ML17328A258
| ML17328A258 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 05/24/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17328A257 | List: |
| References | |
| NUDOCS 9006130284 | |
| Download: ML17328A258 (5) | |
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0 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
23 TO FACILITY OPERATING LICENSE NO. DPR-74 INDIANA MICHIGAN POWER COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NO.
2 DOCKET NO. 50-316
1.0 INTRODUCTION
In response to Generic Letter 88-11, "NRC Position on Radiation Embrittlement of Reactor Vessel Materials and Its Effect on Plant Operations,"
the Indiana Michigan Power Company (the licensee) requested permission to revise the pressure/temperature (P/T) limits for the Donald C.
Cook Nuclear Power Plant, Unit No. 2.
The request was documented in letters from the licensee dated December 5,
1988 and October 25, 1989.
This revision also changes the effectiveness of the P/T limits from 32 to 12 effective full power years (EFPY).
The proposed P/T limits were developed based on the data from actual surveillance capsules.
The proposed revision provides up-to-date P/T limits for the operation of the reactor coolant system during heatup, cooldown, criticality, and hydrotest.
To evaluate the P/T limits, the staff uses the following NRC regulations and guidance:
Appendices G and H of 10 CFR Part 50; the ASTM Standards and the ASME Code, which are referenced in Appendices G and H;
Regulatory Guide (RG) 1.99, Rev. 2; Standard Review Plant (SRP) Section 5.3.2; and Generic Letter 88-11.
Each licensee authorized to operate a nuclear power reactor is required by 10 CFR 50.36 to provide Technical Specifications for the operation of the plant.
In particular, 10 CFR 50.36(c)(2) requires that limiting conditions of operation be included in the Technical Specifications.
The P/T limits are among the limiting conditions of operation in the Technical Specifications for all commercial nuclear power plants in the U.S.
Appendices G and H of 10 CFR Part 50 describe specific requirements for fracture toughness and reactor vessel material surveillance that must be considered in setting P/T limits.
An acceptable method for constructing the P/T limits is described in SRP Section 5.3.2.
Appendix G of 10 CFR Part 50 specifies fracture toughness and testing requirements for reactor vessel materials in accordance with the ASME Code and, in particular, that the beltline materials in the surveillance capsules be tested in accordance with Appendix H of 10 CFR Part 50.
Appendix H, in turn, refers to ASTII Standards.
These tests define the extent of vessel embrittlement at the time of capsule withdrawal in terms of the increase in 9006120284 900524 PDR ADOCK 05000316 P
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Appendix G also requires the licensee to predict the effects of neutron irradiation on vessel embrittlement by calculating the adjusted reference temperature (ART) and Charpy upper shelf energy (USE).
Generic Letter 88-11 requested that licensees and permitters use the methods in RG 1.99, Rev. 2, to predict the effect of neutron irradiation on reactor vessel materials.
This guide defines the ART as the sum of unirradiated reference temperature, the increase in reference temperature resulting from neutron irradiation, and a margin to account for uncertainties in the prediction method.
Appendix H of 10 CFR Part 50 requires the licensee to establish a surveillance program to periodically withdraw surveillance capsules from the reactor vessel.
Appendix H refers to the ASTN Standards which, in turn, require that the capsules be installed in the vessel before startup and that they contain test specimens made from plate, weld, and heat-affected-zone (HAZ) materials of the reactor beltlinc.
2.0 EVALUATION The staff evaluated the effect of neutron irradiation embrittlement on each beltline material in the D. C.
Cook Unit No.
2 (Cook 2) reactor vessel.
The amount of irradiation embrittlement was calculated in accordance with Section 2
of RG 1.99, Rev. 2.
The staff has determined that the material with the highest ART at 12 EFPY for Cook 2 was intermediate shell plate C5556-2 with Oe15% Cu, 0.57% Ni, and an initial RTndt of 58'F.
The licensee has removed three surveillance capsules from Cook 2.
The results from capsules T, Y, and X in Unit 2 were published in Southwest Research Institute Reports 06-5928, SwRI-7244-002/1, and 06-8888, respectively.
All surveillance capsules contained Charpy impact specimens and tensile specimens made from base metal, weld metal, and HAZ metal.
For the Cook 2 limiting beltline material, intermediate shell plate C5556-2, the staff calculated the ART to be 177.5'F at 1/4T (T = reactor vessel beltline thickness) a~d 149'F for 3/4T at 12 EF/Y.
The staff used a neutron f1uence of 4.69E18 n/cm at 1/4T and 1.66E18 n/cm at 3/4T.
The ART was determined by Section 1 of RG 1.99, Rev. 2, because the most limiting beltline was not in the surveillance capsule.
The licensee used the method in RG 1.99, Rev. 2, to calculate an ART of 178'F at 1/4T at 12 EFPY for the same limiting weld metal.
Substituting the ART of 178'F into equations in SRP 5.3.2, the staff verified that the proposed P/T limits for heatup,
- cooldown, and hydrotest meet the beltline material requirements in Appendix G of 10 CFR Part 50.
In addition to beltline materials, Appendix G of 10 CFR Part 50 also imposes P/T limits based on the reference temperature for the reactor vessel closure flange materials.
Section IY.2 of Appendix G states that when the pressure exceeds 20% of the preservice system hydrostatic test pressure, the temperature of the closure flange regions highly stressed by the bolt preload must exceed the reference temperature of the material in those regions by at least 120'F for normal operation and by 90'F for hydrostatic pressure tests and leak tests.
Based on the flange reference temperature of 30'F, the staff has determined that the proposed P/T limits satisfy Section IV.2 of Appendix G.
Section IV.B of Appendix G requires that the predicted Charpy USE at end of life be above 50 ft-lb.
Using the method in RG 1.99, Rev. 2, the predicted Charpy USE of intermediate shell plate C5521-2 at the end of life will be 62.3 ft-lb.
This is greater than 50 ft-lb and, therefore, is acceptable.
The staff concludes that the proposed P/T limits for the reactor coolant system for heatup, cooldown, leak test, and criticality are valid through 12 EFPY because the limits conform to the requirements of Appendices G and H of 10 CFR Part 50.
The licensee's submittal also satisfies Generic Letter 88-11 because the licensee used the method in RG 1.99, Rev.
2 to calculate the ART.
- Hence, the proposed P/T limits may be incorporated into the Cook 2 Technical Specifications.
3.0 ENVIRONh1ENTAL CONSIDERATION This amendment involves a change in a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and a change in a surveillance requirement.
He have determined that the amendment involves no significant increase in the
- amounts, arid 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 Corrmission has previously issued a proposed finding that this amendment involves nio significant hazards consideration and there has been no public covalent on such finding.
Accordingly, this amendments meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
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; (2) such activities will be conducted in compliance with the Commission s regulations, and (3) issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
)lay 24, 1990 Principal Contributor:
J. Tsao, DET/EI1CB
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