ML20151A517
| ML20151A517 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/28/1988 |
| From: | Andognini G SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Miraglia F Office of Nuclear Reactor Regulation |
| References | |
| GCA-88-199, TAC-67001, NUDOCS 8804070053 | |
| Download: ML20151A517 (3) | |
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SACRAMENTO MUNICIPAL UTILITY DISTRICT O P. O. Box 15830, Sacramento CA 95852-1830,(916) 452 3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA MAR 2 81938 GCA 88-199 U. S. Nuclear Regulatory Commission Attn: Frank J. Miraglia, Jr.
Associate Director for Projects 11555 Rockville Pike Rockville, MD 20852 Docket No. 50-312 Rancho Seco Nuclear Generating Station License No. DPR-54 COMPLETION OF TDI PRE-RESTART TESTING
Dear Mr. Miraglia:
Pursuant to the restart conditions set forth at the Commissioners' meeting on March 22,1988, the District has completed the work required for the TDI diesel generators in preparation for restart of Rancho Seco.
Based on the successful completion of modifications, analysis, and testing, both TDI diesel generators have been declared OPERABLE per Technical Specification 3.7.1.
In order to bring vibration levels for the engines and support systems into compliance with ANSI /ASME OM-3-1982, final modifications required to achieve compliance have been completed. Post-modification testing was performed and vibration data obtained. Data analysis has verified that these vibration readings were at an acceptable level.
Testing, including the repeat 24-hour run of the "B" TDI diesel generator, has been completed.
The District has placed the TDI diesel generators in stand-by service in accordance with Technical Specification requirements.
Although future enhancement modifications to improve engine performance and reliability are anticipated, no further modifications are necessary for the engines to satisfy the design basis safety requirements. The District will continue to monitor vibration levels post-restart to ensure early detection of unanticipated changes.
During a 24-hour run of the B2 TDI diesel on March 25, 1988, one of four mounting bolts on the turbocharger mounting foot failed. The engine continued to operate with no apparent change in vibration.
Prior to modifications made in 1987, the turbocharger experienced unacceptably high vibration levels which may have contributed to this failure.
The four mounting bolts on the B2 engine have been replaced in an effort to preclude a reoccurrence of this eve r,t.
The remaining 3 bolts were NDE inspected and no problems were i den ti fi ed.
The cause of failure for the broken bolt will be investigated.
The corresponding four A2 engine bolts will be replaced as part of the Action [(
Plan outlined below.
In addition to the three bolts from the turbocharger support foot, eight other bolts as detailed on the Attach.w'1t were also removed and successfully NDE'd.
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8804070053 080328 DR ADOCK 0500 2
RANCHO SECO NUCLEAR GENERATING STATION O 1444o Twin Cities Road, Herald, CA 95638-9799;(209) 333 2935
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MAR 2 81933 Mr. Miraglia, Jr. GCA 88-199 The District has also developed a TDI Mechanical Joints Action Plan to replace fasterners associated with the TDI diesels which may have experienced I
excessive vibration levels during the testing and modification program. This pregram is scoped to include both fasteners and other mechanical joints.
Since no mechanical joint failure to date has resulted in the engine not being able to perform its safety function, and the current vibration levels meet ANSI /ASME OM3-1982 requirements, the diesel generators are operable to provide emergency power.
Please contact me if you have any questions. Members of your staff with questions requiring additional information or clarification may contact Mr. Steve Crunk at (209) 333-2935, extension 4913.
Sincerely,
/44 G. Ca And nini Chief Executive Officer, Nuclear Attachment cc:
G. Kalman, NRC, Rockville A. D'Angelo, NRC, Rancho Seco J. B. Martin, NRC, Walnut Creek
to GCA 88-199 ATTACHMENT TDI B2 DIESEL BOLTS REMOVED FOR NDE Number 1.
Side Cover, Cylinder 6 (1) 2.
Side Cover, Cylinder 8 (1) 3.
Turbocharger Intercooler Support Bracket (1) 4.
Air-Start Header Support Bracket, Cylinder 8 (1) 5.
Lube Oil Pot Outlet Support Bracket (1) 6.
Standpipe Support Brace (1) 7.
Shroud Support Bracket (2) i
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