ML20085M718

AO 50-267/75/15A:on 750709,during Repair of Minor Oil Leak on Gasoline Engine of Emergency Fire Pump,Inlet Manifold Piping Found Cracked.Caused by Component Failure.Manifold Repaired

ML20085M718
Person / Time
Site:	Fort Saint Vrain
Issue date:	12/22/1975
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: ML20085M718 ML20085M725
References
AO-50-267-75-15, P-75034, NUDOCS 8311090182
Download: ML20085M718 (4)

Text

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7 O O R:" mT DATE: DecenFyr- 2I. 19 75 ALNORMAL OCCURRENCE 75/15A ~

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':Cs.U;:nLSCE DATE: Julv 9. 1075 P. O. Box"361, Platteville, Colorado 80651 l

FORT ST. VRAIN NUCLEA:t GENERATING STATION l l '

Pt.'3LIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO E0051 REPORT No. 50-267/75/15 A December 22, 1975 Final Fort St. Vrain Unit No. 1 P-75034 .!

IDENTIFICATION OF 'L 7 l GCCURRENC2:

MY. ET Mo &la Howard, Director N

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wht:. Nuclear. Regulatory: Commission on the gasoline engi:te of

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firJtegion TV.n.,tS',

on July 9,1975, the =echanic noticed t- T t '. '

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=an Of f_ ice; of: Inspectioniand. Enforcement Suite 1000 #g -

Thi Ar.lington, Texasif 760122 an abnormal occurrence, as per pa: f

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Section (F) of the Technical Specifications. 8 Ref: Facility Operating License CCNDITIONS PRIOR No. DPR-34 TO OCCURRENC": Steady State ruwer Routine Shutdown Hot Shutdown Routine Load Change

Dear Mr. Howard:

X Cold Shutdown Other (specify)

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/

75/15A, fications. Final, submitt;ed_p.erJthe requirements # of the-Technical-Speci-Routine Startup Very truly yours Tha cajor plant parcseters at the tame at rua event were as to11cva: _

Power RIT.

• O MWth Frederic E. Swart n 3f .e EL , Superintendent ,-Nuclear-Produc tion -

Secondary Coolant Fort St. Vrain Nuclear PrecGeddrating-Station" FES/alk Temperature 115 *F cc: Mr. Roger S. Boyd #/hr.

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Flow 0

Primary Coolant

• Pressure- O.5 p91g Te=perature 115 *F Core Inlet 8311090182 751222 115 'F Core Cutlet PDR ADOCK 05000 S . Flow 32.500 Jihr. , ,

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O o REPORT DATE: Decembep 22.' 1975 ABNORMAL OCCURRENCE 75/15A Page 1 of 3 OCCURRENCE DATE: July 9, 1975 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/75/15A Final TDFNTIFICATION OF A 1RENCE:

While repairing a minor oil leak on the gasoline enginc of the emergency '-

fire pump (P-45013) 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 (F) 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 were as follows:

Power RTR 0 MWth ELECT 0 MWe Secondary Coolant Pressure 235 psig Temperature 115 *F Flow 0 #/hr. I Primary Coolant

• Tressure 0.5 psig i' Temperature 115 *F Core Inlet 115 *F Core Outlet

-flow_ 32,500 f/hr. , , ., ,

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e l v O l ABNOR1Ud. OCCURRENCE 75/15A f

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.. DESCRIPTION OF OCCURRENCE:

Curing the repair of a small oil leak, inspection of the gasoline engine on the emergency fire pump (P-4501S) found what was thought to be a crack on one of the inlets of the inlet / exhaust manifold. Further checking with a dye renetrant showed that the manifold had cracks (partial circumferential). At least four of the six cylinder inlets appear to have small cracks. The 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 Environment Manufacture X Component Failure Installation /Const. Other (specify)

Operator Procedure ANALYSIS OF OCCURRENCE:

The reason for the cracks in the inlet passage of the manifold has not been identified. Three possible causes of the failure could be:

1) Cyclic temperature stresses, because the one piece manifold contains

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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. ,

CORRECTIVE  :

ACTION:

It has been determined that a new manifold is not available. The original mani-'

fold will be repaired. The quarterly preventive maintenance inspection procedure has been revised to make a visual. inspection of the manifold. The annual pre-ventive maintenance inspection procedure has been modified to include a dye-penetrant check of any suspected cracks.

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• t ABNORMAL OCCURRENCE 75/15A Page 3 of 3

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FAILURE DATA /SIMILAR REPORTED OCCURRENCES:

None PROCRAMMATIC IMPACT:

None CODE IMPACT:

None .

- ... -s Submitted by:

H! W. Hil ard, Jr'. -

Technica Services [ Supervisor

. Reviewed by:

Frank M. Mathie Superintendent, Maintenance N .

Approved by: m- - - -

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G. b pedericE. Swart Superintendent, Nuclear Production 3

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