ML20085E875
| ML20085E875 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/11/1976 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | Knuth D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20085E878 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8308160623 | |
| Download: ML20085E875 (2) | |
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831 Power Buildin TENNESSEE VALLEY A HORITY CH ATTANOOGA. T ENNESSEE 374ot
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{SePember 11, 1976
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6 Dr. Donald F. Knuth, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Dr. Knuth:
BROWNS FERRY NUCLEAR PLANT UNITS 2 AND 3 - REPORTABLE DEFICIENCY -
USE OF IMPROPER SCHEDULE PIPE IN STANDBY LIQUID CONTROL SYSTEM Initial report of the subject reportable deficiency was made to G. R. Klingler, NRC-IE, Region II on January 12, 1976. In g
compliance with paragraph 50 55(e) of 10 CFR Part 50, we submit the enclosed final report of the deficiency.
Very truly yours, J. E. Gilleland Assistant Manager of Power 8308160623 760911 PDR ADOCK 05000 s
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l ENCLOSURE BROWHS FERRY NUCLEAR PLANT UNITS 2 AND 3 I
USE OF IMPROPER SCHEDULE PIPE IN STANDBY LIQUID COIffROL SYSTEM DDR 225 - FINAL REPORT j
l Description of' Occurrence While examining documents associated with a change in the Standby Liquid Control System (SLCS), an engineer discovered that an incorrect schedule of pipe had been called for on a work drawing which had been revised by an earlier change. This led to installation of an incorrect schedule of piping in the SLCS in units 2 and 3 Cause of ths Deficiency The SLCS pump discharge relief valve piping for units 2 and 3 had been' modified by raising the relief valves approximately eight feet. A revised l
vork drawing issued for this modification inadvertently referenced schedule 40 pipe instead of the required schedule 80.
Section 3.8 of the Browns Ferry Nuclear Plant FSAR states that the design _.
pressure of the - SLCS.is 1500 psig...Jn the temperature range experienced _by--
the SLCS, schedule 40 pipe has a maximum working pressure below this requirement. Schedule 80 has a maximum working pressure above the design pressure.
Safety Implications The SLCS is a safety-related system.. Since the schedule 40 pipe has a maximum working pressure lower than the design pressure, it is conceivable that the schedule 40 pipe could have ruptured at some time during the plant's operating history.
Such a rupture would incapacitate the SLCS since the rupture would have occurred downstream of the SLCS pumps. The pumps would then feed the break.
The SLCS valving arrangement keeps it isolated from the primary reactor coolant pressure boundary. Thus a rupture in the SLCS would not lead to a loss of coolant accident.
Description of-Corrective Action The schedule 40 pipe will be replaced with schedule 80 pipe.
Means Taken to Prevent a Recurrence i
The documentation for the earlier modification has been reviewed.to ensure that the-correct schedule pipe is referenced.
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