ML19317G842
| ML19317G842 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/03/1977 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8004010668 | |
| Download: ML19317G842 (3) | |
Text
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u.s. NUCLEAR 71ERULAT;'RY CQWAISSION DOCKET NUMOED N; C PrRu 19$
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50-312 (2 788 j
N$C DISTRIBUTION roR PART 50 DOCKET MATERIAL TO-FROM:
DATE OF DOCUMENT Sacramento Municipal Utility Dist.
3/3/77 Mr. Robert W. Reid Sacramento, California DATE RECE:vEo J. J. Mattimoe 3/10/77
$(LE TTE R O NOTORIZ E D PROP INPUT FORM NUMBER OF COPIES RECEIVED RiGINAL EhNCLASSIFIED g
DESCRIPTION ENCLOSU RE Ltr. re our 1/7/77 ltr.'and their 2/11/.77 ltr.... furnishing response to NRC request for a list of applicable thermal margin credits for future reference....
ACKNOWLEDGED i
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PLANT NAME.
DO NOT REMOVE Rancho Seco SAFETY FOR ACTION /INFORMATION EmrTun 3/10/77 RJL ASSIGNED AD:
m AggTcMyn An.
BRAliqH CHIEF; Reid (d)
RWAMM (MTFT.
MPAQJECT MANAGER:
Roonev PROJECT MANAGER:
ALIC. ASST. :
Inzram LIC. ASST. :
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INTERNAL DISTRIBUTION KllEG FILE j SYSTEMS SAFETY PLANT SYSTEMS SITE SAFETY &
KNRC PDR _
HEINEMAN TEDESCO ENVIRO ANALYSIS X I&E (4-)
YOELD SCHROEDER BENAROYA DENTON & MUT T.FR f.ATNAR VGOSSICK & STAFF ENGINEERING IPPOLITO ENVIRO TECH.
MIPC MACARRY KIRKWOOD ERNST CASE BOSNAK BALLARD HANAUER SIHWEIL OPERATING REACTORS SPANGLER HARLESS PAWLICKI STELLO SITE TECH.
PROJECT MANAGEMENT REACTOR SAFETY OPERATING TECH.
GAMMILL BOYD ROSS EISENHITT (J;c],.)
STEPP P, COLLINS NOVAK X
SHAO HULMAN HOUSTON ROSZTOCZY
' X BAER PETERSON CHECK V
BITTLER SITE ANALYSIS MELTZ V GRIMES VOLLMER HELTEMES AT & I BUNCH SKOVHOLT SALTZMAN X J. COLLINS RUTBERG KREGER EXTERNAL DISTRIBUTION CONTROL NUMBER M PDR: Sacramanto. Cal.
NAT. LAB:
BROOKHAVEN MAT. T AR.
XTICR REG V.IE ULRIKSON (ORNL) i MSIC:
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CONSULTANTS:
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SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 s street, Box 15830, sacramento, California 95813; (916) 452-3211 March 3,1977
'.u Director of Nuclear Reactor Regulation
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Mr. Robert W. Reid, Chief g
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Operating Reactors, Branch 4
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U. S. Nuclear Regulatory Conmission
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d Washington, D. C.
20555 T
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Rancho Seco Nuclear Generating s
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Station, Unit No.1
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Dear Mr. Reid:
Please refer to your letter of January 7,1977 requesting a list of applicable thermal margin credits for future reference on the Rancho Seco docket. This letter is in response to that request and replaces our earlier submittal of February 11, 1977.
The evaluation of margins available to offset a potential DNBR penalty resulting from fuel rod bow has resulted in the identi-fication of the following offsets for Rancho Seco:
1.
Flow Area Reduction Factor:
This factor, used in subchannel analyses, accounts for manufacturing variations in fuel rod pitch. This factor has been shown to be equivalent to a 1% DNBR penalty.
2.
Densification Power Spike Penalty:
This penalty, 3.3% DNBR for Cycle 1 of Rancho Seco, has been sh wn to be no lo.nger necessary.
3.
Reactor Coolant System Flow Rate in ~ Excess 'of Design Flow Rate:
Based upon measurements taken prior to and during first
\\W cycle operation of Rancho Seco, the RCS flow rate is 108.6%
's of the design flow rate, with a maximum uncertainty of 3.5%.
(This increase in flow had conservatively been estimated to s
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be equivalent to 4.0% DNBR.)
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Robert W. Reid March 3,1977 The initial rod bow penalty evaluation for Rancho Seco was based upon the NRC bow prediction for B&W fuel and a linear inter-polation of the Westinghouse data.
This results in the following DNBR penalties:
Previously Identified Burnup
'DNBR ' Penal ty Offsets Net Penalty 15,000 8.2%
8.2%
0%
24,000 9.8%
8.2%
1.6%
33,000 11.2%
8.2%'
3.0%
The Babcock & Wilcox Company is performing a thennal hydraulic analysis for licensing of Fuel Cycle 2.
This analysis should provide an acceptable method of accommodating the DNBR reductions for increased fuel burnup and will be included in our submittal for licensing of Fuel Cycle 2.
Sincerely yours,
.. Adth J. J. Mattimoe Assistant General Manager and Chief Engineer
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