ML20041B683

Forwards Request for Addl Info Re HPI Nozzle Analysis. Inadequacies in Computations Identified

ML20041B683
Person / Time
Site:	Rancho Seco
Issue date:	02/03/1982
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT
References
NUDOCS 8202250053
Download: ML20041B683 (7)

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G YUK L PDR TERA Docket No. 50-312 NSIC ORB #C4Rdg

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SUBJECT:

HPI fl0ZZLE ANALYSIS - REQUEST FOR INFOR!!ATION We have perfomed a preliminary review of your I!Pi nazzle analysis, and hcve identified inadequacies in your computations.

Your analysis of IIPI nozzle themal strees did not use the appropriate llPI flow rate following manual initiation of itPI. A total flow rate of 425 gpm was used, corresponding to a nomal reacter coolant systen (RCS) pressure of 2150 psig. Our review of B&W operating experience shows that RCS pressure usually drops to 17500psig following reactor trip before manual actuation of HPI would occur.

At 1750 psig, the HPI flow would be 760 gpm. The effect of the incrdased flow would be to increase the heat transfer coefficient between the noz2.le metal and the fluid.

In order for us to complete our review, the infomation.r'equested in is needed. Within 7 days of receipt of this letter, please give us your schedGle for supplying this infomation to us.

We also understand that $140D has established procedurchfor manual PPI actuation following a reactor trip if pressurizer level begins.to fall, Utilizing this procedure, itPI is manually initiated and directed only to the normal make-up nozzle. The purpose of this procedural change is to assure that the other three HPI nozzles are not subjected to any additional themal cycling.

In order for us to verify that no additional cycling is occuring on the nomal make-up nozzle, please submit to us your analysis in support of this conclusion. Also, please give us a copy of your procedures for keeping track of the number of cycles experienced by the four HPI nozzles.

Please subait a schedule for supplying this additional information in your 7 day response,

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. The reporting requironents contained in this letter affect fewer than ten respondents; therefore OID clearance is not required undar P.L.96-511.

Sincerely,

1. ORIG J 'Jf 3 SIGL*2D BY' JC;;1 i :T: Z e John F. Stolz, Chief Operating Reactors Cranch M Divisionoof Licensing

Enclosure:

Request fcr Additional Information cc w/ enclosure:

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UNITED STATES 1

NUCLEAR REGULATORY COMMISSION W ASHINGTON. D. C. 20555 February 3,1982 3

Docket No. 50-312 Mr. J. J. Mattimoe Assistant General Manager and Chief Engineer Sacramento Municipal Utility District 6201 S Street P. O. Box 15830 Sacramento, California 95813

SUBJECT:

HPI N0ZZLE ANALYSIS - REQUEST FOR INFORMATION We have perfonned a preliminary review of your HPI nozzle analysis,

.I and have identified inadequacies in your computations.

Your analysis of HPI nozzle thermal stress did not use the appropriate HPI flow rate following manual initiation of HPI. A total flow rate of 425 gpm was used, corresponding to a normal reactor coolant system (RCS) pressure of 2150 psig. Our review of B&W operating experience shows that RCS pressure usually drops to 1750 psig following reactor trip before manual actuation of HPI would occur.

At 1750 psig, the HPI flow would be 760 gpm. The effect of the increased flow would be to increase the heat transfer coefficient betweea the nozzle metal and the fluid.

In order for us to complete ove retiew, the information requested in is needed. Within 7 days of receipt of this lect $e, please give us your schedule for supplying this information to us.

1 We also understand that SMUD has established procedures for manual HPI actuation following a reactor trip if pressurizer level begins to fall.

Utilizing this procedure, HPI is manually initiated and directed only

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to the normal make-up nozzle. The purpose of this procedural change-is to assure that the other three HPI nozzles are not subjected to any additional thermal cycling.

In order for us to verify that no additional cycling is occuring on the normal 4nake-up nozzle, please submit to us your analysis in support of this conclusion. Also, please give us a copy of your procedures for-keeping track of the numb'er of cycles experienced by the four HPI nozzles.

Please submit a schedule for supplying this additional information in your 7 day response.

