ML20155H706

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Troubleshooting Action Plan for Action List Item 11b, Sys Response,Auxiliary Feedwater FWS-063 & FWS-064
ML20155H706
Person / Time
Site: Rancho Seco, 05000000
Issue date: 01/04/1986
From: Field J
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20155H523 List:
References
RTR-NUREG-1195 NUDOCS 8605160356
Download: ML20155H706 (4)
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{ $. TROUBLESHOOTING ACTION PLAN

ACTION LIST ITEM NUMBER 11b ACTION LIST DESCRIPTION SYSTEM RESPONSE. AUXILIARY FEEDWATER FWS-063 FWS-064 QUARANTINED EQUIPENT LIST ITEM NUMBER 12d RESPONSIBILITY OF Jim Field i PREPARED BY George Pactzun DATE: Januarv 4. 1986 DESCRIPTION OF ISSUE:

This action plan addresses the failure of the Auxiliary Feedwater to "A" Steam Generator Manual Isolation Valve, FWS-063, identified during the December 26, 1985 trip recovery. In addition this action plan provides for investigation of the 4

similar Auxiliary Feedwater to "B" Steam Generator Manual Isolation Valve, 3 FWS-064.

a FWS-063 and FWS-064 are normally locked open valves and were open prior to the transient. During the transient, operators were dispatched to manually close the upstream flow control valves, FV-20527 and FV-20528. Operators closed FV-20528, FV-20527 was stuck open. In an effort to reduce auxiliary feedwater flow the operator attempted to close FWS-063 with a large cheater. The valve remained stuck open.

SUP94ARY OF INFORMATION SUPPORTING PROBABLE CAUSE:

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) FWS-063 and FWS-064 are manually operated Velan pressure seal forged gate

] valves 6" in diameter rated for 900 psig service. Velan Engineering Companies Instruction Manual, VEZ-PS-3, applies to these valves. The Velan Manual i

l l states that excessive handwheel effort can indicate the following:

a. Improperly lubricated or damaged valve stem. l
b. Valve packing glad too tight.

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c. Faulty or damaged valve parts.

Based on maintenance history and vendor manual recommendations the following is l

i a list of probable causes for the FWS-063 failure:

a. Failed yoke nut bearing.
b. Valve packing to tight.

. c. Lack of stem / bearing / packing lubrication

d. Failed valves internals.

I 8605160356 860306 i PDR ADOCK 05000312 S PDR

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  • TROUBLESHOOTING ACTION PLAN (continued)

REVIEW OF MAINTENANCE, SURVEILLANCE TESTING AND MODIFICATION HISTORY:

A review of maintenance history shows no maintenance has been performed on l

FWS-063 during the operational life of the plant.

I A maintenance history review of valves similar to FWS-063 was performed for

, the following valves. These manual valves are not covered in the present i Preventive Maintenance program. All of the valves are maintenance valves i and are locked open ASME XI Class E valves. No regular testing require-f ments are imposed on Class E locked valves.

t i FWS-064 AFW to B OTSG Manual Isolation l FWS-053 P-318 Pump Discharge Valve t

FWS-054 P-319 Pump Discharge Valve FWS-119 AFW from P-319 Isolation to OTSG B i FWS-120 AFW From P-318 Isolation to OTSG A

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The attached work request history summary sheet details all documented work on

the above valves. Two valves, FWS-064 and FWS-053, have had failures of the

[ yoke nut bearings causing the valves to stick in the open position. .

POTENTIAL ROOT CAUSE(s):

Theprimary.probablevalvefailurecauskisthefailedyokenutbearing.

Based on this primary hypothesis tne potential root cause is improper lubrication.

h Other potential root causes are improper valve packing maintenance, damaged valve

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stem or faulty or damaged valve parts.

OUTLINE OF TROUBLESHOOTING PLAN:

The scope of this plan extends to only the yoke nut bearing and valve packing.

Based on the history of the similar valves this plan will concentrate on the -

yoke nut bearing.

I The objective of the troubleshooting plan is to find the root cause and correct the problem. The instructions for both FWS-063 and FWS-064 are identical.

1. Document as found conditions of the valve operator (limit to those conditions which can be recorded without changing conditions). Take photographs to assist in the documentation.
2. Attempt valve closure - measure closure torque (breakaway)

! (maximum 333 ft-lbf )  ;

) 3. Measure closing torque (if valve is free to move).  ;

'I 4. Compare closing torque with design maximum.

] 5. Disassemble yoke nut assembly.

j 6. Inspect yoke nut bearing. .

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TROUBLESHOOTING ACTION PLAN (continued)

6. Determine root cause from evidence.

! 7. Replace yoke nut bearing per Manufacturers Inst'uction r Manual

8. Reassemble yoke nut housing per Manufacturers Instruction Manual l 9. Stroke valve and check operation of valve.

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10. Repack valve and lubricate stem.

! 11. Stroke valve and check operation of valve.

{ 12. Revise Troubleshooting Action Plan if required.

13. Perform breakaway torque measurement and fullstroke of valves FWS-053/054/119/120 I .

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J APPROVED BY: DATE:

Action List Coordinator-SMUD h

j RELEASED FOR IPFLEENTATION BY:

i A .

1 DATE:

Action List Coordinator-SMUD .

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_ -m i WORK REQUEST HISTORY FWS-063 DATE REQUEST WORK PERFORMED 1

7/13/77 Clean stem and replace WR voided packing l 7/20/77 Clean stem and replace WR voided i packing

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7/25/77 Clean stem and repack WR voided I FWS-064 h

12/13/74 Packing leak Adjusted packing 3;i 5

7/13/77 Clean stem and replace WR voided packing 2/20/80 Valve will not close Replaced operator bearings, manually frozen in open did not open up system position.

t 2/2/83 Packing leak -

. Void duplicate WR -

l t 2/5/83 Tighten packing before Adjusted packing and stroked.

secondary side hydro FWS-053 11/20/79 Can't stoke valve closed Inspected valve, disassembled upper manually per SP 210.01A yoke bearing group.

Noted rust & seized thrust bearing &

bushings. Cleaned and dressed bearing registers and bushing. Installed new thrust bearing, packed assembly with grease and reassembled yoke. Stroked satisfactory.

FWS-054 None

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j FHS-119 None FWS-120 1

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