ML19322B318
| ML19322B318 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/25/1976 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19322B297 | List: |
| References | |
| NUDOCS 7912020167 | |
| Download: ML19322B318 (3) | |
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UNITED STATES d
NUCLEAR REGULATORY COMMIMtON j
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is, SAFETY EVALUATION BY Tl!E OFFICE OF NUCLEAR REACTOR R SUPPORTING AMENDMENT NO. 26 TO FACILITY LICENSE NO. DP AMENDMENT NO. 26 TO FACILITY LICENSE NO. DPR-47 AMENDMENT N9 23 TO FACILITY LICENSE NO. DPR-55 DUKE POWER CO'iPANY OCONEE NUCLEAR STATION, UNITS 1, 2 AND 3_
DOCKET NOS. 50-269, 50-270 AND 50-287
-n, Intro 3uction By letter dated May 7,1976, Duke Power Company (the licensce) requested an exemption from the requirements of 10 CFR Part 50, Appendix II, Section o
II.C.2 to permit the operation of Oconce Unit No. 2 during cycle R with the reactor vessel surveillance capsules removed from the reactor vessel.
The licensec requested corresponding changes to the Technical Specifications appended to Facility Operating Licenses Nos. DPR-38, DPR-47 and DPR-SS These changes for the Oconce Nuclear Station, Units Nos. 1, 2 and 3.
would reficct the removal of the reactor vessel surveillance capsules during Unit No. 2 cycle 2 operation and would require the submittal of a revised surveillance capsule withdrawal schedulo prior to-Unit No. 2 cycle 3.
Discuss' ion The Oconce Unit No. 2 design includes three reactor vessel surveillance capsule holder tubes located adjacent to the reactor vessel inside Each holder tube contains two surveillance capsules which hold wall.
the specimens to be irradiated in accordance with the requirements of the reactor vessel material surveillance program, as described in The purpose of the surveillance program Appendix H to 10 CFR Part 50.is to monitor changes in the fracture toughn materials in the reactor vessel beltline region resulting from exposure to neutron irradiation and the thermal environment.
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By letter dated March 16, 1976, the licensee indicated awareness of damage to the reactor vessel surycillance holder tubes at another BSW In order to minimize the possiullity of similar damage to the reactor.
Oconce Unit No. 2 surveillance holder tubes, the licensee has proposed to remove the reactor vessel surveillance capsules and holder tubes
.for cycle 2 operation.
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Evaluation As required by Paragraph II.C.2 of Appendix H to 10 CFR part 50, the surycillance capsules of Oconce Unit No. 2 are positioned during reactor operation such that the neutron flux received by the specimens is at 1 cast as high as but not more than three times as high as that received by the reactor vessel inner surface.
More specifically, as reported in
- Babcock and Wilcox Topical Report BAW-10100A, February 1975, the specimen capsule locations in the Unit No. 2 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.
This cat se,s the integrated neutron flux (r fluence) of the specimens to accumulate faster or " lead" the fluence to but not more than three times greater than that received by the reactor -
vessel inner surface. More specifically, as reported in Babcock and Wilcox Topical Report BAW-10100A, February 1975, the specimen capsule locations in the Unit No. 2 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.
This causes the integrated neutron flux (or
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fluence) of the specimens to accuuulate faster or " lead" the fluence accumulating in the veswl wall itself.
This lead factor between the center of the specinns and the 1/4t vessel wall location is considered when determining the relative fracture toughness properties of the beltline region materials.
Although Oconce Unit No. 2 has currently accumulated only 1.21 effective full power years (EFPY) of exposure at the vessel wall, the capsule specimens have acctunulated an exposure
.cquivalent to 2.90 EFPY.
Since operation to the end of Oconee Unit No.
2, cycle 2 will produce a total of 2.04 EFPY we conclude that there is ample margin between the fluence aircady accumulated in capsule specimens when compared to the maximum achievable exposure to be accumulated at the 1/4t reactor vessel beltline location by the end of cycle 2 operation. The irradiation effects accculated by the specimens during cycle 1 operation can with proper storage condition be preserved unaltered and appropriate allowances can be made to review the capsule withdrawal schedule and thus insure that the required data is obtained.
In addition, ins required by section 4.2.9 of the Oconec Technical Specifications, a type B capsule was removed
'from Oconce Unit No. 2 during the current outage. The results of the analyscs conducted on the specimens in the capsule will be included in the licensce's revised Unit No. 2 uithdrawal schedule which is expected to be submitted at Icast 90 days in advance of Cycle 3 operation.
