ML20097J215
| ML20097J215 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 09/17/1984 |
| From: | Swartz E COMMONWEALTH EDISON CO. |
| To: | Harold Denton, Dentor H Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19269A542 | List: |
| References | |
| 9196N, NUDOCS 8409210158 | |
| Download: ML20097J215 (3) | |
Text
,.
N C mm:nw=lth Edison
/ One First National Plaza. Chicago Illinois
~'
Address Reply to. Post Office Box 767
.Q' Chicago. Illinois 60690 l
l
\\
September 17, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Sub ject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Elimination of Postulated Pipe Breaks In The RCS Primary Loop NRC Docket Nos. 50-454/455 and 50-456/457 References (a):
D. G. Eisenhut letter to All PWR OLs, cps, and Applicants dated February 1, 1984 (Generic Letter No. 84-04)
(b):
R. A. Wiesemann letter to H. R.
Denton dated June 1, 1984
Dear Mr. Denton:
Reference (a) provided the NRC Safety Evaluation of certain Westinghouse Topical Reports dealing with the elimination of postulated pipe breaks in the Reactor Coolant System (RCS) primary loop for the Westinghouse A-2 Owners Group plants.
The NRC evaluation concluded that an acceptable technical basis exists so that the asymmetric blowdown loads resulting from double-ended pipe breaks in the RCS primary loop need not be considered as a design basis, provided that certain conditions can be met for plants such as our Byron and Braidwood Stations.
The purpose of this letter is to provide plant specific analyses to demonstrate the applicability of the Westinghouse generic conclusions to our Byron and Braidwood Stations, and to initiate dialogue with appropriate NRC management concerning the elimination of pipe whip restraints and associated jet impingement shields on the RCS primary loop at both sites.
Reference (a) indicates that Applicants may request exemptions from the requirements of GDC-4 with respect to asymmetric blowdown loads from discrete breaks in the RCS primary loop if they can demonstrate the applicability of the modeling used and conclusions reached in the generic Westinghouse analyses.
Westinghouse has provided Commonwealth Edison with a report which demonstrates that the Byron and Braidwood plant specific parameters are enveloped by their generic analyses discussed in Reference (a).
This information has been provided to Commonwealth Edison in the I
form of WCAP-10553 (proprietary version) and WCAP-10554 bh opg
%3hc 0
Gl #
90 %
A lbd
. (non-proprietary version) entitled " Technical Bases for Eliminating Large Primary Loop Pipe Ruptures as the Structural Design Basis for Byron Units 1 and 2 and Braidwood Units 1 and 2",
each dated May, 1984.
We are providing copies of both the proprietary and non-proprietary versions of-this information for your review.
However, as explained below, we respectfully request that the proprietary version be withheld from public disclosure.
Additionally, Reference (a) indicates that the NRC acceptance of the leak-before-break concept on a case-by-case basis is predicated on the Applicant's leak detection capability to detect the leakage from the postulated circumferential throughwall crack utilizing the guidance of Regulatory Guide 1.45.
The Byron and Braidwood Station capabilities for detecting and monitoring leakage through the RCS pressure boundary meet these requirements and are described in the Byron and Braidwood FSAR Section 5.2.5.
The following table provides the approximate percentage of installation completion of the RCS primary loop pipe whip restraints and associated jet deflector shields at our Byron and Braidwood Stations:
RESTRAINTS JET DEFLECTORS Byron Unit 1 COMPLETE COMPLETE Byron Unit 2 98%
95%
Braidwood Unit 1 33%
99%
Braidwood Unit 2 16%
0%
NRC staff acceptance of this exemption request will benefit the Commonwealth Edison Company.
Cost savings attributable to construction will result where restraints or deflectors have not yet been installed, or where shimming for hot gaps can be eliminated by their removal.
Removal of restraints will allow for better insulation of the RCS piping thus helping to reduce Containment heat loads.
Further, restraint removal will benefit ALARA considerations in terms of reducing personnel exposures due to future plant inspection and maintenance activities.
We hereby request NRC staff review of the enclosed information.
We understand that other utilities are in various stages of justifying the elimination of pipe whip restraints on the RCS primary loop that were initiated by requests for partial exemption from the provisions of GDC-4.
We request NRC staff guidance as to what additional specific information remains to be provided by the Commonwealth Edison Company in order to proceed in this matter.
s.
The' enc'losed WCAP-10553 contains information-proprietar;-to the Westinghouse Electric Corporation which is supported by the e'nclosed. Reference (b) affidavit signed by Westinghouse, the owner-of-the information.
The affidavit sets forth the basis on which the information may be withheld from public disclosure'by the Commission-
.in accordance'with 10 CFR 2.790(b)(1),~and~ addresses the specific
' considerations of 10 CFR 2.790(b)(4).
Accordingly, we~ respectfully frequest that the information which is proprietary to Westinghouse be
< withheld from public' disclosure in accordance with 10 CFR 2.790.
Correspondence with regard to the proprietary aspects of the Application for Withholding'or the supporting Westinghouse affidavit
.should reference CAW-84-44, and should be addressed to R. A.
Wiesemann, Manager, Regulatory and Legislative Affairs, Westinghouse Electric Corporation, P.O. Box 335, Pittsburgh, Pennsylvania 15230.
One signed original of this-letter and Reference-(b), along Jwith fifteen copies'are provided for your use.
Additionally,
- fifteen copies each of WCAP-10553 and WCAP-10554 are provided.
Please advise this office as soon as possible as to the NRC staff requirements in this matter, and the earliest date to arrange a meeting to.further discuss this subject.
Very truly yours,
_/ - '>2 E.
sS Nuclear Licensing Administrator EDS/ rap cc:.:J. G. Keppler - RIII J. A.,Stevens - LB1
~L.
N. Olshan - LB1-R..J.-Bosnak - MEB
't
-9196N
.w
?
~
___m
_m___.___
_ _ _ _