ML20153F771
| ML20153F771 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, Quad Cities, Zion, LaSalle, 05000000 |
| Issue date: | 05/02/1988 |
| From: | Morgan W COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 4570K, IEB-85-003, IEB-85-3, NUDOCS 8805110042 | |
| Download: ML20153F771 (36) | |
Text
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[^ f One First National Plaza. ChW Illinois
( , J Address Reply tx Post Office Box 767 Ny Chicago, Illinois 60690 0767 May 2, 1988 Mr. A. Bert Davis Regional Administrator U.S. Nuclear Regulator ' taudission Region III 799 Roosevelt Road '
Glen Ellyn, IL 60137 Sobject: Quad Cities Stations Units 1 & 2 Zion Station Units 1 & 2 '
LaSalle County Station Urtits 1 & 2 Byron Station Units 1 & 2 Braidwood Station Units 1 & 2 Response to Request for Additional Information to IEB 85-03 NRC Docket Nos. 50-254/265, 50-295/304, 50-373/374, 50-454/455 and 50-456/457 References (a): E.G. Greenman letter to C. Reed dated 3-30-88 (b): E.G. Greenman letter to C. Reed dated 3-24-88 (c): E.G. Greenman . letter to C. Reed dated 3-31-88 (d): E.G. Greenmaa letter to C. Reed dated 3-21-88 Dear Mr. Davis The above referenced letters requested the need for additional information pertaining to Quad cities, Zion, LaSalle County, Byron and Braidwood Stations responses to IEB 85-03, "Motor-operated Valve Common Mode Failures During Plant Transients Due To Improper Switch Settings". This information is needed before the program to assure valve operability can be approved.
The responses to the request for additional information are attached in enclosures 1 through 5 respectively.
Commonwealth Edison verbally requested and received an extension until May 2, 1988 for Zion, Byron and Braidwood Station's responses. This was discussed with Mr. J. Hinds of your staff on April 20, 1988.
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d A.B. Davis May 2, 1988 To the best of my knowledge and belief, the statements contained above are true and correct. In some lespect these statements are not based on personal knowledge, but obtained information furnished by other Coaunonwealth Edison employees, contactor employees, and consultants. Such information has been reviewed in accordance with company practice, and I believe it to be reliable.
Please address any questions that you or your staff may have concerning this response to this office.
Respectfully, W.E. .gan Nuclear Licensing Administrator V8M/rf Attachments cc: Resident Inspector - QC/L/Z/BY/BW Document Control Desk Subscribed and swo a co befo e e this N , da/
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Attachment 1 Quad Cities Response to NRC Request for Additional Information on IEB 85-03 Submittals l
I NRC Request #1 Revise the response dated 05-15-86 to include values of differential i
pressure for opening and closing the MOVs, in accordance with Action i
Item a of the bulletin.
Quad Cities Response The maximum values of differential pressure for Quad Cities MOVs i within the Bulletin scope were presented to the NRC in CECO's January 15, 1988 dubmittal. Enclosure 2 Attachment A of the January 15, 1988 submittal provided differential pressure values that represented the maximum (i.e., most conservative) conditions expected for MOV operation in either the open or closed direction.
Stem thrust requirements calculated uning these maximum differential pressures were applied in the testir ' resetting of both the open and closed direction torque switcher NRC Request #2 Revise the response dated 05-15-86 to include the following MOV: of the HPCI System, or justify their exclusion. They are shown on drawings M-46 Revision AK (Unit 1) and M-87 Revision AB (Unit 2),
and on Page 70 of BVROG Report NEDC-31322 dated September 1986.
(a) MOV 2301-15 is shown as CST Test Return Valve MOV 6 of the BWROG Report.
(b) MOV 2301-48 is shown as MOV 10.
(c) MOV 2301-49 is shown as MOV 11.
Quad 1 ties Response (a) MOV 2301-15 is excluded from the Bulletin scope because of the low probability of the HPCI system being in the test mode during the occurance of an abnormal event.
As stated in BWROG Report NEDC-31322 Section 3.3.1.2, design basis events described in the FSAR assume that the HPCI system is in its normal stand-by condition at the start of the event. MOV 2301-15 is normally closed and is only open for a minimum period of time during system flow testing. After system flow testing, procedures require that the MOV be restored to the normally closed position. In its normal position, MOV 2301-15 is not required to perform any active sa! ty function during a design basis event.
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(b)&(c) MOVs 2301-48 and 2301-49 are excluded from the Bulletin scope because these valves are already in their safety positions during normal plant operation and thus are not required to perform an active safety function. MOV 2301-48, which provides HPCI turbine cooling water return to the KPCI pump suction is normally open, and MOV 2301-49 which providas HPCI turbine cooling water return to the CST, is normally closed. The normal and safety positions (48-open and 49-closed) are specifically required in system procedure QoP 2300-1. In addition, surveillance procedures QoS 2300-1, 2300-2, and 2300-3 specifically return these two valves to the normal safety positions after in-service testing activities.
NRC Request #3 Revise the response dated 05-15-86 to include the following MOVs of the RCIC System, or justify their exclusion. They are shown on drawings M-50 Revision AC (Unit 1) and M-89 Revision T (Unit 2), and on pages 72 and 74 of the BWROG Report.
(a) Valves 1301-49 (Mov 1), 1301-60 (MOV 2), 1301-22 (Mov 3),
1301-25 (Mov 4), 1301-26 (MOV 4a), 1301-53 (MOV 5), 1301-48 (MOV 8) and 1301-62 (MOV 9) are located in the RCIC Water System. The normal positions of these valves agree with Page 72 of the BWROG Report. Assume inadvertent equipment operations for valves 1301-22 (MOV 3) and 1301-48 (Mov 8),
as required by Action Item a of the bulletin and as requested in items 4(a) and 4(b) below.
(b) Valve 1301-61 (MOV I) is shown normally closed in the RCIC Steam System. See Page 74 of the BWROG Report.
Quad Cities Response The RCIC system MOVs referenced in the above NRC question are excluded from the Bulletin scope because these valves are not required to be tested in accordance with the Quad Cities Inservice Testing program, i.e., 10CFR 50.55 a(g). In addition, the design basis events described in the accident analysis section of the FSAR do not take credit for RCIC operation. ESF equipment (HPCI, LPCI, core spray, and Automatic Pressure Relief System) operation as assumed in the accident analysis will provide core cooling and l mitigation of accident consequences.
