ML20147D072
| ML20147D072 | |
| 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 7810130226 | |
| Download: ML20147D072 (13) | |
Text
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UNITED STATES g
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NUCLEAR REGULATORY COMMISSION ggt POR g
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OCT 5 1978
...o 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 Bgthesda, 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 i
which the equipment being posered 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 sunplies. 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 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.
(A copy of the slides used by GE in its presentation is provided as Enclosure 2.) The design would provide 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 proposed 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 4.
GE quer.tioned whether a second additional set of protective circuitry, identical to that proposed, would provide the required redundancy.
We 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.
5.
GE suggested that a technical specification be provided to limit the 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.
6.
With regard to implementation, we emphasized to GE that we expect the 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.
Y0 (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 J. Fray F. Rosa R. Brugge T. Ippolito B. Grim D. Tondl H. Ornstein J. Beard B. Clayton S. Rhow O. Verrelli M. Chiramal A. Hintze J. Calvo C. Thomas m
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[D REPORTS OF FAILURE OF TE TYPE POST-ULATED.
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" CLASS 1E SYSTB1 APPROVED BY TIE C0111SSIG1 CAPABLE OF DE-BIERGlZlllG THE REACTOR PRO-TECTI 0il SYSTB1 PGER SUPPLY lalBi ITS ORPlff VOLTME EXCEEDS OR FALLS BELDW LIMITS WITHiti tallCH TIE EQUIPIDIT BElllG PGERED FROM TIE PGER SUPPLY llAS BEEN DESIGED NID QUALIFIED TO OPERATE CONTINUQUSLY #fD WITHolH DE-GRADATION."
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CONFORMMCE TO DE NBl REQUIEIMS
- QUALIFICAT10i1 :
- NEW CNEL ONLY
- SEISMIC
- BNIR00fBRAL 010 MING)
- EDUNDNICY:
- DIO PROECTIVE CIRCUITS PER t% SET
- SEPARATION:
- BOTH OMELS PER M-G SET POWERED BY TE SAT NON-1E M-G SET VOLTAGE
- PHYSICALLY SEPAPATED CIRCUITS IN SEPARATE B4CLOSUES, GE M0lHTED 01 TE l% SET #4D TE OTER SEPARATE FRGi TE M-G SET, l
- SINGLE FAILUE CRITERIA:
- [DUNDNfT CLASS 1E PROTECTIVE CIRCulTS ASSUE TliAT A PORR SUPPLY WUUi4CT101 COUU) f40T CAUSE SlHJLTNEOUS FAILUE IN EDUNDN4T RPS OMiELS,
- TESTABILITY:
- PJLLY TESTABLE DURING EACTOR OPERATION,
- BYPASS INDICAT101:
- NO BYPASSES AE EQUIRED OR PROVIDED, B. P. G - 8 L_-
C0flFORMNICE TO TE I4EW REQUIREfFlffS (ccehl
- fW1UAL lillTIAT10ll:
- f% SET CN1 E fW1UALLY TRIPPED BY TRIPPlf4G ElllER CIRCulT BREAKER 01 TE l% SET GUTPUT, B.P.G.-9
EBEDULE FOR llPlBMATION o
DESIG1 APPRWAL BY NRC OCT. 78 x
F EQUIPfB R QUALIFICATION APR.79 l
FIRST INSTALLATION (HATCH 2 REFUELING)
DEC.79 B.P.G.-10
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