ML20043B037
| ML20043B037 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 05/17/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20043B034 | List: |
| References | |
| NUDOCS 9005240107 | |
| Download: ML20043B037 (6) | |
Text
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NUCLEAR REGULATORY COMMISSION e
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i
SUPPORTING AMENDMENT NO. 116 TO FACILITY OPERATING LICENSE NO. DPR-36 MAINE YANKEE' ATOMIC POWER COMPANY MAINE-YANKEE ATOMIC POWER' STATION DOCKET NO. 50-309 i
1.0 INTRODUCTION
Py letter dated January.16, 1990, Maine Yankee Atomic Power Company (Ref. 1) submitted a proposed change to facility Operating License No. OPR-36 that would modify the Maine Yankee Technical Specifications to support Cycle 12 operations.
The Cycle 12 Core Performance Analysis Report (Attachment D to the January 16, 1990 letter) presented the core design and results of the design analysis for.
t Cycle 12. These include core fuel leading, fuel description, reactor power-distribution, control rod worths, reactivity coefficients, the results of the safety analysis performed to define and justify plant operational limits and I
the Reactor Protective System (RPS) setpoints assumed in the safety analysis.
t 2.0 EVALUATION OF FUEL DESIGH The refueling will. involve the discharge of 73 fuel assemblies and the insertion of 72 new assemblies and one previously irradiated assembly. The
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new fuel' assemblies are fabricated by Combustion Engineering and are not significantly different from those used at Maine Yankee for other cycles.
The Cycle 12 loading pattern uses a low-leakage design similar to the Cycles 7 through 11 patterns. The low-leakage design is achieved by-placement of fresh fuel assemblies in selected core interior locations and burned fuel assemblies on the core edge.
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2 The fresh reload fuel is similar.to previous cycle reload fuel except for an increase in fuel pellet average density from 94.75% to 95.25% of theoretical density and an increase in the fuel rod plenum volume due to a redesigned plenum spring.
Some of the ENC supplied fuel will achieve exposures higher than the original design analysis and has been reanalyzed to demonstrate compliance with the appropriate design criteria at these higher exposures.
3.0 EVALUATION OF THERMAL-HYDRAULIC DESIGN The thermal hydraulic characteristics for Cycle 12 are not significantly different from those of Cycle 11 at the 2700 Mwt rated power. The potential effects of fuel red bow on thermal-hydraulic performance have been evaluated.
Using the channel closure correlation the fuel assembly with the highest burnup L
was calculated to be 25.2 percent for the CE fuel and less than 33 percent for the ENC fuel. Tests indicate that degradation in DNB performance is not experienced until channel closure exceeds 50 percent. Therefore no fuel rod bow penalty is required.
l 4.0 EVALUATION OF PilYSICS DESIGE l
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The physics characteristics for Cycle 12 are very similar to those for Cycle l
- 11. The unrodded and rodded power distribution for BOC, M00, and E0C are presented in the Core Evaluation Report. The radial peakings are all-within 6 percent of those for Cycle 11. The control element assembly (CEA) pattern for Cycle 12 is identical tc that used in Cycle 11. The CEA group worths for l
Cycle 12 are decreased slightly relative to those of Cycle 11 due primarily to increased core enrichment and higher core average exposure.
Relative to Cycle 11, the Cycle 12 moderator temperature coefficient (MTC) is slightly more positive at BOC due to the higher criticel boron concentration. The E0C Cycle 12 MTC value is more negative than Cycle 11 due to higher average enrichment and the increased core average exposure.
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3 3-5.0 SAFETY ANALYSIS Maine Yankee has reviewed the parameters which influence the results of the transient and accident analyses for Cycle 12 to determine which events require reanalysis. The acceptance criteria for the Cycle 12 evaluation are identical to those used for Cycle 11-and are thus acceptable. Likewise the analytical-methods used to demonstrate conformance of the Cycle 12 design are identical to those used fo'r Cycle 11 and are thus acceptable.
