ML20237C176
| ML20237C176 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/11/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237C170 | List: |
| References | |
| NUDOCS 8712210101 | |
| Download: ML20237C176 (2) | |
Text
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UNITED STATES
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
TO FACILITY OPERATING LICElSE NO. DPR-22 i
NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263
1.0 INTRODUCTION
By letter dated June 22, 1987, Northern States Power Company (the licensee) requested an amendment to Facility Operating License No. DPR-22 for the Monittello Nuclear Generating Plant. The amendn.ent would change the Technical Specifications dealing with the requirement for the standby liquid control system (SLCS). The licensee's proposed changes address the requirement of 10 CFR 50.62(c)(4) reflecting the SLCS minimum flow capacity and boron content equivalent in the control capacity to 86 GPM of 13 weight percent of sodium pentaborate solution.
Specifically, the proposed changes to the Technical Specifications in order to meet the requirements of 10 CFR 50.62 include (a) increasing the required pump flow rate from 24 to 26 GPM; (b) adding a new Figure 3.4-1 showing the tank volume as a function of concentration of the new enriched boron; (c) modifying the format of Figure 3.4-2 (wt. % sodium pentaborate solution vs. solution temperature); (d) adding the boron enrichment surveillance requirement; and (e) adding a limiting condition of operation for an inoperable SLCS.
2.0 EVALUATION The changes proposed by the licensee have been reviewed by the staff against the requirements of the ATWS rule (10 CFR 50.62), and Generic Letter 85-03,
" Clarification of Equivalent Control Capacity for Standby Liquid Control Systems,"
dated January 28, 1985. The licensee proposed a varying sodium pentaborate concentration as a function of storage tank volume as illustrated by Figure 3.4-1 in order to meet the requirements of 10 CFR 50.62.
In conjunction with the concentration requirement, the flow rate of 26 GPM and the reactor vessel diameter of 206 inches will provide negative reactivity in an ATWS event which is equivalent to the control capacity of 86 GPM of 13 weight percent sodium penetaborate solution for the larger, 251-inch diameter reactor vessel common to BWR5 and BWR6 designs. Therefore, Figure 3.4-1 which provides boundaries of the area of operation consistent with the purpose of 10 CFR 50.62, and therefore is acceptable.
The licensee's proposal to test one SLCS system pump at a time instead of two pumps is also acceptable. This is based upon the need for only one pump to deliver the required flow rate. To assure the operability of the second pump, the licensee will alternate the monthly pump testing so that each pump is tested once every two months. The staff firds this surveillance method acceptable.
Other surveillance dealing with monitoring the boron enrichment end concentration l
were also found acceptable.
8712210101 871211 PDR ADDCK 05000263 P
PDR l
. The Technical Specification changes proposed by the licensee are acceptable because they are consistent with the purpose of 10 CFR 50.62.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a requirement with respect to the installa-tion or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and a change to a surveillance requirement. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 61.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
The staff has 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 manner; and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will nct be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Dom Dilanni Dated:
December 11, 1987 l
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