Based on the above we conclude that the licensce's proposed action to remove the Unit No. 2 reactor vessel surveillance capsuics during Cycle 2
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operation oryly, will not adversely affect the overall Unit No. 2 surveillance program being relied upon to ensure the lifetime ductility of the reactor pressure vessel.
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f the plant Denial of the exemption request would prevent operation o i t lled.
The until the surveillance capsule holder assemblies ar b
cannot be accomplished before September 1976.
b r would result advised us that the shutdown of Unit No. 2 until Septem e ficcted in in substantial additional generating costs that would be reBalan be gained from costs against the lack of an identified safetp benefit to increased customer rates.
ting of the not granting the requested exemption we conclude that gran I
en paption request is in the public interest.
ption In summary, we have concluded that the licensce's request for exe by law; from the requirements of 10 CFR 50, Appendix 11, is authorized d security will not endanger life or property or the common defense an and is otherwise in the public interest.
Environmental Consideration in We have determined that the amendments do not authorize a chan level and will effluent types or total amounts nor an increase in powerllaving made this not result in any significant environmental impact. de l
f environmental an action which is insignificant from the standpoint o l statement, impact and pursuant to 10 CFR 551.5(d)(4) that an environme l need not be negative declarruion, or environmental impact appraisa prepared in connection with the issuance of these amendments Conclusion that:
We have. concluded, based on the considerations discussed ab in the (1) because the change does not involve a significant increase d and does probability or consequences of accidents previously conside h
e does not involve a significant decrease in a safety margin, the c ang is reasonabic not involve a significant hazards consideration, (2) there be endangered assurance that the health and safety of the public will not ill be by operation in the proposed manner, and (3) such activities w d the issuance conducted in compliance with the Commission' f
nd security or to the health and safety of the public.
A Date: June 25, 1976 q,y; g
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c UNITED STATES HUCLEAR REGULATORY COMMISSION DOCKET NOS. 50-269, 50-270 AND 50-287 DUKE P0b'ER COMPANY NOTICE OF ISSUANCE OF AMENDMENTS OPERATING LICENSES TO TACILITY The U. S. Nuclear Regulatory C Amendment Nos. 26, 26, and 23 to F ommission (the Commission) ssued DPR-47, and DPR-55, respectiv l acility Operating Licenses Nos
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. DPR-38, Technical Specifications for oe y, issued to Duke Power Company which revised Nos.1, 2, and 3 located in O peration of the Oconee Nuclear St ation Unit are eficctive 'as of the date of iconee County, South Carolina The amendments ssuance.
These amendments result fro of 10 CFR Part 50, Appendix Hm an exemption granted from therequirements Requirements," and provide fo" Reactor Vessel Material Su rveillance Program capsules for Unit No. 2 cycle 2 oper the removal of the re sel surveillance drawal schedule be revised priration and require that the capsul e with-or to cycic 3.
The application f'or these am of the Atomic Energy Act of 1954endments co requirements r s and the Commission's rules and re
, as amended (the Act), and gulations.
findings as required by the Act The Commission has made appropri ate in 10 CFR Chapter I, which ar and the Commission's rule;s and re
,r gulations public notice of these amendmentse set forth in the license amend ments.
Prior not involve a significant hazards cwas not required since the ame d n ments do onsideration.
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Sp6%%eme y
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t The Commission has determined that the issuance of th i
d that pursuant will not result in any significant environmental impact an negative declaration to 10 CFR $51.5(d)(4) an environmental statement, in connection or environmental impact appraisal need not be prepared with issuance of these amendments.
to this action,<see (1) the 1
For further details with respect 7, 1976, (2) Amendment Nos.26,
application for amendments dated May i
l and 26 and 23 to Licenses Nos. DPR-38, DPR-47 and DPR-55, respect ve All of these items are (3) the Commission's related Safety Evaluation.
blic Document Room, available for public inspection at the Commission's Pu 20555 and at the Oconee County N. W., Washington, D. C.
1717 H Street, 29691.
Library, 201 South Spring, Walhalla, South Carolina A copy of items (2) and (3) may be obtained upon request add D. C.
- 20555, to the U. S.. Nuclear Regulatory Commission, Washington, Director, Division of Operating Reactors.
Attention:
day of June 1976.
Dated at Bethesda, Maryland, this 25 FOR THE NUCLEAR REGULATORY COMMIS
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A. Schwencer, Chief -
Operating Reactors Branch #1 Division of Operating Reactors 4
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