1 NRC Request #4 l
Assume inadvertent equipment operations for the following MOVs, as l required by Action Item a of the bulletin:
(a) RCIC MOV 1301-22 is shown normally open on drawings M-50 revision AC (Unit 1) and M-89 Revision T (Unit 2), and as CST Suction Valve MOV 3 on Page 72 of the BWROG Report. It is not listed in the response. How would suction from thc CST be ensured if this valve were to be (a) actuated inadvertently to the closed position upon intended initiation of the system or (b) left closed inadvertently, e
t (b) RCIC MOV 1301-48 is shown normally open on the drawings indicated in Item 4(a) above. It is identified as MOV 6, Injection Valve Test Valve, on Page 72 of the BWROG Report.
It is not listed in the response. How would injection be ensured if this valve were to be operateJ inadvertently as described in Item 4(a) above?
Ouad Cities Response The RCIC system MOVs referenced in the above NRC question are excluded from the Bulletin scope because these valves are not required to be tested in accordance with the Quad cities Inservice Testing program, i.e., 10CFR 50.55 a(g). In addition, the design basis events described in the accident analysis section of the FSAR do not take credit for RCIC operation. ESP equipment (HPCI, LPCI, core spray, and Automatic Pressure Relief System) operation as assumed in the accident analysis will provide core cooling and mitigation of accident consequences.
MRC Request #5 According to the second paragraph of the response dated 05-15-86, operability of MOVs is to be deraonstrated for normal system operating modes. Revise this plan to include both normal and abnormal events, as required by Action Item a of the bulletin.
Ouad cities Response For those MOVs tested, operability has been demonstrated for normal dnd abnormal syst3m operating modes. The maximum expected differential pressure values for opening and closing provided in CECO's January 15, 1988 submittal for Quad Cities (Attachment 7, Table 1) are based upon both normal and abnormal system operating modes.
NRC Request #6 According to the supplemental response to 01-15-88, MOVATS has been included in the Mov testing program. If MOVATS is planned for application to some MOVs which are not included in its database, commit to and describe an alternate method for determining the extra thrust necessary to overcome pressure differentials for these valves.
Quad Cities Response Liagnostic testing such as MOVATS has been used in lieu of full flow testing to determine MOV thrust output for the as-left torque switch settings. The measured thrust output is compared with the thrust calculated using the standard OEM methodology for operation against maximum expected differential pressure. The MOVATS data base was not utilized in determining valve thrust requirements for any of the MOVs.
NRC Request #7 The proposed program for action items b, e and d of the bulletin is incomplete. provide the following details as a minimum:
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. (c) commitctnt to a training progrtm for sotting switches and maintaining valve operators, (b) commitment to justify continued operation of a valve determined to be inoperable, (c) description of a method possibly ne ded to extrapolate valve stem thrust determined by testing at less than maximum differential pressure, (d) justification of a possible alternative to testing at maximum differential pressure at the plant, and (e) consideration of pipe break conditions as required by the bulletin.
Quad Cities Response (a) Training on Motor Operated Valves is presently a part of production Training Center program. This is covered in Module 8 Unit 6 of Electrical Maintenance Training. A site specific lesson plan is presently being developed to be completed by December 31, 1988.
This will be included in the Continuing Training program for Electrical Maintenance personnel.
(b) When a valve is determined to be inoperable, an evaluation will be performed with respect to the operating license conditions and applicable Technical Specifications. Appropriate actions will be taken in accordance with the Technical Specifications.
(c) The Quad Cities program for IEB 85-03 testing includes the use of diagnostic techniques (e.g., MOVATS). Data acquired by such techniques is compared to calculated thrust requirements based on the standard OEM methodology to determine appropriate torque switch settings. MOVATS, we believ4, is an accepted alternacive to differential pressure testing.
(d) An alternative to cesting at maximum expected differential pressure is the use of diagnostic techniques such as MOVATS to verify proper switch settings ;; ..mure MOV operation at maximum expected design differential pressure conditions. This alternative is justified because maximun expected differential pressure testing at Quad Cities would require abnormal system configurations that may jeopardize equipment safety. In addition, certain maximum differential pressure conditions cannot be attained regardless of any system configurations without the simulation of design basis accidents which is specifically not required by the Bulletin.
5 ' pipe break conditions. enveloped by the plant's design basis have (e) been considered in the calculations of maximum expected differential pressure which were submitted to the NRC in CECO's IE Bulletin 85-03 submital dated 1/15/88.
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Attachment 2 l
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Basis for Inclusion of ouad Cities i MOVs into IEB 85-03 Scope
- General The NRC initial review of the Quad Cities IEB 85-03 submittals to '
Basis date has identified several MOVs in the RCIC System that, based on the NRC's review of the BWR Owners Group Report NEDC-31322, should be included in the IEB 85-03 scope for testing. The basis of the NRC interpretation appears to be that these Quad Cities MOVs perform equivalent functions to the generic RCIC System MOVs referenced in the BWROG Report.
pSD's review of these Quad Cities MOVs concluded that these valves do perform active safety actions as generally described in the BWROG Report. The BWROG Report defines an "active safety action valve" as that which is required to actuate so that the functions of either reactor vessel inventory makeup or reactor and containment isolation can be performed. Based on this, the MOVs discussed below fall under the testing scope requirements.
The RCIC system is described in the FSAR (Section 4.5) and is required by the Technical Specifications (sections 3/4.5E). Given-this background, the RCIC system would certainly appear to the NRC as a system that is "important to safety", even if it does not meet the letter definition for "Safety-Related." Based on this, it is reasonable to expect that the NRC will require the inclusion of the RCIC system MOVs into the Bulletin scope.
An argument can certainly be offered that the RCIC valves are not part of the inservice test (IST) program (10CFR 50.55 a(g)) and therefore are exempt from the Bulletin scope. However, given the functional importance of these RCIC MOVs as discussed below, it is reasonable to expect that the NRC will require their inclusion into the IST progrma as well as the IEB 85-03 scope.
MOV 1. MOV 1301-49, the RCIC injection valve, is normally Specific closed during plant operation. During design basis events Bases requiring RCIC system operation, this valve is required to perform an active safety function by actur'ing to its open position to allow high pressure injection for reactor coolant inventory makeup and core cooling. Also see Ites 7 of MOV Specific Bases.
