This notification is to report a condition involving degraded control power wiring that resulted in an adverse impact on the ability to perform Fire
Safe Shutdown for a postulated fire in the Main Control Room / Cable Spreading Room (MCR/CSR) complex. Therefore, this notification is being made pursuant to
10CFR 50.72(b)(3)(ii)(B).
At approximately 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> [EDT], based on inspections being performed as part of an extent-of-condition review, Engineering personnel concluded that a degradation existed involving transfer / isolation switches that potentially impacted the ability to mitigate an Appendix R fire postulated to occur in the MCR/CSR complex. During scheduled maintenance outage windows on March 6, 2014 and May 5, 2014, broken wires were identified and repaired while the associated systems were out of service. Based on completion of the extent of condition walkdowns today, an additional location was identified, raising the potential that this condition existed for a longer period of time. The wiring degradation is limited to the capability of using Shutdown Method 'D' as described in the Peach Bottom Atomic Power Station Fire Protection Program. Shutdown Methods 'A', 'B' and 'C' used for other postulated fire areas were not affected by this condition. The postulated fire would have had to cause the normal control power fuses to fail for the issue to impact the safe shutdown function.
Compensatory measures have been established until the condition is corrected.
The NRC Resident Inspector has been informed of this notification.
In the event of fire resulting in a loss of control power, compensatory measures will allow restoration of control power by replacing blown fuses. The compensatory measures are detailed in a temporary change to the MCR/CSR complex fire response procedure. The condition will be repaired during future equipment outages at the earliest opportunity.
