ML20155H706
| 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) | |
Text
_
(
i -
g
{ $. 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:
j l
) 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.
1
- 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
>l L__ ._
y- - w n --
.-. . . . _ ~ -
~~.w- ~-
T . , _ . .
I
- 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
(
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
]
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. .
l f
i a
h- -
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.
Y
- 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 .
1 i
J APPROVED BY: DATE:
Action List Coordinator-SMUD h
j RELEASED FOR IPFLEENTATION BY:
i A .
1 DATE:
Action List Coordinator-SMUD .
1 i
+ . .
_ -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
.l f
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
)
j FHS-119 None FWS-120 1
None l
l
. i l
l 1
m ;