ML20147F234
| ML20147F234 | |
| Person / Time | |
|---|---|
| Issue date: | 10/05/1978 |
| From: | Thomas C Office of Nuclear Reactor Regulation |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7810190048 | |
| Download: ML20147F234 (13) | |
Text
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e UNITED STATES c
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NUCLEAR REGULATORY COMMISSION POR
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0 WASHINGTON, D. C. 20555 l
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OCT 5 1978 g
MEMORANDUM FOR:
John F. Stolz, Chief, Light Water Reactors Branch No.1, Division of Project Management FROM:
Cecil 0. Thomas, Project Manager, Light Water Reactors Branch No. 1, Division of Project Management
SUMMARY
OF SEPTEMBER 14, 1978 MEETING WITH GENERAL ELECTRIC COMPANY CONCERNING BWR REACTOR PROTECTION SYSTEM POWER SUPPLY MODIFICATION On September 14, 1978, we met with representatives of General Electric Company (GE) in Bethesda, Maryland to discuss GE's conceptual design of a system capable of de-energizing the reactor protection system power supplies of certain GE boiling water reactors when their output voltages exceed or fall below or their output frequencies fall below limits within which the equipment being powered by the power supplies has been designed and qualified. The reactors affected are those utilizing non-seismic Category I alternating current motor-generator sets as the normal reactor protection system power supplies. A list of attendees is presented as.
The significant points of the meeting were as follows:
1.
GE described its conceptual design of a system capable of de-energizing the reactor protection system power supplies when their output voltaces exceed or fall below or their output frequencies fall below limits within which the equipment being powered by the power supplies has '
.i designed and qualified.
(A copy of the slides used by GE in its presentation is provided as Enclosure 2.) The design would providr additional protective circuitry similar to that already provided for the motor-generator sets.
However, the additional protective circuitry would be qualified as Class IE whereas that already provided has not been qualified as Class IE.
2.
We noted that the design would not provide redundant Class IE protection in that single failures can be postulated that could result in the loss of capability to scram the plant.
We reiterated our position that the systems that will be relied upon to de-energize the reactor protection system power supplies provide redundant Class IE protection.
3.
Since the prnposed additional protective circuitry is similar to that already provided for the motor-generator sets, GE questioned whether it would be possible to qualify the existing protective circuitry in order to achieve, with the protective circuitry to be added, the required Class IE redundancy. We pointed out that it would likely be very difficult to qualify the existing protective circuitry, since, as GE recognized, components identical to those utilized in the existing protective circuitry may no longer be available.
In addition, the extension of the qualification to the existing physical configurations by analysis would likely be very difficult to accomplish.
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. OCT 5 1978 GE questioned whether a second additional set of protective circuitry, 4.
We identical to that proposed, would provide the required redundancy.
advised GE that although we have not had the opportunity to review the details of its proposed design, we believed that such an arrangement would provide the required redundancy.
GE suggested that a technical specification be provided to limit the 5.
length of time the alternate reactor protection system power supply can be connected to either of the reactor protection system buses in order to provide assurance that the probability of a postulated failure due to a seismic event would be acceptably low. We noted that a seismically-induced failure of the alternate reactor protection system power supply or the switch which allows the alternate reactor protection system power supply to be connected to either of the reactor protection system buses could be postulated that could result in the loss of capability to scram the plant. At our request, GE agreed to investigate this as well as any other postulated failure that could result in damage to the reactor protection system components with the attendant potential loss of capability to scram the plant.
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With regard to implementation, we emphasized to GE that we expect the 6.
affected utilities to install the required systems as expeditiously as possible in order to obviate the need for granting additional exemptions from the Commission's regulations related to this matter.
7.
GE indicated that it would advise its affected customers of the matters discussed at the meeting.
Y 0, (M.
Cecil 0. Thomas, Jr., Project Manager Light Water Reactors Branch No. 1 Division of Project Management
Enclosures:
1.