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- 2. MOV 1301-60, the RCIC minimum flow bypass. valve, is normally closed during plant operation. On an automatic RCIC initiation signal and with low RCIC pump discharge flow, this valve is required to open to provide a flow path to the suppression pool for RCIC pump protection. When RCIC flow increases beyond a predetermined setpoint, this valve is required to close to ensure that maxinum RCIC flow is delivered to the core. This valve is also required to close on reactor high level or RCIC turbine trip signals to provide RCIC isolation. Based on the above, MOV 1301-60 performs on active safety function in both the open and closed directions.
- 3. MOV 1301-22, the CST suction valve, is normally open. This valve is required to remain open during RCIC operation when taking suction from the CST. This valve is required to perform an active safety function by actuating to its closed position during abnormal events when RCIC system suction is transferred from the CST to the suppression pool.
- 4. MJVs 1301-25 and 1301-26, which are the RCIC suppression pool suction valves, are normally closed. These valves perform an active safety function by actuating to the open position when RCIC suction is transferred to the suppression pool from the CST during abnormal events. MOV 1301-25 alsa performs an active safety functicn (via manual actuation) in the closed direction to provide containment isolation if required during abnormal events.
- 5. MOV 1301-62, the turbine accessories cooling water valve, is normally closed. This valve performs an active safety function by actuating to the open position on the auto RCIC initiation signal of low reactor level. The valve provides cooling water to the RCIC turbine lube oil cooler and barometric condenser which are components required to support RCIC turbine pump operation.
- 6. MOV 1301-61, the RCIC turbine steam admission valve, performs an active function in the open direction to provide motive power to the RCIC turbine on auto RCIC initiation signal of low reactor level. It also performs an active safety function in the closed direction to isolate steam from the RCIC turbine on reactor high level or certain RCIC turbine trip signals.
- 7. Mov 1301-48, the RCIC injection valve test valve, can be either closed or open. Station procedures, QOP 1300-01 and QoS 1300-03, provide the flexibility of requiring that one of the two injection valves (48 or 49) be in the open position and the other be in the closed position. Because of this flexible arrangement, both valves may perform an active safety function to open. Therefore, both McVs are required to be tested.
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e Attachment 2 Zion Station's Response to NRC Request for Additional Information on IEB 85-03 Submittals NRC Request #1 Has water hammer due to valve closure been considered in the determination of pressure differentials? If not, explain.
Zion Response Valve closure induced water hammer was not considered in determining the differential pressures for the valve testing program at Zion Station. Due to the slow valve closure time of the valves selected as the result of this bulletin, (fastest acting valve being 10 secs.), and, in most cases, due to the damping effect of the check valves downstream, water hammer generated as a result of valve closure is unlikely.
NRC Request #2 The response of 10-15-86 does not include the maximum differentiel pressures expected during opening and closing valves for both normal and abnormal events. Revise the response to include differential pressures, as required by Action Item a of the bulletin.
Zion Response pWR Engineering has determined and compiled a list of the maximum differential pressures for each valve that this bulletin addresses. The design basis accident considered for the calculation of each differential pressure is the large break LOCA or steam break as applicable. These values are considered to envelope all necessary valve operations during both normal and abnormal events. This list is included as an attachment to this letter.
Please Note: The attached list of differential pressures supercedes the previous list due to improper assumptions.
NRC Request #3 MOVs SI8814 and SI8813 are shown normally open in series in the SI pump miniflow line, in Zone B-8 of Drawing M-64 Revision 2 (Unit 1) and Zone B-3 of Drawing M-521 Revision M (Unit 2). These MOVs are not included in Attachment A of the response of 05-15-86. However, they are shown as HV-8814A and HV-8813 on Page 25 of the WOG Report of March 1986. Revise Attachment A to include these MOVs, or justify their exclusion. As required by Action Item a of the bulletin, assume inadvertent equipment operations.
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Zion R*sponst SI8813,14 are used only during Cold Leg Recirculation. Valves stroked as part of Cold Leg Recirculation were not considered as being IE Bulletin 85-03 valves since cold leg recirculation requires the operability of the RHR system valves. However, Emergency Procedures are written such that if these valves were required to stroke closed against accident delta
, pressure and they failed to stroke, the operator would be directed to stop the Safety Injection pumps associated with these valves (based on RV3T level), removing the delta pressure. For these reasons, valves SI 8813,14 should not be included in the list of valves considered in response to IE Bulletin 85-03.
MRC Request $4 The following MOVs in the AFV System are not included in Attachment A of the response of 05-15-86. Explain this exception to the Westinghouse recommendation that "all MoVs within the AFW system should be included in
. the list of valves tc be examined for maximum differential pressure", as stated on Page 5 of the WOG Report. Revise Attachment A of the response of 05-15-86 to include these valves, or justify their exclusion. As required by Action Item a of the bulletin, assume inadvertent equipment operations, a) MOVs FWOO50, FWOO51, FWOOS2, FW0053, FWOO54, FWOO55, FW0056, and FWOO57 are shown normally open on the left side of Drawing M-22 Revision UU (Unit 1), in the AFW pump discharge lines to the steam generators. these MOVs are shown on Page 27 of the WOG Report.
Zion Response i These valves were tested as part of the bulletin valves and were tested against maximum delta pressure in both the opening and closing direction.
l b) MOVs FWOO74, FWOO75 and FW00076 are shown normally open in suction lines from the secondary storage tank to the AFW pumps, in zones E-5
! and E-4 of Drawing M-37 Sheet 1 Revision AC (Unit 1) and in 2cnes E-5
, .and E-4 of Drawing M-37 Sheet 2 Revision T (Unit 2). These MOVs are shown as HV-35, -36 and -34, on Page 27 of the WOG Report.
Zion Response j These valves are normally open and are closed only upon loss of normal l condensate suction. The procedure used directs the operator to stop the affected Aux. FW Pump prior to closing the suction valve. % hen this is done, zero delta pressure exists across the valve. Should the valve be inadvertently closed with the Aux. FW pump running, a suction pressare switch will trip the Aux. FW pump, removing the delta pressure. If the pump fails to trip, the pump will most likely fail, rendering the suction r
i flowpath useless. For these reasons, MOV FV74, 75, 76 should not be l considered as' bulletin valves.
c) Steam admitting MOVs MS0005 and Ms00ll are shown normally open in zones E-8 and C-8 of Drawing M-20 Revision AN (Unit 1) and in :ones B-7 and D-6 of Drawing M-500 Revision AE (Unit 2), in the steam supply lines from steam generators A and D to the AFW Turbine. These MOVs are shown'normally closed on Page 28 of the WOG Report.
