January 29, 2016

Takahama reactor achieves criticality

http://www3.nhk.or.jp/nhkworld/english/news/20160130_12.html

Jan. 29, 2016 - Updated 23:08 UTC+1

Kansai Electric Power Company says a reactor that's been restarted in central Japan achieved criticality, a self-sustained nuclear reaction on Saturday morning, which should allow it to start generating power.

The Takahama plant's No.3 reactor in Fukui Prefecture is the third to restart under tougher government regulations introduced after the 2011 Fukushima Daiichi nuclear crisis.

On Friday, the plant's engineers removed some of the control rods from the reactor, and then restarted the facility.

After extracting 3 fourths of the control rods they cautiously adjusted nuclear fission reaction by controlling the density of materials in cooling water.
The utility plans to have the reactor generate power on Monday, if no problems are found with the performance of the control rods and other equipment. The resumption of commercial operation is planned for late February.

The operator says it will closely monitor whether the reactor's equipment is functioning properly after being offline for almost 4 years.

Part of the fuel used is a MOX type, a mixture of plutonium extracted from spent nuclear fuel and uranium. It forms part of Japan's nuclear fuel recycling system.
The reactor would be the first to use MOX fuel under the new regulations.

Two reactors at the Sendai nuclear plant in the southwestern prefecture of Kagoshima resumed operations last year.

January 29, 2016

Japan restarts 2nd nuclear complex under tighter post-Fukushima rules

http://mainichi.jp/english/articles/20160129/p2g/00m/0dm/074000c

FUKUI, Japan (Kyodo) -- A reactor at a nuclear plant in western Japan resumed operation Friday, becoming the second complex to restart, and the first running on uranium-plutonium mixed oxide fuel, under stricter safety rules set after the 2011 Fukushima nuclear disaster.

Kansai Electric Power Co. said it reactivated the No. 3 reactor at its Takahama plant in Fukui Prefecture nearly a year after it gained approval for resumption from the Nuclear Regulation Authority.

It is the third reactor operating under post-Fukushima regulations, following two reactors at Kyushu Electric Power Co.'s Sendai plant in Kagoshima Prefecture, which were restarted last August and October, respectively.

The government is pushing ahead with nuclear restarts after all of the country's 48 reactors were shut down for safety reviews following the Fukushima accident.

The state looks to generate at least 20 percent of Japan's overall electricity with nuclear power by 2030 despite public opposition to nuclear power remaining strong since the disaster at the Tokyo Electric Power Co. plant.

Last April, a district court banned Kansai Electric from restarting the Nos. 3 and 4 reactors of the Takahama plant, citing safety concerns.

The same court lifted the injunction last month, allowing the utility to resume the two units, both 870-megawatt pressurized water reactors that began commercial operations in 1985.