ML17326B228
| ML17326B228 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 05/16/1986 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| AEP:NRC:0966, AEP:NRC:966, IEB-85-003, IEB-85-3, NUDOCS 8605270226 | |
| Download: ML17326B228 (27) | |
Text
INDIANA8 MICHIGAN ELECTRIC CONPANY P.O, BOX 16631 COLUMBUS, OHIO 43216 May 16, 1986 AEP:NRC:0966 Donald C.
Cook Nuclear Plant Unit Nos.
1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
RESPONSE
TO IE BULLETIN NO. 85-03 Mr. James G. Keppler, Regional Director U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr. Keppler:
This letter and its attachment respond to Mr. James M. Taylor's letter of November 15, 1985 entitled "IE Bulletin No. 85-03:
Motor-Operated Valve Common Mode Failures During Plant Transients due to Improper Switch Settings."
The attachment to this letter contains a status report which addresses the preliminary information requested in the bulletin under part (e) of "Actions for All Holders of Operating Licenses or Construction Permits."
Me plan to perform the actual valve testing during the next refueling outage and/or subsequent startup for each unit.
Furthermore, we anticipate forwarding to you, within 60 days of completion of the entire program, a
written report which summarizes these activities.
Should unforeseen problems significantly change this schedule, we will notify you accordingly.
Currently, refueling outages are scheduled in April 1987 for Unit 1 and in February 1988,for Unit 2.
Since the completion of testing for Unit 2 will exceed the two-year deadline of November 15, 1987 called for in the bulletin, we are requesting relief from this requirement.
Very truly yours, M.. Ale ich'f.
Vice President'4P MPA/rjn Attachment
Nr. James G. Keppler AEP:NRC:0966 cc:
John E. Dolan W.
G. Smith, Jr.
- Bridgman R.
C. Callen G. Charnoff G.
Bruchmann NRC Resident Inspector
- Bridgman
ATTACHMENT TO AEP:NRC:0966 II STATUS ORT IMPLEMENTATION PLAN TO ADDRESS IE BULLETIN 85-03 FOR THE DONALD C.'COOK NUCLEAR PLANT UNITS 1 AND 2
0
ATTACHMENT TO AEP:NRC:0966 TABLE OF CONTENTS I.
BACKGROUND II.
STATUS REPORT III.
TABLES IV.
TABLE JUSTIFICATIONS V.
FIGURES
ATTACHMENT TO AEP:NRC:0966 On November 15,
- 1985, the NRC Office,of Inspection and Enforcement issued IE Bulletin 85-03, "Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings."
The purpose of the bulletin was to "request licensees to develop and implement a program to insure that switch settings on certain safety-related motor-operated valves (MOVs) are selected, set and maintained correctly to accommodate the maximum differential pressures expected on these valves during both normal and abnormal events within the design basis."
The bulletin originates, in part, from the Davis-Besse event of June 9,
1985.
During this event, normally open motor-operated auxiliary feedwater valves failed to reopen on either an automatic or manual signal from the main control room after they were inadvertently closed during the event.
Subsequent troubleshooting activities at Davis-Besse after the event concluded that the cause of the MOV failures was improper settings of the torque bypass switch in each valve's control circuit Bulletin 85-03 focuses on the MOVs in two systems:
the high pressure coolant injection system and the emergency feedwater system.
The bulletin requires the following six actions:
(a)
(b)
Determine the maximum differential pressure across the subject MOVs.
Document the valve design basis.
Using the differential pressures from (a), establi'sh the correct motor operator switch settings.
(c)
Demonstrate valve operability by testing the valve at maximum differential pressure, where.feasible.
Where not feasible, provide justification.
(d)
Revise the switch setting procedures, as necessary.
(e)
Submit a written report documenting (a) and containing a program schedule to address (b) through (d).
(f)
Submit a final report upon program completion.
The purpose of this letter is to provide a status report as requested in action (e) of the bulletin.
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ATTACHMENT TO AEP:NRC:0966 II.
Status Re ort (a)
For the D.
C.
Cook Nuclear Plant, the following system perspectives were used to identify those motor-operated valves (MOVs) to be addressed in this program.
