ML20129B275
| ML20129B275 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/30/1985 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | Harold Denton, John Miller Office of Nuclear Reactor Regulation |
| References | |
| GL-84-04, GL-84-4, TAC-57864, TAC-57865, NUDOCS 8506050172 | |
| Download: ML20129B275 (3) | |
Text
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WISCONSIN Electnc ma cwa 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI 53201 May 30, 1985 Mr.
H. R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D.
C.
20555 Attention:
Mr.
J. R. Miller, Chief Operating Reactors, Branch'3 Gentlemen:
DOCKET NOS. 50-266 AND 50-301 GENERIC LETTER 84-04 REQUEST FOR EXEMPTION FROM GDC-4 REACTOR COOLANT SYSTEM PIPE BREAK CONSIDERATION POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 Generic Letter 84-04 dated February 1, 1984 provided the Nuclear Regulatory Commission's safety evaluation of Westinghouse Topical Reports dealing with elimination of postulated pipe breaks in pressurized water reactor primary main coolant loops.
The Staff's evaluation concluded that an acceptable technical basis has been provided so'that the asymmetric blowdown loads resulting from double-ended pipe breaks in main coolant loop piping need not be considered as a design basis for the Westinghouse Owners Group plants provided the two conditions identified in Generic Letter 84-04 were met.
As noted in' the letter, the Point Beach Nuclear Plant, Units 1 and 2, are included in Westinghouse Owners Group plants.
The first condition concerned maximum permissible bending moments and is not applicable to Point Beach.
The second condition concerns leakage detection systems.
As discussed in Generic Letter 84-04, leakage detection systems at the facilities should be sufficient to provide adequate margin ~to detect the leakage from the postulated circumferential through-wall flow, utilizing the guidance of Regulatory Guide 1.45, with the exception that the seismic qualification of the airborne particulate radiation monitor is not necessary.
At least one leakage detection system with a sensitivity capable of detecting 1 gpm in four hours must be operable.
Leakage detection systems utilized at the Point Beach Nuclear Plant have sensitivity capabilities which meet or exceed this standard.
Technical Specification 15'3.1.D.1, the basis for this specification, and FSAR Section 6.5 discuss the 6050M f 6 P 00, L
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Mr. H. R. Denton May 30, 1985 leakage detection provisions for primary coolant leakage available at Point Beach.
The most sensitive of the systems available, the containment air particulate monitor, is capable of detecting leaks as small as approximately.013 gpm within twenty minutes after initiation.
Another system, the cooling coil condensate measuring system, is capable of detecting leakage rates of 0.5 gpm within one hour or less.- Therefore, the second condition for acceptability of the NRC staff's safety evaluction for elimination of postulated pipe breaks is satisfied at our Point Beach Nuclear Plant.
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The NRC staff also concludes in Generic Letter 84-04 that the NRC may authorize non-installation of restraints which
'would have otherwise been required to accommodate double-ended break asymmetric dynamic loading in the primary coolant loop provided licensees request and justify an exemption from General Design Criteria.4 (GDC-4).
We have been requested by members of your staff to provide such an exemption request.
We do not necessarily believe that an exemption is required for the Point Beach Nuclear Plant since 10'CFR 50 Appendix A sets forth requirements for design criteria that must be included in applications for proposed facilities and it has not been established that the applicable requirements apply to facilities, such as Point Beach, which were already operating prior to the issuance of Appendix A.
Nonetheless, since sufficient justification for an exemption has been presented in the Staff's safety evaluation and an exemption will have effectively no impact on plant operation, we are requesting, as directed, an exemption from GDC-4 as set forth below.
Therefore, pursuant to the provisions of 10 CFR 50.12, Wisconsin Electric Power Company, licensee for the Point Beach Nuclear Plant, Units 1 and 2, hereby requests an exemption from those provisions of 10 CFR 50 Appendix'A, GDC-4, to eliminate
.the consideration of large reactor coolant system primary loop pipe
-breaks in the structural design basis of the Point Beach Nuclear Plant, Units 1 and 2.
This exemption request is based upon the use.of advanced fracture mechanics technology, as applied to primary loop piping and described in Westinghouse Electric Corporation's topical reports WCAP-9558 (Rev.12) and WCAP-9787.
These reports provide a substantial and adequate basis for limiting postulated design basis flaws in stainless steel reactor coolant system piping and provide the resolution of generic issue A-2,
" Asymmetric Blowdown Loads on PWR Primary Systems".
The justification for the acceptability of this exemption request is established in the Topical Report Evaluation provided as Enclosure 1 to NRC Generic Letter 84-04 dated February 1, 1984 and is
- Mr.-H..R. Denton May 30,' 1985
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_ incorporated in this request by reference..This request is'also supported by the " Regulatory Analysis of Mechanistic Fracture Evaluation of Reactor. Coolant Piping A-2 Westinghouse Owner Group
' Plants" which was provided as ~ Enclosure ~ 2 to. Generic ~ Letter' 84-04.
This analysis and the " Leak Before Break Value-Impact Analysis" which is attached to the report are applicable to the: Point Beach Nuclear Plant and are also incorporated-in this' exemption request by reference.-
We believe that the Commission will find that the requested exemption will not endanger life or property or the common defense and security and is in the public interest and, thus, the exemption may be granted.
Very truly yours, Vice President-Nuclear Power C.~ W.. Fay Copy.to NRC Resident Inspector g,
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