ML20056D092
| ML20056D092 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 07/12/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20056D090 | List: |
| References | |
| NUDOCS 9308030346 | |
| Download: ML20056D092 (4) | |
Text
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l ga arggg UNITED STATES 5
NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 20*,W0001 j
SAFETY E;ALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 86 TO FACILITY OPERATING LICENSE NO. DPR-22 NORTHERN STATES POWER COMPANY
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MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263
1.0 INTRODUCTION
By letter dated December 31, 1992, the Northern States Power Company (NSP, the itcensee) requested an amendment to the Technical Specifications (TS) appended t
to facility Operating License No. DPR-22 for the Monticello Nuclear Generating Plant. The proposed amendment would revise the surveillance requirements associated with Technical Specification 3.3.A.2, " Reactivity 14argin - Stuck Control Rods." The current technical specification requires that "..each partially or fully withdrawn operable control rod shall be exer'cised one notch at least once each week..."
The specification then provides an exception to weekly testing which states that "...one rod in any two by two array need not i
be exercised more than one notch at least once each month..."
The specification continues by providing guidance for applying this exception.
The licensee has found that this exception is subject to misinterpretation and is therefore proposing to delete the exception by this amendment.
The licensee has also proposed to reorganize the remainder of the existing specification to achieve additional clarity.
2.0 EVALUATION The part of the technical specification to be deleted by the proposed j
amendment is an option to exercise one control rod in each 2 X 2 array on a monthly instead of weekly basis. The option was incorporated into the plant Technical Specifications on October 15, 1976 as Amendment 24 to the t
Provisional Operating License. This option, which was'more restrictive than had been proposed by the licensee in its License Amendment Request dated January 26, 1976 and its supplemental letter dated July 2,1976, resulted from discussion between NSP and the NRC staff.
Limitations on the number of rods that could be tested monthly, and conditions that needed to be met to utilize l
the option, were imposed due to staff concerns over cracks found in collet retainer tubes at other utilities.
The licensee's primary reason for proposing in 1976 that control rod drive notch' testing frequency be extended from weekly to monthly was'that analysis had shown that notch testing at high power levels contributed to early fuel 9308030346 930712 PDR ADOCK 05000263 PDR p
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. failure.
It was therefore necessary to undergo a temporary power reduction each week to perform the test.
Since that time, the introduction of new barrier fuel designs has eliminated this concern and it is no longer necessary to reduce power to perform control rod drive rod notch testing.
The licensee has now found that the operational benefit derived from testing 25% of the rods monthly is marginal and does not justify the level of effort necessary to ensure all conditions are satisfied to maintain this option. As noted in Licensee Event Report 92-005-00, the licensee has returned to performing notch testing of all operable fully or partially withdrawn control rods on a weekly basis in accordance with the basic specification. As a follow-up action, the licensee considers it prudent to remove the monthly test option from the plant Technical Specifications to preclude misinterpretation of the special conditions currently contained in specification 4.3.A.2.
The other changes to specifications 3.3.A.2 and 4.3.A.2 clarify, but do not alter, current Technical Specification requirements.
By reducing the potential for misinterpretation, these changes serve to improve compliance with the specifications, thereby enhancing safety.
The standard technical specification for BWRs (See SR 3.1.3.1, d be tested by page 3.1-10, et seq.) essentially requires that each fully withdrawn control re insertion of at least one notch every 7 days.
Partially withdrawn control rods are to be tested by insertion of at least one notch every 31 days. The standard technical specification does not contain the exception proposed for deletion from the Monticello technical specifications. The test frequency at Monticello exceeds the frequency in the standard technical specification.
Since the frequency for testing the control rods at Monticello exceeds the test frequency recommended in the standard technical specifications, and since the proposed amendment would eliminate an exception which would reduce test frequency, this aspect of the proposed amendment is acceptable, The remaining aspect of the proposed amendment is to reorganize the test requirements for clarity. No change in test requirements is intended or achieved by this reorganization.
Therefore, there is no safety significance to the reorganization. This proposed change is acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Minnesota State Official was notified of the proposed issuance of the amendment. The State Official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes 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 effluent that may be released offsite, and that there is no significant increase in individual or cumulative
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. occupational radiation exposure. The Commission has previously-issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (58 FR 32388). Accordingly, the amendment meets the eligibility. criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR. 51.22(b), no environmental impact statement or environmental: assessment need
-i be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
i (1) there is reasonable assurance that the health and safety of-the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, i
and (3) the issuance of the amendment will not be. inimical to the common defense and security or to the health and safety of the public.
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Principal Contributor:
Robert B. Samworth Date: July 12, 1993
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