ML20096C248

Proposed Tech Specs,Revising Bases Section 3/4.7.1.2 to Indicate Current Operational Functions of turbine-driven AFW Level Control Valves Modified During Unit 1 Cycle 7 Refueling Outage

ML20096C248
Person / Time
Site:	Sequoyah
Issue date:	01/03/1996
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20096C238	List: ML20096C235 ML20096C248
References
NUDOCS 9601170185
Download: ML20096C248 (2)

Text

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PIANT SYSTEMS ,

m BASES.

The limiting Design Basis Accidents (DBAs)L and transients for the AFW R210 System are as follona:

c. Feedwater Line' Break (FWLB); and j

b. Loss of main feedwater (MFW). .

,t In addition, the minimum available AFW flow and system characteristics are credited-for removing decay heat in the analysis of a small break loss of l

coolant accident (LOCA).

The AFW System design is such that it can perform'its function following

' c'FNLB between the MFW isolation valves and containment,. combined with a loss of offsite power following turbine trip, and a single active failure of the ,

cteam turbine-driven AFW pump (above 50% power) or one motor-driven AFW pump '

(below 50% power with steam generator low. level reactor trip time delay) . For 50% power operation and higher, one motor-driven AFW pump is assumed to deliver ['

to the broken MFW header at the pump run-out flow. Sufficient flow would be .

delivered'to the. intact steam generator by the redundant motor-driven AFW pump.

For partial power operation (below 50% power with trip ' time delay .

cetive), one motor-driven AFW pump is assumed to fail. All flow from the turbine-driven AFW pump and the redundant motor-driven AFW pump'is assumed to BR-8 deliver to the broken MFW header until the faulted steam generator is isolated.

After isolation of the faulted steam generator, sufficient flow is delivered to the intact steam generator by the turbine-driven and redundant motor-driven AFW R210 pump. ,

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The Engineered Safety Feature Actuation System (ESFAS) automatically cetuates the AFW turbine-driven pump and associated valves and controls when .j required to ensure an adequate feedwater supply to the steam generators during

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loss of power.

The surveillance requirements (SRs) provide a means of ensuring the AFN.

cystem components are capable of supplying required flow to the steam generators, the flow path is aligned correctly, and the automatic functions.

cetuate as designed. The automatic functions are verified through either an

- cetual or simulated actuation signal. The actuation signal associated with SR 4.7.1.2.3 (automatic valve actuation) include the AFW actuation test signal cnd the lov AFW pump suction pressure test signal. The actuation signal i essociat.ed with SR 4.7.1.2.4 (automatic pump start) includes only the AFW ]

cctuatica-test signal.

Bach motor-driven auxiliary feedwater pump (one Train A and one Train B) BR-1 cupplies flow paths to two steam generators. Each flow path contains an cutomatic air-operated level control valve (LCV). The LCVs have the same train designation as the associated pump and are provided trained air. The turbine-driven auxiliary feedwater pump supplies flow paths to all four steam BR-7 generators. Each of these flow paths contains an automatic opening (non-modulating) air-operated LCV, two of l

i November 17, 1995 B"J/4 7-2a Amendment No. 115, 155, 196, 206 SEQUOYAH - UNIT 1 i

9601170185 960103 PDR ADOCK 05000327 P PDR I

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i l 4}> ,,j a

PLANT SYSTEMS 4

BASES 3

The limiting Design Basis Accidents (DBAs) . and transients for the AFW R196 j

System are'as follows

s

c. Feedwater Line Break (FWLB); and

b. l Loss of main.feedwater (MFW). .

In addition,-.the minimum available AFW flow and system characteristics are

' credited for removing decay heat in the analysis of a small break loss of j- coolant accident (LOCA).

The AFW System design is such that it can perform its function following a FWLB.between the MFW isolation valves and containment, combined with a loss i: of offsite power following turbine trip, and a single active failure of the

cteam turbine-driven AFW pump (above 50% power) or one motor-driven AFW pump 1

(below 50% power with steam generator low level reactor trip time delay).

For i 50% power operation and higher, one motor-driven AFW pump is assumed to deliver i

to the broken MFW header at the pump run-out flow. Sufficient flow would be i delivered to the intact steam generator by the redundant motor-driven AFW pump.

}

For partial power operation (below 50% power with trip time delay

cetive), one motor-driven AFW pump is assumed to fail. All flow from the

[ turbine-driven AFW pump and the redundant motor-driven AFW pump is assumed to deliver to the broken MFW header until the faulted steam generator is isolated. BR-9 o

! After isolation of the faulted steam generator, sufficient flow is delivered to '

the intact steam generator by the turbine-driven and-redundant motor-driven AFW .

R196 pump.

The Engineered Safety Feature Actuation System-(ESFAS) automatically cctuates the AFW turbine-driven pump and associated valves and controls when required.to. ensure an adequate feedwater supply to the steam generators during loss of power.

The surveillance requirements (SRs) provide a means of ensuring the AFW cystem components are capable of supplying required flow to the steam generators, the flow path is aligned correctly,'and the automatic functions cetuate as designed. The automatic functions are verified through either an actual or simulated actuation signal. -The actuation signal associated with SR 4.7.1.2.3 (automatic valve actuation) include the AFW actuation test signal and the low AFW pump suction pressure test signal. The actuation signal casociated with SR 4.7.1.2.4 (automatic pump start) includes only the AFW l

cetuation test signal.

Each motor-driven auxiliary feedwater pump (one Train A and one Train B) BR-1 cupplies flow paths to two steam generators. Each flow path contains an cutomatic air-operated level control valve (LCV) . The LCVs have the same train designation as the associated pump and are provided trained air. The turbine-driven auxiliary feedwater pump supplies flow paths to all four steam lBR-7

generators. Each of these flow paths contains an automatic opening BR-1 (non-modulating) air-operated LCV, two of which are designated as Train A, receive A-train air, and provide flow to the same steam generators that are cupplied by the B-train motor-driven auxiliary feedwater pump. The remaining two LCVs are designated as Train B, receive B-November 17, 1995 SEQUOYAH - UNIT 2 B 3/4 7-2a Amendment No. 196