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{{#Wiki_filter:}} | {{#Wiki_filter:June 17, 1986 Dr. A. David Rossin, Director Nuclear Safety Analysis Center 3412 Hillview Avenue P.O. Box 10412 Palo Alto, California 94303 | ||
==Dear Dr. Rossin:== | |||
==Subject:== | |||
Preliminary Case Study Report--Operational Experience Involving Losses of Electrical Inverters The Office for Analysis and Evaluation of Operational Data has performed a study of reported operating events involving losses of electrical inverters. | |||
The study addresses events which occurred during calendar years 1982, 1983, and 1984. Our enclosed preliminary report documents the review and evaluation of these events. Based on this review, the study concludes that a major con-tributing cause for the occurrence of many of these events was incompatibility between actual plant service conditions and the service conditions assumed in the design for these units. The two parameters which appear to be dominant contributors to fa.ilure are high ambient temperature and/or humidity within inverter enclosures, and voltage spikes and perturbations at inverter terminals. Other contributing factors or causes are inadequate maintenance and testing procedures or inappropriate personnel actions. The study also finds that technical specifications which address inverters and/or attendant buses for comparable plant unit designs are not consistent. In addition, inverter-related operating experiences indicate that a portion of the electrical circuitry associated with a specific type of reactor protection system should be reassessed for acceptability. Our prelimi.tary report contains specific recomendations which are aimed at addressing these items. | |||
The purpose of this letter is to provide you with the opportunity to review the report, particularly with regard to its completeness and accuracy, prior to the issuance of the AE0D final report. Changes to the findings, conclusions, and recommendations will be considered only if the underlying information concerning the details of the plant design, systems operation or sequence of events is in error. Therefore, comments are being solicited on the technical accuracy of the report. The findings, conclusions, and recommendations are provided for your information in order that you may understand the significance AE0D places on this issue and therefore obtain a more complete picture of the total report. | |||
8607160380 860617 PDR ORG NEXD PDR | |||
. .}} | |||
Latest revision as of 12:04, 1 January 2021
| ML20202H596 | |
| Person / Time | |
|---|---|
| Issue date: | 06/17/1986 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Rossin D NUCLEAR SAFETY ANALYSIS CENTER |
| Shared Package | |
| ML20202H594 | List: |
| References | |
| NUDOCS 8607160380 | |
| Download: ML20202H596 (2) | |
Text
June 17, 1986 Dr. A. David Rossin, Director Nuclear Safety Analysis Center 3412 Hillview Avenue P.O. Box 10412 Palo Alto, California 94303
Dear Dr. Rossin:
Subject:
Preliminary Case Study Report--Operational Experience Involving Losses of Electrical Inverters The Office for Analysis and Evaluation of Operational Data has performed a study of reported operating events involving losses of electrical inverters.
The study addresses events which occurred during calendar years 1982, 1983, and 1984. Our enclosed preliminary report documents the review and evaluation of these events. Based on this review, the study concludes that a major con-tributing cause for the occurrence of many of these events was incompatibility between actual plant service conditions and the service conditions assumed in the design for these units. The two parameters which appear to be dominant contributors to fa.ilure are high ambient temperature and/or humidity within inverter enclosures, and voltage spikes and perturbations at inverter terminals. Other contributing factors or causes are inadequate maintenance and testing procedures or inappropriate personnel actions. The study also finds that technical specifications which address inverters and/or attendant buses for comparable plant unit designs are not consistent. In addition, inverter-related operating experiences indicate that a portion of the electrical circuitry associated with a specific type of reactor protection system should be reassessed for acceptability. Our prelimi.tary report contains specific recomendations which are aimed at addressing these items.
The purpose of this letter is to provide you with the opportunity to review the report, particularly with regard to its completeness and accuracy, prior to the issuance of the AE0D final report. Changes to the findings, conclusions, and recommendations will be considered only if the underlying information concerning the details of the plant design, systems operation or sequence of events is in error. Therefore, comments are being solicited on the technical accuracy of the report. The findings, conclusions, and recommendations are provided for your information in order that you may understand the significance AE0D places on this issue and therefore obtain a more complete picture of the total report.
8607160380 860617 PDR ORG NEXD PDR
. .