Coming on the heels of the five-year anniversary of the Fukushima nuclear disaster, Japan’s Kansai Electric Power Co said Monday a radioactive coolant water leak at an idled reactor in western Japan was the result of insufficient tension of a bolt used in a valve installed in a pipe.
The power company said an estimated 34 liters of coolant water leaked in a building attached to the No. 4 reactor at the Takahama nuclear power plant in Fukui Prefecture, containing a radioactivity level below that which needs to be reported to the state.
Kansai Electric will now implement measures to prevent a recurrence and resume the final start-up test for the restart of the reactor it suspended Saturday after the accident.
The leakage may put off the plan for the reactor’s reboot which would make it the fourth reactor in Japan to operate under stricter safety rules set after the 2011 Fukushima nuclear meltdown.
The No. 4 unit would become the second reactor to run on uranium-plutonium mixed oxide (MOX) fuel under post-Fukushima regulations.
MOX fuel is a key component of the nuclear fuel cycle program pursued by the nuclear power industry and the government, created by plutonium and uranium extracted from spent nuclear fuel.
The No. 3 reactor at the same nuclear complex came back online late last month.