On August 1, we received verbal instructions from NISA to report on the partial peel-off on the upper part of the channel box^* found in the past at Kashiwazaki-Kariwa Nuclear Power Station and we have provided the outline of this matter. (Previously announced on August 2, 2012)

In accordance with the verbal instructions, we have summarized a report on the outline of the matter, investigation conducted and countermeasures implemented, and submitted it to NISA today.

On the document shared on August 2, it said that the similar peel-off issue was found on 4 channel boxes used in Unit 3 of the power station in "November 1998". However, upon our investigation (in the process of summarizing the report this time) we found that the issue was found in "November 1997", not in November 1998.

* Channel box: Square metal tube cover installed on the fuel assembly. By installing the channel box, the coolant flow path through the fuel assembly can be fixed. It also functions as a guide when the control rods operate and protects the fuel assembly.

Attachment: "Partial peel-off on the upper part of the channel box found in the past at Kashiwazaki-Kariwa Nuclear Power Station"(PDF 503KB)
Appendix: "Out line of the partial peel-off on the upper part of the channel box (Revised)" (Revised version of the document shared on August 2, 2012)(PDF 11.6KB)
Aforementioned documents are available only in Japanese. We apologize for the inconvenience this may cause.