ML072780144

August 2007 - Transition to National Fire Protection Association (NFPA) 805 - Non-Power Operations - Progress Energy - Briefing Materials/Meeting Handouts

ML072780144
Person / Time
Site:	Harris
Issue date:	08/07/2007
From:	Miskiewicz D Nuclear Generation Group, Progress Energy Co
To:	Office of Nuclear Reactor Regulation
Oudinot D
Shared Package
ML072830337	List: ML072780114 ML072780118 ML072780120 ML072780124 ML072780126 ML072780133 ML072780138 ML072780144 ML072780152 ML072780155 ML072780167 ML072780214 ML072780267 ML072780284 ML072780319 ML072780325 ML072830283 NEI 04-02, August 2007 - Transition to National Fire Protection Association (NFPA) 805 - NEI 04-02 FAQs Pathway to Resolution - Progress Energy - Briefing Materials/Meeting Handouts
References
Download: ML072780144 (13)

Text

NFPA 805 Transition August Pilot Observation Non-Power Operations Dave Miskiewicz, PSA August 7, 2007 Bethesda, MD

NFPA 805 and NPO Current Methodology O NUMARC 91-06 Z Provides the guidance that most plants current use to manage risk Z Key Safety Functions Z Shutdown Conditions Z Defense-in-Depth Methodology Page 2

NFPA 805 and NPO Shutdown Conditions O Shutdown Conditions Z RCS vented Z Head on/off Z RCS water level Z Refueling operations Page 3

NFPA 805 and NPO Key Safety Functions O Key Safety Functions Z Decay Heat Removal Z Inventory Control Z Electrical Power Z Reactivity Control Z Containment Page 4

NFPA 805 and NPO Defense-in-Depth O Primary Mitigating Systems O Alternate mitigation paths O Recovery strategies O Contingency plans O The level of DID required above Technical Specifications is developed as a function of risk Page 5

NFPA 805 and NPO Risk O The risk during NPO should be measured relative to at-power.

O CDF is the appropriate metric O CDF is defined as core uncovery (boiling is a conservative surrogate)

O CDF = (Initiating Event Frequency) *

(Primary Mitigation Failure) *

(Alternate Mitigation Failure) *

(Recovery)

Page 6

NFPA 805 and NPO Initiating Events Treatment O Prevention of initiating events is inherent to the standard practices and procedures and already include measures for reducing the likelihood of fire induced events.

(i.e. - fire risk is already considered at all times during NPO)

O The implementation of NFPA-805 does not create a higher likelihood of fires during shutdown. and additional measures for preventing fires should only be needed when indicated by the risk assessment O The methodology for NPO risk management generally focuses on implementing a robust DID by providing alternate methods of mitigation of core damage given a loss of the primary method O When warranted, compensatory measures are implemented to offset potential risk Page 7

NFPA 805 and NPO Primary Mitigation Capability O Steam generators/Feedwater (non-vented RCS, high decay heat)

O1 train of Decay Heat Removal O Loss of the primary mitigation system is typically the the initiating event Page 8

NFPA 805 and NPO Alternate Mitigation Capability O Direct cooling Z Standby train of RHR (preferred option)

Z Spent fuel cooling O Makeup/Safety injection with cold water Page 9

NFPA 805 and NPO Time to Core Uncovery O The time-to-core uncovery is an important parameter for determining what alternate methods should be credited O Can vary from minutes to days O Some alternate mitgation is based on extending the time by maintaining inventory Page 10

NFPA 805 and NPO Time to Core Uncovery O When the refueling canal is full, uncovery time is typically greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Z Relatively easy to add inventory Z Plenty of time to implement less conventional mitigation strategies O The most challenging period is typically the first reduced inventory (uncovery could occur in less than 1hr)

Z Only proven and reliable alternate strategies get much credit. (such as standby RHR train)

Page 11

NFPA 805 and NPO Fire Compensatory Actions O Existing fire prevention measures will be continued for most shutdown conditions (documentation may be enhanced)

O When there is limited alternate mitigation capability additional fire compensatory measures may be justified Page 12

NFPA 805 and NPO Examples O Example - reduced inventory when the backup RHR train is required to be available, having a fire which could cause a LOC and loss of the standby RHR should be specifically addressed O Example - spurious valve operation which could cause a drain down event beyond the capability of normal makeup should be identified Page 13