ML20085M725
| ML20085M725 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 07/18/1975 |
| From: | Hillyard H, Mathie F, Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| Shared Package | |
| ML20085M720 | List: |
| References | |
| AO-50-267-75-15, NUDOCS 8311090185 | |
| Download: ML20085M725 (4) | |
Text
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O C) ss public service company e conomito P. O. Box 361, Platteville, Colorado 80651 July'18, 1975 g to
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Mr. E. Morris Howard, Director e j.;
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Region IV p/-m#
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Office of Inspection and Enforcement
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Suite 1000 Arlington, Texas 76012 Ref: Facility Operating License No. DPR-34 Docket No. 50-267
Dear Mr. Howard:
Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/75/15, Final, submitted per the requirements of the Technical Specifications.
Very truly yours,
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Y Frederic E. Swart Superintendent Nuclear Production Fort St. Vrain Nuclear Generating Station FES:il
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Mr. Angelo Giambusso g
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July 18, 1975 ABNORMAL OCCURRENCE l
l OCCURRENCE DATE:
July 9. 1975 ll FORT ST. VRAIN NUCLEAR CENERATING SIATION l
1 PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/75/15 Final 1
IDENTIFICATION OF OCCURRENCE:
While repairing a minor-oil leak on the gasoline engine of the emergency fire pump (P-4501S) on July 9,1975, the mechanic noticed that the inlet
. manifold piping was cracked.
This has been identified as an abnormal occurrence, as per paragraph 2.1, Section'.(E) of the Technical Specifications.
CONDITIONS PRIOR TO OCCURRENCE:
Steady State Power Routine Shutdown Hot Shutdown Routine Load Change X
Cold Shutdown Other (specify)
. Refueling Shutdown Routine Startup The major plant parameters at the time of the event wcre as follows:
Power
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MWth
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MWe Secondary Coolant Pressure 325
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Temperature 115
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Flow 0
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Primary Coolant Pressure 0.5 psig Temperature 115
'F Core Inlet 115
'F Core Outlet Flow 32.500 f/hr.
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DESCRIPTION OF OCCURRENCE:
I Curing the repair of a small oil leak, inspection of the gasoline engine on the emergency fire pump (P-4501S) found what vere thought to be a crack l
on one of the inlets of the inlet / exhaust manifold. Further checking with a dye-penetrant showed that the manifold had cracks (partial circumferential).
At least four of the six cylinder inlets appear to have small cracks. The s
cracks were in each case located at the junction of the air passage with the mounting flange of the cast iron manifold.
APPARENT CAUSE OF OCCURRENCE:
Design Unusual Service Cond.
Including Environm,ent Manufacture X
Component Failure Installation /Const.
Other (specify)
Operator e,
Procedure' ANALYSIS OF OCCURRENCE:
The reason for the cracks in the inlet passage of the canifold has not been identified.
Three possible causes of the failure could be:
- 1) Cyclic temperature stresses, because the one piece manifold contains.
'six inlet ports, six exhaust ports, and cooling water passage ways.
- 2) Possibly the manifold was misaligned when installed.
- 3) Combination of vibration and size of the manifold.
The engine was, and is,, operable with these cracks. Even with further cracking the engine would be operable but at reduced power.
l CORIECTIVE ACTION:
A new manifold has been ordered and the defective casting will be replaced.
l The quarterly preventive maintenance inspection procedure will be~ revised to make a visual inspection of the manifold. A dye-penetrant check of any suspected cracks will be made during the annual preventive maintenance in-spection.
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Page 3 FAILURE DATA /SIMILAR REPORTED OCCURRENCES:
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None PROGRAMMATIC IMPACT:
None CODE IMPACT:
None M.
i Submitted by:
H. W.11111 yap Jr.
Technical Services Supervisor Fort St. Vrain Nuclear' Generating Station Reviewed by:
Frank M. Mathie Superintendent, Maintenance Fort St. Vrain Nuclear Generating Station Approved by:
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FfedericE. Swart Superintendent, Noclear Production Fort'St. Vrain Nuclear Generating Station e
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