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- f. ion Response These valves are normally open and one of them could be closed during a Steam Generator Tube Rupture, Excessive Leakage event, or Steam Line Break. This configuration is tested during normal monthly performance testing. Inadvertent closure with the Aux. Fw Pump running would be bounded by this tested configuration. Inadvertent closure would produce no delta pressure for the valve to stroke open against. Failure to close during a line break is bounded by existing Steam Break analysis. If one valve were closed when the second valve were needed to close, the valve could be exposed to a delta pressure upon closing. For this case, failure to close does not affect the ability of the Aux. FW system to perform it's design function. Failure to open after inadvertent closure could render the Turbine Driven Aux. FW pump inoperable. In this case, one of three Aux. FW Pumps would be unavailable for service. One Aux. FW Pump is required for post accident heat removal and failure of MOV MS 0005 or MS 0011 to open after closure could not cause a common mode failure of the j
motor driven Aux, FW Pumps. Therefore, for the concerns addressed in Bulletin 85-03, these valves are considered part of the Main Steam System, and should not be considered as Bulletin Valves, d) Steam supply isolation valve MS0006 is shown normally open in Zone F-8 of Drawing M-20 Revision AN (Unit 1) and in Zone A-7 of Drawing M-500 Revision AE (Unit 2), in the steam supply line from steam generators A and D to the AFW TurLine.
Zion Response MOV MS0006 is normally opened and closed only as a backup action if MOV MS0005/00ll fail during the tube rupture event, or as part of an Aux. FW pump out of service condition. For out of service conditions, the typical restoration method is co manually throttle the valve open to slowly warm up the down stream piping, then return the pump to service. As a backup action to MS 0005/11, failure to close would cause the turbine driven Aux.
FW pump to continue to operate until Steam Generator Level (3 out 4) was restored to greater then 10% narrow range level. At that point, an air operated valve in series with MOV MS0006 could be closed. Inadvertent closure with the pump off is bounded by existing periodic testing.
Inadvertent closure with the pump running could render the turbine driven Aux. FW Pump inoperable. In this case, one of three Aux. FW Pumps would be unavailable for service. This would also be the case for a line break downstream of MOV MS00n6. In either case, the accident would be bounded by existing safety analysis. In addition to the turbine driven Aux. FW Pump, two motor driven Aux. Fw Pumps are installed. One Aux.FW pump is required for post accident heat removal and failure of MOV MS0006 to open after closure could not cause a comnon mode failure of the Motor Driven Aux. FW Pumps. Therefore. for the concerns addressed in Bulletin 65-03, this valve is considered part of the Main Steam System and should not be considered as a Bulletin Valve, e) Unlisted MOV FW 0105 is shown normally closed in Zone C-4 of Drawing M-32 Sheet 2 Revision AS (units 1 and 2), in a suction line from the service water system to motor-driven AFW Pump 1C.
Zion Response This valve was test'd e as part of the IE Bulletin 85-03 test program.
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NRC Request #5 According to the second paragraph of the response of 05-15-86, demonstration of operability for normal system operating loads is proposed. Include abnormal loads, as required by Action Item a of the bulletin.
Zion Response pWR Engineering has reviewed the results of the testing that was performed at Zion. The tests show that the affected valves were tested as close to the calculated pressures as reasonably achievable without any indicated failures. The testing encompassed both normal and abnormal loads. The attachment to this letter shows the actual valve test differential pressures versus calcu'.ated maximum differential (normal / abnormal) pressures.
NRC Request #6 According to the response of 05-15-86 to Action Item b, the valve supplier must certify compliance with the requirements established by the plant designer, and "therefore, no further review of the method for establishing torque switch settings is necessary or practical". Verify that the pressures used in setting the switches envelope the maximum pressures determined in Action Item a and that additional factors such as friction, margin of safety, degradation and wear are addressed.
Zion Response The Limitorque recommended torque switch settings are based on the Westinghouse design specification for each specific valve. The Westinghouse design differential pressure for each valve has been verified to be greater than the maximum calculated and test differential pressures.
In addressing the additional factors mentioned above (considered to be beyond the original scope of the bulletin), the torque switch is bypassed during the initial phase of valve opening thereby allowing maximum limitorque thrust until the valve strokes beyond its peak lead. The signature of the limitorque current is the basis for the bypass setting.
This is applicable to all of the affected valves.
l In the initial closing phase of valve operation the most critical stage of valve closure is during tne last 5 to 10 percent of valve stroke. To i account for this problem, the station relies on the recommended manufacturer settings and actual testing to ensure that the valve does not l
torque out just prior to full closure.
i Additionally, since the valves' torque switches are set to the manufacturer's recommended setting based on valve design pressure, any valve operating characteristics that change due to degradation or wear would be encompassed in the margin between the actual faulted differential
! pressure and the valve design differential pressure.
NRC Request #7 The proposed program for action items b,c, and d of the bulletin is incomplete. provide the following details as a minimum:
a) commitment to a training program for setting switches and maintaining valve operators.
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Zion Response Zion Station's training program incorporates training for personnel using the MOV switch setting procedure and MOV overhaul procedure, b) commitment to justify continued operation of a valve determined inoperable.
Zion Response All valves tested in response to Bulletin 85-03 were determined to successfully stroke against the subjected delta pressures, therefore all valves were considered operable.
c) Descciption of a method possibly needed to extrapolate valve stem thrust measured at less than maximum differential pressure.
Zion Response Due to the test methods employed, the maximum obtainable dulta pressure was used based on plant configuration. In some cases, delta pressure was greater than maximum expected. In all cases,the testing showed that the valves were able 'o perform their design function. For these reasons, no method is requir r to extrapolate valve stem thrust measured at less than maximum differential pressure.
d) justification of a possible alternativo to testing at the maximum differential pressure at the plant.
Zion Response Due to the test methods employed, no testing alternatives are required, e) consideration of pipe break conditions as required by the bulletin.
