ML20210K852
| ML20210K852 | |
| Person / Time | |
|---|---|
| Issue date: | 04/22/1986 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Herbert R Terry Steam Turbine Co. |
| Shared Package | |
| ML20210K832 | List: |
| References | |
| NUDOCS 8604290097 | |
| Download: ML20210K852 (3) | |
Text
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1
? a o UNITED STATES g
g g NUCLEAR REGULATORY COMMISSION g ;y WASHINGTON, D. C. 20555
\*****/ g 22 M6 I
Mr. Russell T. Hebert, Product Manager -
Products and Services Steam Turbine Division Terry Corporation P.O. Box 555 l Windsor, Connecticut 06095 ;
l
Dear Mr. Hebert:
l
Subject:
Request For Peer Review Comments--Preliminary Case Study-- i Operational Experience Iqvolving Turbine Overspeed Trips l'
A preliminary AE0D case study report on domestic nuclear plant operating experiences involving overspeed trips of auxiliary feedwater (AFW) system steam turbines is enclosed. The preliminary study also includes a review of overspeed trip events involving high pressure coolant injection (HPCI) system turbines and reactor core isolation cooling (RCIC) system turbines, to aid in the identification of causes for AFW turbine overspeed trips. A total of 124 turbine overspeed trip events involving AFW, HPCI and RCIC systems were reviewed. The events studied occurred during the period from early 1972 to September 1985 and were identified primarily from Licensee Event Reports. Each of the events involves a steam turbine designed and built by the Terry Steam Turbine Corporation and a governor supplied by the Woodward Governor Company. This study was performed in response to the NRC staff -
investigations of the June 9, 1985 event at Davis-Besse.
Our preliminary study report concludes that the dominant causes of AFW turbine overspeed trips are speed control problems associated with the governor, and trip and reset problems associated with the trip valve and overspeed
~ . trip-mechanism. The governor speed control problems involve: (1) slow response of the governor during quick startup, (2) entrapped oil in the Woodward Model PG-PL governor speed setting cylinder, (3) incorrect governor setting, and (4) water induction into the turbine. The trip and reset problems stem from the complexity of reset operations and a lack of trip position indication. These problems are primarily the result of inadequate performance by plant personnel, inadequate procedures and irsufficient system design considerations. Preliminary recommendations for preventing or reducing these unwanted turbine overspeed trips have also been developed and are included in the enclosed report.
In accordance with our " peer review" process and prior to finalization and distribution of our case study reports, we are providing a copy of the preliminary report for your review and comment. We are particularly interested in-obtaining your view on the accuracy and completeness of the technical details. We would like to point out, however, that changes to the 8604290097 860422 ~
V Mr. Russell T. Hebert findings, conclusions, and recomendations will only be considered if the underlying information concerning the details of equipment design or systems operation is in error. Therefore, coments are being solicited on the technical accuracy of the report. The findings, conclusions, and recomendations are provided for your information in order that you and your staff may understand the significance which AE0D places on these events and obtain a more complete picture of the total report. We would welcome coments either informally by telephone or formally by memorandum. By separate transmittal memoranda and letters we have also forwarded a copy of the preliminary report to a number of NRC program offices, the NRC regional offices, INP0 and NSAC, in order to solicit additional peer review coments.
Since we wish to issue the final report shortly, we ask that any coments be received by us within 30 days from receipt of the preliminary report. Should your staff require additional time beyond that point, please let us know; otherwise, it will be assumed that there are no coments.
Please be advised that AE0D repotts represent neither official NRC positions nor requirements of the responsible NRC program offices. Our reports are one input to an ongoing review and evaluation process, and any recomendations contained in our final report will be considered and perhaps modified or dropped by the responsible NRC office.
A copy of the preliminary 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 study, please feel free to contact !
Chuck Hsu of my staff. Mr. Hsu can be reached at (301) 492-4443.
Sincerely, I
a_-L \
C temes,TJi'. , Director l Of for AnalyN s and Evaluation !
of Operational Data l
Enclosure:
l As Stated 1
l l
e Mr. Russell T. Hebert ;
findings, conclusions, and recommendations will only be considered if the I underlying information concerning the details of equipment design or systems operation is in error. Therefore, coments are being solicited on the technical accuracy of the report. The findings, conclusions, and ,
recomendations are provided for your information in order that you and your staff may understand the significance which AE0D places on these events and obtain a more complete picture of the total report. We would welcome comments '
either infonnally by telephone or formally by memorandum. By separate transmittal memoranda and letters we have also forwarded a copy of the preliminary report to a number of NRC program offices, the NRC regional offices, INP0 and NSAC, in order to solicit additional peer review coments.
Since we wish to issue the final report shortly, we ask that any coments be received by us within 30 days from receipt of the preliminary report. Should your staff require additional time beyond that point, please let us know; otherwise, it will be assumed that there are no coments.
Please be advised that AEOD reports represent neither official NRC positions nor requirements of the responsible NRC program offices. Our reports are one input to an ongoing review and evaluation process, and any recommendations contained in our final report will be considered and perhaps modified or dropped by the responsible NRC office.
A copy of the preliminary 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 study, please feel free to contact Chuck Hsu of my staff. Mr. Hsu can be reached at (301) 492-4443. ,
Sincerely, C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
Enclosure:
As Stated Distribution:
PDR AE0D CF AE0D SF ROAB CF ROAB SF CHsu MChiramal SRubin KBlack WLanning FHebdon CJHeltemes, Jr.
OFC :ROAB :SC:ROA :AC:ROAB G ) :DD:AEOD : :
____ :. __________:________ :..... __ % :___ d_...:D:AEOD...__:.___________:__________.
NAME :CHsu:rw M :MChiramal :SRubin :FH d n h :CJ : t es : :
DATE :4/// /86 :4/I?/86 :4/l?/86 :4f80/86 : & : :
0FFICIAL RECORD COPY l