ML20008G195
| ML20008G195 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/12/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-81-463-000 10CFR-050.55E, 10CFR-50.55E, PT21-81-463, PT21-81-463-000, NUDOCS 8107020426 | |
| Download: ML20008G195 (2) | |
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400 Chestnut Street Tower II
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M Mb Mr. James P. O'Reilly, Director yyt 0163 h
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A Office of Inspection and Enforcement U.S. Nuclear Regulatory Comisaicts Region II - Suite 3100
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Dear Mr. O'Rei'.ly:
SEQD0YAH NUCLEAR PLANT UNIT 2 - EXCESSIVE PRESSURE DROPS ACROSS THE ERCW STRAINERS - SQRD-50-328/81 FINAL REPORT The subjoot deficiency was initially reported to NRC-0IE Inspector R. W.
Wright en January 28, 1981, in accordance with 10 CFR 50.55(e) as NCR SQN MEB 8006R1. Interia m ports wara submitted en February 27 and April 27 and May 27, 1981. Enclosed is our final report. We consider 10 CFR 21 applicable to this deficiency.
If you have any questiata, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly you:s, TENNESSEE VALLEY AUTHORITT L. M. Milla, Manager Nuclear Regulation and Safety l
Enclosure j
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Mr. Victor Stallo, Director (Enclosure),v Offia* al Inspection and Enforcement 7.3. Nuclear Regulatory Cammminaion Washington, DC 20555 8107 0 2 6 t/.2(p g
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n ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 EXCESSIVE PRESSURE DROPS-ACROSS THE ERCW STRAINERS SQRD-50-328/81-17 10 CFR 50.55(e)
FINAL REPORT Descriotion of Deficiency During preoperational testing at Sequoyah unit 1, it was discovered that pressure drops in excess of that designed for existed across the ERCW strainers.
S. P. Kinney Engineering in Carnegie, Pennsylvania, supplied these strainers and predicted their pressure drop. The actual pressure drop, however, was much larger than the stated value. As a result, reduced flow rates could occur due to increased system resistance.
Safety Imolications Tha ERCW System is designed to supply a continuous flow of cooling water to various heat loads in systems and components necessary for plant safety.
As a result of the excessive pressure drops across the strainers, flow rates less than the values claimad in the plant safety analysis could have resulted, which could have adversely affected the safety of the plant.
Corrective Actions TVA has reevaluated the total system flow requirements and adjusted them downward as discussed in NCR SQNSWP8107 and has completed the l
preoperational flow balance test on the ERCW system. The test results indicate the system is capable of providing the sufficient flows to the main auxiliary building headers without removing or replacing the strainers, although the flows to certain individual components continue to l
be deficient (refer to NCR SQNSWP8107). Any design modifications to the ERCW system and the required surveillance test program will be reported in NCR SQN NEB 8035 and NCR SQN SWP 8107. Should a surveillance test program indicate that modifications to the system are required, TVA has determired that other more effective potential design modifications exist which could eliminate the need to replace, modify, or remove the ERCW strainers, while at the same time, combating the corrosion problem.
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