ML19254F111
| ML19254F111 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 10/16/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19254F110 | List: |
| References | |
| TASK-05-06, TASK-5-6, TASK-RR NUDOCS 7911070050 | |
| Download: ML19254F111 (3) | |
Text
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o UNITED STATES y
g NUCLEAR REGULATORY COMMISSION y
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g WASHINGTON. D. C. 20666
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 42 TO PROVISIONAL OPERATING LICENSE NO. DPR-16 JER3EY CENTRAL POWER & LIGHT COMPANY
_R OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219 1.0 Introduction By letter dated October 3,1979, which supersedes letter dated January 9, 1975, Jersey Central Power & Light Company (JCPL) sutmitted an application for an amendment to the Appendix A Technical Specifications appended to Provisional Operating License DPR-16 for Oyster Creek.
The requested changes would modify the reactor coolant system pressure-temperature limits to account for increases in the reactor vessel metal reference nilducility temperature (RTNDT) due to irradiation.
2.0 Discussion 10 CFR Part 50, Appendix G, " Fracture Toughness Requirements," requires that pressure temperature limits be established for reactor coolant system heatup and cooldown operations, inservice leak and hydrostatic tests, and reactor core operation. These limits are required to ensure that the stresses in the reactor vessel remain within acceptable limits. They are intended to provide adequate margins of safety during any condition of normal operation, including anticipated operational transients.
The pressure-temperature limits depend upon the metallurgical properties of the reactor vessel materials. The properties of materials in the vessel belt-line region vary over the lifetime of the v'essel because of the effects of neutron irradiation. One principle effect of the neutron irradiation is that it causes RTNDT to increase with time. The pressure-temperature operating limits must be modified periodically to account for this radiation induced increase in RTNDT by increasing the temperature required for a given pressure.
The operating limits for a particular operating period are based on the material prcperties at the end of the operating period.. By periodically revising the pressure-temperature limits to account for radiation damage, the stresses and stress intensities in the reactor vessel can be held within acceptable limits.
At the beginning of life, material other ^.han that in the beltline region may be the limiting material because it is s.ojected to high stresses and stress intensities.
However, since materia'. outside the beltline region is not sub-jected to high level irradiation, its RTNDT will not change as the beltline region will and at some period of life, the beltline materials will become limiting.
l } O g l j', g 7911 070 9
. The magnitude of the shif t in RT is proportional to ',he neutron fluence to which the materials are exposed.NDIhe shif t in RTNDT can be predicted from the results of tests on material surveillance specimens or from the guidance contained in Regulatory Guide 1.99.
3.0 Evaluation The revised operating limits are based on the calculational methods contained in ASME Code,Section III and Appendix G to 10 CFR Part 50. The operating limits are proposed for operation through 10 Effective Full Power Years (EFPY).
The fluence predicted on the vessel wall at 10 gPY is based on an er.d of life 2
fluence value on the vessel all ID of 3.3 x 10 n/cm.
The amount of radiation damage, increase in RT
, resulting from this fluence is estimated from the guidance contained in Rhlatory Guide 1.99, Revision 1.
Weld metal, having a copper content of 0.27%, was fcund to be the limiting material.
We have reviewed the proposed changes to Sections 3.3.A. 3.3.B. the bases, references and the proposed pressure-tmperature operating limits for Oyster Creek and have perfomed independent calculations to verify compliance with Appendix G.
We conclude that the proposed operating limits are in accordance with Appendix G,10 CFR Part 50 for operation through 10 EFPY and are therefore acceptable for this operating period.
Confomance with Appendix G to 10 CFR Part 50 in establishing s'fety operating limitations will ensure adequate safety margins during operation, testing, maintenance and postulated accident conditions and constitutes an acceptable basis for satisfying the requirements to NRC General Design Criterion 31, Appendix A,10 CFR Part 50. We, therefore, find the proposed amendment to the Technical Specifications acceptable.
4.0 Environmental Consideration We have determined that the amendment dces not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant enviromental impact.
Having made this detemination, we have further concluded that the amendment involves an action which is insigni{icant from the standpoint of enviromental impact and, pursuant to 10 CFR 551.5(d)(4), that an enviromental impact statsent or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
5,0 Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable 1290 140
, assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Comission's regulations and the issuance of this amendment will not be inimical to the cm non defense and security or to the health and safety of the public.
Date: October 16, 1979 1290 141
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