FUKUOKA (Kyodo) -- Kyushu Electric Power Co. suspended the operation of a second reactor at its Sendai nuclear plant Wednesday as it will miss the regulators' deadline to implement antiterrorism measures, following a halt of the other unit at the complex in March.
The No. 2 reactor at the Sendai plant in Kagoshima Prefecture, southwestern Japan, went offline in the afternoon ahead of the Thursday deadline for the completion of antiterrorism steps.
The utility aims to bring the reactor back online on Jan. 26 next year after making the required changes to facilities and undertaking regular safety inspections.
The suspension of the Sendai No. 1 reactor was the first such case under stricter rules introduced in 2013 following the 2011 Fukushima nuclear crisis.
With both of the two Sendai reactors halted, Kyushu Electric said it will make up for the electricity shortage with fossil fuel-driven thermal power generation and ensure there will be no disruption in power supply.
But the additional fuel costs, estimated at around 25 billion yen ($232 million), are expected to weigh on the Fukuoka-based company's bottom line, industry watchers say.
The utility, which supplies electricity across the southwestern main island of Kyushu, also expects to spend about 242 billion yen in total on antiterror steps at the two Sendai plant reactors.
In the wake of the Fukushima crisis, the severest nuclear accident since the 1986 Chernobyl disaster, the Nuclear Regulation Authority obliges plant operators to build facilities that can withstand terrorist attacks such as planes being flown into them without succumbing to major damage such as massive leakages of radioactive materials.
Equipment such as coolant pumps and emergency power sources are supposed to be placed roughly 100 meters away from a reactor to avoid being affected by a terror attack.
Kyushu Electric said that as of late April, about 70 percent of electric and machinery work was completed, while 90 percent of civil engineering work was done.
Kansai Electric Power Co. is also expected to suspend operations from later this year at its Nos. 3 and 4 reactors at the Takahama plant in Fukui Prefecture, central Japan, for the same reason.