ML19319A754
| ML19319A754 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/23/1976 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19319A750 | List: |
| References | |
| NUDOCS 7912030397 | |
| Download: ML19319A754 (4) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR R
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SUPPORTING AMENDMENT NO.36TO FACILITY LICENS AMENIMENT NO. 35 TO FACILITY LICENSE NO. DPR-47 l
_ AMENDMENT NO. 32 TO FACILITY LICENSE NO. DPR-1 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS NOS. 1, 2 AND 3 DOCKETS NOS. 50-269, 50-270 AND 50-287 9
i Introduction 24, 1976 Duke Power Company.(the licensee) ix requested an exemption from the requirements of 10 CFR Part By letter dated September H,Section II.C. 2 to perinit the operation of Oconee Unit 3 duri with the reactor vessel surveillance capsules removed form the reactorJ The licensee also requested a corresponding change to the
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l Technical Specifications appended to Facility Operating Licenses Nos.
vessel.
I DPR-38. DPR-47 and DPR-55 for the Oconee Nuclea
. l This change would re? lect the removal of the Unit 3 reactor vessel surveillance capsules for Cycle 2 operation and would require 2 and 3.
the submittal of a revised surveillance capsule withdrawal schedule prior to Unit 3 Cycle 3 operation.
fl I Discussion _
The Oconee Unit 3 design includes three reactor vessel surveillance capsule holder' tubes located adjacent to the reactor vessel insid Each holder tube contains two surveillance capsules which hold the specimens to be irradiated in accordance w wall.
is to
. H to 10 CFR Part 50. The purpose of the surveillance programhness p l
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M monitor changes in the fracture. ougta the reactor vesse i
mostron irradiation and the thermal emetrosament.
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.During the refueltog shutdown of tuonee Unit 1 in March 1976, evidence of wear was noted at various locations of the surveillance capsule holder j
i tubes. Subsequent inspections of the holder tubes in Oconee Units 2 and i
3 revealed similar wear. The licensee decided to remove the surveillance j
capsules and holddown assemblies from each of the three units and in the case of Units 1 and 2, the holder tubes were also removed to preclude t
the possibility of-LiMr wear occurring due to flow induced stresses during operation. To ellow continued operation with the surveillance capsules removed, the licensee justified, and was granted exemptions to the reqairements of Appendix H to 10 CFR Part 50 for Oconee Units 1, 2 and 3 by letters dated March 26, June 25 and April 16, 1976, respectively.
The exemption granted for Oconee Unit 3 expired at the completion of Cycle 1 operation on September 18,1976. The holder tubes which had remained in the reactor vessel for the period of the exemption are being removed during the current refueling outage. The licensee had expected that a redesigned holder tube would have been qualified for use in Unit 3 during Cycle 2 operation, har er, due to delays in the qualification program, the redesigned holder Abe is not expected to be qualified and approved for use before January 1977, at the earliest. Oconee Unit 3 c.
however, has been scheduled to restart following refueling for Cycle 2 operation in early November 1976. The licensee has therefore requested an exemption from the requirements of Appendix H to allow operation of Unit 3 during Cycle 2 with the surveillance capsules removed from the reactor vessel.'
Evaluation As required by Paragraph II.C.2 of Appendix H to 10 CFR Part 50, the f'
surveillance capsules of Oconee Unit 3 are positioned during reactor i
operation such that the neutron flux received by the specimens is at least as high as, but not more than three times as high as, that received
- 4 by the vessel inner surface. More specifically, as reported in Babcock and Wilcox Topical Report BAW-10100A, February 1975, the specimen capsule locations in the Unit 3 reactor vessel provide a neutron flux 2.4 times greater than the inside 1/4 wall thickness (1/4t) location of the reactor vessel beltline. The lead factor between the center of the specimens and the 1/4t vessel wall location is considered when detemining the relative fracture toughness properties of the beltline region unterials.
-, -The Safety Evaluation 5-iv Ung the examptico to Appendix H granted for indicated that the irradiatica accasulated
._. Ocomme Unit 3.ca Aprf1 16,1976.
by the specimens in the capsules removed at that time was 2.30 Effective Full-Power Yeers (EFPY). This accumulation provided considerable margin
.to the maximum expected orpnews of the reactor vessel beltline region I
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at the completion of Cycle 1 operation.1.33 IFPY. In its letter of 24,1976, the licensee has predicted that the specimens will September continue to lead the reactor vessel exposure which at the completion of The specimens of one of the i
Cycle 2 operation will only be 2.03 EFPY.
capsules removed in April 1976 are being analyzed as part of the reactor c
vessel surveillance program and will provide data for establishing the I
mvised withdrawal schedule prior to comencement of Cycle 3 operation.
The irradiation effects accumulated by the specimens of the other capsules not be altered and appropriate removed from the Unit 3 reactor vessel will allowances can be made to account for the time that they are removed from l
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Based on the above we conclude that the licensee's proposed i
the vessel.
action to operate Oconee Unit 3 during Cycle 2 with the surveillance i
"7 capsules removed will not adversely affect theUnit 3 surveillance program and presents no danger to the public health and safety.
19, 1976, the licensee stated that it is his
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By letter dated Octoberintention to comply with the regulations established l
~j Appendix H or to propose a technically acceptable alternative for 1
This exemption is being NRC approval prior to operation of Cycle 3.
granted on the condition that after Cycle 2 and prior to operation of Cycle 3,the licensee will comply with the Consnission's regulations on surveillance requirements existing at that time.
Should the exemption request be denied, operation of the plant wou1d' be prohibited until the redesigned surveillance capsule holder tubeThis would resu assembly can be made available and approved for use.
The licensee,:
in Unit 3. being shut down for at least three months. stated that a delay of t by letter dated October 19, 1976, would result in increased generation costs of at least fourteen
~ Balancing these substantial certain added costs million dollars.
against the lack of an identified safety benefit to be gained from not granting the exemption. we conclude that granting of the exemption is in the public interest.
In sumary, we have concluded tL.t the licensee's request for exemption from the requirements of 10 CFR Part 50 Appendix H is authorized by law; will not endanger life or property or the cocanon defense and security
. and is otherwise in the public.intemst.
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-.Envinnanntal Consideratism,
.11e have detemined that these amendments do not suum 2ein change in I
effluent types or total amounts mor an increase is poner level and will Having made this not result in ariy significant environmental impact.
determination, we have further concluded that these amendments involve l
en action which is insignificant fetus the standpoint of environmental impact and pursuant to 10 CFR 551.5(d)(4) th N
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in connection with the issuance of these amendaemts.
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that: (1)
Conclusion We have concluded, based on the conside i the idered and do probability or consequences of accidents previously cons ndnents do not involve a significant decrease in a safet there is reasonable assurance that the health and safety of the public wi by operation in the proposed manner, and f these d security or to amendments will not be inimical to the comon defen the health and safety of the public.
Date-October 23, 1976 9
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