Receipt of Preliminary Assessment Results from the Nuclear Regulation Authority in Regards to the Partial Loss of Nuclear Material Protective Equipment Function at the Kashiwazaki-Kariwa Nuclear Power Station
March 16, 2021
Tokyo electric power Company holdings, Inc.
At the meeting of the Nuclear Regulation Authority (NRA) today, March 16, a report was given about the partial loss of nuclear material protective equipment function at the Kashiwazaki-Kariwa Nuclear Power Station, and the NRA agreed on preliminary assessment results deeming the importance level assessment* to be "Red."
We are taking the fact that the NRA agreed with these preliminary assessment results very seriously.
As a nuclear operator, ensuring nuclear security is one of TEPCO's most important responsibilities. Unfortunately, we have experienced a rash of nuclear material protection-related incidents at the Kashiwazaki-Kariwa Nuclear Power Station since the unauthorized use of an ID card last year. We would like to deeply apologize for the concern we have caused amongst regional residents, and society as a whole, as a result of these incidents.
TEPCO will examine the reasons why the NRA decided on the preliminary assessment mentioned above and will quickly respond to the NRA.
Repairs have already been completed on malfunctioning nuclear material protection equipment in all locations. No unauthorized access has been found to have occurred at the aforementioned locations.
Furthermore, we have constructed a mechanism for implementing effective substitute measures to counteract any new malfunctions of nuclear material protection equipment.
An overview of this incident was already given on February 19, 2021 (Japanese only), and we will continue to provide additional information on the status of nuclear regulatory inspections, etc. to the extent possible without compromising nuclear material protection.
*Safety Importance Level Assessment:
Safety importance levels are classified as Red, Yellow, White or Green depending on the degree to which safety at nuclear power facilities has been degraded. Each classification is defined as follows.
Red: Large impact on safety functions or performance.
Yellow: Impact on safety functions or performance, and decrease in safety margins.
White: Impact on safety functions or performance, and decrease in safety margins, but improvements can be made with regulatory involvement.
Green: Impact on safety functions or performance, but such impact is limited or extremely small, and therefore improvements can be made by operators on their own.