The licensees must be knowledgeable and vigilant and must take more initiative in ferreting out details of potential plant weaknesses. As part of this obligation, you should examine installed safety-related electrical equipment, and ensure appropriate documentation of its qualification to function under postulated accident conditions. Specific guidance on the subject of environmental qualification can be found in IEEE 323-1971 and 1974, as augmented by Regulatory Guide 1.89. A failed penetration prompted issuance of IE Bulletin 77-06. Preliminary review by the staff of responses to IE Bulletin 78-04 indicates such switches are installed in similar applications at other facilities.
Corrective action is presently in progress.
The review of these issues may result in the need for other followup or corrective actions. No written response to this Circular itself is required. Each licensee should determine the applicability of the qualification items identified above for its facility. Appropriate corrective action should be taken for any problem identified by the licensee as a result of its review. NRC inspectors will review these matters with licensees in future inspections.