List of Attendees 2.
Slides used by GE in its presentation
ENCLOSURE 1 LIST OF ATTENDEES SEPTEMBER 14, 1978 MEETING WITH GENERAL ELECTRIC COMPANY General Electric Company Nuclear Regulatory Commission E. Fuller R. Tedesco F. Rosa J. Fray T. Ippolito R. Brugge B. Grim D. Tondi H. Ornstein J. Beard B. Clayton S. Rhow
- 0. Verrelli M. Chiramal A. Hintze J. Calvo C. Thomas
g RPS M-G SET FIX
- EXISTING PROVISIGIS
- HISTORY OF PERFORMCE
- IiEW IRC REQUIRDEfffS
- PROPOSED IDDIFICATIGIS
- CGFORMCE TO NDI REQUIRDUlTS
- SOEDUlf FOR IMPlBE{TATIG1 B.P.G. - 1
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" CLASS.1E SYSTB1 APPROVED BY lilE C0111SSIG1 CAPABlf 0F DE-BERGlZlilG THE REACTOR PRO-TECTIGl SY51B1 PGER SUPPLY M101 ITS OlffPlff VOLTAGE EXCEEDS OR FALL.S BELDW LIMITS WITHIN MllCH TIE EQUIPINT Bell 1G PGERED FROM TIE PGER SUPPLY HAS BEEN DESIGED #0 QUALIFIED TO OPERATE CONTINUQUSLY NO WITliolff DE-GRADATION."
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PROPOSED MODIFICAT101S.
- TE01 SEC 04 TE LBOTli T TIE TIE ALTERiATE POWER SOURCE CAN E CONNECTED TO EITIER RPS BUS, TIE (UEER SHOULD BE HIGl BIOUGH TO ALLal FOR M-G SET l%INTEtWEE WITil00T EDUCING Pl#1T AVAILABILITY BUT WW BIOUGH TO PROVIDE KASGMBLE ASSUPANCE THAT PROPABILITY OF llE POSTULATED FAILUE IS ACCEPTABLY 1.0W.
B.P.G.-7
CONFORMANCE TO T[ NEW EQUIEMENTS
- QUALIFICATI0i1 :
- NEW GMEL ONLY
- SEISMIC
- B1VIR0ifBiTAL 040 AGING)
- EDlt0AtlCY:
- TWO PROTECTIVE CIRCUITS PER M-G SET
- SEPARATION:
- BOTH OWifELS PER l% SET POWEED BY TE SAME NG4-1E l% SET VOLTAGE
- PHYSICALLY SEPARATED CIRCUITS IN SEPARATE B4CLOSUES, GE MOUIRED G4 TIE f% SET AND TE OTER SEPARATE FROM THE f% SET.
- SINGlf FAILURE CRITERIA:
- REDUNDNE CLASS lE PROTECTIVE CIRCulTS ASSUE THAT A POWER SUPPLY l%lfUi1CT101 COULD NOT CAUSE SIMJLTNEOUS FAILURE IN EDUNIW4T RPS GM4ELS.
- TESTABILITY:
- FULLY TESTABLE DURING EACTOR OPERATION.
- BYPASS INDICATIGi:
- NO BYPASSES AE EQUIRED OR PRWIDED.
B. P. G. - 8
CONFORMNICE TO TE IB1 EQUIEfB4TS (CON'T)
- fW4UAL ltilTIATION:
IM SET C#4 E M4UA11Y TRIPPED BY TRIPPING EIMR CIRCulT BREAKER Gl TE IM SET GUTPlR.
B.P.G.-9
1 SWEDULEFORIlPlBEfTATIGi ESIG1 APPROVAL BY NRC OCT 78 EQUIPIM QUALIFICATIG4 APR.79 FIRST INSTAU.ATION (HATCH 2 REFUELING)
DEC,79 B.P.G.-10
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