ML20207N247
| ML20207N247 | |
| Person / Time | |
|---|---|
| Issue date: | 01/12/1987 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Harold Denton, Taylor J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18041A146 | List: |
| References | |
| NUDOCS 8701140076 | |
| Download: ML20207N247 (3) | |
Text
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-l JAH i t W i MEMORANDUM FOR: Harold R. Denton, Director Office of Nuclear Reactor Regulation
', James M. Taylor, Director Office of Inspection and Enforcement FROM: C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data 4
SUBJECT:
CASE STUDY REPORT - OPERATIONAL EXPERIENCE INVOLVING LOSSES OF ELECTRICAL INVERTERS t 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, a
the Regions, INPO, and Brookhaven National Laboratory. The final report also
]i includes a brief analysis and evaluation of inverter loss events that occurred in calendar year 1985 which were not included in the preliminary report.
The study was initiated based primarily on the observation of a lack of overall industry-wide 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 is incompatibility between the actual equipment 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 3 spikes and perturbations at inverter terminals. The study notes that these two i factors have potential common cause implications. Other contributing factors !
' ', - or causes are inadequate maintenance and testing procedures or inappropriate personnel actions.
In addition, the study finds that technical specifications that address inverters and/or attendant buses for comparable plant designs are not consistent. Further, inverter-related operating experiences indicate 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 conclusions.
b,'
It is requested that IE give appropriate consideration to recommendation number 1, and that NRR give appropriate consideration to recommendations numbers 2 and !
- 3. However, in view of the common NRC and industry objective of resolving
!! safety issues relating to the operation of nuclear plants in the most effective fl 8701140076 870112 PDR ORG bEXD
,, POR
- . 4 Multiple Address:es
- l manner..those recommendations dealing with procedures, training, and hardware modifications could be provided to an appropriate industry group for consideration and supplemental follow-up actions. '
If you have any questions regarding the enclosed report, please contact Frank Ashe of my staff. Mr~. Ashe can be reached on X24442.
ongnat sian d by C. J. Heltemos, Jr.
C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated cc w/ enclosure:
V. Stello, ED0
'J. Roe, D/E00 J. Sniezek,'D/ROGR D. Humenansky, OCM S. Newberry, NRR I. Villalva, RI A. Rubin, NRR D. Wigginton,-NRR H. Schierling, NRR D. Thatcher, NRR
PDR M. Chiramal AE0D CF F. Ashe AE0D SF M. Williams ROAB CF K. Black ROAB SF W. Lanning J. Heltemes F. Hebdon S. Rubin i
- See next sheet for previous concurrence l 0FC : AEOD:ROAB : AEOD:ROAB : AEOD:ROAB : AE00:DD : AE00c.D : :
_____:____________:____________ f y ____________:___________
iNAME : FAshe:cg : MChiramal : SRubin : FHebdon :CJH emes : :
DATE : 12/18/86* : 12/19/86* : 12/19/86* : 12/31/86 :12/3\/86 -
OFFICIAL RECORD COPY
l Multiple Addressees plants in the most effective manner, those recomendations dealing with proce-dures, training, and hardware modifications could be provided to an appropriate industry group for consideration and supplemental follow-up actions.
If you have any questions regarding the enclosed report please contact Frank Ashe of my staff. Mr. Ashe can be reached on X24442.
/
/
C. J. He'1 temes , J r. , Di recto r Office' for Analysis and Evaluation of/0perational Data l
Enclosure:
As stated .
/
cc w/ enclosure: /
V. Stello, ED0 J. Roe, D/ED0 J. Sniezek, D/ROGR D. Humenansky, OCM S. Newberry, NRR I. Villalva, RI A. Rubin, NRR D. Wigginton, NRR H. Schierling, NRR D. Thatcher, NRR
PDR - M. Chiramal AE0D CF / F. Ashe AE0D SF / M. Williams ROAB CF / K. Black R0AB SF / W. Lanning J. Heltemes F. Hebdon' S. Rubin' 0FC : AEOD:ROAB : AEOD:ROAE t : COD:ROAB : AEOD:DD : AEOD:D : :
_____:__f_ A ______:________ w ____________:-___________:____________:____________:___________
NAME : FAshe:cg : MChiramal : SRubin : FHebdon :CJHeltemes : :
DATE : 12/is/86 : 12/\d/86 : 12/M/86 : 12/ /86 :12/ /86 : :
OFFICIAL RECORD COPY
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