ML20209B175
| ML20209B175 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/20/1986 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Lyon P INSTITUTE OF NUCLEAR POWER OPERATIONS |
| Shared Package | |
| ML20209B180 | List: |
| References | |
| AEOD-C602, NUDOCS 8609080184 | |
| Download: ML20209B175 (3) | |
Text
N August 20, 1986 Mr. Peter W. Lyon, Group Vice President AE0D/C602 Analysis and Engineering Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339
Dear Mr. Lyon:
)
Subject:
Case Study Report--Operational Experience Involving Turbine Overspeed Trips Followirg resolution of peer review comments received from INPO, the Terry Corporation, and various NRC offices, the Office for Analysis and Evaluation I
of Operati.onal Data has finalized its case study report on operational experience involving turbine overspeed trips in light water reactors. We have enclosed a copy of our final report for your information and use as you may deem appropriate.
This study was performed in response to action item 8(f) of the actions directed by the ED0 to respond to the NRC staff investigations of the June 9, 1985 event at Davis-Besse. A total of 128 turbine overspeed trip events involving AFW, HPCI and RCIC systems were reviewed. Overspeed trips of AFW turbines were found to be relatively widespread and one of the major causes for loss of operability or unavailability of AFW systems. This study concludes that the dominant attributed 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 cperations and a lack of trip position indication. These problems are primarily the-result of inadequate performance by plant personnel, inadequate procedures, and insufficient design considerations.
The enclosed casa study report contains several specific recommendations aimed at addressing the root causes of the reported failures. These recommendations are currently being reviewed by the Nuclear Regulatory Commission staff.
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A copy of the final case studi report and this letter are being placed in the Public Document Room a: 1717 H Street, N.W. Washington, D.C. 20555.
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Mr. Peter W. Lyon If you or your staff have any questions regarding this report, please contact Chuck Hsu of my staff. Mr. Hsu can be reached at (301) 492-4443.
Sincerely,
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dnpameasd by
- a. s. m a.
C. J. Heltemes, Director Office for Analysis and Evaluation of Operational Data
Enclosure:
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- 8/ 2CV86 *
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s Mr. Peter W. Lyons If you or your staff have any questions regarding this report, please contact Chuck Hsu of my staff. Mr. Hsu can be reached at (301) 492-4443.
Sincerely, C. J. Heltemes, Director Office for Analysis and Evaluation of Operational Data
Enclosure:
As Stated cc:
Z. Pate, INP0 DISTRIBUTION:
PDR AE0D SF' AE00-CF ROAB SF R0AB CF CHsu MChiramal SRubin WLanning KBlack MWilliams FHebdon CHeltemes l
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NAME : CHsu:as
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DATE : 8//f /86
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- 8/ /86 0FFICIAL RECORD COPY