ML13330A030

Notifies That Evaluation of Potential Magnitude & Effects of Postulated Water Hammers Will Include Development of Forcing Functions for Classic textbook-type Water Hammers.Evaluation Will Be Completed by 800930

ML13330A030
Person / Time
Site:	San Onofre
Issue date:	04/22/1980
From:	Haynes J SOUTHERN CALIFORNIA EDISON CO.
To:	Ziemann D Office of Nuclear Reactor Regulation
References
TASK-05-13, TASK-5-13, TASK-RR NUDOCS 8004220446
Download: ML13330A030 (4)

Text

Southern California Edison Company P.O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 Director of Nuclear Reactor Regulation Attention: Mr. D. L. Ziemann, Chief Operating Reactors Branch No. 2 Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D.C.

20555 Gentlemen:

Subject:

Docket No. 50-206 Steam Generator Water Hammer San Onofre Nuclear Generating Station Unit 1 By letter dated February 14, 1980 we informed you that we would be performing an evaluation of the potential magnitude and effects of postulated water hammers at San Onofre Unit 1. As sub sequently discussed with members of the NRC Staff, this program will include the development of forcing functions for classic textbook type water hammers such as valve closure and pump start.

Steam generator water hammer as postulated by Creare will not be included as part of this evaluation. This evaluation is to be completed by September 30, 1980.

If you have any questions regarding this matter, please let me know.

Very truly yours, J. G. Haynes Chief of Nuclear Engineering 8;0 04 2 2 Oq*I

L~hi~i LIJK Southern California Edison Company P.O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 April 21, 1980 3 1 U. S. Nuclear Regulatory Commission Region V Suite 202, Walnut Creek Plaza 1990 North California Blvd.

Walnut Creek, California 94596 Attention:

Mr. R. H. Engelken, Director DOCKET No. 50-206 SAN ONOFRE UNIT 1

Dear Sir:

This letter describes a reportable occurrence involving the Emergency Power System.

Submittal is in accordance with the reporting requirements stipulated in Section 6.9.2.b(2) of Appendix A to the Provisional Operating License DPR-13.

On March 24, 1980 at 1106 the No. 2 diesel generator was declared inoperable after fuel oil transfer purrps G-75A and G-75B experienced current overload trips while running for the purpose of obtaining fuel oil samples.

Operability of two offsite transmission lines and the remaining diesel generator was successfully demonstrated within one hour as required by Technical Specification Section 3.7.2.B.

An investigation revealed that the surp purps in the transfer pump vault had failed to operate allowing rain water to accumulate in the vault after a series of severe storms and to rise to the level of the transfer pump-motor coupling.

Meggar readings were obtained for both transfer pumps and indicated that the current overload was not due to an electrical short circuit.

The sunp pumps were repaired and returned to service.

When the water in the vault was removed both transfer pumps were restarted and run successfully.

Mbtor current readings taken at this time were verified to be at normal values.

The transfer puiips were returned to service and the No. 2 diesel generator declared operable on March 24 at 1510.

U. S. Nuclear Regulat*

Commission Page #2 The high inservice current which resulted in the current overload trips was apparently due to the increased frictional drag caused ly the water surrounding the pump-motor coupling.

The meggar readings taken before the water was removed indicated that the water was not causing an electrical short circuit.

Both pumps operated normally after the water was removed from the vault.

A review of the vault drainage system design will be performed.

Corrective action taken as a result of this review will ensure adequate water removal from the vault.

The evaluation noted above will be copleted by July 1, 1980.

There was no degradation of plant safety during this incident as redundant systems were available.

Plant operation with one operable diesel generator is permitted for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> ly Technical Specification 3.7.2.B.

If you should require additional information concerning this occurence, please contact me.

H. L. Ottoson Manager of Nuclear Operations WWS/SS:jg3

Attachment:

Licensee Event Report 80-012 cc:

Director, Office of Inspection and Enforcement (30)

Director, Office of Management Information & Program Control (3)

Director, Nuclear Safety Analysis Center (1)

NRC FORM 366 S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK:

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6

EIW ICIAIS 10 S 11 01D1 00-10100 10-00 J0 1 1 1 1

Jill 11 7

8 9

LICENSEE CODE 14 15 LICENSE NUMBER 25 26 LICENSE TYPE 30 57 CAT 58 CON'T SOURCE LU0 lo 12 10_16 10 13 12 14 000 010) l0l12l0l810 7

8 60 61 DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES IDuring normal operations, while obtaining diesel fuel oil samples, the No. 2 O diesel generator fuel oil transfer pumps G-75A & G-75B tripped on current overload Irendering the diesel inoperative, Operability of two offsite transmission lines land the remaining diesel generator was successfully demonstrated as required by T.S.

Fo 6 13.7.2.B. There was no degradation of plant safety during this incident. Plant operatlon 7 with one operable diesel generator is permitted for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> by T.S. 3.7.2.B.

7 8 9 80 SYSTEM CAUSE CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE 09 IEJl E L

LIJ I9U IM IP IX IX 1q W(

Ll

6) 7 8

9 10 11 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION LER/RO EVENT YEAR REPORT NO.

CODE TYPE NO.

REPR 18 10 1

1l2 O3I NUMBER 0

LOJ 11112 1 L --

10J~

L3 L0J L

21 22 23 24 26 27 28 29 30 31 32 ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP.

COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB.

SUPPLIER MANUFACTURER

_10 10RS R

1 I0J(

I 5

1G12 10 10 33 34 35 36 37 40 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 1 Sump pumps in transfer pump vault failed to operate.

Resulting high water level in Ivault created drag on pump-motor coupling causing high motor current flow. After I water was removed from vault both transfer pumps operated successfully. No 2 diesel generator was returned to service within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

f FI I

7 8 9 80 FACILITY METHOD OF STATUS

%POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION J@ I1 0 I0 II N.A.

I jI Overcurrent trip 7

8 9

10 12 13 44 45 46 80 ACTIVITY CONTENT 8

RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 1 z 6 @ 1 z 0LN.A.

I I N.A.

7 8

9 10 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION II ] l01 01 l

z7 1(31 N.A.

7 8

9 11 12 13 80 PERSONNEL INJURIES NUMBER DESCRIPTIONS 0 10 10 11 N.A.

7 8

9 11 12 80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION L TIN.A.

7 8

9 10 80 PUBLICITY ISSUED DESCRIPTION 4 NRC USE ONLY 20 eL N..A.

7 8

9 10 68 69 80; NAME OF PREPARER J.

M. Curran P.

(71 )

9 0

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