ML20059M004
| ML20059M004 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/01/1993 |
| From: | Cooper R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9311180067 | |
| Download: ML20059M004 (2) | |
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UNITED STATES
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D, KING OF PRUSSIA, PENNSYLVANIA 19406-1415 SEP 1 E93 MEMORANDUM FOR:
Steven A. Varga, Director Division of Reactor Projects - I/II, NRR FROM:
Richard W. Cooper II, Director Division of Reactor Projects, Region I
SUBJECT:
RFQUEST FOR TECHNICAL ASSISTANCE REGARDING EIOTOR CONTROL CENTER 5 AT HADDAM NECK An Augmented Inspection Team was dispatched to review the failure of the automatic bus transfer (ABT) of motor control center 5 (MCC-5) to operate at the Haddam Neck Plant.
The inspection was conducted on June 30 - July 9,1993, and the results of the inspection are provided in the enclosed NRC Inspection Report No. 50-213/93-80. The inspection team noted that the automatic bus transfer scheme is required to function properly for successful emergency core cooling system functions. However, it appears that the design of the logic for performing the automatic bus transfer should be enhanced to provide a more reliable source of power for MCC-5. Based on the inspection findings, the AIT developed the following questions for NRR resolution:
Attachment No. I provides a group of selected facts regarding the current automatic bus transfer for MCC-5, and also provides questions regarding the licensing of this configuration.
QUESTION #1 Was the NRC aware of the single failures, which could lock out MCC-5 during the licensing of this design?
QUESTION # 2 Is the risk of the current automatic bus transfer ABT design acceptable 7 0
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QUESTION # 3 Does the licensee need an exemption from the single failure requirements invoked by 10 CFR 50.46(d)?
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QUESTION # 4 Should a design change be made to enhance the reliability of the automatic bus transfer, would this be a strong candidate for a backfit?
If you have any questions regarding this request for information or the inspection report findings, please contact Jim Trapp at (215) 337-5186.
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I d W. Cooper II, ir or Division of Reactor Proj -
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cc w/o Attachments:
T. Martin, RA W. Kane, DRA A. Wang, NRR W. Raymond, SRI-HN T. Shedlosky, DRP F. Burrows, NRR M. Hodges, DRS J. Durr, DRS L. Doerflein, DRS R. Blough, DRP Attachments 1.
MCC-5 Single Failure Vulnerability 2.
NRC Inspection Report No. 50-213/93-80 3.
ACRS Transcripts 4.
Diagrams of MCC-5 and ABT i
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