ML20213D460
| ML20213D460 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Sequoyah |
| Issue date: | 10/31/1986 |
| From: | Mills W, Murphy M, Russell J TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML082401853 | List: |
| References | |
| 301.11-SQN, 301.11-SQN-R, 301.11-SQN-R00, NUDOCS 8611120110 | |
| Download: ML20213D460 (9) | |
Text
y, s'
TVA EMPLOYEE CONCERNS REPORT NUMBER: 301.11-SQN SPECIAL PROGRAN REPORT TYPE: Sequoyah Nuclear Plant Element REVISION NUMBER: 0 TITLE: Valve Closure Problems REASON FOR REVISION:
Revision 0 Initial Issue PREPARATION PREPARED BY:
10/22/86 W. R. Mills SIGNATURE DATE REVIEWS PEER:
, ///rf$ h M E5 fb
' DNfE
/ [ SIGNATURE TAS
[8
-~
SIGNATURE DATE CONCURRENCES (0-Z'5-3 d CEG-H: k) q~-
- N ' b SRP; W
8 DATE SIGNATURE DATE G
SIGNATURE
- APPROVEDBY'Ah 1V S p-w a ala ECSP MANAGER DATE MANAGER OF NUCLEAR POWER DATE CONCURRENCE (FINAL REPORT ONLY)
- SRP Secretary's signature denotes SRP concurrences are in files. 2019T 8611120110 861105 PDR ADOCK 05000259 P
TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT EMPLOYEE CONCERNS TASK GROUP OPERATIONS CEG Subcategory: Mechanical Equipment Reliability / Design Element: Valve Closure Problem Report Number: 301.11 - SQN i
IN-85-400-OO1 Evaluator:
U. k,
/O!2!Ob W. Mills /
Date
/o!
fl.
Reviewed by:
/0
!7[
Approved by:
'D tae W. R. Lagerpre n 1632T
- -. ~,,, - - - -
,,.---,p p
.._-.,.ym._.
,.3
.._---,-,-,----,------x-.,
u.,...:
t o
I.
VALVE CLOSURE PROBLEM The This evaluation report addresses employee concern IN-85-400-001.
scope of this report is limited to the evaluation of the possible incomplete closure of flow control valves and automatic open/close valves, and the possible effects of partially open valves allowing leakage during routine / emergency maintenance activities that require total or partial system isolation.
II.
SPECIFIC EVALUATION METHODOLOGY The concern, as stated on the K-Form, reads as follcws:
Generic Concern - Flow control valves and automatic IN-85-400-001 open-close valves in unit 1 & 2 (RHR, SIS, CVCS and RC) do not completely close to prevent flow of water.
CI is concerned Average closure was expressed as 98%.
that this could be detrimental to plant operation and personnel safety, particularly af ter nuclear operations For example: instances where routine / emergency begin.
maintenance activities may require total or partial system isolation. Concern is generic in nature, with no further specifics available.
This evaluation reviewed the K-Form, maintenance instructions (mis),
surveillance instructions (sis), IE bulletins, vendor correspondence, DPM sections of the FSAR, NQAM, and the SQN Technical Specifications.
N75M1, which identifies vendor and Nuclear Central Office recommendations for torque and limit switch settings, and 10 CFR 50, These reviews were conducted to ensure Appendix J were also reviewed.
regulatory requirements relating to leak rate limits are implemented properly at SQN.
Interviews were conducted with personnel from the Mechanical Test the Electrical Maintenance Group, and the Application
- Group, Engineering Group.
III.
FINDINGS The concerned individual (CI) stated that the flow control valves A.
and automatic valves do not completely close to prevent flow of water.
This evaluation has determined that SQN has an extensive valve One requirement is to perform a seat leakage test testing program.
A review of the FSAR, on designated valves during refueling.
Section 6.8 (Reference 15), gives valve descriptions in accordance with the January 1978 "NRC Staff Guidance for Preparing Pump and Valve Test Program Descriptions and Associated Relief Requests Pursuant to 10 CFR 50.55a(g)." This NRC Staff Guidance provides guidance for preparation of valve testing programs for compliance with ASME Boiler and Pressure Vessel Code,Section XI.
