ML17319A562
| ML17319A562 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 07/25/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17319A561 | List: |
| References | |
| NUDOCS 8009050470 | |
| Download: ML17319A562 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMEHDMEHT HO.
38 TO FACII ITY OPERATING LICENSE HO.
DPR-58 INDIANA AHD MICHIGAN ELECTRIC COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NO.
1 DOCKET NO. 50-315 Back round In a letter dated May 12, 1980, Indiana and Michigan Electric Company proposed revisions to the D.
C.
Cook Unit 1 Technical Specifications which will allow operation with Exxon Nuclear Company (ENC)
Power Distribution Control Phase I I (PDC-II) pItocedures.
The revisions are based on ENC Topical Reports XN-NF-77-57
. and XN-HF-77-57, Supplement 1
Evaluation Our review of the Exxon PDC-II topical report and its supplement has been completed.
A topical report review is being prepared and will be issued shortly.
Our finding is that PDC-II is an acceptable methodology for use in ensuring that the core total peaking factor, F, will not in normal operation exceed the axially-dependent limits assumed as input for the loss-of-coolant accident.
We have reached this conclusion based upon our evaluation of the analyses reported in the topical reports and upon inde-pendent verification of some of the calculational results iIy our technical assistance consultants at Brookhaven National Laboratories I.'e also have earlier aproved PDC-II for use in Prairie Island Units 1
and 2, based on the status of our review at that time.
Basically, PDC-II uses the same procedures and Technical Specifications used for power distribution control in Westinghouse reactors for a number of years.
These show analytically, assuming the procedures are fol'lowed, that a maximum F
is not exceeded iri normal operation of the power plant.
The salient procedure is that the axial flux difference measured by excore flux detectors is maintained within +5% of the unrodded full power value.
This prevents, the formation of axial xenon maldistributions and subsequent occurrence of xenon oscillations, which can cause larger values of F Typically, this methodology shows that F
will not exceed 2.32 times any axial shaping factors that may apply.
I) a lower F limit is imposed (because oi the LOCA surveillance of f is initiated using tie movable incore detectors at power levels above that whIch is the ratio of the F~ limit to that justified by the analysis usin'g excore detectors.
~ I PDC-II separates F
into transient and stea4y-state components.
By analyses Exxon has developed a curve V(Z) which bounds the transient component as a functi on of axi al hei ght, Z, for a vari ety of maneuvers more limiting than expected in normal operation of a reactor.
By then using measured steady-state value of F (Z) multiplied by the V(Z) curve, the Fg which will not be exceeded is d termi ned and compared to the limit. 'If the ratio of these numbers is less than one at any elevation, this determines the fraction of power at which incore surveillance of F
must be initiated. If the ratio is one or greater, full power operation if permitted.
The proposed Technical Specification changes implement PDC-II and are acceptable because they will continue to ensure that the core peaking factor wi 11 not exceed the axially-dependent limits used as input for the LOCA analysis in normal operation of the power plant.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in arp significant environmental impact.
Having made this determination, we have further concluded that the amendment involves 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 issuance of this amendment.
Conclusion
.We have concluded, based on the consideratioris discussed above,"that:
(1) because the amendment does not involve a significant increase
-in the probability or consequences of -accidents previously considered and do not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (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 Cori ssion'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 publ i c.
A Date:
July 25, 1980
REFERENCES l.
XN-NF-77;57, Exxon Nuclear) Company,"Exxon Nuclear Power Distribution Control for.,Pressurized Water Reactor's, Phase 2," January 1978.
2, XN-NF"77-57, Supplement 1, Exxon Nuclear Comany, "Exxon Nuclear Power Distribution Cont) ol for Pressurized Mater Reactors, Phase II," June 1979.
3.
Mike Todosow, et al., Brookhaven'National Laboratory, "Axial Power Distribution. Control Strategies for PWRs."
(In publication) l 4.
U. S. Nuclear Regulatory Commission,'Amendment Nos.
35 and 29 to Facility Operating License Nos.
DPR-42 and DPR-60 for the Prairie Island Nuclear Generating Plant, Unit Nos. l and 2, Respectively," April 20, 1979.