Second Japanese reactor restarted

15 October 2015

Unit 2 of the Sendai nuclear power plant in Japan's Kagoshima prefecture was restarted today, plant owner Kyushu Electric Power Company announced. It becomes the second Japanese reactor to resume operation after the country idled its entire fleet following the March 2011 accident at the Fukushima Daiichi plant.  

Sendai 460 (Kyushu)
Both units at Sendai are now in operation (Image: Kyushu)

Kyushu said the control rods were extracted from the reactor's core and it started up at 10.30am today. The 890 MWe pressurized water reactor was expected to achieve criticality - a self-sustaining reaction - at around 11.00pm the same day.

The utility expects Sendai 2 to begin supplying electricity again on 21 October. The unit's output will gradually be increased while tests are conducted and, following a final inspection by the Nuclear Regulation Authority, it is expected to re-enter commercial operation in mid-November.

Takahama units approach restart

Kansai Electric Power Company has applied to the Nuclear Regulation Authority (NRA) for pre-start-up inspections at unit 4 of its Takahama nuclear power plant in in Fukui prefecture.

The utility has already been granted all approvals in NRA's three-step review process for Takahama units 3 and 4, both 870 MWe pressurized water reactors. However, it requires pre-start-up inspections before their operation can resume.

'Pre-use' inspections got under way at unit 3 on 17 August. Kansai reportedly aims to restart the two reactors by the end of this year but requires a temporary injunction imposed by the Fukui District Court prohibiting their restart to be lifted.

Kyushu president Michiaki Uriu said in a statement, "We see this startup as one of the important steps of the nuclear reactor's restart process." It added, "We will continue to sincerely make an all-out effort to deal with the Nuclear Regulation Authority's inspections, and carefully carry out the remaining process, putting utmost priority on safety, with a sense of alertness more than ever."

Unit 1 of the Sendai nuclear power plant was the first of Japan's operable reactors to resume operation since September 2013 when it was restarted in August.

The two units at Sendai were taken offline for periodic inspections in May and September 2011, respectively. As with all of Japan's reactors, the restart of the units has been delayed until it has been confirmed they meet new safety standards introduced after the Fukushima Daiichi accident. The restart of the Sendai units has been prioritised, in part due to local support in Kagoshima prefecture.

Following the accident at Fukushima Daiichi, all of Japan's reactors were gradually taken offline for periodic inspections and safety checks. Unit 1 of the Ohi plant was the last to be taken offline in September 2013.

Twenty more reactors are currently progressing through the restart process, which is expected to gradually speed up after the first few units are back in normal operation. In addition to the two Sendai units, three other reactors have cleared the regulator's safety inspections: Takahama units 3 and 4 and Ikata unit 3.

The Japanese government envisages a return to using nuclear power for 20-22% of its electricity needs by 2030 as part of a plan to reduce carbon dioxide emissions by 26% compared to fiscal year 2013.

Researched and written
by World Nuclear News