ML20050A850
| ML20050A850 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 03/19/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8204020328 | |
| Download: ML20050A850 (2) | |
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TENNESSEE VALLEY AUTHORITY r s i A T T A MX '. A T I N ';I : 6 L F.
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March 19, 1982 BLRD-50-438/82-17 J
BLRD-50-439/82-16
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U.S. Nuclear Regulatory Commission Region II
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Mr. James P. O'Reilly, Regional Administrator f'
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Atlanta, Georgia 30303 i
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Dear Mr. O'Reilly:
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p BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - IMPROPER USE OF CIRCUITAREA_KERS' TO SilED NON-CLASS IE LOADS - BLRD-50-438/82-17, BLRD-50-439/82 FIRST INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on February 19, 1982 in accordance with 10 CFR 50.55(e) as NCR DLN EEB 8201. Enclosed is our first interim report. We expect to submit our next report by June 24, 1982.
If you have any questions concerning this matter, please get in touch with R.11. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Man ger Nuclear Regulation and Safety Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 l
,a,R CG 0204020329 820319 I
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 IMPROPER USE OF CIRCUIT BREAKERS TO SHED NON-CLASS IE LOADS BLRD-50-438/82-17, BLRD-50-439/82-16 10 CFR 50.55(e)
FIRST INTERIM REPORT Description of Deficiency During an FSAR review it was discovered that the non-Class IE switchgear control power is derived from the 125V vital Class IE power system (EU).
Isolation of the non-Class IE loads from the 125V Class IE power supply is provided by a series of coordinated fuses and circuit breakers.
Isolation devices actuated only by fault currents are not considered to be isolation devices within the context of Regulatory Guide 1.75, " Physical Independence of Electrical Systems," RO, February 1974. Devices actuated by an accident signal are acceptable as isolators.
TVA Design Criteria N4-EU-D775 provided for the connection of the non-Class IE switchgear control power to the Class IE 125V de boards. This design was accomplished subject to the development of a suitable isolator with the ability to isolate without interrupting the non-Class IE circuits. No such device is available at this time and, thus, the design relies on fuses and circuit breakers for isolation.
Interim Progress TVA will take exception to Regulatory Guide 1.75 in this instance and will, by analysis, verify that the configuration is safe. The analysis will be documented and referenced in the FSAR and will demonstrate at least three fuse / breaker coordination levels that will prevent a malfunction (short circuit) in the non-Class IE a cuits from causing unacceptable influences in the Class IE portion of tho system.
The FSAR committed, with no exceptions, to full compliance with Regulatory Guide 1 75 and will be amended to document and provide justification for the exception taken.
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