Tion Response The testing configuration, where possible, attempted to simulate pipe break conditions for the valves. For the ECCS Pump discharge valves, valves were stroked during the Station's periodic "Full Flow" test which is conducted with the Reactor Head OFF which simulates a large hole in the Reactor Coolant System. For Aux. FW pump Discharge Valves, the valves were stroked against maximum delta pressure by discharging into depressurized Steam Generators. simulating a Main Steam Line Break.
For Pump Suction Valves tested, line break considerations could not be duplicated. However, line breaks associated with pump suction valves are not a concern since a line break associated with these valves would render the associated pump (s) inoperable. Tnerefore, the testing program considered pipe break conditions, where appropriate.
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ATTACHMENT IEB 85-03 MOTOR OPERATED VALVE LIST Zion Station Units 1 & 2 w/ Diffet'ential Pressures '
TEST DP DESIGN U1/U2 CALC. DP DP MOV ID. DESIGN BASIS FUNCTION (psig) (psig) (psic),
MOV-SI8800A Cold Leg Injection Isol.- 2550/2550 2571 2750 Mov-SI8800B Normally open, confir MOV-SI8800C matory open signal upon MOV-SI8800D Safety Injection.
MOV-SI8801A BIT Outlet Isolation, 2550/2550 2565 2750 MOV-SI8801B normally closed, opens upon Safety Injection.
MOV-SI8003A BIT Inlet Isolation, 2550/2550 2565 2750 MOV-SI8803B normally closed, opens upon Safety Injection.
MOV-SI8802 SI Pp Cold Leg Injection 1495/1460 1546 2750 Isolation, normally open, confirmatory open signal upon Safety Injection.
MOV-SI8806 SI Pp Suction from RWST, 18.0/18.0 19 200 norr. ally open, confir-matory open signal upon Safety Injection.
MOV-SI8923A SI Pp Suction Isolation, 19.3/19.3 20 200 MOV-SI8923B normally open, confir-matory open signal upon Safety Injection.
MOV-SI9010A Cold Leg SI Cross Tie 1495/1460 1546 2750 MOV-SI9010B Isolation, normally open, confirmatory open signal upon Safety Injection.
MOV-VC8105 Normal Charging Isolation, 2542/2589 2567 2750 Mov-VC8106 normally open, closes upon 2567/2539 Safety Injection.
Mov-VC8110 Charging Pp Mini-flow 2576/2546 2567 2750 McV-VC8111 Isolation, normally open, manipulated based upon RCS pressure.
Mov-VC112B Charging Pp Suction Isola- 59.4/53.6 80 200 MOV-VCll2C tion from VCT, normally open, closes upon Safety Injection.
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i TEST DP DESIGN U1/U2- CALC. DP DP (psic) (psig) -(psig)
'MOV ID. DESIGN BASIS FUNCTION MOV-VCil2D Charging Pp Suction Isola- 15.8/16.3 16.4 200 MOV-VC112E tion from RWST, normally closed, opens upon Safety Injection.
MOV-SWO101 A W Pp Suction Isolation 115/100 115 125 MOV-SWO102 from SW, normally closed, 161/165 115 125 MOV-SWO103 Manually opened upon low 115/100 115 125 MOV-SWO104 pump suction pressure. 158/165 115 125 MOV-SWO105 158/165 115 125 ,
MOV-FWOO50 AW Discharge Isolation, 1525/1550 1662* 1619 2000 MOV-FWOO51 normally open, required 1525/1550 1662* 1619 2000 MOV-WOO 52 closed on affected S/G 1525/1550 1669* 1626 2000 MOV-FWOO53 during SGTR event. 1525/1550 1669* 1626 2000 MOV-FWOO54 1525/1550 1672* 1629 2000 MOV-FV0055 1525/1550 1671* 1628 2000 MOV-WOO 56 1525/1550 1663* 1620 2000 MOV-FWOO57 1525/1550 1663* 1620 2000
- DP expected while supplied with turbine driven pump.
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LaSalla County Response to
'NRC Raouest #1 NRC Request for Additional Information on IEB 85-03 Submittals According to the second paragraph of the response of 05-1$-86, differential pressures are determined for normal system operating modes. As required by Action Item a of the bulletin, both normal and abnormal events should be considered. In addition, differential pressures are not tabulatad in Attachment A of that response. Revise Attachment A by including differential pressures for opening and closing the HOVs, considering abnormal events to the extent required by the bulletin.
Although differential pressures are tabulated in the supplemental response of 01-15-88, there are no indications that they apply to (a) both opening and closing and (b) abnormal events. Resolve this discrepancy.
LaSalle Response The maximum values of differential Dressure for t75411e HOVs within the Bulletin scope were presented to the NRC in Ceco . January 15, 1988 submittal. Enclosure 4 Attachment A of the January 15, 1988 submittal provided diffarential pressure values that represented the maximum (i.e., most conservative) conditions expected for MOV operation in either the open or closed direction. Stem thrust requirements calculated using these maximum differential pressures were applied in the testing and resetting of both the open and closed direction torque switches.
NRC Recuest #2 When determining differential pressures per Item 1 above, assuma inadvertent equipment operations of the following MOVs, in accordance with Action Item a of the bulletin:
(a) HPCS HOV E22-7001 is shown normally open in Zone A-4 of Drawing H 95 Revision W (Unit 1) and Orawing H-141 Revision AO (Unit 2), and as HOV 3 on Page 67 of BWROG Report HE00-31322 dated
!' Septmoer 1986. How would suction from the CST be ensured if l this valve were to be (a) actuated inadvertently to the closed l position upon intended initiation of the system or (b) left
- closed inadvertently?
l (b) RCIC H0v E51-F010 is shown normally open in Zone A-a of Orawing H-101 Sheet 2 Revision 2 (Unit 1), and Drawing H-141 Sheet 2 Revision Y (Unit 2), and as HOV 3 on Page 12 of the BWRC3 Report. The question in Itam 2(a) above applies here also.
(c) HPCS HOV E22-F023 [see item 3(a) below) is shown nortrally closed in a 14 inch test line in Ione C-4 of Drawing M-i!
