ML20008D852
| ML20008D852 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/30/1980 |
| From: | Hovey G METROPOLITAN EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-20, TLL-484, NUDOCS 8010230306 | |
| Download: ML20008D852 (2) | |
Text
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Metropolitan Edison Company Post Office Box 480 4
Middletown, Pennsylvania 17057 Wnter's Direct Dial Number September 30, 1980 TLL 484 Office of Inspection and Enforcement Attn:
Mr. Boyce H. Grier, Director Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406
Dear Sir:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating License No. DPR-i3 Docket No. 50-320 IE Bulletin 80-20 This response is submitted as required by IE Bulletin 80-20.
The subject bulletin, " Failures of Westinghouse Type W-2 Spring Return to Neutral Control Switches" concerns the conditions where tne switch contact closure is intermittent with the switch in the neutral position. This in-consistent contact closure could possibly prevent the proper operation of the equipment or function which the switch serves.
A review of the Unit 2 facility has shown that the subject switches are being utilized in two applications within the facility. These switches function as local permissive switches for all 4160 volt breakers in the unit and as the Control Room's control switches for the 4160V Class lE Diesel Generators' breakers. The systems addressed in the Interim Recovery Technical Specifications in which the subf'ct switches are installed are:
- Class IE and BOP distribution system (for portions required to support core cooling)
- Makeup and Purification
- Emergency Feedwater
- Nuclear Services River Water
- Condensate
- Circulating Water
- Long Term "B" There is a total of 53 of the subject switches in the above described systems.
The continuity check required by item 2 of the bulletin has been performed for all safety-related applications with no open contacts observed.
8010230 3 0 6
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Metropolitan Edson Company is a Member of the General Public Utsties System
' w.'.Boycc H. Gricr TLL 484 Modifications will be accomplished to eliminate the local permissive switch contact for all 4160V breakers. This same function can also be accomplished by controlling the breaker position, i.e.,
racked in, test position, or racked out.
Therefore, there will be no loss of permissive control. The diesel generator breakers' control logic will be modified to provide Control Room indication of the normal position contact of the generator breaker control switches. Until these modifications are accomplished, continuity checks will be performed every 31 days or af ter operating a safety-related W-2 switch.
In preparing the response to this bulletin, approximately 28 manhours were expended.
It is estimated that an additional 170 ma.'. hours will be expended in performing the modifications and checks specified in this bulletin response.
Sincerely, K/
G. K. Hovey Director, TMI-2 GKH:SDC: dad cc:
John T. Collins Bernard J. Snyder
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