ML20205Q235
| ML20205Q235 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/14/1986 |
| From: | Knester G, Koester G KANSAS GAS & ELECTRIC CO. |
| To: | Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-85-003, IEB-85-3, KMLNRC-86-091, KMLNRC-86-91, NUDOCS 8605280220 | |
| Download: ML20205Q235 (9) | |
Text
s KANSAS GA ' AND ELECTRIC COMPANY THE ELECTAC COMPANY GLENN L MOESTER veCE Pets otmer. seveteam May 14, 1986 Mr. R. D. Martin, Regional Administrator g ) 9 \\986 %i U.S. Nuclear Regulatory Ccmnission V
ih lI Region IV 611 Ryan Plaza nrive, Suite 1000 Arlington, Texas 76011 U.S. Nuclear Regulatory Connission Document Control Desk washington, D.C. 20555 KMLNRC 86-091 Re:
Docket No. STN 50-482 Subj:
Response to Bulletin 85-03 Gentlemen:
The purpose of this letter is to provide a response for Wolf Creek Generating Station (WCGS) to the subject Bulletin advising holders of nuclear power reactor operating licenses or construction permits of events in which motor-operated valves (MOV) failed on danand, in a cmmon mode, due to irrproper switch settings.
The Bulletin requested licensees to develop program to ensure that switch settings on certain safety-and implement a related motor-operated valves are selected, set, and maintained correctly to acconmodate the maximum differential pressures expected on these valves during both normal and abnormal events within the design basis. Action e in Bulletin 85-03 requires that, within 180 days of the date of the Bulletin, the licensee subnit a' written report to the Nuclear Regulatory Conmission (NRC) that:
(1) reports the results of item a and (2) contains the program to accomplish items b through d including a schedule for completion of the items.
requires the licensee to review and document the design basis for Action a each motor-operated valve in the high pressure coolant injection / core spray and emergency feedaater systems that are required to be tested for operational readiness in accordance with 10 CFR 50. 55a (g), develop and 8605280220 860514 PDR ADOCK 0D000482
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201 N. Market - Wictuta, Kansas - Mail Address: RO. Box 208 I Wichita, Kansas 67201 - Telephone: Area Code (316) 2616451
P Mr.'R. D. Martin KMLNRC 86-091 Page 2 May 14, 1986 inplement a program to ensure that valve operator switches are selected, set and maintained properly.
This docmentation should include the maximum differential pressure expected during both opening and closing the valve for both normal and abnormal events.
For each motor operated valve in the high pressure coolant injection system and the auxiliary feedwater system, Table 1 and Table 2 give the valve description, the valve number, the design equipment specification differential pressure for opening and closing the valve, the maximum operating differential pressure for opening and closing the valve, a
justification for the maximum operating differential pressure, and confirmation of operating assumptions by a Westinghouse Dnergency Response Guideline (ERG) survey.
The maximum operating differential pressure represents the maximum pressure producing capability of the system equipment for the system operating modes.
Maximum operating differential pressures were developed for both open and close operations of each MOV.
For each differential pressure a justification is given based on system configuration and equipment constraints.
These maximum operating differential pressures were compared against the valve design equipnent specification differential pressure to verify adequate design. Finally, the ERG survey determined when the selected MOVs are required to function for emergency operation.
The ERG survey identified other inportant characteristics of the system operation which impact the MOVs capability to function. Therefore, the ERG Survey provided a check of current ERG operations against the original fluid systems design assumptions for MOV operating modes.
A yes appears in the
" ERG Confirmation" colm n if the ERGS and the fluid system assumptions are consistent.
We operating differential pressures in Table 1 and Table 2 are for off-normal situations.
We auxiliary feedwater and high pressure coolant injection systems generally function during off-normal situations where either emergency feedwater is needed or safety injection flow is required.
Even though these two systems have normal operative functions, the maximum operating differential pressures for motor-operated valves in these sytems bound any pressure differential condition which may be encountered during normal operation.
A schedule for implementing action items b though d in Bulletin 85-03 is included in Table 3.
To acconplish item b,
the design equipment specification differential pressures were used to establish the correct switch settings for each MOV.
