Safety upgrades impact operation of Japanese units 

29 January 2020

The restart of unit 2 of the Tokai nuclear power plant will be delayed by almost two years as construction of improved safety measures is taking longer than originally planned, Japan Atomic Power Company (JAPC) announced yesterday. Kansai Electric Power Company has also said Takahama units 3 and 4 will be taken offline later this year for extended period inspections while construction of back-up control centres is completed.

Unit 2 of the Tokai plant (Image: NRA)

JAPC applied to the Nuclear Regulation Authority (NRA) in November 2017 to extend the operation of the unit - a 1060 MWe boiling water reactor that started commercial operation in 1978 - by 20 years. The company announced a year later that the NRA had approved the extension. Tokai 2's operating licence had been due to expire on 28 November 2018.

The NRA approved the restart of Tokai 2 - which has been offline since March 2011 - on 26 September 2018 after concluding that safety measures proposed by JAPC passed revised safety standards.

Construction work on such countermeasures - including a 1.7km-long sea wall to protect the plant from a potential tsunami as high as 17.1 meters - was scheduled to be completed in March 2021. The company expects investment of about JPY180 billion (USD1.65 billion) is needed to put additional safety measures in place at the plant.

"However, based on the progress of the construction and a study of the schedule, the completion time of the construction has been changed from 2021 March to December 2022," JAPC has now said.

After completing all construction work related to the extended operation of the unit, JAPC will still need the approval of local municipalities in Ibaraki prefecture prior to the resumption of operation of Tokai 2.

Takahama units

Meanwhile, Kansai Electric Power Company has announced operation of units 3 and 4 of its Takahama plant in Fukui prefecture will be temporarily suspended as it will miss the deadline set by the NRA for the construction of bunkered back-up control centres.

These centres are a requirement of new regulations introduced in July 2013 in response to the March 2011 accident at the Fukushima Daiichi plant. The NRA ruled in November 2015 that such facilities must be completed within five years after regulatory approval of each plant's engineering and construction work programme.

Kansai has now said it will suspend operation of Takahama 3 on 2 August and unit 4 on 7 October for periodic inspections. Unit 3 is scheduled to resume operation on 22 December, with unit 4 following on 10 February 2021. During the periodic inspection outages, work will be carried out on the construction of the required safety countermeasures, including a permanent DC power supply, it added.

Researched and written by World Nuclear News