NRC Generic Letter 77-07, Reliability Of Standby Diesel Generator Units

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December 15, 1977

ALL POWER REACTOR LICENSEES

The demonstrated reliability of standby diesel generator (DG) units in operating nuclear power plants has been less than anticipated. The NRC has concluded that a systematic review and analysis of operating problems associated with diesel generator units is necessary to establish what practical measures may be taken to enhance the reliability of these units. The NRC, with the assistance of the University of Dayton, has initiated such a study. It is our intent that this study will provide practical results that will prove useful to each nuclear utility, therefore, each operating reactor licensee is requested to respond to the enclosed questionnaire.

An analysis will be performed on the information received and the results of this analysis, along with recommendations that may lead to improved reliability, will be transmitted to licensees and applicants for their use. We believe that this information will assist in identifying as well as avoiding or minimizing operating experiences encountered by others. We view this effort as one of mutual interest.

We ask that a single completed copy of the enclosed questionnaire be returned to the Director of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555, by January 20, 1978. Please include on a separate sheet the name, address and phone number of the person(s) at the reactor site responsible for completing the questionnaire and responsible for responding to any follow-up communications concerning the questionnaire or for arranging a reactor site visit.

The responses to the majority of the questions can be answered with just a few words or by checking the appropriate space. In responding to those questions which do not apply to a particular installation and/or situation, please indicate "N/A" for "not applicable". If the question does apply to a particular installation or situation but the answer is not known, please indicate "UN" for "unknown". For those entries on the questionnaire where the requested information is not known by January 20, 1978, please provide it in follow-up correspondence when it becomes available.Further, the detailed information obtained in this study will be subject to disclosure pursuant to the Freedom on Information Act Regulations as implemented by 10 CFR Part 9 - Public Records.

In the event that any information requested as a part of this study, is considered by you (or your contractor) to be proprietary, it is necessary that you make a written application to withhold such information from public disclosure. Any such application must be accompanied by an affidavit executed by the owner of the information, which identifies the document or part sought to be withheld, and which contains a statement of reasons which address with specificity the items which will be considered by the Commission as listed in subparagraph (b)(4) of Section 2.790 of NRC's "Rules and Practice", Part 2, Title 10, Code of Federal Regulations. The information sought to be withheld shall be incorporated as far as possible into a separate part of the affidavit.

In the event any portion of the questionnaire needs clarification, please contact F. Clemenson at (301)492-8077.

This request for generic information was approved by GAO under a blanket clearance number B-180225 (R0072); this clearance expires July 31, 1980.

Sincerely,

Karl R. Goller, Assistant Director for Operating Reactors Division of Operating Reactors

Enclosure:

Questionnaire