Page 1 of 6 4
[
Leak rate limits will be established by the licensee in accordance with 10 CFR 50, Appendix J.
SQN Technical Specifications, 4.6.1.2.d, 4.6.1.2.e, 4.6.1.2.g, and 4.6.3.4 (Reference 16), are the plant documents that commit the plant to ASME Boiler and Pressure Vessel Code,Section XI, and 10 CFR 50, Appendix J SQN procedures SI 158.1 (Reference 6) and TI-58 (Reference 17) are the plant procedures that implement leak testing of the designated valves. SI 158.1 (Reference 6) measures the leakage rate for the containment isolation valves listed in the FSAR and TI-69 (Reference 9). TI-58 (Reference 17) gives general directions for measuring the leakage rate of other valves not covered by SI-158.1 (Reference 6).
Two Residual Heat Removal (RHR) containment isolation valves that are NOT leak tested by SI 158.1 (Reference 6) are FCV-74-1 and FCV-74-2.
SI-166.18 (Reference 18) is used to leak test these valves. The RHR valves are always closed during normal operation and are open only when the reactor is in modes 4, 5, and 6.
Additionally, two Upper Head Injection (UHI) valves, FCV-87-7 and FCV-87-8, are leak-tested not only in accordance with SI 158.1 (Reference 6) but also by SI 166.34 (Reference 19).
B.
The CI expressed that the average closure was 98 percent.
Based on interviews and the various documents reviewed, it was determined that some limit switches are set at 98 percent closure to prevent damage to the valves. Setting the limit switches above 98 percent may result in valve damage because of the amount of over travel by the valve after power is removed from the motor.
Setting the limit at 98 percent closure allows some valves to seat by the overtravel, via momentum of the valves. Other valves use the limit switch for indication only and rely on a torque switch to de-energize the valve operator af ter full closure is achieved.
On high-speed valves (i.e., 8 inches per minute for globe valves, 18 inches per minute for gate valves, 36 inches per minute for all other valves), it may be necessary to reduce the amount of over-travel due to the inertia of the actuator and valve's moving parts. This is done by setting the limit switches to open at less than 98 percent, in accordance with DPM N75M1 (Reference 1).
The Nuclear Regulatory Commission (NRC) initiated IE Bulletin No. 85-03 (Reference 11) requesting licensees to develop and implement a program to ensure that switch settings on certain safety-related motor operated valves (MOVs) are selected, set, and maintainod correctly to accommodate the maximum differential pressure expected during both normal and abnormal events within the design basis.
Sequoyah implements these program requirements in accordance with DPM N75M1 (TS-04.02.06.14.02, Reference 1), in Maintenance Instruction MI 11.2A, B, C, D (Reference 13), and MI 10.43.
MI 11.2 sets guidelines for adjustment of the MOVs and MI 10.43 (Reference 12) is the procedure for testing of MOVs using the MOVATS-2000 system.
Page 2 of 6
DPM N75M1 gives the general requirements for the torque and limit switch settings for MOVs.
DPM N75M1 states: On valves where the limit switch is parallel with the torque switch, the close limit switch shall be set to open the contacts at 97 to 98 percent travel of the stem by physical measurement, but this alone will not stop the valve movement.
Valve travel will continue and valve seating will be ensured by the parallel torque switch. On valves where the limit switch is in series with the torque switch, the close limit switches shall be set to open the contacts at 97 to 98 percent travel of the stem by physical measurement, this will de-energize the valve motor and allow its momentum to fully close the valve..
The torque switch shall be used for protection against a failed limit switch or friction overloads.
C.
The CI stated that incomplete closure of valves could be detrimental to plant operation and personnel safety.
