ML053250162

Att. 4 Millstone Power Station Appeal Faq 55.2

ML053250162
Person / Time
Site:	Millstone
Issue date:	11/22/2005
From:	Deconto R, Douglas Dodson, Janus C, Macmanus R Dominion
To:	NRC/FSME
Thompson JW, NRR/DIPM/IIPB, 415-1011
References
Download: ML053250162 (19)

Text

Or oominion Millstone Power Station Appeal of FAQ'55.2 HPSISafety System Unavailability Richard K. MacManus David V4V.Dodson Raymond E. DeConto Christine M. Janus November 1. 2005 1

f9i IDominion, Millstone Power Station

• Purpose

- To demonstrate that DNC treatment of unavailabilityassociatedwith MP3 HPSIpump oil leaks is in full compliance with NEI 99-02 guidance.

2

Dominion Millstone Power Station

• Agenda

- Overview of Millstone 3 ECCS

- Discussion of oil leak

- Discuss NEI 99-02 guidance

- Conclusion 3

ominion Millstone Power Station

• NEI 99-02 HPSI monitoring requirements

- Function: "Ability of a HPSI train to take suctionfrom a primary water source, orfrom the emergency sump, and inject into the RCS at ratedflow and pressure."

(page 54, lines 24-28)

- "Recirculationis provided by taking suction from the RHR pump discharges." (page 55, lines 32 -33) 4

sominion, Millstone Power Station HPSI Injection LcSI RCS Cold egs I RSS I 5

I No&

Millstone Power Station o

uomni0n, HPSI Hot Leg Recirculation

Pr9Dominion, Millstone Power Station NEI 99-02 HPSI monitoring requirements

- Millstone 3 HPSI is defined as 4 trains "Four loop Westinghouse may be representedby Figure 5.4.

This designfeatures two centrifugalpumps that operate at high pressure, two centrifugalpumps that operate at an intermediatepressure, a cold leg injection path, and two hot-leg injection paths. Recirculationis provided by taking suction from the RHR pump discharges. Each of the two intermediate pressure trains is comprised of the safety injection pump, the suction valves, and the hot-leg injection valves electrically associatedwith each pump. The HPSI system representedin Figure5.4 is considereda four train system for monitoring purposes. (page 55, lines 29-37 & 38-39) 7

I Dominion" Millstone Power Station

• NEI 99-02 RHR monitoring requirements

- RSS is monitored under RHR indicator "Because RHR and HPSI are monitored as separate systems with each having its own performance indicator, there is no need to cascade RHR unavailabilityinto HPSI. " (page54, lines 10-12) 8

uominion" Millstone Power Station

• Oil Leaks

- 'A' SIH pump oil leak

• 6dpm

• 10/14/04-11/04/04

- 'B' SIH pump oil leak

• 4dpm

• 8/8/02-4/16/03 9

D 0 uominion,

• ! 0 Millstone Power Station

• HPSIActive Function Determination

- The DB /LB does not identify an SIH pump mission time or ECCS mission time

- "In some instances, engineering evaluation is necessary to determine whether or not a train may be considered available. " (NEI 99-02, page 22, line 20) 10

Orpvominion; Millstone Power Station HPSI Active Function Determination

- Plant conditions at time of complete loss of oil

• RSS pump providing water to SIHflow path

• On Hot Leg Recirculation

- The engineeringevaluation concluded at 6 days there was sufficient flow from the existing/requiredRSS suction boost through SIH without SIH pump running

- No Operatoractions required 11

uominion, Millstone PowerStation

• NEI 99-02 Guidance - Purpose of the indicator

- "The purpose of this indicatoris to monitor the readiness of important safety systems to perform their safety functions in response to off-normal events."

(page 24, lines 28-29) 12

VPrDominion, Millstone Power Station

• NEI 99-02 HPSI monitoring requirements

- Function: "Ability of a HPSI train to take suctionfrom a primary water source, orfrom the emergency sump, and inject into the RCS at ratedflow and pressure."

(page 54, lines 24-28)

- "Recirculation is provided by taking suction from the RHR pump discharges." (page 55, lines 32 -33) 13

9plDominion, Millstone Power Station

• NEI 99-02 Guidance - Train Definition

- "A train consists of a group of components that together provide the monitored functions of the system and as explained in the enclosures for specific reactortypes. "

(page 23, lines 25-26) 14

OVDominion Millstone Power Station NEI 99-02 Guidance - Train Availability

- "A train is available if it is capable of performing its safety function" (page 29, line 22)

• HPSI safety function was met

- "Small oil, water, or steam leaks that would not preclude safe operation of the component during an operationaldemand and would not prevent a trainfrom satisfying its safety function are not counted. (page 29, line 18-20)

• HPSI safety function was met 15

Dominion, Millstone Power Station

• NEI 99-02 Guidance - Use of Engineering Evaluations

- As noted before - "In some instances, engineering evaluation is necessary to determine whether or not a train may be consideredavailable." (page 22, line 20) 16

Dt'ominion, Millstone Power Station NEI 99-02 Guidance - Use of Engineering Evaluations

- "Faultexposure hours are not countedfor a failure to meet design or technical specifications, if engineering analysis determines the train was capable of performing its safety function during an operational event." (page 29, lines 29-31) 17

O^Dominion, Millstone Power Station

• No CreditforAlternate System Taken

- "Except as specifically stated in the indicator definition and reporting guidance, no attempt is made to monitor or give credit in the indicator resultsfor the presence of other systems at a given plant that add diversity to the mitigation or prevention of accidents."

(page 24, lines 11-13) 18

OrDominion" Millstone Power Station Conclusion

- EngineeringEvaluation concluded the safety function was maintained

- The SIH and RSS systems performed their requiredsafety functions

- The HPSI train remained available to perform its safety function with an idle SIH pump

- All requirements of NEI 99-02 were met.

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