ML20135H855
| ML20135H855 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 09/16/1985 |
| From: | Adensam E Office of Nuclear Reactor Regulation |
| To: | Tucker H DUKE POWER CO. |
| References | |
| TAC-59005, TAC-59006, NUDOCS 8509240303 | |
| Download: ML20135H855 (3) | |
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September 16, 1985 Docket Nos: 50-369 DISTRIBUTION:
and 50-370 (Docket File NRC POR '
Local POR PRC System Mr. H. B. Tucker, Vice President NSIC Nuclear Production Department LB #4 r/f Duke Power Company MDuncan 422 South Church Street DHood i
Charlotte, NC 28242 OELD, Attorney ACRS (16) j
Dear Mr. Tucker:
JPartlow RGrimes EJordan
Subject:
Request for Additional Infonnation Regarding Main Steamline Break 1
in the Doghouse, McGuire Nuclear Station, Units 1 & 2 i
The NRC staff has reviewed your evaluation of a main steamline break (MSLB) in the McGuire Doghouse fowarded by your coverletter dated June 21, 1985.
i We find that additional information, identified in the enclosure, is needed j
for completion of our review.
i i
Your response to the enclosure is requested within 60 days of this letter.
Contact our Project Manager, Darl Hood, at (301)492-8408 if you have questions j
regarding the enclosure or are unable to meet the requested response date.
l The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely, 3
1 wb u l
1 Elinor G. Adensam, Chief l
Licensing Branch No. 4 Division of licensing l
Enclosure:
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As stated l
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Mr. H. B. Tucker Duke Power Company McGuire Nuclear Station i
cc:
Mr. A. Carr Dr. John M. Barry Duke Power Company Department of Environmental Health P. O. Box 33189 Mecklenburg County 422 South Church Street 1200 Blythe Boulevard Charlotte, North Carolina 28242 Charlotte, North Carolina 28203 Mr. F. J. Twogood County Manager of Mecklenburg County Power Systems Division 720 East Fourth Street Westinghouse Electric Corp.
Charlotte, North Carolina 28202 i
P. O. Box 355 Pittsburgh, Pennsylvania 15230 Chairman, North Carolina Utilities Commission Mr. Robert Gill Dobbs Building
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Duke Power Company 430 North Salisbury Street Nuclear Production Department Raleigh, North Carolina 27602 i
P. O. Box 33189 Charlotte, North Carolina 28242 Mr. Dayne H. Brown, Chief Radiation Protection Branch J. Michael McGarry, III, Esq.
Division of Facility Services Bishop, liberman, Cook, Purcell Department of Human Resources and Reynolds P.O. Box 12200 t
1200 Seventeenth Street, N.W.
Raleigh, North Carolina 27605 Washington, D. C.
20036 Senior Resident Inspector c/o U.S. Nuclear Regulatory Commission Route 4. Box 529 Hunterville, North Carolina 28078 i
Regional Adninistrator, Region II U.S., Nuclear Regulatory Commission.
101 Marietta Street, N.W., Suite 2900
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Atlahta, Georgia 30323 i
L. L. Williams Operating Plants Projects Regional Manager 1
Westinghouse Electric Corporation - R&D 701 P. O. Box 2728 Pittsburgh, Pennsylvania 15230
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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION REGARDING McGUIRE UNITS 1 & 2 STEAM LINE BREAK Provide the following additional information in regard to your analyses of a main steamline break (MSt.8) in the McGuire "anhouse as forwarded by cover letter dated June 21, 1985:
1.
The steam line break analyses in support of Doghouse equipment qualifi-I cation were performed with an updated but unapproved version of LOFTRAN.
l Provide a detailed description of the modifications made to LOFTRAN and its validation.
Also, confirm the appropriateness of the break flow model for superheated conditions.
2.
Superheated break flow co'nditions could lead to higher heat loss rates from the reactor coolant system when compared to saturated break flow conditions. This could imply that previous versions of the LOFTRAN computer program are non-conservative and that the results submitted in WCAP-9226, " Reactor Core Response to Excessive Secondary Steam l
Releases," (as referenced in the FSAR) may not be valid for all con-ditions. Address, in detail, the consequences of modeling superheat and its effect on core response.
Provide detailed comparative analyses of the results calculated with the two models (saturated versus superheated steam models).
l 3.
As a consequence of equipment failures from adverse environmental con-i ditions, the main steam isolation valves in the affected Doghouse were assumed to reopen. This led to blowdown of the two steam generators:
(a) Provide details and justification of the reactivity methodology used in the analyses as well as the nodalization and the primary coolant mixing coefficients applied in the reactor vessel.
(b) Provide the data and justification to support the mixing coefficients applied to the reactor coolant as well as the reactivity feedback models.
(This information was requested by the NRC in 1983 on the WCAP-9226 submittal but Westinghouse has not responded to the request.)
l (c) Describe how the analyses were performed when assuming the stuck rod cluster control assembly to be positioned in loop 1 core sector versus loop 2 core sector.
1 4.
Provide your evaluations of offsite dose, including in particular the case with two steam generator blowdown.
o.
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