Press Release
Results of FY2020Q4 Nuclear Safety and Regulatory Inspections Performed by the Nuclear Regulatory Agency at TEPCO Nuclear Power Stations
May 19, 2021
Tokyo Electric Power Company Holdings, Inc.
The results of FY2020Q4 nuclear safety and regulatory inspections performed by the Nuclear Regulatory Agency were reported on at today’s meeting of the Nuclear Regulation Authority. Issues at the Fukushima Daiichi Nuclear Power Station and issues pertaining to nuclear material protection at the Fukushima Daini Nuclear Power Station were classified as follows:
<Fukushima Daiichi Nuclear Power Station (safety inspection)>
(Issue 1)
•Misconnection of Unit 1 reactor pressure vessel temperature gauge
Violation category: Minor violation (Monitoring required)
(Issue 2)
•Facial contamination at process main building
Violation category: Minor violation (Monitoring required)
(Issue 3)
•Sounding of non-fire alarm in side entrance building
Violation category: Minor violation (Monitoring required)
<Fukushima Daini Nuclear Power Station (regulatory inspection)>
(Issue 1)
•Insufficiently managed boundary hallway door
Safety significance: Green*1, Violation severity level: IV*2
(Issue 2)
•Inadequate procedures for reentry to protected zone from surrounding protected zone
Safety significance: Green, Violation severity level: IV
(Issue 3)
•Loss of invalid ID card
Safety significance: Green, Violation severity level: IV
An overview of the nuclear material protection-related issues at the Fukushima Daini Nuclear Power Station has been provided in the attachment to the extent possible without compromising nuclear material protection.
TEPCO is currently in the process of ascertaining the causes of the series of incidents related to nuclear material protection that occurred at the Kashiwazaki-Kariwa Nuclear Power Station. Going forward we will formulate a corrective action plan aimed at strengthening our nuclear material protection systems and addressing these issues.
*1: Safety significance: Green
Safety significance is classified using one of four colors (red, yellow, white, green) in accordance with the extent of degradation of safety at nuclear facilities. “Green” indicates that the impact on safety functions or performance has been limited and extremely small, and that the operator may implement corrective measures on its own.
*2: Violation severity level (SL) IV
Violation severity level is classified as either SL I, SL II, SL III, or SL IV depending upon the severity of the violation. SL IV indicates that the impact, or potential impact, on nuclear safety and/or nuclear material protection was limited.
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