ENS 40049
ENS Event | |
|---|---|
20:30 Aug 6, 2003 | |
| Title | |
| Event Description | On 8/06/2003 at 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br />, the Beaver Valley Power Station (BVPS) Unit 2 control room was notified by Engineering that the manual operator actions specified in Unit 2 post-fire procedures are not adequate for defeating a potential fire-induced spurious operation of the Power Operated Relief Valves (PORVs). The procedure step de-energizes the PORVs by opening breakers at the d-c distribution panel. This action alone would not be sufficient to prevent a cable-to-cable hot short from re-energizing the circuit since the de-energized circuit is routed in cable trays with other energized circuits in the affected fire areas. Preliminary reviews have identified the following potentially affected fire areas:
CB-1 Control Building Instrumentation and Relay Area CB-2 Control Building Cable Spreading Room CB-3 Control Building Main Control Room CB-6 Control Building West Communication Room CT-1 Cable Tunnel CV-1 Cable Vault and Rod Control Area SB-1 Emergency Switchgear Room (Orange) RC-1 Reactor Containment An hourly roving fire watch patrol has been established for the affected fire areas as compensatory measures, with the exception of the Main Control Room and the Reactor Containment area, until the condition is fully evaluated and resolved. The Main Control Room is continuously manned and does not require an hourly fire watch patrol. The Reactor Containment area is not accessible during normal power operations and, as such, compensatory measures for this area will include a once-per-shift verification of remote instrumentation by operations personnel to confirm that there are no abnormal conditions or indications for this area. This condition was discovered during the review of manual operator actions for fire-induced spurious operations to confirm the safe shutdown circuit analysis is consistent with the manual actions identified in the procedures. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii) as an unanalyzed condition that significantly degraded plant safety since the failure to assure the PORVs remain in the closed position could result in the failure to meet the fire protection safe shutdown criteria. BVPS Unit 2 was licensed to the NUREG 0800 Standard Review Plan 9.5.1 "Fire Protection Program", and License Condition 2.F requires compliance to the provisions of the approved fire protection program as described in the Final Safety Analysis Report. UFSAR Section 9.5A.1.2.1.6 states that the safe shutdown capability should not be adversely affected by a fire in any plant area which results in spurious actuation of the redundant valves in any one high-low pressure interface line. Even though there is a very low likelihood of multiple shorts causing a spurious PORV actuation in an ungrounded DC circuit, the existing actions to prevent re-energizing the circuit and causing a spurious actuation of the PORVs is not consistent with the NRC guidance for high-low pressure interface valves. The NRC resident inspector has been notified.
On 8/07/03 at 1515, the following additional areas were identified as being potentially affected by this condition: CV-2 Cable vault and Rod Control Area (East) CV-3 Cable vault and Rod Control Area (Elev 755'6") SB-2 Emergency Switchgear Room (Purple) SB-3 Service Bldg. Cable Tray Area ASP Alternative Shutdown Panel Room Interim compensatory measures in the form of hourly roving watch patrols have been expanded to include the above noted areas until the condition is fully evaluated and resolved. The NRC Resident Inspector has been notified. Notified the Region 1 Duty Officer (C. Anderson)
The licensee is retracting this report based on the following: Beaver Valley Power Station (BVPS) Unit No. 2 retracts the notification made on 08/06/2003 at 19:12 hrs regarding the event reported under 10 CFR 50.72(b)(3)(ii)(B) [ENS #40049]. The previous notification identified a potential unanalyzed condition that significantly degraded plant safety since the failure to assure the PORVs remain in the closed position could result in the failure to meet the Fire Protection Program safe shutdown criteria. The postulated event for spurious PORV opening due to an external cable-to-cable hot short from a fire was subsequently analyzed. It was determined that since the reactor core does not experience an unrecoverable plant condition and the radiological conditions remained bounded by analyzed DBAs, the plant's safe shutdown capability for a fire event is maintained. Although the now-credible spurious opening of a PORV is a deviation from the current Fire Protection Program criteria, the results of the spurious PORV opening does not adversely impact the plant's safe shutdown capability and hence is not a significant degradation of plant safety. Therefore this condition is not reportable pursuant to either 10 CFR 50.72(b)(3)(ii)(B) nor 50.73(a)(2)(ii)(B) as an unanalyzed condition that significantly degraded plant safety. Compensatory measures in the form of shiftly fire watch patrols for the affected fire areas, with the exception of the Main Control Room and Reactor Containment area (as described in prior notifications), will remain in place until the Fire Protection Program non-conformance issue is dispositioned. The licensee informed the NRC Resident Inspector. Notified R1DO(Gray). |
| Where | |
|---|---|
| Beaver Valley Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+-1.3 h-0.0542 days <br />-0.00774 weeks <br />-0.00178 months <br />) | |
| Opened: | George Storolis 19:12 Aug 6, 2003 |
| NRC Officer: | Bill Gott |
| Last Updated: | Sep 18, 2003 |
| 40049 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |