ML17228A656

Proposed Tech Specs for Main Feedwater Line Isolation Valves to Be Consistent w/NUREG-1432,standard TS for C-E Plants

ML17228A656
Person / Time
Site:	Saint Lucie
Issue date:	07/25/1994
From:	FLORIDA POWER & LIGHT CO.
To:
Shared Package
ML17228A655	List: ML17228A654 ML17228A656
References
RTR-NUREG-1432 NUDOCS 9408030026
Download: ML17228A656 (8)

Text

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3.7. 1.6 Eac main feedwater line isolation valve shall be OPE LE.

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MGOE 1- With one in feedwater line iso/ation valve inoperable but open, POWER PERATION may conPfnue provided the inoperable valve is resto ed to OPERA+8 4 status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; otherwise, be in at least QSTANO within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

MODES 2, 3- With one or both mai feedwater line isolation valve(s) and 4 inoperable, subseq en peration in MODE 2, 3, or 4 may proceed provide the isol ion valve(s) is (are) maintained closed. Othe ise, e in a least HOT STANDBY within the next 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUT N within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> I

The pr isions of Specification 3. 4 are not applicable.

SURVEILLANC EgUIREHENTS SQRSSRSSR RSSRWSRRRSS'SSR  %%%%%'N%%'O'ESRWRSRRSRS'SSSSRSSS'SSSQ'SRSRRSS Sa&R 4.7. . Each main feed ater line isolation valve shall be demonstrate OP BLE by verifying ll closure within 5. 15 seconds when tested pursua Specification 4.0.

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St. Lucie Unit 2 L-94-139 Docket No. 50-389 Proposed License Amendment Main Feedwater Isolation Valves PLANT SYSTEMS MAIN FEEDWATER ISOLATION VALVES LIMITING CONDITION FOR OPERATION 3.7.1.6 Four main feedwater isolation valves (MFIVs) shall be OPERABLE.

APPLICABILITY:* MODES 1, 2, and 3, except when the MFIV is closed and deactivated.

ACTION a. With one MFIV inoperable in one or more main feedwater lines, OPERATION may continue provided each inoperable valve is restored to OPERABLE status, closed, or isolated within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Otherwise, be in HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

b. With two MFIVs inoperable in the same flowpath, restore at least one of the inoperable MFIVs to OPERABLE status or close one of the inoperable valves within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Otherwise, be in HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE REQUIREMENTS 4.7.1.6.a Each MFIV shall be demonstrated OPERABLE by verifying full closure within 5.15 seconds when tested pursuant to Specification 4.0.5.

The provisions of Specification 4.0.4 are not applicable for entry into MODE 3.

4.7.1.6.b For each inoperable MFIV, verify that it is closed or isolated once per 7 days.

• Each MFIV shall be treated independently.

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PLANT SYSTE lS BASES 3/4.7 1.4 ACTIVITY The limitations on secondary system specific activity ensure that the resul tant offset te radia'tion dose will be limited to a small fraction of 10 CFR Part 100 limits in the event of a steam line rupture. This dose also includes the effects of a coincident 1.0 gpm primary to secondary tube leak in the steam generator of the affected steam line and a concurrent loss of offsite electrical power. These values are consistent with the assumptions used in the safety analyses.

3/4.7.1.5 .'<AIN STEA~t LINE ISOLATION VALVES The OPERABILITY of the main steam line isolation valves ensures that no more than one steam generator will blow down in the event of a steam line rupture.

This restriction is required to (1) minimize the positive reactivity effects of the Reactor Coolant System cooldown associated with the blowdown, and (2) limit the pressure rise within containment in the event the steam line ruoture occurs within containment. The OPERABILITY of the main steam isolation valves within the closure times of the Surveillance Requirements is consistent with the assumptions used in the safety analyses.

The specified 6.75 second full closure time represents the addition of the maximum allowable instrument response time of 1.15 seconds and the maximum allowable valve stroke time of 5.6 seconds. These maximum allowable values should not be exceeded because they represent the design basis values for the plant.

3/4.7.1.6 t1AIN FEEOMATER LINE ISOLATION VALVES The main feedwater line isolation valves are required to be OPERABLE to ensure that (1) feedwater is te'rminated to the affected steam generator following a steam line break and (2) auxiliary feedwater is delivered to the intact steam generator following a feedwater line break. If feedwater is not terminated to a steam generator with a broken main steam line, two serious .effects may result:

(1) the post-trip return to'power due to plant cooldown will be greatef'i.th resultant higher fuel failure, and (2) the steam released to containment will. RCPNcf exceed the design.

to removal of the main feed check valve from the. plant desi its

'f replacemen h a second main feedwater line isolation valve e is nothing other than the ma edwater line isolation valves to nt back flow of a feed line br This may result in ss of condensate inventory AF'('ollowing and the potential for not being to f e steam generator .

inoperable exten The concern close with'he other is the fa one main n feedwater line isolation 'v ter line isolation valve to stuck open). It is thus desired to prec eriods with a main feedwater line isolation valve known e open position.

in that line being eration for stuck The specified 5.15 second full closure time represents the addition of the maximum allowable instrument response time of 1.15 seconds and the maximum allowable valve stroke time of 4.0 seconds. These maximum allowable values should not be exceeded because they represent the design basis values for the plant.

ST. LUCIE - UNIT 2 B 3/4 7-3 Amendment No.

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St. Lucie Unit 2 L-94-139 Docket No. 50-389 Proposed License Amendment Main Feedwater Isolation Valves When the main feedwater isolation valves (MFIVs) are closed or isolated, they are performing their required safety function, e.g.,

to isolate the main feedwater line. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action completion time for one inoperable MFIV in one or more main feedwater lines takes into account the redundancy afforded by the remaining operable MFIVs, and the low probability of an event occurring during this time period that would require isolation of the main feedwater flow paths. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> action completion time for two inoperable MFIVs in the same feedwater line is considered reasonable to close or isolate the affected flowpath. It is based on operating experience and the low probability of an event that would require main feedwater isolation during this time period.

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