Revision W (Unit 1) and Drawing H-141 Revision AD (Unit 2), and as HOV 7 on Page 67 of the SWROG Report. According to page 54 and Note o en Page 66, the utility response should provide differential pressures for tasting this valve. How woLid adequate injection to the reactor vessel be ensured if this valve were to be openeo or lef t open inadvertently n descritad in item.2(a) abovei l
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laSalle hibohlt The issue of inadvertent actuation was raised by the HRC in its request for additional information with respect to MOVs E22-F001, E51-F010, and E22-F023. As explained in the BWROG Report NE00 31322 Section 3.3,1.3, inadvertent valvo actuation is not within the BWR design basis.
However, the design of the plant as described below, ensures that these valves will remain in their respective safety positions during design basis events.
(a) HPCI MOV E22-F001, which is the CST suction valve, is normally open and is required to remain open during initiation and operation of the HPCS system when taking suction from the CST.
In the unlikely event (outside the design basis) that E22-F001 was inadvertently closed, suction f rom the CST is ensured by an auto-open initiation signal f rom low reactor level or high drywell pressure which are the same signals for HPCS initiation. When suppression pool level reaches the design basis setpoint for the transfer of HPCS suction to the suppression pool, E22-F015 will open. Whth F015 ranches the open position, E22-F001 will receive a signal to close.
Therefore, the active safety function of the valve is to close.
(b) The above discussion also applies to RCIC MOV E$1-F010 except that the auto-close initiation signal will be E51-F031 (suppression pool suction for RCIC) in its open position.
(c) HPCS MOV E22-F023, which is the suppression pool isolation and test bypass valve, is excluded from the Bulletin scope because of the low probability of the HPCS system in the test mode during the ocurrence if an abnormal event. This valve is normally closed and is only open for a minimum period of time during system flow testing. As stated in the BWROG hoort NEDC-31312 Section 3.3.1.2, design basis events described in the FSAR assume that the HPCS system is in its normal stand-by conditions at the start of the event. In its normal position (i.e., closed), MOV E22-F023 is not required to perform any active safety function during a design basis event. Hcwever, tne design cf the plant provides for auto-initiation of the valve to its closed positten upon a HPCS initiation signal of low reactor level or high drywell pressure.
HRC Recuest 43 Revise Attachment A to the rescense dated 01-15-89 to include the following valves, or justify their exclusion. These MOVs are listed in responses for tne other two GE Class 5 facilities.
(a) HPC5 MOVs E22-F010. E22-F01) and E22-F023 are shown nomally closed in :enes 0-4, 0-3 and C-4 of Orawing M-95 Revision W (Unit 1) an: Orawing M-141 Revision AD (Unit 2). These valves are snown as valves 5, 6 and 7, respectively, on Page 67 of tne SWROG Repers.
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iRGV TYIIsr0X Telecopter 'lu d M 5 YO U 41PN i tNTO 9 (b) RCIc MOV E51-F022 is shown normally closed in Zone E-6 of l.
Drawing M-101 Sheet 2 Revision I (Unit 1) and Drawing H-147
) Sheet 2 Revision Y (Unit 2). This valve is shown as MOV S on l Page 72 of the BWROG Report.
(c) RCIC MOV E51-F059 is shown normally closed in Ione E-5 of Drawing M-101 Sheet 2 Revision 2 (Unit 1) and Drawing M-147 Sheet 2 Revision Y (Unit 2). This valve is shown as HOV 6 on Page 73 of the BWROG Report.
LaSalle R_esconte (a) HPCS HOVs E22-F010. E22-F011 and E22-F023 are excluded from the Bulletin scope because these valves, when in their normal position, do not provide any active safety functions. These valves provide HPCS test line isolation functions and therefore are closed during nortnal plant operation. Consistent with the BWROG Report HEDC-31322 Sections 3.3.1 and 4.4.2, these valves are not required to be tested.
(b)&(c) RCIC HOVs E51-F022 and E51-F059 are excluded f rom the Bulletin scope because these valves, when in their normal position, do not provide any active safety functions. These valves provide RCIC test line isolation functions and therefore are closed during normal plant operation. Consistent with BWR00 Report NEOC-31322 Sections 3.3.1 and 4.4.2, these RCIC valves are not required to be tested.
NRC Raouest #4 The valve identified as HOV X on Page 14 of the BWROG Report is shown as an MOV without a number in Igne 0-4 of Drawing H-101 Sheet 1 Revision AE (Unit 2). Revise Attachment A to the response of 01-15-88 to include this RCIC MOV, or justify its exclusion.
D $alle Resoonse The RCIC system MOV that was referenced in the NRC's request for information is the RCIC Turbine Trip and Throttle Valve (E51-F360).
The active safety function of this valve is to trip closed to protect the RCIC 1,urbine and pump upon the receipt of a RCIC turbine trip signal. This valve is excluded from the Bulletin scope because its active safety function is achieved via mechanical spring actuation.
The motor operator for this valve does not perform an active safety function.
pc Reauest #5 According to the supplemental response of 01-15-88 MOVATS has been included in the MOV testing program, if NOVATS is planned for application to some HnVs which are not included in its data base.
comit to and describe an alternate method for determining the extra thrust necessary to overcome the pressure ditf erentials for these valves.
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LaSalle Responsi Diagnostic testing such as MOVATS has been used in lieu of full flow testing to determine MOV thrust output for the as-left torque switch settings, The measured thrust output is compared with the thrust calculated using the standard OEM methodology for operation against maximum expected difforential pressure. The MOVATS data base was not utilized in determining valve thrust requirements for any of the MOVs.
NRC Recuest #ti The proposed program for action items b, e and d of the bulletin is incomplete. Provide the following details as a minimum:
(a) comitment to a training program for setting switches and maintaining valve operators, (b) comitment to jusify continued operation of a valve determined to be inoperable.
(c) .
description of a method possibly needed to extrapolate valve stem thrust determined by testing at less than maximum differential pressure.
(d) justification of a possible alternative to testing at maximum difforential pressure at the plant, (e) consideration of pipe break conditions as required by the bulletin, and (f) stroke testing when necessary to meet bulletin requirements, usalle Resoonst (a) LaSalle Station utilizes a combination of onsite and offsite training on Motor Operated Valves. This training which is described in the following paragraphs consists of general maintenance techniques as well as specific switch setting guidelines.
Genersi training on Motor Operated Valves is provided by the corperste production training center. This program coaststs of general Motor Operated Valve maintenance practicas.
