ML021970080
| ML021970080 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 04/29/2002 |
| From: | NRC/RGN-III |
| To: | |
| References | |
| IR-01-017 | |
| Download: ML021970080 (10) | |
Text
Point Beach Potential Common Mode Failure of Auxiliary Feedwater Regulatory Conference April 29, 2002 NRC Inspection Report 50-266/01-17; 50-301/01-17
POpening Remarks
J. Grobe, Director, DRS PDescription of Issues
R. Langstaff, Inspector, DRS PLicensee Presentation PClosing Remarks
J. Dyer, Regional Administrator Agenda Regulatory Conference
PAFW recirculation valves require IA to open PLoss of IA causes AFW recirculation valves to fail shut by design POperator actions to control AFW flow (in conjunction with recirculation valves failed shut) could result in low/no flow conditions for AFW pumps PPump damage would result within a short period of time due to low/no flow conditions Potential Common Mode Failure Auxiliary Feedwater Pumps
PEOPs directed operators to control AFW flow in response to
RCS Overcooling
SG Overfill PEOPs did not specify method to control AFW flow (i.e., throttling/closing valves versus securing pumps)
POperators would typically throttle/close valves versus secure pumps Operator Actions EOP Guidance
POperator actions to control AFW flow may be required within a few minutes of the transient PAt the time operators control flow, recirculation valves may still be open due to remaining IA header pressure PRecirculation valves may subsequently shut due to decreasing IA header pressure Operator Actions Overcooling of RCS
POperator actions to control AFW flow to mitigate SG overfill typically required > 10 minutes into transient PRecirculation valves expected to already have failed shut due to loss of IA POperators may fail to recognize recirculation valves had failed shut and associated consequences Operator Actions Overfilling SGs
PEOPs for Reactor Trip Response were not appropriate for the circumstances PProcedures did not provide adequate guidance to operators regarding the potential to damage AFW pumps while controlling AFW flow upon low IA header pressure PApparent Violation of 10 CFR 50, Appendix B, Criterion V Inadequate Procedure Guidance Regulatory Issue
PLicensee had seven prior opportunities to focus on the impact of recirculation valve closure PApparent Violation of 10 CFR 50, Appendix B, Criterion XVI Inadequate Corrective Action Regulatory Issue
PRelatively high frequency of applicable initiating events involving loss of IA
Loss of IA
Loss of Off-Site Power
Loss of Service Water
Seismic Event PSubstantially reduced mitigation capability
Pressurizer PORV Reliance on IA Risk Significance Preliminary Red (High Safety Significance)
CFR - Code of Federal Regulations
EOP - Emergency Operating Procedure
GL - Generic Letter
IA - Instrument Air
PORV - Power Operated Relief Valve
SG - Steam Generator Abbreviations