ML20076E507
| ML20076E507 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/12/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20076E503 | List: |
| References | |
| NUDOCS 9108200171 | |
| Download: ML20076E507 (3) | |
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UNITED STATES f
NUCLEAR REGULATORY COMMISSION k
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WASHINoToN. D.C. 20H6 g... e..f-SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
-3 ELATED TO AMENDMENT NO. 80 TO FAtillTY OPEPATING LICENSE NO. DPR-22 NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263
1.0 INTRODUCTION
t By letter dated June 13, 1991, Northern States Power Company (the licensee) requested an amendment to the Technical Specifications (TS) appended to Facility Operating License No. DFR-22 for the Monticello Nuclear Generating Plant. The proposed amendment would (a) change the description of the drywell vacuum breaker limiting conditions for operation to correctly describe the controls and instrumentation provided for cycling the vacuum breakers open and closed, and (b) change the minimum diesel generator fuel supply from 32,500 gallons to 34,500 gallons.
A discussion of each requested change and the NRC staff's evaluation and findings relative to each are addressed in Section.2 of this Safety Evalua+1on.
2.0 DISCUSSION AND EVALUATION Drywell Vacuum Breakers: The Monticello primary containment contains eight normally-closed torus-to-drywell vacuum breakers. Each vacuum breaker is an IS-inch check valve with an air operator. Dual open and dual closed (four total) position switches are provided on each vacuum breaker. Yhese switches operate status lights in the control room and reactor building and also annunciate control room alarms. The air operators are used to cycle-the vacuum breakers open and closed as a monthly. operability test.
In addition, Limiting Condition for Operation (LCO) 3.7.A.4.d states:
Drywell-suppression chamber vacuum breakers may be cycled, one at a time using the exercise-test push button during containment inerting and deinerting operations to assist in purging-air or nitrogen from the suppression chamber vent header.
The licensee proposes to change the LCO to read:
Drywell-suppression chamber vacuum breakers may be cycled, one at a time during containment inerting and deinerting operations to assist in purging air or nitrogen from the suppression chamber vent header.
9108200171 910812 PDR ADOCK 05000263 l
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i The words ""using the exercise test push button" would be deleted. The f
exercise test push button is the control used to activate the air operator.
The proposed change would reflect the fact that the exercise controls are no longer, and need not necessarily be, of the push-button type.
The licensee replaced the forper push-button controls with a single vacuun breaker selector switch and non-return detent switch. The nodification was perforned during the 1989 refueling outage as part of a hunan factors design inprovenent
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progran. During a Maintenance Tean Inspection in 1991, HRC inspectors discovered a violation in that the licensee's safety evaluation for the
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nodification had failed to deternine that a Technical Specifications change l
was required (Ref: InspectionReport91-002).
The licensee's response to the violation, dated June 3, 1991, indicates that the need for a Technical Specifications change was not overlooked but was given low / routine priority.
An anendnent application was subnitted on a expedited basis in response to the violation.
The staff has reviewed the infornation provided in the June 13, 1991 application and deternined that switch replacenent and associated Technical Specification change are acceptable.
The new controls provide sone added neasure of safety in that they preclude the capability of opening nore than j
one vacuun breaker at a tine. However, a concern arose that the nodified t
controls night pernit a vacuun breaker to be inadvertently lef t open, thereby
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rendering the prinary containnent inoperable.
The staff considered these factors and concluded tnat the nodified switch design used for selecting and cycling vacuun breakers is functionally the sane as the replaced design, and involves no significant safety concern.
The position indicators and annunciated alarns provide the operators with sufficient infornation to ensure that a vacuun breaker is not unintentionally left open, and are unaffected by the nodification or the anendnent.
Diesel Fuel Storage Tank: Technical Specification Liniting Condition for j
Operation 3.9.B.3.c states:
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For the diesel generators to be considered operable, there i
shall be 32,500 gallons of diesel fuel (7 days supply for 1 diesel generator at full load 0 2500 KW) in the diesel oil storage tank.
The proposed anendnent would change "32,500" to "34,500."
During the October-Novenber 1990 Electrical Distribution Systen functional
-Inspection (Ref: Inspection Report 90-018), NRC inspectors deterrined that the
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7-day fuel calculation was incorrectly perforned. The licensee had assuned a 30 degree API gravity for the fuel, wherm a -38 degree API gravity should have been used. The proposed change raflects the new 7-day fuel requirenent
_i based on a corrected calculation and 's acceptade.
Bases: Consistent with the above-described changes, the proposed anendnent would also revise the associated beset, j
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3.0 STATE CONSULTATION
In accordance with the requirenents of 10 CFR 50.91(b), a state consultation i
i was atten pted. We were inforned, however, that our contact no longer has any official interest in the activities of Minnesota's nuclear power plants.
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n-By nenorandun dated January 4,1991 fron L. B. Marsh to C. Kannerer, the NRC Office of Governnental and helic Affairs was requested to identify an appropriate Minnesota contact so that state consultation nay resune.
4.0 ENVIRONMENTAL CONSIDERATION
The aiendnent changes requirenents with respect to inst 611ation or use of a facility conponent located within the restricted area as defined in 10 CFR Part 20. We have deternined that the anendaent involves no significant increase in the anounts, and no significant change in the types, of any effluents that nay be relecsed offsite, and that there is no significant increase in individual or cunulative occupational radiation exposure, The Connission has previously published a proposed finding that this anendnent involves no significant hazards consideration and there has been no public connent on such finding. Accordingly, this anendnent neets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environnental inpact statenent or environnentcl assessnent need be prepared in connection with the issuance of this anendnent.
5.0 CONCLUSION
We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed nanner, (2) such activities will be conducted in conpliance with the Connission's regulations, and (3) the issuance of this anendnent will not be ininical to the connon defense and security or to the health and saf ety of the public.
Principal Contributor:
W. Long Dated: August 12. 1991 t