Tohoku Electric Power : Review of the Construction Schedules for Safety Measures at Onagawa and Higashidori Nuclear Power Stations

TOHOKU ELECTRIC POWER CO., INC.

February 7, 2017

Tohoku EPCO has been implementing construction work on safety measures at Onagawa and Higashidori Nuclear Power Stations in parallel with responding to assessments on conformity to the new regulatory standards. We intend to incorporate this new standard and the latest findings in our safety measures and to complete the construction by April 2017. After the construction is finished, we will resume our nuclear power reactors while gaining the understanding from local communities.

However, due to the following reasons, we need to reassess the construction schedules.

In relation to Onagawa Unit 2 (BWR), new regulatory conformity examination process has been progressed steadily. In the earthquake/tsunami-related examination, our design basis tsunami and ground motion evaluation of major faults were evaluated as basically valid. On the other hand, the plant-related examination, conducted in parallel with other BWR plants owned by other companies, has made relatively slower progress than anticipated; therefore, we need to expect the examination will take a certain period of time before its completion. Meanwhile, we should reflect the findings and evaluations earned in the examination process in our construction work on safety measures, including design, in which we have been exerting ourselves.

In light of the situation stated above, we have reassessed the construction schedule at Onagawa Unit 2 to be completed in the second half of fiscal 2018.

Regarding Higashidori Unit 1 (BWR), new regulatory conformity examination will take even longer period than that of Onagawa Unit 2, because the evaluation process concerning fault activity in the premises required more time than we expected. Meanwhile, just like Onagawa Unit 2, we should incorporate the findings obtained from other plants that are in a more advanced stage of examination in our work on design and construction.

Consequently, we have reassessed the construction schedule at Higashidori 1 to be completed in fiscal 2019.

We are resolved to make continuous efforts to improve safety at our nuclear power stations

beyond the framework of the new regulatory requirements.

(Attachment) Efforts to Safety Measures and Resumptions of Our Nuclear Power Stations

Efforts to Safety Measures and Resumptions of Our Nuclear Power Stations

• We submitted applications for assessment on conformity to new regulatory requirements for Onagawa Unit 2 and Higashidori Unit 1 and have been making efforts

  to respond to conformity examinations as well as implement construction work to improve safety.

• We intend to take steadfast steps toward restarting our nuclear power reactors with the understanding from local communities.

▼ Resumption Immediately after the

▼March 11, 2011

The Great East Japan Earthquake

Safety functions secured a cold shutdown even in

Safety level at which no Fukushima

Current Status

1. Response to regulatory

   Conformity to New Regulatory

   completion of work

2. Measures for voluntary safety standards improvement

Further enhanced safety level that incorporates the characteristics of each plant and the latest

knowledge

the hypocenter- nearest Onagawa

(1) Emergency safety measures, and others

Daiichi-level

accidents will occur

requirements

Requirements

Current Status

▼ Completed (Planned)

Onagawa Unit 2: Second half of FY2018

Higashidori Unit 1: FY2019

Construction work on safety measures *1

Conformity

Examinations

Inspection before reactor start-up *2

▼ Application

▼Approval

Onagawa Unit 2: Dec. 2013

Higashidori Unit 1: Jun. 2014

Continuous efforts to improve safety

Understanding from local communities

*1 Facilities mainly for specific severe accidents are to be constructed within five years after approval of construction plans.

*2 "Inspection before reactor start-up", an essential prerequisite for resumption of a nuclear power reactor, is to check whether construction work is implemented as planned and satisfies technical standards.