ML20207N238
| ML20207N238 | |
| Person / Time | |
|---|---|
| Issue date: | 01/12/1987 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Lyon P INSTITUTE OF NUCLEAR POWER OPERATIONS |
| Shared Package | |
| ML18041A146 | List: |
| References | |
| AEOD-C605, NUDOCS 8701140067 | |
| Download: ML20207N238 (3) | |
Text
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I JAN 121987 AE00/C605 Mr. Peter W. Lyon, Group Vice President Analysis and Engineering Ir.stitute of Nuclear Power Operations 1000 Circle 75 Parkway, Suite 1500 Atlanta, GA 30339
Dear Mr. Lyon:
SUBJECT:
CASE STUDY REPORT - OPERATIONAL EXPERIENCE INVOLVING LOSSES OF ELECTRICAL INVERTERS The Office for Analysis and Evaluation of Operational Data (AE00) has finalized its case study report on operational experience involving losses of electrical inverters.
The report addresses the peer review comments provided by NRR, RES, the Regions, INP0, and Brookhaven National Laboratory.
The final report also includes a brief analysis and evaluation of inverter loss events that occurred in calendar year 1985 which was not included in the preliminary report. We have enclosed a copy of our final report for your information and use as you may deem appropriate.
The study was initiated based primarily on the observation of a lack of overall improvement in the operational performance of safety and nonsafety - related inverters.
The study indicates that events involving inverter losses raises two principal concerns:
(1) increased frequency of plant transients, and (2) inoperable or improper functioning of both safety-related and other important plant equipment.
Based on a review of events which occurred during calendar years 1982, 1983, and 1984, the study concludes that a major contributing cause for inverter loss events attributed to component failures is incompatibility between the actual equip-ment service conditions and the service conditions assumed in the design of these units. The two factors which appear to be dominant contributors to such failures are high ambient temperature and/or humidity within inverter enclosures and voltage spikes and perturbations at inverter terminals. The study notes that these two factors tave potential common cause implications. Other contri-buting factors or causes are inadequate maintenance and testing procedures or inappropriate personnel actions.
In addition, the study finds that techni-cal specifications that address inverters and/or attendant buses for comparable plant designs are not consistent.
Further, inverter-related operating experience indicates that a portion of the electrical circuitry associated with the Westinghouse Solid State Reactor Protection System (SSPS) should be reassessed for acceptability. The enclosed report contains specific recommendations to address the study's findings and conclusi These-recomendations are currently being reviewed by the Nuclear %ons.gqiatofy Commission staff.
8701140067 870112 PDR ORO fEXD PDR
~Mr. Pet:r W..Lyon 'A copy of the final case study report and this letter are being placed in the Public Document Room at 1717 H Street, N.W., Washingtcn, D.C.
20555.
If you have any questions regarding this report, please contact Frank Ashe of my staff. Mr. Ashe can be reached at (301) 492-4442.
Sincerely, onens signed by C.J.HeManass Jr.
C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated cc w/ enclosure:
M. Beaumont, W C. Brinkman, UE R. Borsum, B&W L. Gifford, GE cc w/o enclosure:
V. Stello, ED0 J. Roe, D/ED0 J. Sniezek, DEDR0GR Distribution:
PDR M. Williams AE0D CF K. Black AE0D SF W. Lanning ROAB CF AE0D SF J. Heltemes F. Hebdon S. Rubin M. Chiramal F. Ashe
- See previouse copy for concurrence.
OFC : AEOD:ROAB* : AEOD:ROAB* : AE00:ROAB* : AEOD:DD
- AEOD:D
_____:____________:____________:____________: __ 4.h ____:_
NAME : FAshe:cg
- MChiramal
- SRubin FHebdon ltemes :
DATE : 12/18/86
- 12/19/86
- 12/19/86
- 12/31/86
- 12/1l/86 OFFICIAL RECORD COPY
M r. Petar W. Lyon A copy of the final case study report and this letter are being placed in the Public Document Room at 1717 H Street, N.W., Washington, D.C.
20555.
If you have any questions regarding this report, please cont c Frank Ashe of my staff. Mr. Ashe can be reached at (301) 492-4442.
Sincerely, I
C. J., eltemes, Jr., Director -
Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated cc w/ enclosure:
/
M. Beaumont, W C. Brinkman, EE R. Borsum, B&W L. Gifford, GE
/
j cc w/o enclosure:
/.
V. Stello, ED0 f'
J. Roe, D/ED0
/
J. Sniezek, D/ROGR /
/
Distribution:
/
K. Black AE0D SF W. Lanning ROAB CF AE0D SF
.J. Helterpes F. Hebdo'n S. Rubin M. Chiramal F. Ashe
- 0FC
- AEOD:ROAB : AEOD:ROAB
- AEOD:ROAB
- AEOD:DD
- AEOD:D
_ _ _ _ _ : _ _ h& c... _ _ _ _ : _ _ _ _ _ _ _ L: _ _ _ _ _ _.. :____________:_____._____:. __________:____.....__
NAME : FAshe:cg
- MChiramal
- SRubi FHebdon
- CJHeltemes :
12/8/86 DATE :-12/ag/86 12/s /86
- 12/ /86
- 12/ /86 c
OFFICIAL RECORD COPY