ML20029B282
| ML20029B282 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 03/01/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20029B251 | List: |
| References | |
| NUDOCS 9103060380 | |
| Download: ML20029B282 (2) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION -
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5 WAsHINo T ON, 0. C. 20666 :
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SffETYEVALUATIONBYTHEOFFICEOFNUCLEARREACTORREGULATION RELA L,,0 TO REQUESTS FOR REllEF FROM INSERVICE TESTING REQUIREMENTS J
$MPREllEFREQUESTNO.2.1.5,VALVERELQFREQUESTNO.3.1.56 ENTERGY OPERATIONS, INC WATERFORD STEAM ELECTRIC STATION, UNIT NO. 3 DOCKET NO. 50-3F2 INTRODUCTION By letter dated August 21, 1989, Enterv 0 rations Inc. submitted Change 1 to Revision 6 of the Waterford Steam Electric Station, Unit No. 3 irservice testingprogram(IST). Additional informaticri was submitted by letter dated January 10, 1991, in response to staff concerns discussed with the licensee on August-16,_and November 6, 1990.- The IST change requested relief from
-ASME Code testing requirements for pumps and iAlves.
Relief request No. 2.1.5
- applies to IWP-3300,~lWP=3500(b), erd-lWp-4310 test requirements for measuring The prt'r d
sternatA e is to use vibration and pump bearing temnera h hydraulic parameters e a of berr1.m temperatures to-detect bearing degrada-tion.
Relief r? quest 3 L SA applies to IWP-3417 test requirements for power operated valves.
The proposed olternative is to use_a reference valve stroke time in lieu of the previous test valve stroke time, pump _ Relief Request 2.!.5 The licensee has requested relief from the ASME Code,Section XI, Paragraph IWP-3300, IWP-3500(b), and IWP-4310 (Code) require-ments to-run each pump until the bearing temperature stabilizes then measure bearing-temperature annually for all pumps in the IST program.
Basis f.or Relief.
Bearing temperature increases rapidly with impending bearing
-failure. Year.ly measurement of bearing temperature-is not_ expected to detect bearing degradation. Vibration and hydraulic parameters provide significantly better evidence of pump degradation which could result--in or from a bearing failure.
Alternate Testing.
V1Drationandhydraulic(pressureandflow)-measurements taken during each test will identify pump degradation causing or resulting from
-bear _ing failure.
Evalual c<
industry experience has shown that bearing temperature measure-ments G 2 influenced by many factors unrelated to bearing degradation-such ds ambient temperature, fluid temperdture, and bearing lubricant temperature.
Running pumps for an extended time (to stabilize bearing temperatures) imposes a hardship on the licensee while not_-contributing significantly to the evalua-tion of-pump operational readiness and plant safety. The licensee's proposed
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? alternate of vibration end hydraulic testing to detect bearing degradation.
should give adequate assurance of operationa' readiness and provides a
. reasonable' alternative to the Code requiremetts, t
Based on;the determination that compliance with the Code requirements presents o hardship to the licensee and does no_t significaatly increase the level of safety, and.considering the' licensee's proposed testing, relief should be granted from the Code requirement es requested pursuant to 10 G 5.556(a)(3)(11).
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Valve Relief Request-3.1.56.
The licensee has requested relief.from ASME Code,Section XI, Peragraph IWV-34174-(Code) requirements fer power operated
. valves'to take corrective' actions based on comparing the most recent stroke time to the previous stroke time.and proposed to take corrective actions based on comparing the most recent stroke-time to a current beseline value for that-valve.
Basis for Relief. Comparing stroke times to the previous value fails to identify slowly degrading valves for increased testing and observation.
Comparing stroke time data to'a valve reference value provides a better -
analysis.of stroke times.
The valve reference value i_s an average stroke time when the valve is known to be in good condition and operating' properly.
Significant deviations from this reference value will require increased testing and surveillance.
. Alternate Testing.
A reference stroke time value will be established based on the averege stroke-time when the valve is known to be in good condition and operating properly.
7 "If, for. power operated valves, an increase in stroke time of 25% or more "from the reference value for valves with full-stroke times greater than 10 seconds or 50% or more for valves with full-stroke times less than or equal to 10: seconds is observed, test frequency shall be increased to once each month until corrective action is teken, at which time original test frequency shell be resumed."
A Evaluation'. -Utilizing the trending criteria outlined in the Code could allow significent increases in valve stroke times-over several tests without' requiring-corrective action.
A-reference-stroke time-value assigned to each valve based on performance' data obtained fron, thet valve when known to be in good condition j
provides the baseline to compare subsequent tests.
Comparison of actual stroke times to baseline stroke times, rather than the:
previous' stroke times, could result in mointenance being performed on these
-valves earlier than would._be required by the Code. This proposed alternate L
-testing provides an-ecceptable level of safety and quality and'a reasonable J
- alternative ~to.the Code requirement. - Therefore, relief should be granted for the. licensee.to establish a baseline to compare stroke time Alert and Required j
- Action limits pursuant 10 CFR 5.55a(a)(3)(1),
principel Contributors:
J. Calaccino,'EMEB t
j L. R. Wharton, PDIV-1 l
- Dated:- March i,: 1991
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