Additional information will be obtained from the valve and motor-operator manufacturers to help verify that the switch settings are correct.
Once the correct switch settings are
- verified, each setting will be checked in the field and changed, as appropriate,
Mr.-R. D. Martin 10ERRC 86-091 Page 3 May 14, 1986 to those established in item b.
The valve will be demonstrated operable by testing the valve at the maximum differential pressure with the exception that testing motor-operated valves under conditions simulating a break in the line containing the valve is not required..
Justification will be provided for any cases in which this testing cannot practically be performed. To accomplish item d, procedures will be in place to' ensure that correct switch settings are determined and maintained throughout the life of the plant.
Upon completion, a written report will be subnitted to provide a suranary.of data and findings of this program.
If you have any questions concerning please contact me or Mr. O. L.
Maynard of my staff.
Very truly yours, N
do Glenn L. Koester Vice President - Nuclear GLK:see cc: PO'Connor (2)
JCumnins i
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Mr. R. D. Martin May 14, 1986 Attachment I to KMIERC 86-091 Page 1 of 6 TABLE 1 HIGi PRESSURE CDOUNr IlUICTIN SYSTEM VALVE DIFFERENTIAL PRESSURES Maxinum ERG Design Operatirn Justification Confirmation (E-SPEC) AP AP for Max of Operating MOV Valve Number Close Open Close Open Operating 6P Assunptions Safety Injection 8806 A&B 200 200 200 50 Open-2 Yes Ptmp Suction Close - 1 fra WST Safety Injection 8923 A&B 200 200 200 50 Open - 2 Yes Pump Suction Close - 3 from WST CVCS Punp Suction IIV-ll2 D&E 200 200 200 50 Open - 4 Yes from WST Close - 4 CVCS Ptmp suction Irv-112 B&C 100 200 100 100 Open - 5 Yes frm VCr Close - 5 SI Punp 8821 A&B 1500 1500 1500 1500 Open - 15 Yes Cross-Connect Close - 14 SI Punp Discharge 8835 0
2750 0
1750 Open - 7 Yes Isolation Close - 6 CVCS Nornal 8105 2750 2750 2750 2750 Open - 8 Yes Discharge 8106 Close - 8 Isolation BIT Inlet 8803 A&B 0
2750 0
2750 Open - 9 YES Isolation Close - 16 BIT Outlet 8801 A&B B
2750 0
2750 Open - 9 YES Isolation Close - 16 SI Ptmp Miniflow 8813 2750 2750 1750 1750 Open - 11 Yes 8814 A&B Close - 10 CVCS Ptmp 8110 2750 2750 2750 2750 Open - 13 Yes Miniflow 8111 Close - 12
Mr. R. D. Martin May 14, 1986 Attachment I to KMLNRC 86-091 Page 2 of 6 JUSTIFICATION FOR TABLE 1 1.
This valve must be able to close to isolate the RNST from the discharge of the RHR pumps during the recirculation mode of operation, as a precautionary measure in the event of backleakage through check valve 8926A (or B).
For this scenario, the differential pressure across 8806A (or B) could be as high as the RHR pump discharge head of approximately 200 psig.
2.
This valve is normally open, and is closed only for stroke testing and/or pump isolation for maintenance. The valve must be able to open against a full RNST head of water. This is approximately 50 psig.
3.
This valve must be capable of isolating (closing) one high head safety injection pump, given a passive failure in that train of TCS.
For this scenario, the differential pressure across 8923A or B could be as high as the RHR punp discharge head of approximately 200 psig.
4.
Same as 8806A, B (for both close and open), except these valves are in the suction of the centrifugal charging pumps and not the high head safety injection pump.
5.
These valves must close on an "S" signal; the maximum differential pressure across the valve is defined by the volone control tank at its design pressure (relief valve setpoint) of 75 psig plus elevation head of the VCT above the valves.
This is estimated to be approximately 100 psig.
6.
Valve is only closed when pump is not operating; no flow and no differential pressure.
7.
Punp testing on miniflow circuit, differential pressure is determined by the miniflow head of high head safety injection pump (appproximately 1750 psig).
