ML19309F438
| ML19309F438 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 04/24/1980 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML19309F433 | List: |
| References | |
| NCR-SQN-NEB-800, NUDOCS 8004290461 | |
| Download: ML19309F438 (1) | |
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ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 UH1 HYDRAULIC ISOLATION VALVE ACCUMULATOR. WEIGHING SYSTEM 4
j NCR SQN NEB 8007 (FORMERLY NCR NEB 80-14) 10 CFR 50.55(e) t FIRST INTERIM REPORT i
Description of Condition The UHI hydraulic isolation valves were equipped with an accumulator weighing device which was intended'to verify proper charge in the l
accumulators. The accumulators are initally charged by pressurizing the j
internal nitrogen bladder to a precsure of 1500 psig and then filling the accumulator with hydraulic fluid until the system pressure reaches 3000 psig. A change in the weight of the accumulator would indicate either a fluid or gas leak. load cell readout devices were provided in the main control room so that the operator could verify proper accumulator charge.
In practice, the weighing syste= is inconsistent, and it is i
j difficult to obtain repeatability in accumulator weights.
The problem i
with this system is evidently caused by the stiffening of connecting l
hydraulic lines under pressure, i
Corrective Action j
Westinghouse has proposed a design change that will use direct pressure indications to verify proper accumulator charge.
TVA is reviewing this alternative to determine if it is acceptable.
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