The MOVs included for the high pressure coolant injection (HPI) system were identified as follows:
1.
MOVs in those portions of the Emergency Core Cooling System (ECCS) down to but not including the accumulator injection system.
Safety injection (SI) and Chemical and Volume Control System (CVCS) are included; residual heat removal (RHR) is not included.
2.
MOVs in those portions of the above included systems necessary to establish flowpaths from the Refueling Water Storage Tank (RWST) to the Reactor Coolant System (RCS).
3.
MOVs in only those portions of the ECCS required during the cold leg injection phase, up to but not including the transfer to recirculation injection from the containment sump after the RWST empties.
The MOVs included for the Emergency Feedwater
- System, termed the Auxiliary Feedwater (AFW) System at the Cook Plant, were identified as follows:
1.
MOVs used to establish a flowpath from the AFW safety-grade water source (or its backup) to the steam generators.
2.
MOVs used to establish a steam delivery flowpath to the AFW turbine to enable turbine-driven AFW pump to start.
The specific valves identified using these perspectives are noted in Tables I and II which follow. Justifications for the maximum operating differential pressures and figures which locate the valves on various system schematics are also included for further clarity.
(b)
Based on the results of action (a), it original design torque switch settings for setting all affected switches will necessary, to ensure that all switches was concluded that the are valid.
Plant procedures be reviewed and revised, if are set correctly.
(c)
Each valve will be stroke-tested, to the extent practical, to verify that the setting determined from action (b) has been properly implemented, even if testing with differential pressure cannot be performed.
Where necessary to accomplish the objective of this
- test, procedures will be developed and implemented to stroke-test the appropriate valves at the highest practical differential pressure.
The testing of each valve will be evaluated on an individual basis to weigh the consequences of failure against the practical difficulties of the test.
In those cases where practical
ATTACHMENT TO AEP:NRC:0966 and where consequences of valve failure are high, stroke-testing at the highest practical differential pressure will be incorporated into periodic surveillances.
For the remaining valves, this stroke test will be a one-time test.
ln those cases where testing cannot be reasonably performed at the maximum differential pressures identified in item (a), justification for such cases will be documented with an alternative method for verifying the correct switch settings.
(d)
Procedural controls for setting switches are currently in place.
The design torque switch settings have been reviewed and determined to be correct.
Existing plant procedures for setting motor operator switches will be reviewed, and where appropriate procedural enhancements will be added.
Furthermore, an evaluation of state-of-the-art MOV testing systems will be performed and an appropriate test system will be chosen.
Procedural revision will be completed to accommodate the test system selected prior to the next refueling outages (1987 for Unit 1 and 1988 for Unit 2).
The actual valve testing will be performed during the 1987 (Unit 1) and 1988 (Unit 2) refueling outages or their ~~bsequ~nt startups.
ATTACHMENT,TO AEP:NRC:0966 III. TABLES These tables present the details requested in action (a) of IE Bulletin 85-03.
The tables include the valves involved as well as their respective differential pressures.
The justifications noted for the maximum operating differential pressures are explained in the Table Justifications section of this report.
