ML20080H336
| ML20080H336 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/25/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-83-03, IEB-83-3, NUDOCS 8402140166 | |
| Download: ML20080H336 (2) | |
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TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II January 25, 1984 U.S. Nuclear Regulatory Commission
' Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303
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 a revised response to the subject bulletin for the Browns Ferry Nuclear Plant. This response revises portions of those submitted by my letters to you dated June 15 and November 7, 1983 If you have any questions, please call Jim Domer at FTS 858-2725.
To the best.of my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNES3EE VALLEY AUTHORITY b
L. M. Mills, Manager Nuclear Licensing Enclosure cc:
U.S. Nuclear Regulatory Commission (Enclosure)
Document Control Desk Washington, D.C.
20555 l
l 8402140166 840125 PDR ADOCK 05000259 G
/
An Equal Opportunity Employer
ENCLOSURE REVISED RESPONSE TO IE BULLETIN 83-03 PATED MARCH 10, 1983 BROWNS FERRY HUCLEAR PLANT
References:
- 1. TVA letter from L. M. Mills to J. P. O'Reilly dated June 15, 1983
- 2. TVA letter from L. M. Mills to J. P. O'Reilly dated November 7, 1983 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.
No change to that list is proposed.
Response to Item 2 The check valves in the Emergency Equipment Cooling Water (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 (MMI). The ASME section XI Inservice Testing Instruction will not be modified to backflow test the D/G chcck valves since this would be redundant verification.
Response to Item 3 (Schedule)
The EECW check valves to one of the units 1 and 2 D/Gs were inspected in October 1983 The check valves to the other seven D/Gs will be inspected by January 1, 1985. This time period allows for completion of each D/G's annual Inspection.
Response to Item 4 The valve integrity verification will be performed by disassembly. Review of available maintenance history records and discussions with informed maintenance personnel revealed that there ve been no failures or significant problems associated with these valves.
EECW flow to each D/G engine cooler is presently being verified every six weeks. To date, none of these tests has indicated that a D/G is receiving 5
$nadequate flow because of the EECW check valves. Additionally, flow from each individual EECW header is being verified every quarter, and none of these tests has shown any ficw problems caused by the check valves. These tests will continue to be performed at the stated frequency for this purpose until the initial inspections can be performed.
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 crud, 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 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.
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