A new or revised analysis was performed for those transients where the parameters for Cycle 12 were not bounded by previous safety analysis. These transients are:
(1) Boron Dilution (2) Excess Load (3) CEA Ejection Other transients that required a partial reanalysis or review are:
(1) Seized RCP Rotor (2h CEA Withdrawal (3) Loss of Feedwater (4) Loss of Coolant Flow (5) Stean Line Rupture (6) Steam Generator Tube Rupture (7) LOCA (8) CEA' Drop (9) Loss of Load Each reanalysis was done using NRC approved methods and demonstrated that the
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applicable acceptance criteria for the accident or transient continue to be met. Table 5.3 lists the transients that were reanalyzed, the acceptance l
criterion for judging the results, the Reference Safety Analyses, and the i
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4 Cycle 11 and: Cycle 12 results. The staff has reviewed these results and finds them acceptable.
6.0 TECHNICAL SPECIFICATION CHANGES The licensee has proposed several changes to the Technical Specifications for the Cycle 12 reload core. The staff's review and evaluation of these changes follows the numbering corresponding to that presented in Reference 1.
e 1.
Technical Specification 2.1.1.b l
(a) the TM/LP trip A coefficient is modified (b) Figure 2.1-la is modified (c) Figure 2.1-lb is modified These changes are acceptable because they reflect the Cycle 12 power distributions and RpS setpoints.
2.
Technical Specification.2.2 L
The steady-state peak linear heat rates are modified. This change is acceptable because it reflects the Cycle 12 Specified Acceptable Fuel Design Limits (SAFDL) for prevention of centerline melting.
3.
Technical Specification 3.1 (a) Specifications 3.10.A.3 and 3.10.C.7 are modified to correct l
typographical errors.
(b) Specification 3.10.C.1 is modified. This is acceptable since it reflects conservative application of axial fuel densification and thermal expansion factor to all fuel types.
(c) Specification 3.10.C.2.2.2 is modified to simplify the actions.
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- (d) Specification 3.10.C.3.1.1 and Figure 3.10-5 are modified. This is acceptable since it reflects Cycle 12 power distributions and RpS 4
setpoints.
(e) Specifications 3.10.C.4.2.1 and 3.10.C.4.2.2 are changed to clarify wording.
(f) The Bases on page 3.10-7 is changed to correct a typographical error and make wording consistent with change to Specification 3.10.C.2.2.2.
(g)
Figure 3.10-4 is modified to reflect Cycle 12 radial peaking.
(h) Figure 3.10-7 is modified to reflect the increase in shutdown margin required by the Cycle 12 analysis.
(j) Figure 3.10-11-is modified. Thir. is acceptable since it reflects Cycle 12 LOCA analysis results.
7.0 ENV190NMENTAL CONSIDERATION This amendment involves a change in a requirement with respect to the installation or use of a facility co'rponent located within restricted areas as defined in 10 CFR Part 20 and changes to the surveillance requirements. 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 l'
offsite,.and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously published a proposed findir.g that the 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 51.22(c)(g). Pursuant to 10 CFR 51.22(b), no l
environrcntal impact statement or environmental assessment need be prepared in connection with the issuance of this emendment, p
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8.0 CONCLUSION
The staff has reviewed the information provided in the Maine Yankee Cycle 12 Core Performance Analysis Report and Reference 1.
The staff finds the associated modified Technical Specifications acceptable.
Based on the considerations discussed above, the staff has concluded that (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 Comissions regulations, and (3) the issuance H
of this amendment will not be inimicel to the common defense and security or to the health and safety of the public.
9.0 PEFERENCES
'1.
Charles D. Frizzle (MYAPC) letter to the U.S. Nuclear Regulatory Commission, January 16, 1990.
2.
" Maine Yankee Cycle 11 Core Performance Analysis," YAEC-1648, Yankee Atomic Electric Company, July 1988.
3.
" Maine Yankee Cycle 12 Core Performance Analysis," YAEC-1713, Yankee Atomic Electric Company, December 1989.
Principal Contributor: Maroaret Chatterton May17h1990 Date:
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