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. l The reporting. requirements contained in this letter affect fewer than ten respondents; therefore OMB clearance is not required under j

P.L.96-511.

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Sincerely, Jofn!{,$-

L F. Stolz, Chief (OperatingReactorsBranch#4 Division of Licensing

Enclosure:

Request for Additional Information l

cc w/ enclosure:

l Sea next page l

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Sacramento Municipal Utility Rancho Seco, Dncket No. 50-312 District ccw/ enclosure (s):

I David S. Kaplan, Secretary and Christopher Ellison, Esq.

l General Counsel Dian Grueuich, Esq.

l 6201 S Street California Energy Comission 1111 Howe Avenue P. O. Box 15830 Sacramento, California 95813 Sacramento, California 95825 l

Sacramento County Ms. Eleanor Schwartz Board of Supervisors California State Office 827 7th Street, Room 424 600 Pennsylvania Avenue, S.E., Rm. 201 Sacramento, California 95814 Washf ogten. D. C.

20003 Business and Municipal Department Docketing and Service Section Sacramento City-County Library Office of the Secretary l

828 I Street U.S. Nuclear Regulatory Comission l

Sacramento, California 95814 Washington, D. C.

20555 l

l Resider.t Inspcctor/ Rancho Seco 4

i c/o U. S. N. R. C.

0 14410 Twin Cities Road l

Herald, CA 95638 Dr. Rir.hard F. Cole Atomic Safety & Licensing Board Panel U.S. Nuclear Regulatory Commission Washington, D. C.

20555 l

Regional Radiation f.epresentative EPA Reaion IX Mr. Frederick J. Shon 215 Fremont Street Atomic Safety and Licensing Board San Francisco, California 94111 Panel U.S. Nuclear Regulatory Commission Mr. Robert B. Borsum Washington, D. C.

20555 Babcock & Wilcox Nuclear Power Generation Division Elizabeth S. Bowers, Esq.

I Suite 220, 7910 Woodmont Avenue Chainnan, Atomic Safety and Bethesda, Maryland 20814 Licensing Board Panel U.S. Nuclear Regulatory Comission Thomas Baxter, Esq.

Washington, D. C.

20555 Shaw, Pittman, Potts & Trowbridge 1800 M Street, N.W.

Washington, C. C.

20036 Herbert H. Brown, Esq.

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Lawrence Coe Lanpher, Esq.

Hill, Christopher and Pnillips, P.C.

1900 M Street, N.W.

Atomic Safety and Licensing Board Washington, D. C.

20036 Panel U.S. Nuclear Regulatory Comission Helen Hubbard Washington, D. C.

20555 P. O. Box 63 Sunol, California 94586 I

I

Sacramento Municipal Utility '

District Mr. Robert H. Engelken, Regional Administrato?

Atomic Safety and Licensing Appeal U. S. Nuclear Regulatory Commission, Region V Board Panel 1990 N. California Boulevard, Suite 202 U.S. Nuclear Regulatory Commission Walnut Creek, California 94596 Washington, D. C.

2055S Alan S. Rosenthal, Chairman Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Connission Washington, D. C.

20555 Dr. John H. Buck Atomic Safety and Licensing Appseni Board U. S. Nuclear Regulatory Conmission Washington, D. C.

20G55 Christine U. Kohl Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Commission

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Washington, D. C.

20555 California Department of Health ATTN: Chief. Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814 4

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to ltr. dtd. 2/3/82 REQUEST FOR ADDITIONAL INFORMATION B&W Document 32-1121811-00 does not completely document the Code analysts. Additional information is necessary, regarding equations used, how stresses were calculated under various transients, and which specific fatigue curves were used to obtain the cumulative usage factors. The use of a " ratio method" in the report for obtaining new stresses by extrapolation may be acceptable only if adequate information.on original calculations are available for our review.

Based on the above reasons, we request that the B&W stress analysis report 32-1121811-00 be updated to include.the following additional information:

1.

Update pressure and thermal stresses based on 1750 psig and 760 gpm.

2.

Specify code equations used and provide sample calculations for each category of stress and stresses in combination.

3 Provide detailed tabulation'.of resultant stresses under various HPI transients.

4.

Attach fatigue curves used.

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