ML20114B533

Forwards Updated Response to IE Bulletin 83-03 Re Check Valve Failures in Raw Water Cooling Sys of Diesel Generators,Revising Portions of Lm Mills 830615 & 1107 & 840115 Responses

ML20114B533
Person / Time
Site:	Browns Ferry
Issue date:	01/24/1985
From:	Domer J TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-83-03, IEB-83-3, NUDOCS 8501290294
Download: ML20114B533 (4)

Text

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TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot 1630 Chestnut Street Tower II January 24, 1985 U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator

.101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

Dear Mr. O'Reilly:

INSPECTION AND ENFORCEMENT BULLETIN 83 CHECK VALVE FAILURES IN RAW WATER COOLING SYSTEMS OF DIESEL GENERATORS - BROWNS FERRY NUCLEAR PLANT Enclosed is an updated response to the subject bulletin for the Browns Ferry Nuclear Plant. This response revises portions of those responses submitted by L. M. Mills' letters to you dated Jme 15 and November 7, 1983 and January 15, 1984. If you have any questions, please call Dennis McCloud at FTS 858-2725.

This concludes all actions as required by IE Bulletin 83-03 To the best of my knowledge, I declare the statements contained herein are complete and true.

Very_truly yours, TENNESSEE VALLEY AUTHORITY M

J. A. Domer Nuclear Engineer Enclosure cc (Enclosure):

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Mr. R. J. Clark Browns Ferry Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 8501290294 850124 PDR ADOCK 05000259 G PDR

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• An Equal Opportunity Employer

ENCLOSURE REVISED RESPONSE TO IE BULLETIN 83-03 .

DATED MARCH 10, 1983 l l

References:

1. Letter from L. M. Mills to J. P. O'Reilly dated June.15, 1983

2. Letter from L. M. Mills to J. P. O'Reilly dated November 7,1983

3. Letter from L. M. Mills to J. P. O'Reilly dated January-25, 1984 Response to Item 1 The Emergency Equipment Cooling Water (EECW) check valves to diesel generators subject to the bulletin requirements were identified in reference 1. A revised list is. attached (attachment A). The revised list deletes the EECW pump discharge check valves as allowed by the subject IE bulletin.

Response to Item 2 The check! valves in the EECW system to the diesel generator (D/G) coolers at Browns Ferry will be disassembled and inspected annually. The inspection frequency will correspond to the present annual D/G inspection frequency. - The D/G cooler EECW check valves will be inspected per a plant-approved Mechanical Maintenance Instruction. The ASME Section XI Inspection Testing Instruction will not be modified to backflow test the i- D/G-check valves since this would be redundant verification.

. Response to Item 3 (Schedule) 7 All EECW check valves identified in attachment A have been disassembled l . and their integrity _ verified. . Also, all the valves have been replaced swith new stainless steel check valves.

. Response to Item 4 The valve integrity verification has been performed. Review of available maintenance history records and discussions with informed maintenance personnel revealed that there have been no failures or significant.

problems associated with these valves, except as noted below in item 5.

EECW flow to each D/G engine cooler is presently being_ verified every six L weeks. To date, none of these tests have indicated that a D/G is

! t - 1 receiving inadequate flow because of the EECW check valves.

cAdditionally, flow from each individual EECW header is being _ verified every quarter, and none of these tests have shown any flow problems caused by the' check valves. The EECW system will continue to be tested-per ASME;Section XI Inservice Testing requirements.

b

Response to Item 5 (Results of Inspections)

During the inspection of the units 1 and 2 D/G in October 1983, two of

-the EECW check valves were found frozen open by crude, and two of the check valves would not operate through the full design range of the flapper swing. The D/G coolers have two separate sources of EECW with a

two check valves in series in each source. One of the check valves was cleaned and returned to service. The other three check valves were replaced.

'The remainder of the EECW check valves identified in attachment A have

~been disassembled and visually inspected. No failures were identified.

As discussed above, all the EECW check valves have been replaced with stainless steel check valves, therefore, no EECW check valve failures are expected in the future. The annual valve integrity inspections mentioned in item 2 will, however, be continued until sufficient operational experience exists for reconsideration.

b c

L _

W Attachment A -

Listing of Emergency Equipment Cooling Water (EECW) Check Valves to Diesel Generator (D/G) Coolers D/G 1A Cooler D/G 3A Cooler 67-5'8 67-693 67-529 67-694 67-534 67-695 67-535 67-6 %

D/G 1B Cooler D/G 3B Cooler 67-521 67-703 - 67-522 67-704 67-630 67-705 67-631 67-706 D/G 1C Cooler D/G 3C Cooler 67-514 67-713 67-515 67-714 67-624 67-715 67-625 67-716

.D/G 1D Cooler D/G 3D Cooler 67-507 67-723 _

67-508 67-724 67-627 67-725 67-628 67-726 7*

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