ML20094C840
| ML20094C840 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/27/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20094C815 | List: |
| References | |
| NUDOCS 8408080165 | |
| Download: ML20094C840 (4) | |
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WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION, S_UPPORTING AMENDMENT N0. 83 TO FACILITY OPERATING LICENSE NO. DPR-51 ARXANSAS POWER & LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT 1 DOCKET NO. 50-313
. Introduction By letter dated February 27, 1984, Arkansas Power and Light Company (AP&L or thelicensee)requestedamendmanttotheTechnicalSpe-ifications(TSs) appended to Facility Oparating License DPR-51 for Arkansas Nuclear One, Unit 1 (ANO-1). The amendment would change the ANO-1 pressure-temperature limit curves for hydrostatic test, normal heatup, and normal cooldown (Figures 3.1.2-1, 3.1.2-2 and 3.1.2-3 of the TSs), to be applicable for a period of
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time corresponding to 15 effective full power. years (EFPY). The proposed change would require these proposed pressure-temperature curves to be updated prior to reaching 15 EFPY of operation.
Background and Discussion Pressure-temperature limits must be calculated in accordance with the requirements of Appendix G,10 CFR 50, which became effective on July 26, 1983.
Pressure-temperature limits that are calculated in accordance with the requirements of Appendix G,10 CFR 50, are dependent upon the initial RTNDT
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for the limiting materials in the beltline and closure flange regions of the reactor vessel and the increase in RTNDT resulting from neutron irradiation damage to the limiting beltline material.
The ANO-1 reactor vessel was procured prior to the issuance of the Appendix G, 10 CFR 50 regulation. However, the ANO-1 reactor vessel materials must meet the safety margins and testing requirements of the regulation. Appendix G, 10 CFR 50, requires that samples from each reactor vessel material be L
. fracture toughness tested to determine their initial (unirradiated) RTNDT*
The limiting beltline material was fracture toughness tested to determine its initial RT However, due to the unavailability of sample materials from NDT.
the ANO-1 reactor vessel closure flange region, the initial RTNDT of the closure flange region materials were detennined using generic materials properties data. The generic materials properties data were documented in BAW Topical Report BAW-10046, " Methods of Compliance with Fracture Toughness and Operational Requirements of 10 CFR 50, Appendix G."
This topical report was reviewed by the staff and found acceptable for referencing in licensing applications. The staff's review is documented in a letter from S. A. Varga to J. H. Taylor dated June 22, 1977. Based on the safety evaluation, which was attached to the Varga signed letter, the licensee's estimate for the initial RT for the closure flange region material may be used in NDT detennining the ANO-1 reactor vessel pressure-temperature limits. The increase in RT of the limiting beltline materials resulting from neutron NDT irradiation damage was estimated by the licensee using the methodology documented in Regulatory Guide 1.99, Rev.1, " Effects of Residual Elements on Predicted Radiation Damage to Reactor Vessel Materials." This estimate is reported in Table 8-1 of B&W Report BAW 1698, " Analysis of Capsule ANI-B From Arkansas Power & Light Company's Arkansas Nuclear One, Unit 1."
The licensee indicates that, using this Regulatory Guide met.hodology, the limiting beltline material is weld metal WF-112. This material was not tested as part of the ANO-1 reactor vessel material surveillance program. However, it was tested as part of the B&W Owners Group Integrated Reactor Vessel M3terial
' Surveillance Program, in which AP&L is an active member. The effect of neutron irradiation on the RT f weld metal WF-112 is documented in B&W NDT Report BAW-1436, " Analysis of Capsule OCI-E, Duke Power Company, Oconee Nuclear Station-Unit 1."
The WF-112 weld metal was irradiated in the Oconee Unit I 18 reactor vessel and had been irradiated to 1.5 x 10 nyt. Our review of the Charpy V-Notch data documented in BAW-1436 indicates that WF-112 weld metal 18 had an increase in RT f 83"F as a result of irradiation to 1.5 x 10 nyt.
NDT Using the WF-112 weld metal chemical composition reported in B&W Proprietary Report BAW-1511P, " Irradiation-Induced Reduction in Charpy Upper-Shelf Energy of Reactor Vessel Welds," and the Regulatory Guide 1.99, Rev.1, method of estimating neutron irradiation damage, the estimate of increase in RT at NDT
. 18 1.5 x-10 nyt is 120 F.
Since the increase in RTNDT. f WF-112 surveillance weld metal is significantly less than that predicted by Regulatory Guide 1.99, Rev.1, the Regulatory Guide should provide conservative estimates as to the amount of neutron irradiation damage to weld metal WF-112.
F. valuation We have ured the unirradiated RT for beltline and closure flange NDT materials, which were previously discussed, the Regulatory Guide 1.99, Rev.1, method of estimating neutron irradiation damage, and Standard Review Plan 5.3.2 method of calculating pressure-temperature limits to evaluate the licensee's proposed pressure-temperature limits. Our evaluation indicates that the proposed pressure-temperature limit curves meet the safety margins of Appendix G,10 CFR 50, for a period of time corresponding to 15 EFPY.
Hence, the proposed curves are acceptable for incorporation into ANO-1 TSs.
As previously discussed in this evaluation, the limiting ~ANO-1 reactor vessel beltline material, weld metal WF-112, is being irradiated as part of the B&W Owners Group Integrated Reactor Vessel Materials Surveillance Program.
According to B&W Report BAW-1543, Rev. 1, " Integrated Reactor Vessel Material Surveillance Program," weld metal WF-112 is contained in surveillance capsules OCI-A, -C and -E.
Since the test results from these capsules will evaluate the effect of neutron irradiation on the ANO-1 limiting material, AP&L must use the test results from these capsules in determining the safety L
nargins required for their pressure-temperature limits.
If test results from these capsules indicate that the ANO-1 pressure-temperature limits are non-conservative, the licensee must revise the limits and submit them for NRC staff review.
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. p Environmental Consideration This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
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 51.22(c)(9). Pursuant to 5
10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
Conclusion We have 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 Comission'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.
r Dated: July 27, 1984 Principal Contributors: Barry Elliot and Guy Vissing 4
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