ML20084U515
| ML20084U515 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/11/1976 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | Knuth D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, DDR-225, NUDOCS 8306290096 | |
| Download: ML20084U515 (2) | |
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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 STA!'DBY 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 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 143H33903 AUOn*&$*y S'i 'f)3l_,s;...,C$0 "M
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ENCLOSURE BROWHS FERRY HUCLEAR PLANT UNITS 2 AND 3 USE OF IMPROPER SCHEDULE PIPE IN STANDBY LIQUID CONTROL SYSTEM DDR 225 - FINAL REPORT Description of Occurrence While examining documents associated with a chan6e 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 f
Cause of the 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 work 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. In 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 systcm. Since the schedule 40 pipe has a maximum working pressure lover than the design pressure, it is conceivable that the schedule 40 pipe could have ruptured at some time during the plant'c operating history. Such a rupture vould incapacitate the SLCS since the rupture vould have occurred downstream of the SLCS pumps. The pumps vould then feed the break.
The SLCS valving arranEement 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 vill be replaced with schedule 80 pipe.
Means Taken to Prevent a Recurrence The documetation for the earlier modification has been reviewed to ensure that the cora ct schedule pipe is referenced.
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