Onsite training is provided to Electrical and Mechanical maintenance personnel relating to inspection, rebuild, signature trace and switch setting procedures. This training ensures proper maintenaMe practices based on approved Station procedures.
Refresher training is performed by crew foremen prior to each shift turnover when MOV work is involved. This training ensures a flew of information relating to a specific job.
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an evaluation will (b) Mhen a valve is detemined to be inoperable,icense conditions
- be performed with respect to the operating l and applicable Technical Specifications. Appropriate actions will be taken in accordance with the Technical Specifications and other applicable administrative and licensing requirements including reports to the NRC, as applicable.
(c) The LaSalla program for IEB 85-03 testing includes the use of diagnostic techniques (e.g., MOVATS).. Data acquired by such techniques is compared to calculated thrust requirements based on the standard OEM methodology to determine appropriate torque switch settings. Extrapolation of valve stem thrust requiracents by testing at less than maximum difforential pressure is not performed.
(d) An alternative to testing at maximum expected differential pressure is the use of diagnostic techniques such as M0 VATS to verify proper switch settings to ensure MOV operation at maximum expected design dif f arential pressure conditions.
This alternative is justified because maximum sixpected differential pressure testing at LaSalle would require abnormal system configurations that may jeopardize equipment safety. In addition, certain maximum differential pressure conditions cannot be attained regardless of any system configurations without the simulation of design basis accidents which is specifics 11y not required by the Bulletin.
(c) Pips break conditions enveloped by the plant's design basis have been considered in the calculations of maximum expected differential pressure which were submitted to the NRC in Ceco's
!! Bulletin 85-03 submital dated 1/15/88.
(f) Stroke testing of the Bulletin scope valves is accomplished wnen performing diagnostic tasting (e.g., H0 VATS).
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y Attachment 4 Byron Station Response to NRC Request for Additional Information on IEB 85-03 Submittals NRC Request #1 Has water hammer due to valve closure been considered in the determination of pressure differentials? If not, explain.
Byron Response Water hammer has the potential of being a concern only for normally open valves. This question thus concerns eight motor operated valves, which will be discussed below:
1,2CV112B,C: 1,2CV8105; 1,2CV8106: 1,2SI8806 Water hammer due to valve closure is not considered to impact operation of these valves. The valves were successfully stroke tested against maximum expected differential pressures without any water hammer effects.
1,2SI8821A.B: 1,2SI8835 These valves are only required to close when switching from cold leg to hot leg recirculation. The procedure requires that the safety injection pumps be stopped prior to any valve realignment. With no flow present during closure, water hammer is not a concern.
RRC Request #2 The response of 05-15-86 does not include the maximum differential pressures expected during opening and closing valves for both normal and abnormal events. Revise the response to include differential pressures, as required by Action Item (a) of the bulletin.
Byron Response The maximum expected differential pressures were provided in Enclosure 5 of Commonwealth Edison's January 15, 1988 response and envelope the opening and closing differential pressures for the subject valves.
Further review of the design basis event and system configurations for the Auxiliary Feedwater (AF) and High Pressure Safety Injection (HFSI)
Systems have yielded revised differential pressures. These revised differential pressures are based on events up to but not including the transfer to cold leg recirculation and exclude gross check valve failure. The revised differential pressures and their basis are provided in Tables 1 and 2. Attachment A provides the description and function of each valve and defines the plant specific design basis.
The revised differential pressures impact the test results for 1,2AF006A,8; 1,2CVll2D.C and 1,2CVll2D,E. The following justification is provided for the a'eceptability of the testing conducted:
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e 1,2CVll2B,C At Byron these MOVs were tested at the maximum practical differential pressure of 30 psi and 22 psi for Units 1 and 2 respectively. The revised differential pressure of 77 psi considers the VCT pressurized to the tank's relief valve setpoint and the elevation head. Plant procedures limit the maximum VCT pressure to less than or equal to 65 psi. The maximum expected differential pressure therefore would be 67 psi with the elevation head accounted for.
These valves are of identical-design as the Braidwood Unit 2 CVil2B,C valves and the torque switches are set either the same or higher than the Braidwood Unit 2 MOVs. At Braidwood, the 2CVll2B,C valves were tested against a differential pressure of 66.6 psi and 65.6 psi which includes the elevation head.
In addition to the JP testing performed at Braidwood, these valves were procured for a 200 psi design pressure and the manufacturers recommended switch-settings are based on these pressure. Therefore, based on the Braidwood Unit 2 testing and the extra design margin built into the valve and switch settings, these valves are considered operable at Byron Station.
1,2CVll2D,E These valves are of identical design as the 2CV112D,E valves at Braidwood Unit 2. The Braidwood 2CVil2D,E valves were tested successfully at a WP of 33.4 psi. These MOVs were procured for a system design pressure of 200 psi which is well above the maximum expected WP of 34 psi.
Given the low AP these MOVs have to function against, the fact that the open torque switch.i.s bypassed for the initial 21% of the full valve stroke, the fact that the operator torque capability is at least 35%
above the torque required to unseat the valve under 200 psi, these valves are considered operable given the revised differential pressure value.
NRC Request e3 The following HOVs of the HPSI System are not included in Attachment A of the response of 05-15-86. However, these 11oVs are included in the WOG Report of March 1996. Revise Attachment A to include these MOVs, or justify their exc1':sion. As required by Action Item (a) of the bulletin, assume inadvertent equipment operations.
(a) MOVs SI6814 and SI8920 are shown normally open in the SI pump miniflow lines in zones F-6 and E-6 of Drawing M-61 Sheet lA Revision AH (Unit 1),
and in zones D-4 and c-4 of Drawing M-136 Sheet 1 Revision AH (Unit 2).
These valves are shown as HV-8814-A and -B on Page 25 of the WOG Report.
(b) MOVs SIB 923A-1 and SI8923B-2 are shown normally cpen in the SI pump suction lines in zones E-3 and C-3 of Drawing M-61 Sheet 1A Revision AH (Unit 1), and in zones C-5 and B-5 of Drawing M-136 Revision AH (Unit 2). These valves are shown as HV-8923-A and -B on Page 25 of the WoG Report. ,
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(c) MOVs CV8111-2 and CV8110-1 are shoen normally open in the CCP miniflow lines in zones A-5 and A-3 of Drawing M-64 Sheet 3A Revision AM (Unit 1),
and in zones A-3 and A-5 of Drawirg M-138 Sheet 3A Revi 'on AL (Unit 2).