8.
These valves must be able to isolate the RCS from the CVCS, with a maximum possible differential pressure of approximately the shutoff head of the centrifugal charging pumps.
9.
Given a miniflow test of the centrifugal charging pumps, the BIT isolation valves must be able to open with a differential pressure approximately equal to the charging pump shutoff head.
10.
Valves must close to isolate miniflow so that high pressure injection switchover to recirculation may proceed.
In the worst case, the differential pressure will be equal to the pump developed head on miniflow (approximately 1750 psig).
Mr. R. D. Martin' May 14, 1986 Attachment to KMLNRC 86-091 Page 3 of 6 11.
Similar to 10, except valve must be able to open during miniflow testing of the high head safety injection punp.
12.
Valves must close to ensure adequate high pressure injection flow (on "S"
signal) against miniflow differential pressure (approximately 2750 psig).
13.
Similar to 12, except valve must be able to open during miniflow testing ~..
14.
Must be able to move to allow realignment of BJCS to recirculation mode, and for EOCS train separation.
Differential pressure could be as high as 1500 psig (approximately equal to miniflow head of high head safety injection pump).
15.
Must be able to open to allow train separation during the recirculation phase of EOCS operation.
Differential pressure same as closing.
16.
We ERG guidelines to teminate safety injection (isolate the BIT) and I-return to normal charging are performed with the centrifugal charging pumps operating.
This termination method reduces net ICS makeup in a i
controlled manner _ and maintains continuous reactor coolant pmp seal l
l injection.
Since the charging punps are operating, the BIT isolation valves must close against a differential pressure.. This differential pressure could be large for some SI termination scenarios (RCS could be as low as 200 psi - differential pressure could be as high as 2500 psi).
mis is not a safety concern because the~ valve's safety function is to open on a safety injection signal.
If these valves need to be closed and can't because of the differential pressure, the charging punps can be stopped to acconplish this task.
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Mr. R. D.. Martin May 14,' 1986 Attachment I to XMENRC 86-091 Page 4 of 6 TABEJC 2 AUKILIARY FEEDRTER SYS'1TM VALVE DIFFERElfrIAL PRESSURES Maximum ERG Design Operating Justification Validation (E-SPEC) AP AP for Max of Operating MOV Valve Ntznber Close Open Close Open Operating 6P Assunptions
?
Motor-Driven IN-5, 7, 9, 11 1800 1800 1645 1645 Open - 1 Yes Purrp Discharge Close - 1 Flow Control Mechanical Trip HV-312 1275 1275 1220 1220 Open - 2 Yes and Throttle Close - 2 Suction from IW-34, 35, 36 150 150 17 17 Open - 3 Yes CST - All Ptznps Close - 3 Suction from HV-30, 31, 32, 33 200 200 180 180 Open - 4
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Yes Essential Close - 4 r,
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a Mr. R. D. Martin May 14, 1986 Attachnent to KMLNRC 86-091 Page 5 of 6 JUSTIFICATIONS FOR TABLE 2 1.
Motor driven punp discharge head at miniflow.
2.
Iowest steam generator safety valve set presssure plus 3 percent accumulation.
3.
Static elevation head of the condensate storage tank.
4.
Discharge head of the service water punps at miniflow.
5.
Discharge head of the turbine-driven pump at miniflow, adjusted to account for the nnximum pump overspeed condition during startup.
1
p-Mr. R. D. Martin May 14, 1986 Attachment to KMLNRC 86-091 Page 6 of 6 TABLE 3 SCHEDULE FOR COMPLETION OF MOTOR-OPERATED VALVE PROGRAM Task Scheduled Cmpletion 1.
Review and doctanent design basis for 4/22/86 motor-operated valve 2.
Written report for item a 5/14/86 3.
Establish correct switch settings 10/1/86 4.
Check current settings against those 12/1/86 calculated for item b and change any differences 5.
Test valves in accordance with item c 6/1/87 l
6.
Have procedures to maintain correct 11/1/87 switch settings L
7.
Subnit final report 11/15/87 l
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