ML20236P006

Final Part 21 & Deficiency Rept Re Failure of LPSI Pump When Energized.Initially Reported on 840523.Results of C-E Analytical & Test Program Showed That Excessive Shaft Deflection Eliminated by Use of Larger Diameter Motor Shaft

ML20236P006
Person / Time
Site:	Satsop
Issue date:	11/13/1987
From:	Cherry J, Olson P WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
REF-PT21-87-212-000 GO3-87-352, PT21-87-212, PT21-87-212-000, NUDOCS 8711170100
Download: ML20236P006 (5)

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WashingtonLPublic Power Supply System '

Box 1223 ' Elma, Washington 98541 1223 (206)482 4428' )

l f( .Novembei13,1987' G03-87-352.'

Docket-No. 50-508

.. U. S. Nuclear Regulatory Commission Attention: . Document Control Desk Washington, D. C. . 20555 4

Subject:

' NUCLEAR PROJECT 3 POTENTIAL 10CFR50.55(e) DEFICIENCY' LOW PRESSURE SAFETY INJECTION PUMP FAILURE-(D/N #52)

Reference:

Letter (G03-85-364), Mr. A. D. Kohler to V. S. . Nuclear '

Regulatory Commission,c same subject, dated July -1,1985.

.On 'May 23, 1984, The Supply System notified the Commission of _a potential

, , .10CFR50.55(e)Edeficiency concerning the subject . condition. An Interim

. Report was' forwarded-to the Commission which provided details of.the subject

~~ failure; .however, sufficient data- was not available at that time to

' determine'the cause.

The referenced ' letter stated that a Final Report would be prepared as soon as : the L required information was. received from CE and evaluated by Ebasco.

The engineering analysis of the deficiency has been completed. Based on the

'y~ results of the analysis, it has been determined that if the deficiency had remained uncorrected, it could have- adversely affected the safe shutdown of

.the plant. Therefore, the subject condition has been determined to be

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. 4 significant and reportable in accordance with the provisons lof 1 10CFR50.55(e)..  !

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Attached l isLthe Supply System approved Fina1 L Report. The report provides a d

description ' ofl. the deficiency. . safety implications; and ' corrective actions '

taken/ planned.:

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.Should you have any questions'or require further information,' please: contact Jmeldirectly, q

-WNP-3: Site Manager. -l

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. Attachments' j'

-i cc: Mr.'J. A. Adams NESCO . .

Mr.LR.'M.' Boucher;; Pacific Power & Light Co.

- Mr'. W. ' L. Bryan, Washington - Water . Power Co.

Mr. R. E. . Dyer, Portla'nd General. Electric Co.

Mr.'W. J. Finnegan, Puget Sound Power & Light Co.

Mr.'J. R. Lewis' ,.BPA Mr.,0.? Kirsch, U. S. NRC 4 -Mr. J. B. Martin," Region V Administrator-Mr. N.- S. Reynolds, Bishop, Cook; Purcell & Reynolds' Mr. D. Smithpeter, BPA

Ms. R. M. Taylor,.Ebasco'- Elma 1 LMr. A. Toth, U.'S.'NRC Ebasco - New York 1

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WASHINGTON PUBLIC POWER SUPPLY SYSTEM WPPSS NUCLEAR PROJECT N0. 3  !

FINAL REPORT LPSI PUMP FAILURE TO START CONTRACT 3240-02 i

i DEVIATION / NONCOMPLIANCE NO. 052 I

BY:

gmce,ee, DATE: $ f6 87

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! LPSI PUMP FAILURE TO' START DEVIATION / NONCOMPLIANCE N0. 052 r

FINAL REPORT i- i

! DESCRIPTION OF DEFICIENCY k t

[ The Palo Verde Nuclear Generating Station (PVNGS) LPSI pumps, as originally s supplied, have experienced several instances of failure to start when energized.

l An investigation has established the cause of the problem as excessive shaft deflection due to high magnetic forces in the motor during start-up. This causes the impeller to contact the casing ring sometimes preventing shaft acceleration. The WPPSS 3 LPSI pumps may also be subject to this type of

? failure. The WPPSS and PVNGS LPSI motors have identical rotors, bearing i systems, and electrical characteristics. The hydraulic portions of the pumps E

are also identical.

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SAFETY IMPLICATIONS

! ' The LPSI pump provides low pressure injection during a LOCA and also provides

reactor coolant system flow to the shutdown heat exchanger during shutdown

i. cooling. There are two LPSI pumps provided per plant. Since the potential of g this type of failure has been identified, reliability of the ECCS and SDCS can j

. be affected. -

4 This deviation is ' considered to - be significant. If left uncorrected, it could '

? have adversely affected the safe shutdown of the plant and hence is reportable under the provisions of 10CFR50.55(e).

CORRECTIVE ACTION TAKEN E An extensive analytical and test program was instituted by Combustion Engineering 2

to confirm the cause of the problem and determine a solution. The results of the testing showed that excessive shaft deflection was eliminated by the use of a a larger diameter (stiffer) motor shaft. The Palo Verde containment s pump motors have the larger diameter shafts (6 in. versus 5-3/8 and in) werepray (CS) i successfully tested and installed in the Palo Verde LPSI pumps.

An alternate LPSI pump motor was obtained from a cancelled System 80 plant (Duke Power Co.) and shaft deflection tests showed that the impeller radial motion g during starting is similar in magnitude to the Palo Verde CS motor deflection.

The motor has the same horsepower rating (500 HP) as the Palo Verde and WPPSS

@ - LPSI motors but the larger diameter six (6) inch shaft. Tests on this motor

... (Duke'LPSI) provided additional confidence that the failure to start phenomenon j

is limited to the particular design of the original Palo Verde LPSI motors.

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FINAL REPORTE.

lLPSI PUMP FAILURE:TO START

' CONTRACT 3240-02 .

DEVIATION / NONCOMPLIANCE N0.= 052 1

- Combustion-l Engineering will. fu'rnish replacement WNP-3 Low Pressure: Safety.;

Injection Pump. Motors, the (2)' Existing Duke (Cherokee) 500 HP LPSI motors. The enclosures ' for these motors were modified - from a Totally Enclosed Water-Air -

Cooled (TEWAC)' to a Weather Protected -(WP) type ; which is the . same ' as the

existing,WPPSS motors. As modified, this motor is compatible with the original 3

motors. Since~ these.' motors .were recently modified- and tested, no : additional inspecition or testing .would be required.. : Delivery is expected ' January 1988.-

These' motors will be stored at the WNP-3 site until ' restart, at which time they

- will be : installed. The original motors' will . not be put into service 'for this .

application.- NCR 14950: will > remain .open until the replacement'. motors >are -

-. installed.

.No recurrence 'of .this deficiency is expected, 'since the same: type of

.. (replacement). motor has operated reliably- at other Nuclear Power Plants. (SONGS,'

Palo. Verde).

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