Text

NRC Regulatory Conference Slides, Potential Common Mode Failure of Auxiliary Feedwater
	ML021970080
Person / Time
Site:	Point Beach
Issue date:	04/29/2002
From:	; NRC/RGN-III
To:	;
References
	IR-01-017
	Download: ML021970080 (10)
	v • d • e

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

Agenda Regulatory Conference P Opening Remarks

< J. Grobe, Director, DRS P Description of Issues

< R. Langstaff, Inspector, DRS P Licensee Presentation P Closing Remarks

< J. Dyer, Regional Administrator

Potential Common Mode Failure Auxiliary Feedwater Pumps P AFW recirculation valves require IA to open P Loss of IA causes AFW recirculation valves to fail shut by design P Operator actions to control AFW flow (in conjunction with recirculation valves failed shut) could result in low/no flow conditions for AFW pumps P Pump damage would result within a short period of time due to low/no flow conditions

Operator Actions EOP Guidance P EOPs directed operators to control AFW flow in response to

< RCS Overcooling

< SG Overfill P EOPs did not specify method to control AFW flow (i.e., throttling/closing valves versus securing pumps)

P Operators would typically throttle/close valves versus secure pumps

Operator Actions Overcooling of RCS P Operator actions to control AFW flow may be required within a few minutes of the transient P At the time operators control flow, recirculation valves may still be open due to remaining IA header pressure P Recirculation valves may subsequently shut due to decreasing IA header pressure

Operator Actions Overfilling SGs P Operator actions to control AFW flow to mitigate SG overfill typically required > 10 minutes into transient P Recirculation valves expected to already have failed shut due to loss of IA P Operators may fail to recognize recirculation valves had failed shut and associated consequences

Inadequate Procedure Guidance Regulatory Issue P EOPs for Reactor Trip Response were not appropriate for the circumstances P Procedures did not provide adequate guidance to operators regarding the potential to damage AFW pumps while controlling AFW flow upon low IA header pressure P Apparent Violation of 10 CFR 50, Appendix B, Criterion V

Inadequate Corrective Action Regulatory Issue P Licensee had seven prior opportunities to focus on the impact of recirculation valve closure P Apparent Violation of 10 CFR 50, Appendix B, Criterion XVI

Risk Significance Preliminary Red (High Safety Significance)

P Relatively high frequency of applicable initiating events involving loss of IA

< Loss of IA

< Loss of Off-Site Power

< Loss of Service Water

< Seismic Event P Substantially reduced mitigation capability

< Main Feedwater Reliance on IA

< Pressurizer PORV Reliance on IA

Abbreviations

< AFW - Auxiliary Feedwater

< CFR - Code of Federal Regulations

< EOP - Emergency Operating Procedure