ML19263C540

LER 79-012/03L-0 on 790127: Unidentified Primary Coolant Leakage Greater than 5 Gpm Noted. Caused by Blown Packing on Residual Heat Removal Isolation Valve MOV-1700 & Packing Leak on Pressurizer Spray Valve PCV-1455A

ML19263C540
Person / Time
Site:	North Anna
Issue date:	02/20/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19263C534	List: ML19263C533 ML19263C538 ML19263C540
References
LER-79-012-03L, LER-79-12-3L, NUDOCS 7902260460
Download: ML19263C540 (2)

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[ojjj [During the steady state operation, it was found that the unidentified primary coolant l g l leakage was greater than 5 gpm. The plant was in hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in g [ cold shutdown within 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> as required by the Action Statement. During the subse- l g [quent startup on 01-29-79, while in hot standby (flode 3), the primary coolant leakage l g was greater than 1 gpm. The plant was returned to the cold shutdown mode. These 1 o , l events are contrary to T.S. 3.4.6.2 and reportable as per f.S. 6.9.1.9.b. l FirITl i I SS" " 'c^"OY sS^fE cO .wONE N r cour su'rcE SMCMc o 9 lC F @ {@ l B @ VlA L l V l E j X l@ [Ej@ g @ 20 7 8 9 to 11 12 13 18 19 SE OUF NTI AL OCCUHRE HEFORT REVISION lVEN T YE AH HE POHT f.O. CODE TYPE N O.

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34 35 36 3/ 40 42 43 44 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS i o lThe cause of the original leakage was blown packing on residual heat removal isolation l li ii j [ valve MOV-1700. The cause of the subsequent leakage was a nackino leak on pressurizeri g (spray valve PCV-1455A. Immediate corrective action was to reduce power and identify I t,g3; lthe leakage. Further corrective action was to repack both valves. fio further I i, ;4i l corrective action was required. l 7 8 9 80 STA SPO'AEH OTHE R STATUS bl5C E Y DISCOVFHY DESChlPTION li' ls 8[ [E J@ 0l 9 7 jQ ft/A l ld'A l@l Leakrate Test l

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. 4 Virginia Electric and Power Company North Anna Power Station, Unit #1

Attachment:

Page 1 of 1 Docket No.: 50-338 Report No.: LER 79-012/03L-0 Description of Events:

On 1-27-79, during steady state operation, the operator noted an increase in primary system makeup. A calculation of primary coolant leakage showed unidentified leakage was greater than 5 GPM. The plant was in hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and cold shutdown within 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> as required by the Action Statement.

During the subsequent startup on 1-29-79, while in hot standby (Mode 3),

the Primary Coolant Leakage was found to be greater than 1 GPM. The plant was brought to the cold shutdown mode as required by the Action Statement.

These events are contrary to T.S. 3.4.6.2 and are reportable as per T.S. 6.9.1.9.b.

Probable Consequer.ces of Occurrences:

Industry experience has shown that while a limited amount of leakage is expected from the RCS, the unidentified portion of this leakage can be reduced to a threshold value of less than 1 GPM. This threshold value is sufficiently low to ensure early detection of additional leakage.

Since the leakages were immediately identified and the plant was placed in the cold shutdown mode, there was no effect upon the safe operation of the plant.

As a result, the public health and safety was not endangered.

Cause of Occurrences:

The cause of the original leakage was blown packing on Residual Heat Removal Isolation valve MOV-1700. The cause of the subsequent leakage was a packing leak on Pressurizer Spray valve PCV-1455A.

Immediate Corrective Action:

The leakages were identified and the plant reduced to the cold shutdown mode.

Scheduled Corrective Action _: ,

Both leaking valves were repacked.

Actions Taken to Prevent Recurrences:

No further corrective action was required.