ML19341D611
| ML19341D611 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 03/27/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19341D610 | List: |
| References | |
| NUDOCS 8104080003 | |
| Download: ML19341D611 (3) | |
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UNITED STATES O P > -. < ',t auc'e^a aecu'^Toav co==issio" wAsmucros. o. c. 2osss
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f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 3 TO LICENSE NO. DPR-22 NORTHERN STATES P0iiER COMPA'iY DOCKET NO. 50-263
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MONTICELLO NUCLEAR GENERATING PLANT 1.0 -Introduction By letter dated May 15, 1980 Northern States Power Company (NSP or licensee) e requested changes to the Technical Specifications for the Monticello Nuclear Generating Plant. The proposed changes pertiin in part to:
(1) degraded grid voltage protection modifications, (2) reactor protection system surveillance-requirements for main steam isolation valve and turbine stop valve limit switches, (3) changes in the licensee's corporate organ' zation, (4) operability requirements of secondary containment ventilatior dampers and (5) various minor editorial corrections and clarification.
This safety evaluation addresses the aforementioned changes. Other changes requested in the May 15, 1980 submittal are still under staff review and will be addressed by separate safety evaluation and license amendment.
1 2.0 Evaluation 1.
Degraded Grid Voltage Protection The criteria and staff positions relating to degraded grid voltage protection _ were transmitted to Northern States Power Company by NRC generic letter dated June 3,1977.- In response to this, the licensee proposed :ertain design modifications and Technical Specification changes. The-following design codifications and Technical Specifi-cation changes were proposed by NSP:
a.
Installation of second level under-voltage relays, three on each-of the two 4160V class IE buses with a drop out setting at approximately 93% of nominal bus voltage and a ten second time delay. These relays are arranged in a two out of three logic scheme.. The existing loss of voltage scheme was also mdified and arranged in a'one out of two taken twice logic scheme.
b.
3ddition of trip setpoint, limiting conditions for_ operation, and surveillance requirements to the. Technical Specifications associ-ated with the design modifications cited above.
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.. The criteria used in the technical evaluation of the above proposet changes include GDC-17. " Electric Power Systecs" of 10 CR 50 Appendix A; IEEE Standard 279-1971 " Criteria for Protection Systees for Nuclear Powgr. Generating Stations:" IEEE Standard 3G8-1974,
" Class 1E Power Syste~s for Nuclear Power Generating Stations"; and the staff positions defined in the NRC generic letter to NSP dated June 3, 1977.
We have-reviewed the design changes and Technical Specifications and find that (1) the proposed mdifications will protect the class lE equi; cent and systa from a sustained degraded voltage of the offsite power source and (2) the proposed changes to the Technical Specifications meet the criteria for periodic testing of protection r
systems and equipeent. We conclude that the _ licensee's proposed design modifications and changes to the Technical Specifications are acceptable.
2.
Limit Switches - Main Steam Isolation and Turbine Stop Valves Limit switches associated with cain steam isolation valves and turbine stop valves, provide an input to the reactor protection systen for an anticipatory scram. The setpoint is selected to provide an early positive indicatica of valve closure. The current Technical Specifications include requirements associated with this instricentation, as well as
. all other instrumentation providing a scram function, except that no requirement for calibration of these' limit-switches is specified.
Calibration requirements are specified in the Technical Specifications for other instrumentation providing a scram function. The staff position is that such surveillance requirements (calibration) for these limit switches should be included in the Technical Specifications.
to. require l calibration at a minimum frequency of once per operating cycl e.
The proposed Technical Soecifications add requirements to calibrate
- limit switches for main steam isolation and turbine stop valves at a minimum frequency of once Mr operating cycle. The licensee's
- proposed change complies with the staff position and is therefore acceptable.
3.
Secondary Containrent Ventilation Damper Operability.
We have reviewed this change which revises'the limiting conditions-i for operation of. secondary containment to pemit operation for a.
- short period of time with an inoperable secondary containment isolation
. da=per and have detemined that it_ is consistent with NUREG-0123
" Standard Technical Specifications for General-Electric Boiling Water-Reactors." Consequently. it is acceptable as~ an administrative change
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irplementing a previously reviewed and approved action of the Coeviission.
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Miscellaneous Corrections and Clarifications Our review of these changes has concluded that they correct typo-graphical errors and terminology and provide additional clarification of Technical Specification requirements. These changes do not change any Technical Specification requirements and are administrative in nature.
We find them acceptable.
5.
Organizational Changes We have determined that these changes incorporate a change in corporate organization involving electric generating plant responsibilities and a change in Power Production Department organization to provide greater participation in, and technical support for, nuclear plant activities.
These changes are administrative in nature and are acceptable.
3.0 Environmental Consideration,s We have determined that the amendment does not involve a change in effluent types.or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR Section 51.5(d)(4) that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amendment.
4.0 Conclusions We have concluded, based on the considerations discussed above, that:
'(1) 'aecause the amendment' does not involve a significant increase in the proDability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration;-(2) ther.e is reasonable assurance that:the health and safety of the public will not be endangered by, operation in the proposed manner, and (3) such activities will be con.
ducted in compliance with the tommission's regulations and the issuance of the amendment will not be. inimical to the common defense and security or to the health and safety of the_ public.
Dated: ~ March 27,1981 a
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