ML19253C256
| ML19253C256 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/27/1979 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| GQL-1439, NUDOCS 7911300389 | |
| Download: ML19253C256 (3) | |
Text
Metropolitan Edison Company 9
{j Post Office Box 480 Middletown, Pennsylvania 17057 717 944-4041 Novenber 27, 1979 GQL 1h39 Director of Nuclear Reactor Regulation Attn:
R. W. Reid, Chief Operating Reactors Branch No. h U. S. Nuclear Regulator / Comission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 TMI-1 PORV Actuation With regard to IGC letter of September 28, 1979, enclosed are the responses to the request for additional information. The enclosure addresses only Item 1 of your letter.
Items 2 and 3 are not applicable to TMI-1, therefore, no response has been provided.
Sincerely,
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J. G. Herbein Vice President-Nuclear Operations JGH:DWR:tas Enclosure
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Enclosure to GQL 1h39 TMI-1.PORV Actuation Aequest No. 1 According to statements made by B&W, there are approximately lh6 documented occasions where PORV actuation occurred at B&W facilitias prior to the accident at Three Mile Island, Unit 2 (TMI-2). For each of these events which have occurred at your facility (ies) provide the following information:
a.
The cause of the event; b.
The initial power level prior to the transient; c.
Indicate which of these transients caused the reactor to trip on high RCS pressure and/or caused the safety valves to lift; and, d.
If you assume that the present setpoints for high RCS pressure trip and PORV actuation were in effect at the time of each of these transients,
estimate whether either of the following would have taken place:
- 1) PORV actuation, and
- 2) lifting of the safety valves.
Response
The following matrix provides information for parts a., b., and c., above :
Power Reactor Trip Code Safety Cause of Level on High RCS Valve Eve nt /Date Event Precsure Actuate Reactor Trip #1/
Partial loss of 7
No No 6/18/7h instrument air Reactor Trip #6/
Electrical problems 65 No No 7/12/Th with turbine Reactor Trip #7/
Loss of Feedvater 15 No No 7/13/Th Reactor Trip #8/
Inadvertent grounding 76 No No 7/lh/Th of RCS Tave signal Reactor Trip #10/
Manual turbine trip 98 Yes no 8/13/7h for TP 800/3h Turbine Trip /
Turbine bearing 75 No No 8/30/74 failure Turbine Trip /
High moisture separator 100 No No 1/23/75 drain tank level Reactor Trip #12/
Loss of 125 VDC power 100 No No 3/30/75 to EHC Reactor Trip #13/
High moisture 100 Yes No 5/09/75 separator level Reactor Trip #1h/
Voltage spikes in 100 Yes No 6/18/75 turbine EHC system caused load transient 1442 331
,x
. Power Reactor Trip Code Safety Cause of Level on High RCS Valve Event /Date Event Pressure Actuate Turbine Trip /
Test on plant 80 No No 12/22/75 fire protection (svitch)
Loss of EHC-DC 100 No No 11/15/78 power to turbine generator In response to Part d., if the modified setpoints were in effect at the tine of the transients we do not believe PORV actuation would have occurred.
Since the code safety valves did not actuate with the old set points they are not expected to actuate for the modified setpoints. As requested these assumptions did not take credit for the anticipatory control-grade reactor trip on loss of feedvater or turbine trip.
1442 532