Administrative Instruction AI-3, " Clearance Procedures," is used by the Sequoyah Nuclear Plant to ensure the protection of workmen, the public, and equipment. This procedure contains essential basic information concerning types of clearance and protective tags needed to partially or totally isolate a system during routine or emergency maintenance activities. Within this AI is the requirement to manually isolate the clearance boundary, depressurize and drain the system to ensure leakage is minimized and hence limit radiation exposure.
To ensure plant operation and personnel safety during nuclear operation and maintenance activities, Health Physics provides full-time monitoring for the breaching of radioactive systems in accordance with RCI-14 (Reference 20) and through Section Instruction Letters (Reference 21). These procedures prevent personnel from exceeding the allowable amount of radiation during nuclear operation and maintenance activities.
From the review of the test results for SI-158.1 (Reference 6) and the data summary sheet of SI-160 (Reference 22), which tabulates the total leakage in containment, the leakage rates of the isolation valves comply with the requirements of 10 CFR 50, Appendix J, ANSI N45.4-1972, and ASME Boiler and Pressure Vessel Code,Section XI, for the overall leakage.
Also, the test results for SI-166.18 and SI-166.34, the leakage rates of these valves comply with the requirements of ASME Boiler and Pressure Vessel Code,Section XI.
These test results ensure minimum leakage to limit exposure during plant operation and maintenance activities.
The total leakage from all testable paths shall be equal to or less than 60 percent of the maximum allowable leakage rate as stated in SI-160.
SI-166.18 (Reference 18) and SI-166.34 (Reference 19) verifies that the leak rate of the valves corrected to 2235 psig is less than or equal to 1 gpm as required by Technical Specification LCO 3.4.6.2.
Page 3 of 6
I Conclusion These findings indicate that the limit switches on some motor operated valves are set at 97 to 98 percent closed. This does not present a condition detrimental to plant operations or personnel safety.
SI-158.1, SI-166.18, and SI-166.34 data packages shows that leakage is kept at a minimum for the containment isolation valves.
Administrative and Health Physics instructions ensure plant operation and personal safety during any breaching of a system during maintenance or any other activities done on a For the above reasons, this concern is determined to be system.
not valid.
Based on the findings presented above, there are no nuclear safety-related issues.
IV.
ROOT CAUSE Since the concern was determined to be not valid, there is no identifiable root caused deficiency.
Based on the findings it appears that the CI was not knowledgeable of the reasons for the limit switch settings.
V.
GENERIC APPLICABILITY This concern was generic at the K-Form level. However, this concern and issue is now considered not generic to other TVA nuclear sites.
VI.
REFERENCES 1.
DPM No. N75M1 (TSO4.02.06.14.02) - Torque and Limit Switch Setting For Motor-Operated Valves, dated August 1, 1985 2.
Standard Practice SQO23 - Small Valve Electric Motor - Driven Actuators, RO, dated May 4, 1983 t
3.
Limitorque Type SMB Instruction and Maintenance Manual (Contract 820509-1)
Assessment of Motor - Operated Valve Failures INPO Report 83-037, 4.
dated October 1983 Surveillance Instruction 166.6 - Post Maintenance Testing of 5.
Category A and B Valves, R8 Surveillance Instruction 158.1 - Containment Isolation Valve Leak 6.
Rate Testing, R25 Page 4 of 6
-...~:
7.
Limitorque Type HBC Instruction Manual (Contract 829681)
J 8.
SQM62 - 10 CFR 50.49 Program, R3, dated July 3, 1986 9.
TI Summary of Pre-And Post-Maintenance Valve Tests for ASME Section XI and 10 CFR 50.49 Appendix J, RS, dated January 22, 1986 10.
Technical Specification 3/4.6.3 - Containment Isolation Valves, dated January 29, 1986 11.
IE-Bulletin No. 85 Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings, dated November 15, 1985 12.
MI-10.43 - Procedure for Testing of Motor-Operated Valves using the Movats 2000 System, R4 13.
MI-11.2A, 8, C, D - Limitorque Actuators Corrective Maintenance Procedure, R2 14.
AI Clearance Procedure, R31 15.
SQN FSAR, Section 6.8 - Pump and Valve Inservice Inspection Program, R3 16.