Table I Table II HPI Valve delta Ps AFW Valve delta Ps
0 I
~ I
TABLE I HPI VALVE aPS Design P
si Maximum Operating P
si Justification for Max gOV Valve Number Close
~0 e Close
~0 en Safety Injection Pump Suction from RWST IMO-261 200 200 200 25 Open 2
Close 1
CVCS Pump Suction from RWST CVCS Pump Suction from VCT IM0-910,-911 QMO-451,-452 200 200 200 200 200 100 25 Open 3
Close 3
100 Open 4
Close 4
SI Pump Cross-Connect SI Pump Discharge Isolation IM0-270,-275 1750 1750 1750 ICM-260,-265 2750 2750 1750 Open 5
Close 5
1750 Open 6
Close 7
SI Pump Discharge to Cold Leg IMO-316, -326 1700 1700 200 1750 Open
-14 Close -15 CVCS Normal Discharge Isolation QM0-200,-201 2750 2750 2750 2750 Open 8
Close 8
BIT Inlet Isolation BIT Outlet Isolation SI Pump Miniflow CVCS Pump Miniflow IM0-255-,256 2750 2750 0
2750 ICM-250,-251 2750 2750 0
2750 QMO 225 g 226 2750 2750 IMO 262 g
263 2750 2750 1750 1750 Open 9
Close 7
Open 9
Close 7
Open -ll Close -10 Open
-13 Close -12 ATTACHMENT TO AEP:NRC:0966 Page 7
TABLE II AFW VALVEAPs Design
$~~)si
~C<~s> ~
Maximum Operating
~me 9am Justification for Max Turbine-Driven Pump Discharge Flow Control FMO-211,-221
-231,-241 12QQ 1200 1365 1240 Open 1
Close 2
Motor-Driven Pump Discharge Flow Control FM0-212,-222 1200 232,-242 1200 1335 1430 Open
- 3 Close 2
Mechanical Trip and Throttle QT-506 1190 1190 1097 1097 Open 4
Close 4
Suction from Essential Service Water WM0-744,-753 150
-754 150 105 105 Open 5
Close 5
Steam Admitting Valves MCM-221,-231 758 758 600 0
Open 6
Close 7
ATTACHNENT TO AEP:NRC:0966 Bonn A
ATTACHMENT TO AEP:NRC:0966 IV.
TABLE JUSTIFICATIONS This section details the justifications for maximum operating differential pressures referenced in Tables I and II.
6TTRCNNENT TO REP:NRC:0966 JUSTIFICATION FQR MAXIMUMOPERATING ~ GIVEN IN TABZE I 3
~
46 5 ~
6.
7 ~
This valve must be able to close to isolate the RWST 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 SI101.
For this scenario, the hP across IMO-261 could be as high as the RHR pump discharge head 200 psig.
This valve is normally open and would have to be reopened only in case of inadvertent closing.
In that case, the valve must be able to open against a full RWST head of water, approximately 25 psig.
IMQ-910 and 911 are normally closed and must open to transfer suction of centrifugal charging pumps from the VCT to the RWST.
Maximum valve h,Ps are the same as for IMO-261 These valves must close on an "S" signal; the maximum 5P across the valve is defined by the volume 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 ~100 psig, Must be able to move to allow realignment of ECCS to recirculation
- mode, and for ECCS train separation.
Delta-P could be as high as 1750 psig ~ equal to miniflow head of safety injection pump.
Pump testing on miniflow circuit, 4P is determined by the miniflow head of safety injection pump ~1750 psig.
Valve is only closed when pump is not operating; no flow-no hP.
8 ~
9 ~
These valves must be able to isolate the RCS from the
~2750 psig.
Given a miniflow test of the centrifugal charging pumps, the BIT isolation valves must be able to open with a hP ~ equal to the charging pump shutoff head.
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ATTCHMENT TO AEP:NRC:0966
~
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-ll-JUSTIFICATION FOR MAXIMUMOPERATING ~ GIVEN IN TABLE I 10.
Valves must close to isolate miniflow so that high pressure injection switchover to recirculation may proceed.
Xn the worst case, the bP vill be equal to safety injection jump maximum discharge pressure ~ 1750 psig.
11.
Similar to 10, except valve must be able to open during miniflow testing of the safety in]ection pump.
12.
Valves must close to ensure adequate high pressure in)ection flow (on "S" signal) against miniflow hP ~2750 psig.
13.
Valves must be able to be opened in the event of repressurization of the RCS.
14.
Valves are locked Open.
- However, assuming inadvertent closing, the valves would have to open against S.I.
pump maximum discharge pressure
~175" psig.
Since the "open" torque switch is not wired, open torque switch setting is inconsequential.
The Limitorque operator has ample thrust capacity to open valve with a hP of 1750 psi.
15.
Valves must close for switchover from cold leg to hot, leg in)ection with RHR pump discharge pressure.
ATTACHMENT TO AEP: NRC: 0966 I
' JUSTIFICATION FOR MAXIMUMOPERATING AP GIVEN IN TABLE II 1.
Maximum AP during valve opening would occur during steam generator filling when pump is at minimum flow and steam generator pressure is minimum for AFPT operation, namely 310 psig.
