ML20150F280

Forwards Safety Evaluation Addressing Mods Made to Tdi Diesel Engines to Reduce Vibrations & Acceptability of Resultant Vibration Level.Considers Diesel Vibration Issues Resolved

ML20150F280
Person / Time
Site:	Rancho Seco
Issue date:	03/28/1988
From:	Holahan G Office of Nuclear Reactor Regulation
To:	Andognini G SACRAMENTO MUNICIPAL UTILITY DISTRICT
Shared Package
ML20150F283	List: ML20150F280 ML20150F285
References
TAC-67001, NUDOCS 8804050123
Download: ML20150F280 (3)

Text

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ib March 28, 1988 Docket No.: 50-312 Mr. G. Carl Andognini Chief Executive Officer, Nuclear Rancho Seco Nuclear Generating Station 14440 Twin Cities Road

Herald, California 95638-9799

SUBJECT:

DIESEL ENGINE VIBRATION EVALUATION j Our safety evaluation report (SER) addressing the modifications made.to the Rancho Seco TDI diesel engines to reduce the vibrations and the acceptability of the resultant vibration levels is enclosed. The SER concludes that both the modifications and the current vibration levels are acceptable subject to the following conditions:- (1) anytime a TDI diesel operates continuously for more than 15 minutes, vibration levels of the engine, components, and piping will be monitored, (2) diesel engine piping and components will be inspected for leaks and cracks after each operating cycle or hourly during cycles lasting more than one hour. If due to more urgent operational demands, the above conditions are not met, justification for 1.ne omitted monitoring / inspection will be made to j the onsite resident inspectors.

I The conditions enumerated above will remain in effect until the TDI diesel

! engines are reevaluated / modified to meet the more conservative vibration j criteria specified by the current draft 1986, OM-3 vibration criteria, or if applicable, the final 1986, OM-3 vibration criteria.

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! Following the final 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> qualification run of the "B" TDI diesel generators j on March 26, 1988, a failed bolt was found on the turbo charger mounting post.

Inspection of the failed bolt indicated that approximately 80 percent of the failed surface was corroded. This is an indication that the bolt failure commenced sometime before the final 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> qualification run. The bolt failure raised concerns that other diesel engine bolts n'ay have incipient cracks which began to develop during periods when the engine vibrated excessively, i To resolve this concern, we have reviewed your descri ation of pre-restart test-

) ing of bolts in areas which had been subjected to higi vibrations (GCA 88-199,

, dated March 28,1988) and your commitment to replace all diesel fasteners which j may have been subjected to excessive vibrations as described in the "TDI Mech-i an cal Joint Action Plan". Our Inspectors have verified that the bolts included i tre the pre-restart testing program were found to be without defects.

t 8804050123 DR 880328 p ADOCK 05000312 PDR w_

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Mr. G. Carl Andognini We find that the course of action proposed by you, both pre-restart and longer ,

term, provides reasonable assurance that the diesel engine bolts will perform '

their functions without impacting adversely on TOI diesel operations  :

Based on this discussion and the resolution of diesel engine vibration concerns as described in the enclosed SER, we consider the diesel vibration issues resolved. If you have any questions concerning this matter, please connunicate with the NRC project manager assigned to your plant. ,

Sincerely, l

original signed by Gary M. Holahan, Assistant Director [

for Region III, & V Reactors Division of Reactor Projects - III, IV, Y and Special Projects Office of Nuclear Reactor Projects

Enclosure:

As stated I

cc: See next page DISTRIBUTION Docket FilT NRC & LPDRs PDV Reading GMHolahan JLee GKalman GWKnighton RBevan OFC :DR PDV Y

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gu a OFFICIAL RECORD COPY

1 Mr. G. Carl Andognini Rancho Seco Nuclear Generating Chief Executive Officer Nuclear Station Sacramento Municipal Utility District 14440 Twin Cities Road Herald, California 95638-9799 cc:

Mr. David S. Kaplan, Secretary Mr. John Bartus and General Counsel Ms. JoAnne Scott Sacramento Municipal Utility Federal Energy Regulatory Comission District 825 North Capitol Street, N. E.

6201 S Street Washington, D.C. 20426 P. O. Box 15830 Sacramento, California 95813 Mr. Barclay S. Lew Pacific Gas and Electric Company Thomas A. Baxter, Esq. 77 Beale Street (333/A613)

Shaw, Pittman, Potts & Trowbridge San Francisco, CA 94106 2300 N Street, N.W.

Washington, D.C. 20037 Mr. Steven Crunk Manager, Nuclear Licensing Sacramento Municipal Utility District Rancho Seco Nuclear Generating Station 14440 Twin Cities Road Herald, California 95638-9799 Mr. Robert B. Borsum, Licensing Representative Babcock & Wilcox Nuclear Power Division 1700 Rockville Fike - Suite 525 Rockville, Maryland 20852 1 Resident Inspector / Rancho Seco c/o U. S. N. R. C.

14440 Twin Cities Road Herald, California 95638 Regional Administrator, Region V U.S. Nuclear Regulatory Comission 1450 Maria Lane, Suite 210 1 Walnut Creek, California 94596 Mr. Jack McGurk, Acting Chief Radiological Health Branch State Department of Health Services 714 P Street. Office Building #8 Sacramento, California 95814 Sacranento County Board of Supervisors 1 700 H Street, Suite 2450 ,

i Sacramento, California 95814

Ms. Helen Hubbard

P. O. Box 63 Sunol, California 94586

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