ML19211C092
| ML19211C092 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/28/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19211C085 | List: |
| References | |
| NUDOCS 8001100073 | |
| Download: ML19211C092 (4) | |
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UNITED STATES x%1
't, NUCLEAR REGULATORY COMMISSION i
j WASHINGTON, D. C. 20555 kk e sp f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 42 TO PROVISIONAL OPEPATING LICENSE N0. DPR-22 NORTHERN STATES POWER COMPANY MONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50-263 1.0 Introduction By letterU) dated December 21, 1979, the Northern States Power Company (the licensee) requested amendment to the Technical Specifications appended to Operating License No. DPR-22 for the Monticello Nuclear Generving Plant (MNP). The proposed change would extend the exposure range cf the Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) "ersus average planar exposure values for the type 8DB262 fuel bundles leaded in the core. The proposed extension would provide MAPLHGR limits for the 808262 bundles to an average planar exposure of 40,000 mwd /T, which is 10,000 mwd /T beyond the current exposure range of 30,000 mwd /T.
The Technical Specification change request resulted from the discovery that the average planar exposure for 8DB262 fuel loaded in the core had exceeded 30,000 mwd /T. By References 2 and 3, the licensee reported exceeding this value of fuel exposure, the circumstances associated with the event, and the corrective actions taken by the licensee.
referenced the plant specific results(Specification change, the licensee In support of the requested Technical 4) of the Design Basis Loss-of-Coolant Accident analysis for MNP which had previously been submitted for staff review.
2.0 Evaluation The licensee determined that the average olanar exposure for one fuel type had exceeded 30,000 mwd /T without licensee knowledge because of inadequate licensee and consultant monitoring of fuel nodal exposures.
The licensee has corrected surveillance procedures for nadal exposure monitoring to ensure that exposure of each type of fuel in the core does not exceed the values provided in the proposed Technical Specifications.
1739 097 ECCS Appendix K Analysis On December 27, 1974 the Atomic Energy Commission issued an Order for Modification of License implementing the requirements of 10 CFR 50.46,
" Acceptance Criteria for Emergency Core Cooling Systems for Light Water One of the requirements of the Order was that Nuclear Power Reactors."
"the licensee shall submit a re-evaluation of ECCS performance calculated in accordance with an acceptable evaluation model which conforms to the 8001300 g pg
. provisions of 10 CFR 50.46."
The Order also required that the evaluation shall be accompanied by such proposed changes in Technical Specifications as may be necessary to implement the evaluation assumptions. The 9tqff reviewed and accepted the Loss-of-Coolant Accident Analysis ReporttSi for MNP and approved the accompanying proposed MAPLHGR versus average planar exposure Technical Specification values for the 80B262 fuel assemblies. Our approval was limited to an average planar exposure of 30,000 mwd /T, since the analysis reported by Reference 5 was limited to an exposure of 30,000 mwd /t.
In order to extend the MAPLHGR versus average planar exposure values for the 8DB262 fuel, the licensee re-evaluated the adequacy of ECCS performance for the subject 8X8 fuel at exposures out to 45,000 mwd /T. The supple-mental analysis was performed using analytical procedures previously approved by the staff. Additionally, these methods are considered appli-cable for an average planar exposure of 45,000 mwd /T. Furthermore, the information presented fulfills the documentation requirements outlined in Reference 6 for such analyses. The analysis results show that with MAPLHGR limited to the values in table 3-1 of Reference 4 that the cladding temperature and local cladding oxidation are well below the 2200 F (peak cladding temperature) and 17% (local cladding oxidation) limits allowed by 10 CFR 50.46. Accordingly, we find the proposed MAPLHGR vs. average planar exposure values acceptable.
Thermal-Mechanical Design Considerations Previously reviewed fuel themal-mechanical design and safety analyses ( )
are dependent on local exposure. Additionally, the maximum local (pellet) exposure in a fuel assembly is not independent of the maximum average planar exposure since the former is always greater than the latter.
Accordingly, we have reviewed the adequacy of the previously approved (8) thermal-mechanical design basis for the 808262 fuel in light of th9 pro-posed Technical Specification change. For MNP the licensee statedt9 1 that the maximum local exposure of the 8DB262 fuel will not exceed 40,0 mwd /T during Cycle 7.
Since the staff previously reviewed
)
generic fuel thermal and mechanical performance analysesl7)and accepted for 8X8 fuel peak pellet exposures up to 40,000 mwd /T, we find our generic conclusions and basis for acceptance of the 8X8 fuel thermal and mechanical design valid for peak pellet exposures up to 40,000 mwd /T. The plant-specific aspects of the fuel thermal and mechanical design were also previously addressed in Reference 10 and remain applicable for peak pellet expo-sures up to 40,000 mwd /T. Thus, the conclusions stated in our plant and cycle-specific evaluation of thermal-mechanical performance also remain uneffected.
For Cycle 7, we find that the proposed extension of the MAPLHGR versus average planar exposure values do not invalidate the basis or conclu-sions of any of our previous approvals of the thermal-mechanical design of the 8DB262 fuel for peak pellet exposures up to 40,000 mwd /T.
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. 3.0 Suninary We find the corrective actions taken by the licensee to be appropriate.
We find the proposed Technical Specification change acceptable.
4.0 Environmental Consideration We have determined that the license amendment does not authorize 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 detennination, 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 Sl.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 this amendment.
5.0 Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability 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) there is reasonable assurance that the health and safety of the puoiic will not be endangered by operation in the proposed manner, and (3) such activitics will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Dated: December 28, 1979 1739 099 References 1.
Northern States Power Company letter (L. Mayer) to USNRC (H. Denton) dated December 21, 1979.
2.
Ncrthern States Power Company letter (L. Eliason) to USNRC (J. Keppler) dated December 17, 1979.
3.
Northern States Power Company letter (L. Eliason) to USNRC (J. Keppler) dated December 28, 1979.
4.
"Monticello Nuclear Generating Plant Extended Exposure Fuel Program,"
NED0-20202 dated July 1979 appearing as Exhibit C of Northern States Power Company letter (L. Mayer) to USNRC (H. Denton) dated September 17, 1979.
5.
" Loss of Coolant Accident Analysis Report for Monticello Nuclear Generating Plant," NED0-24050 dated September 1977.
6.
USNRC letter (D. Eisenhut) to General Electric (E. Fuller) dated June 30, 1977.
7.
" Generic Reload Fuel Application" NEDE-240ll-P-A, dated August 1978.
8.
USNRC letter (D. Eisenhut) to General Electric (R. Gridley) dated May 12, 1978 transmitting " Safety Evaluation for the General Electric Topical Report Generic Reload Fuel Application (NEDE-240ll-P)"
dated April 1978.
9.
Telephone conversation between Northern States Power Company (L. Mayer) and USSRC (T. Kevern) on December 14, 1979.
10.
Northern States Power Company letter (L. Mayer) to USNRC (H. Denton) dated August 10, 1978 transmitting " Supplemental Reload Licensing Submittal for Monticello Nuclear Generating Plant, Reload 6, NED0-24133, July 1978.
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