Technical Specifications 4.6.1.2 d,e, 4.6.1.29 and 4.6.3.4, Primary Containment Integrity, dated January 29, 1986 17.
TI Leak Rate Measurement, R6 18.
SI 166.18 - RHR Return Valve Leak Rate Test, R14 19.
SI-166.34 - UHI Pressure Isolation Valve Leak Rate Test, R4 20.
RCI Radiation Work Permit Program, RS 21.
Health Physics Section Instruction Letters 1-37, RO 22.
SI-160 - Primary Containment Local leak Rate Summary R3 NPDCS Cartridge Frame 23.
SI-166.34 Data Sheets:
702 1955 621 0450 441 3744 440 0773 602 & 603 24.
SI-166.18 Data Sheets:
794 702 1930 & 1931 2597 & 2598 587 544 4042 & 4043 509 2534 & 2535 Page 5 of 6
........ - - ~... _
NPOCS Cartridge Frame 24.
SI-166.18 Data Sheets:
451 1642 & 1643 (continued) 368 0525 & 0526 320 1025 & 1026 254 774 & 775 221 408 & 409 221 402 & 403 186 2560 & 2561 164 2048 & 2049 146 1534 & 1535 25.
SI-160 Data Summary Sheet:
733 2431 750 3601 778 2877 794 221 806 3580 817 2906 702 1617 26.
SI 158.1 Data Package: Unit 1 - August 26, 1985 Unit 2 - February 10, 1986 VII.
IMMEDIATE OR LONG TERM CORRECTIVE ACTIONS Based on the findings of this evaluation, this invalid concern does not require any corrective actions for plant operations or personnel safety.
l t
i-i l
Page 6 of 6 l
i
,, + -, - - - - -, - - -.,. -.. ~. - - - -.. - -,,.. - _ - _, - - - -. - - - -.. - - _ - - - -,
.---.-----,-.-,-,,-n.
it 187 PATE TENNESSEE VALLEY AUTHORITY RUN TIME - 12:19:18 FERENCE
- ECPS120J-ECPS121C OFFICE OF NUCLEAR P0HER RUN DATE - 10/05/86 EQUENCY
- REQUEST EMPLOYEE CONCERN PROGRAM SYSTEM (ECPS)
P - 1555 - RHM LIST OF EMPLOYEE CONCERN INFORMATION EGORY: OP PLANT OPER. SUPPORT SUBCATEGORY: 30111 VALVE CLOSURE PROBLEM KEYHORD A S
GENERIC KEYHORD B H
APPL QTC/NSRS P
KEYHORD C f
CONCERN SUB R PLT BBSH INVESTIGATION S
CONCERN KEYHORD D NUMBER CAT CAT D LOC FLQB REPORT R
DESCRIPTION NS GENERIC CONCERN-FLON CONTROL VALVES P0HER 400-001 OP 30111 N H5N NNYY AND AUTOMATIC OPEN CLOSE VALVES IN MAINTENANCE
?
K-FORM UNIT 182 (RHR, SIS,CVCS&RC) DO NOT CO PIPING E
FITTINGS
[
T50013 MPLETELY CLOSE TO PREVENT FLOH OF HA TER.
AVERAGE CLOSURE HAS EXPRESSED y
AS 98%.
CI IS CONCERNED THAT THIS C l
OULD BE DETRIMENTAL TO PLANT OPERATI L
ON AND PERSONNEL SAFETY, PARTICULARL Y AFTER NUCLEAR OPERATIONS BEGIN FOR f
EXAMPLE: INSTANCES HHERE ROUTINE /EM ERGENCY MAINTENANCE ACTIVITIES MAY R i
EQUIRE TOTAL OR PARTIAL SYSTEM ISOLA TION. CONCERN IS GENERIC IN NATURE,
'{
HITH NO FURTHER SPECIFICS AVAIL 1
1 CONCERNS FOR CATEGORY OF SUBCATEGORY 30111 t
9 e
G e
,e T C7