ML20054K055
| ML20054K055 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 06/23/1982 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| Shared Package | |
| ML20054K056 | List: |
| References | |
| NUDOCS 8206300351 | |
| Download: ML20054K055 (3) | |
Text
Distribution g
June 23, 1982 Docket NRC PDR Local PDR ORB Reading NSIC D. Crutchfield Docket No. 50-245 H. Smith J. Shea Mr. W. C. Counsil. Vice President R. Dudley OELD Nuclear Engineering and Operations OI&E Northeast Nuclear Ecsrgy Company P.O. Box 270 ACRS(10)
Hartford, Connecticut 06101 SEPB TAC NO. 10033
Dear Mr. Counsil:
SUBJECT:
MILLSTONE UNIT 1 - DEGRADED GRID PROTECTION FOR CLASS lE POWER SYSTEMS By letter dated June 3, 1977, you were provided staff positions pertaining to degraded grid voltage protection. You responded with letters dated within the period August 1, 1977 to April 21, 1982. We find the undervoltage protection system connected to the Reserve Station Service Transformer bushing potential devices does not conform to the staff's position. It is the staff's requirement that undervoltage protection relays be installed on 4160 volt Class lE buses. As the result of subsequent discussions, you have connaitted to modify the present design and relocate the undervoltage protection relays to the 4160 volt Classi lE buses. However, due to anticipated delays in completing the design and procurement of equipment for the first level loss of power protection relays, that. portion of the system will not be placed in operation until the refueling outage presently scheduled for the sunumer of 1984. This is acceptable to the staff.
The presently installed design and its proposed relocation to the 4160V 5g/
buses incorporates features that require coincident undervoltage and a safety injection signal (LOCA) in order to actuate the undervoltage protection circuitry. This is in conformance with the staff's position y o M C g-)
and is, therefore, acceptable. However, for an undervoltage condition without a LOCA, manual operator action will be required to assure that the Class LE systems are not degraded for this grid transient. This approach deviates from the staff position which requires automatic iso-lation of offsite power for such undervoltage conditions after a time delay.
Acceptability of this alternate approach requires demonstration by you that adequate safety systems will be available to enable safe reactor shutdown under these conditions and that appropriate plant operating procedures are developed and made available to the operator for the required manual operator action.
To address these concerns, you have provided a list of safety systems which are not exposed to degraded grit voltage and are, therefore, available to place the plant in a dafe shutdown status. We have reviewed this list of 8206300351 820623 PDR ADOCK 05000245 P
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Mr. W. G. Counsil systems and concur that this equipment provides the capability for safe plant shutdown under non-accident conditions, provided certain modifications are completed on the Isolation Consenser System. These modifications involve changing one MOV and the condensate transfer pump from AC to DC power, which upon completion will make this system independent from AC power.
You have committed to perform these modifications during the refueling outage presently scheduled for the fall of 1982.
T Based upon the fact that protection devices-(such as breakers, fuses and relays) are provided to prevent damage to operating equipment that may be exposed to a degraded grid, the low probability of this event occurring (no alarm alerts have occurred since 1976 in the licensee's grid system),
installed alarma that will alert the operator to these abnormal conditions, and the availability of redundant safety systems to permit a safe plant shutdown under non-accident conditions, we find this alternate approach acceptable.
You should provida design details for the first level loss of voltage relaying, technical specificati ns which include relay setpoints and l
tolerances, limiting conditions for operation and surveillance tests for this system, and appropriate plant operating procedures to cover operator actions during a degraded grid under non-LOCA conditions. The procedures will be considered as an unresolved issue in the integrated assessment for Millstone 1.
This request relates to an issue specific to Millstone Unit 1 and, therefore, does not require OMB clearance under P.L.96-511.
Enclosed is our related Safety Evaluation Report and the supporting Technical Report prepared by our consultant, Lawrence Livermore Laboratory (LLL Report j
UCID 19139).
Original Signed By W. Paulson for Dennis M. Crutchfield. Chief Operating Reactors Branch f5 t
Division of Licensing
Enclosures:
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Safety Evaluation Report 2.
LLL Report - UCID 19139 cc w/ enclosures:
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. Mr. 'W. G. Counsil cc William H. Cuddy, Esquire State of Connecticut Day, Berry & Howard Office of Policy Management
, Counselors at Law ATN:
Under Secretary Energy One Constitution Pla:a Division Hartford, Connecticut 06103 80 Washington. Street-Hartford, Connecticut 06115 Board of Selectmen Town Hall Resident Inspector Haddam, Connecticut 06103 Haddam Neck Nuclear Power Station c/o U. S. NRC Northeast Nuclear Energy Company
- East Haddam Post Office ATTN:
Superintendent East Haddam, Connec'ticut 06423 Millstone Plant P. O. Box 128 U. S. Environmental Protection Waterford, Connecticut 06385 Agency Region I Office ATTH:
Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203 Resident Inspector c/o U. S. NRC Superintendent
'P. O. Box Drawer XX Haddam Neck Plant Niantic, Connecticut 06357 RFD #1 Post Office Box 127E Ronald C. Haynes, Regional Administrator East Hampton, Connecticut ' 06424 Nuclear Regula' tory Commission, Region I 631 Park Avenue King of Prussic, Pennsylvania 19406 Fir'st Selectman of the Town of Waterford Hall of Records 200 Boston Post Road Waterford, Connecticut 06385 John F. Opeka Systems Superintendent Northeast Utilities Service Ccmpany P. O. Box 270-Hartford, Connecticut 06101 Mr. Richard T. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 t
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