ML20155J212

Final Part 21 & Potential Significant Deficiency Rept 86-07 Re Inadequate Venting of Colt PC-2 Emergency Diesel Generator Sets Fuel Rack Boost Vent Piping.Initially Reported on 860502.Colt Initiating Vent Mods

ML20155J212
Person / Time
Site:	Beaver Valley
Issue date:	05/16/1986
From:	Carey J DUQUESNE LIGHT CO.
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
REF-PT21-86, REF-PT21-86-165-000 2NRC-6-050, 2NRC-6-50, 86-07, 86-7, PT21-86-165, PT21-86-165-000, NUDOCS 8605220238
Download: ML20155J212 (3)

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mit.euren. PA 15205 May 16, 1986 i

United States Nuclear Regulatory Commission Region I l 631 Park Avenue  ;

King of Prussia, PA 19406 ATTENTI m: Dr. Thomas E. Murley Administrator

SUBJECT:

Beaver Valley Power Station - Unit No. 2 i Docket No. 50-412 t Colt PC-2 Emergency D/G Fuel Rack Boost Vent Piping (

Potential Significant Deficiancy Report 86-07 -

REFERENCE:

Colt Part 21 Report from J. M. Moriarty To Mr. James G. Keppler, dated 2/4/86 ,

Gentlemen: i This potentially Reportabla Significant Defic.iency Report rel ating to Colt PC-2 Emergency Diesel Generator Sets Fuel Rack Boost Vent Piping is being submitted pursuant to the requirements of 10CFR50.55(e). This is a final report. It is anticipated that no additional reports will be submitted.  ;

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DUQUESNE LIGfff CmPANY By J. J. Carey V  !

Vice President  !

SDH/ijr At . nt AR AR) cc: Mr. P. Tam, Project Manager (w/a)

Mr. J. M. Taylor, Director (3) (w/a)

Mr. W. Troskoski, Sr. Resident Inspector (w/a)

Mr. L. Prividy NRC Resident Inspector (w/a)

INP0 Records Center (w/a) 2 NRC Document Control Desk (w/a) 8605220238 860516 PDR ADOCK 05000412 ,

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ATTACHMENT 1 BEAVER VALLEY POWER STATION - UNIT NO. 2 DUQUESNE LIGHT COMPANY REPORT ON POTENTIALLY REPORTABLE DEFICIENCY OF THE EMERGENCY DIESEL GENERATOR SETS FUEL RACK B00ST VENT PIPING

1. Summary An overspeed trip of the emergency diesel generators on startup occurred at Public Service of New Hanpshire, Seabrook Unit 1. Reports indicate that the starting air pressure which actuates the governor rack boost, was not being vented from the rack boost promptly after the start signal had been terminated. This caused the rack boost to not respond to the governor, to control the speed. Colt indicated that BV-2 has similar energency diesel generators and the same venting configuration as Seabrook.

2. Immediate Action Taken The Seabrook vent piping schenatics were examined which confirmed this could happen. An alternate vent piping arrangenent was suggested and a field change was initiated by Colt Industries. In addition DLC requested from Colt, via telecon, additional information regarding the cause of the overspeed trips at Seabrook-1. DLC asked why the lube oil pressure shuttle valve had not vented the fuel rack boost and prevented overspeed. Colt replied that they do not think the lube oil shuttle valve always operated in time to provide proper venting if lube oil is at keep wann temperature f o r long periods of time. Colt also stated that there is no need for this shuttle valve once the modification is made, as described in Colt's Part 21 report (Reference ).

The modification corrects the problem experienced at Seabrook. Retaining the lube oil shuttle valve will not be deleterious to proper D/G operation.

S. D. Hall, Sr. Project Engineer, DLC notified Jane Grant, NRC Region I on May 2,1986 under the requirements of 10CFR50.55(e) of this potentially reportable deficiency.

3. Description of Deficiency Air pressure from the diesel air start systen is used through a series of shuttle valves to put the fuel rack boost in -the " Max Fuel" position upon initiation of a diesel start. This will start the engine running and increase the governor oil pressure so the governor can. control the fuel rack position and therefore engine speed. At the point where the governor l

takes control of the fuel rack, the air start solenoid valves are vented.

This is intended to vent all the air start lines downstrean of the solenoid  ;

v alves. The present arrangement has the air shuttle valves piped into the 1 air start lines far downstrean of the vent location and have the main air l start valves between them and the vent. Because of this, the air shuttle )

valves may not be vented quickly enough. j 1

e During discussions with Colt, DLC was advised that spurious overspeeds during starting similar to the Seabrook problem were experienced at other facilities. It was noted that the lube oil pressure shuttle valves may have been the vent path to release the fuel rack boost in the majority of start procedures.

4. Analysis of Safety Implications The emergency diesel generators are required during design basis events to supply electric power to the safety-related components. Improper venting of the air shuttle valves could cause improper operation of the fuel rack boost. This could result in an overspeed trip of the energency diesel generators and attendant delays in providing energency power to vital plant components.

5. Corrective Action to Remedy Potential Deficiencies Colt is initiating a field change order for BVPS-2 to move the air shuttle j valve vent connections to _ a point close to the air start solenoid valves i which do the venting. This change was made at Seabrook and test proved its operability. In addition, DLC will revise Section 9.5.6 and Fig. 9.5-10 of the FSAR to be consistent with the Air Start Systen Modification in Amendment 13 scheduled to be submitted January 1987.

6. Additional Reports This is a final report. No further reports are anticipated.

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