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NRA approves extension of tsunami-hit Tokai No. 2 plant, but restart awaits local agreement

The idled Tokai No. 2 Power Station, right, and the Tokai Power Station that is being decommissioned, are seen in this file photo taken in Tokai, Ibaraki Prefecture, from a Mainichi Shimbun helicopter on July 17, 2018. (Mainichi/Tatsuya Fujii)

TOKYO -- The Nuclear Regulation Authority (NRA) has approved the extension of operations at Japan Atomic Power Co.'s Tokai No. 2 Power Station in the eastern Japan prefecture of Ibaraki by up to 20 years, but the restart of the aging facility still awaits local approval.

The government's nuclear regulator made the decision on Nov. 7 after the nuclear plant passed three inspections, including one to see if the complex meets the new regulatory standards introduced in the wake of the March 2011 outbreak of the Fukushima nuclear crisis.

The move could allow Japan Atomic Power to continue operating the atomic power station in the village of Tokai until Nov. 27, 2038.

Attention is now focused on whether the decision will win approval from the Ibaraki Prefectural Government and six municipalities around the station with which the company has signed safety agreements.

Nuclear reactors can be operated for up to 40 years in principle. However, the period of operations at such plants can be extended just once by up to 20 years. The Tokai No. 2 plant's sole unit is the fourth nuclear reactor for which an extension has been approved following the No. 1 and 2 reactors at Kansai Electric Power Co.'s Takahama plant and the No. 3 reactor at the firm's Mihama plant, both in the central Japan prefecture of Fukui.

The Tokai No. 2 station will be the first nuclear plant for which an extension has been approved among those that sustained damage in the March 2011 Great East Japan Earthquake and tsunami. Furthermore, the plant's reactor is the sole boiling-water unit -- the same type as those at the tsunami-ravaged Fukushima Daiichi Nuclear Power Station -- for which an extension of operations has been green-lighted.

Japan Atomic Power applied to the NRA for safety inspections for the Tokai No. 2 power station in May 2014 with an eye to reactivating it and for permission to extend the operations at the plant in November 2017.

The facility would have been decommissioned if it had not passed the three inspections by Nov. 27 this year. Therefore, the NRA barely made the deadline.

The plant's large boiling-water reactor with an output of 1.1 million kilowatts stopped following the Great East Japan Earthquake on March 11, 2011. The power station temporarily lost its external power source. Moreover, it was hit by up to 5.4-meter-high tsunami waves triggered by the temblor, making one of the three emergency power generators unusable. However, the plant used the remaining two generators to continue cooling the reactor core.

Out of reflection on the trouble, Japan Atomic Power has decided to take additional safety measures, including the installation of a reinforced concrete storm surge barrier on the assumption that the plant could be hit by tsunami waves up to 17.9 meters high.

The NRA deemed these safety measures are appropriate in light of the new regulatory standards.

In inspections of the power station to see if its reactor pressure vessel has deteriorated, the atomic power regulator concluded that it can endure the extension of operations beyond the 40-year limit.

Japan Atomic Power intends to secure 174 billion yen to implement these safety measures after receiving financial assistance from Tokyo Electric Power Co. and Tohoku Electric Power Co. and complete the work by March 2021.

The operator of the Tokai No. 2 station has signed safety agreements with five municipalities around the plant besides the municipal government of Tokai that hosts the power station and the prefectural government, effectively allowing these surrounding municipalities to approve or disapprove reactivation of the plant. Japan Atomic Power's agreements with five surrounding municipalities are the first of its kind allowing municipalities other than those hosting atomic power stations to approve or disapprove operations at such plants.

Among the five municipalities, Toru Umino, mayor of the Ibaraki Prefecture city of Naka, has already clarified the city's opposition to reactivation of the power plant.

Japan Atomic Power's Tokai Power Station, situated on the premises that host the Tokai No. 2 plant, is in the process of being decommissioned.

(Japanese original by Riki Iwama, Science & Environment News Department)

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