Press Release
Result of Nuclear Regulatory Inspections (Additional Inspections pertaining to the Physical Protection) at the Kashiwazaki-Kariwa Nuclear Power Station and Receipt of Notification of Change to Handling Category
December 27, 2023
Tokyo Electric Power Company Holdings, Inc.
We would like to sincerely apologize for the concern amongst regional residents, and society as a whole, caused by the unauthorized use of an ID card and the partial loss of function to physical protection equipment at the Kashiwazaki-Kariwa Nuclear Power Station.
The safety significance*1 of the partial loss of function to physical protection equipment at the aforementioned power station was officially deemed to be “Red,” and on March 23, 2021, we received notification from the Nuclear Regulatory Agency that the Nuclear Regulation Authority determined the handling category*2 of the station to be “Category 4.”
Today, the Nuclear Regulatory Authority has determined to change the handling category*2 of the Kashiwazaki-Kariwa Nuclear Power Station from “Category 4” to “Category 1”, and we received notification from the Nuclear Regulatory Agency.
Furthermore, the eligibility for nuclear power operator has re-confirmed.
While going back once again to the reflections and lessons learned from the Fukushima Daiichi Nuclear Power Station Accident, we will continue to engage in activities in which all personnel voluntarily engage as we strive to become a nuclear power operator that is trusted by the people of the region and society as a whole.
*1: Safety Significance Assessment:
Safety significance levels are classified as “Red”, “Yellow”, “White” or “Green” depending on the degree to which safety at nuclear facilities has 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 utility on their own.
*2: Handling Category
Handling categories for additional inspections are separated into “Category 1”, “Category 2”, “Category 3”, “Category 4”, and “Category 5” depending on the inspection indication significance assessment and safety performance index classification. Each category is defined as follows:
Category 1: Monitored activities satisfy objectives and the utility may make improvements independently.
Category 2: Monitored activities satisfy objectives, but the utility’s safety activities have slightly degraded.
Category 3: Monitored activities satisfy objectives, but the utility’s safety activities have moderately degraded.
Category 4: Monitored activities satisfy objectives, but the utility’s safety activities have significantly degraded, or have been in a degraded state for a long period of time.
Category 5: Plant operation cannot be allowed because monitored activities do not satisfy objectives.
