ML19309C289
| ML19309C289 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/06/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19309C286 | List: |
| References | |
| NUDOCS 8004080408 | |
| Download: ML19309C289 (3) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION g
g WASHING TON, O. C. 20555
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,P SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION L
T SUPPORTING AMENDMENT NO. 55 TO PROVISIONAL OPERATING LICENSE NO. DPR-20 CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255
1.0 INTRODUCTION
By application dated July 2,1979, as revised November 6,1979, Consumers Power Company (the licensee) requested an amendment to the Technical Specifications appended to License No. DPR-20 for the Palisades Plant.
The amendment would conform the operating limits to the requirenents of 10 CFR Part 50, Appendix G " Fracture Toughness 6 mwd t.
Requirenents" for operation to 5.5 x 10 2.0 DISCUSSION 4
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 occurrences.
The pressure-tenperature limits depend upon the metallurgical properties of the reactor vessel materials.
The properties of materials in the vessel beltline region vary over the lifetime of the vessel because of the effects of neutron irradiation.
One principle effect of the neutron irradiation is that it causes the vessel material nil-ductility operating limitgD,fu)st be\\ modified periodically to account for this temperature (RT to increase with time.
The pressure-temperature radiation induced increase in RT by increasing the temperature required for a given pressure.
70doperatinglimitsforaparticular operating period are based on the material properties 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 are maintained within acceptable imits.
80(p1080 hf C> o n
c 4 1 The magnitude of the shif t in RT is proportional to the neutron fluence that the materials are s00}ected to.
The shift in RT can be predicted from Regulatory Guide 1.99.
TocheckthevalkhIty of the predicted shift in RT a reactor vessel material surveillance program is required. SurveiYNn,ce specimens are periodically removed from the vessel and tested.
The results of these tests are compared to the predicted shifts in RT limits are revised accordinglhDT, and the pressure-temperature operating 3.0 EVALUATION Revised operating limits for Palisades are proposed for operation through 5.5 x 106 mwd of themal reactor power.
The limiting vessel materigl is weld metal having an i.'Itial value of RT f 0 F.
At 5.5 x 100 MWdt nce on the vessel wall at tNOT1/4 T* location is estimated themaximumfluy8n/cm.
2 to be 3.78 x 10 Based the test results performed on Palisades material surveillance specimens (o and the damage predictions (increase in I
) in Regulatory Guide 1.99, this fluence causes the RT of the limning weld metal to increase to 150 F.
TherevisedopehS[inglimits
]
are based on this value of RTNDT' We have reviewed the proposed operating limits for Palisades and have perfomed independent calculations to verify compliance with Appendix G,10 CFR Part 50.
We conclude that the limiting material is weld metal that will have an RT 6
NDT of 150 F at 5.5 x 10 mwd
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As part of our review of the operating limits, we also reviewed the Palisades material surveillance program.
To date one surveillance capsule has been rmoved from the vessel and tested.
Our estimates of radiation damage are based on the results of tests on materials contained in this capsule.
We find that the Palisades surveillance program continues to be acceptable and in accordance with Appendix H, 10 CFR Part 50.
We conclude that the proposed operating limits are acceptable and are in conformance with Appendix G,10 CFR Part 50 for operation to 5.5 x 106 mwd -
t Confomance with Appendix G to 10 CFR Part 50 in establishing safe 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 changes, as modified, acceptable.
174 TTs one-fourth the thickness of the vessel wall, measured from the inside.
(1) " Palisades Nuclear Plant Reactor Pressure Vessel Surveillance Program:
Capsule A-240", March 13,1979, submitted by Consumers 4
Power Company letter of July 2,1979.
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4.0 ENVIRONMENTAL CONSIDERATION
We have determined that the amendment does not involve a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insignificant frg the standpoint of environmental impact and, pursuant to 10 CFR 151.5(d)(4), that an environmental impact statement 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 con-sideration, (2) there is reasonable 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 Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: March 6, 1980 l
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