ML20009B890
| ML20009B890 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 07/10/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20009B889 | List: |
| References | |
| TAC-43744, TAC-43745, NUDOCS 8107170318 | |
| Download: ML20009B890 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION Y
I SUPPORTING AMENDMENT NO. El TO FACILITY CPERATING LICENSE NO. O f
AND'APENDMENT NO. 57 TO FACILITY OPERATING LICENSE NO DPR-27 WISCONSIN ELECTRIC POWER COMPANY _
-POINT BEACH NUCLEAR PLANT, UNIT NOS. 1 AND 2 00CKET N0S_. 50-266 AND 50-301 Eackground In a letter dated March 31, 1981, Wisconsin Electric Power Company proposed changes in the Technical Specifications of Point Beach Nuclear Plant Units 1 The proposed changes for both Units 1 and 2 include revisions in and 2.
the reactor coolant system temperature and pressure operating curves and revisions in the reactor vessel surveillance specimen capsule removal schedules.
Discussion 10 LFR Part 50, Appendix G " Fracture Toughness Requirements", requires that pressur?-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 nonnal operation, including anticipated operational occurrences.
The pressure-temperature 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 One principal effect of the neutron irradiation of neutron irradiation.
is that it causes the vessel material nil-ductility temperature (RT,b)be to increase with time. The pressure-temperature operating limits a modifled periodically to account for this radiation induced increase in RTNDT by increasing the temperature required for a given pressure. The operating limits for 3 particular 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 limits.
8107170318 810710 PDR ADOCK 05000266 P
PDR t
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k t
is. proportional to the neutron fluence to The magnitude of _ the shif t RT.'kT i
which the materials are subjec ed. The shif t in RTMT can be predicted from Regulatory Guide _1~ 99. To check. the validity 'of the predicted shift in RTtJ0T..a reactor vessel material surveillance program is required.
t Surveillance specimens are periodica1V removed from the vessel and tested.
"The results of these tests are compared to the: predicted shifts in RT,j0T' and the pressure-temperature _ operating limits are revised accordingly'.
Evaluation -
The proposed revisiens 'in the heatup and'cooldown limitations for Units 'l' and 2 are based on cathods and data prov'ded in Westinghouse Electric s
Corporation Topical Reports ?.lCAP-3743 and 8738 respectively. The revised temperature and ' pressure curves are to be applicable.through fourteen (14) effective full power years (EFPY) of operation for Point Beach Unit 2 which is estimated to end in September.1990. The licensee stated that it is desirable for plant operational reasons that the temperature and pressure curves and beatup and cooldewn limitations for both units be identical.
Accordingly,' the temperature and pressure limitations developed for Unit 2 for 14 EFPY are applicable to Unit I for 21.5 EFPY of operation.
Ve:have performed independent calculations to verify the valicity-of the proposed limits. Our calculations are based on information c'ontained in the
" arch 21,1981 letter, WCAP-8738 and WCAP-8743 and information received from the reactor vessel. manufacturer; we found the proposed operating limits acceptable 'or operation through 14 EFPY, for both Units 1 and 2, instead of 21.5 EFPY and 14 EFPY respectively as specified in the licensee letter of March 21, 1981. Therefore, we find the licensee's proposed reactor coolant system. temperature and pressure operating curves for Unit 2 to be acceptable and for Unit I to be unacceptable. The above mentioned curves for Unit 2 are in conformance with Appendix G to 10 CFR Part 50 in establishing safe operating limits and will ensure adequate safety margins during operation, testing, maintenance and postulated accident conditions and constitue an acceptable basis for satisfying the requirements to NRC General Design Criteria 31, Appendix A,10 CFR Part 50.
If the reactor coolant system temperature and pressure operating curves for Unit 1 are. revised to limit operation to 14 EFPY, we conclude that they will be in conformance with the above requirements.
.We _further conclude that the proposed Technical Specification changes in the reactor vessel surveillance specimen capsule removal schedules as listed in Tables 15.3.1-1 and 15.3.1-2 are in accordance with Appendix H of 10 CFR 50 and therefore are acceptable.
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We have discussed our findings with members of the licensee's staff, and at their request we are issuing an amendment to incorporate the Techt.ical Specification changes for the Unit 2 temperature and pressure operating curves, which we find acceptable. We will' defer issuance of an amendment incorporating the Technical Specificatinn changes.
requested for the Unit 1 temperature and pressure operating curves '
pending the result of further discussions with the ifcensee's staff.
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Envircnmental Consideration
'a'e have deterhined tnat the amendmt.nts do not authorize a change in af fluent types or total amounts nor an increase in pcwer level and will not result in any significant envircnmental impact. Having made this determination, we have further concluded that.the anendments involve an action which-is insignificant from the standpoint of.
environmental impact and, pursuant to 10 CFR $51.5(d)(4), that an environmental impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issusnce of these amendments.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendments do not involve-a significant increase in the probability or consequences of accidents previously considered
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and do not involve a significant decrease' in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance t5at 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 Cennission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Date:
July 10, 1981 Prepared by:
T. G. Colburn, ORB #3 W. Hazelton, MTEB
.H. Walker, HTE8 4