60,000 becquerels.
The No. 4 reactor is 30 years old and has idle for more than 4½ years since being taken offline in July 2011 for a scheduled checkup. That’s longer than the No. 3 reactor, which was reactivated in January, and reactor Nos. 1 and 2 at Kyushu Electric Power Co.’s Sendai plant in Kagoshima Prefecture, which were rebooted last year.
All four reactors have cleared the stiffer safety requirements set up after the March 2011 triple core meltdown at Tokyo Electric Power Co.’s poorly protected Fukushima No. 1 plant, which was wrecked in the nuclear disaster.
In December, the Fukui District Court overturned an injunction on restarting the two Takahama reactors that had been brought by residents who said their safety had not been proven, despite being greenlighted by the Nuclear Regulation Authority.
In Kagoshima, the two Sendai reactors were restarted in August and October 2015, ending a two-year hiatus.
Officials in the town of Takahama have been eager to see the reactors back online. Between 1974 and 2013, the town, with a population of around 11,000, received over ¥35 billion in nuclear-related subsidies.
Prior to 2011, about half its annual budget came from such subsidies, while the roughly annual safety inspections brought in thousands of Kepco and government officials.