Motor operator capability has been demonstrated during numerous start-ups.
2 ~
To perform its safety function, valve must close following a line break downstream of valve.
In this case, the maximum valve closing AP is as shown.
The capability of the valves to close against pump discharge pressure up to 1430 psig has
.been demonstrated during steam generatpr fillingoperations.
Therefore, even though the original torque switch settings were based on a'esign AP of 1200 psi, they have been shown to be adequate by actual valve operation.
3.
Maximum hP during valve opening occurs during steam generator fillingwhen pump is at minimum flow and steam generator pressure is zero.
Since the "open" torque switch is not wired, the "open" torque switch setting is meaningless.
The motor operator has adequate thrust capability to open the valve at this dP as evidenced during numerous fillingoperations.
4.
This normally closed valve may have to open or close against maximum steam generator pressure; i.e.
1097 psig (lowest safety valve setting
+34 accumulation).
5.
The maximum valve M is essential service water pump shutoff head.
6.
. Valves are opened with no hP prior to plant start-up.
They remain open during plant operation.
7.
Maximum AP occurs during steam line break downstream of valve.
Operator action to close valve would occur following low steam generator pressure alarm at 600 psi.
ATTACHMENT TO AEP:NRC:0966 V.
FIGURES This section contains various schematic diagrams which locate the valves listed in Tables I and II.
Figure 1
Schematic Diagram of ECCS Charging System Portion Figure 2
Schematic Diagram of ECCS Safety Injection System Portion Figure 3
Figure 4 Schematic Diagram of AFW System Schematic Diagram of Steam Supply to Auxiliary Feedpump Turbine
TO RCS CL,.
CE NTR IFUGAL CHAR 0 IIIO PUMPS FROM RWST OPl QVO CM I
SEAL WATER HX HORMAL CHAROIII0 D. C.
COOK PLANT UNITS 1
6 2
SCHEMATIC DIAGRAM OF ECCS CHAQGING SYSTEM PORTION Fig.
1 ATTACHMENT TO AEP:NRC:$ 966 page 14
I:i aS
FROLi RWST 8RFETY 1'hlJEC7 /DN PL/MPH TO RCS CL, ~
TO RCS CJ.
TO RCS C.L.
D. C.
COOK PLANT (JNITS 1
6 2
SCHEMATIC DIAGRAM OF ECCS SAFETY IJIJFC~ION SYSTEM PORTION Fig.
2 ATTACHMENT AEP: NRC: 0966 Page 15
TO SO il2 FROM CST TO SO Fan F
I MOTOR MIVEH AFW PUMP FROM ESSE HTIAL SERVICE WATER FROM CST TO SO MOTOR ORIVEH AFW PUMP
.C.
FROM ESSE HTIAL SERVICE WATER H.C.
FROM ESSE HTIAL SERVICE WATER TO SO C
TIIRBINE MIVEH AFW PUMP FROM CST k
D. C.
COOK PLANT UNITS 1
2 SCHEIIATIC DIAGRAH OF AIIXILIARYFEED HATER SYSTEM Fig.
3-ATTACHMENT TO AEP:NRC:0966 Page l6
gv
@NO THROTTLE VALVE TO AFW TURB lHE CD COOK PLANT UNITS 1
6 2
SCHEMATIC DIAGRAM OF STEAM SUPPLY: TO AUXILIARYFEEDPUMP TURBINE Fig.
4 ATTACHMENT TO AEP:NRC:0966 Page 17
Cr
'I
STATE OF OHIO COUNTY OF FRANKLIN M. P. Alexich, being duly sworn, deposes and says that he is the Vice President of Licensee Indiana
& Michigan Electric Company, that he has read foregoing response to IE Bulletin 85-03, AEP:NRC:0966, and knows the contents thereof; and that said contents are true to the best of his knowledge and belief.
M lt P. Ale ch Subscribed and sworn to before me this 16th day of 1986.
(Notary Public)
E<!.EHN M. LODGE NOTARY PUSLIC - STATE OF OHN QY COMMISSlQN EXPIRES MAY7. 10