These valves are shown as HV-8110 and HV-8111 on page 24 of the WOG Report.
Byron Response (a) The original selection of the valves for IEB 85-03 were from those valves tested per 10CFR 50.55a(g), the Inservice Testing (IST) Program and as specified in the bulletin. At the time of the May 15, 1986 submitta),
the Safety Injection pump miniflow valves, 1,2SI8813, 1,2SI8814 a<d 1,2SI8920, were not included in the IST program and thus were not considered within the scope of IEB 85-03. These valves were added to the IST program on October 8, 1986. per the Westinghouse Owners Group report of March 1986, paragraph III.A.3, only those portions of high pressure injection required during the safety injection phase, up to but not including the manual or partial auto transfer to recirculation are considered. Therefore, these valves are excluded from the requirements of IEB 85-03 based on being required to isolate safety injection pump miniflow during transfer to cold leg recirculation.
(b) Valves 1,2SI8923A,B are not part of the IST program and thus are not within the scope of IEB 85-03. These valves are not required to change positions during any design basis event.
(c) At the time of the May 15, 1986 submittal, valves 1,2Cv8110 and 1,2CV8111 were not part of the IST program and thus were not considered within the scope of IEB 85-03. These valves were added to the IST program on October 8, 1986. The valves are excluded from the requirements of IEB 85-03 per the VoG report based on being active during transfer to cold leg recirculation.
m i Request #4 MOVs AF-013A-1, -013B-1, -013C-1, -013D-1, -013E-2, -013F-2, -013G-2, and
-013H-2 are shown normally open, on the left side of Drawing M-37 Revision AF (Unit 1), and on the right side of Drawing M-122 Revision AE (Unit 2), in the AFW pump discharge lines to the steam generators. Four of these valvea are in discharge lines from the n:otor-driven pump; the other four are in discharge lines from the diesel-driven pump. They are not included in the response; however, equivalent valves are shown on Page 27 of the WoG Report. Explain this exception to the Westinghouse recommendation that "all Movs within the AFW system should be included en the list of valves to be examined for maximum differential pressure", as stated on Page 5 of the V0G Report. Revise Attachment A of the response of 05-15-86 to include these MOVs, or justify their exclusion.
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Byron Response As stated in the response to Item 3, the original selection of valves for IEB 85-03 were drawn from the IST program. Valves 1,2AF013A through H were not in the IST program at the time of the May 15, 1986 submittal and thus were not considered within the scope of IEB 85-03. The valves were added to the IST program on October 8, 1986.
Subsequent evaluation of the 1,2AF013A through H valves has found that the valves should be included within the scope of IEB 85-03. These valves are non-active and are maintained in the open position. They can only be closed by operator action to isolate AF flow to a damaged or depressurized steam generator. The maximwa differential pressure and applicable justification for these valves has been included in Tables 1 and 2. The valves are to be tested at the next available outage and are considered operable based on section 10.4.9.3 of the Byron Final Safety Analysis Report (FSAR) which states that the valves are not necessary to immediately isolate flow to a faulted steam generator. A restriction orifice is provided in each of the Auxiliary Feedwater feed lines. The purpose of these orifi is to ensure that the other 3 steam generators are not starved in the event that Auxiliary Feedwater can not be isolated from the faulted steam generator. This isolation orifice also limits the Wp which would be seen by the AF013 valves. The testing of these valves will be tracked with Action Item Numbers 454-225-88-0096 and 455-225-88-0097.
NRC Request #5 According to the second paragraph of the response of 05-15-86, demonstration of operability for normal system operating loads is proposed. Include abnormal loads, as required by Action Item (a) of the bulletin.
Byron Response The revised differential pressures given in Table 1 take into consideration abnormal events. Table 2 provides justification for the maximum differential pressures of Table 1.
NRC Request #6 According to the response of 05-15-86 to Action Item (b), the valve cupplier must certify compliance with the requirements established by the plant designer, and "therefore, no further review of the method for establishing torque switch settings is necessary or practical". Verify that the pressures used in setting the switches envelope the maximum pressures determined in Action Item (a) and that additional factors such as friction, margin of safety, degradation and wear are addressed.
O Byron Response The recommended torque switch settings are based on the valve manufactures design specification for each specific valve. Table 1 verifies that the design pressure is equal to or exceeds the maximum differential pressure the valve would experience during both normal and abnormal events within the plant design bases.
In addressing the additional factors mentioned above (considered to be beyond the original scope of the bulletin), the torque switch is bypassed during the initial phase of valve opening thereby allowing maximum limitorque thrust until the valve strokes beyond its peak load. The signature of the limitorque current is the basis for the bypass setting.
This is applicable to all of the affected valves.
In the initial closing phase of valve operation the most critical stage of valve closure is during the last 5 to 10 percent of valve stroke during which the potential exists for the valve to torque out prematurely. To account for this concern, the station relies on the recommended manufacturer settings and actual testing to ensure that the valve does not torque out just prior to full closure.
Additionally, since the valves torque switches are set to the manufacturer's recommended setting based on valve design pressure, any valve operating characteristics that change due to degradation or wear would be encompassed in the margin between the actual faulted differential pressure and the valve design differential pressure.
NRC Request #7 The proposed program for action items (b), (c) and (d) of the bulletin is incomplete. Provide the following details as a minimum:
(a) commitment to a training program for setting switches and maintaining valve operators.
(b) Commitment to justify continued operation of a valve determined to be inoperable (for Braidwood Unit 1 and Byron Units 1 and 2 only),
(c) Description of a method possibly needed to extrapolate valve sten thrust measured at less than maximum differential pressure, (d) Justification of a possible alternative to testing at maximum differential pressure at the plant, and (e) Consideration of pipe break conditions as required by the bulletin.
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e Byron Response (a) plant procedures are in place to ensure that the material condition of motor operated valves are maintained at the highest standards. procedural compliance is required in all j aspects of plant maintenance and operations. In addition all Electrical Maintenance personnel attend training sessions to assure proper maintenance techniques are utilized for Limitorque motor operators. Continuing training sessions are developed by the On-site Training Department in conjunction with Electrical Maintenance to assure any changes in technique are passed on to the workmen. All Electrical Maintenance personnel have recently completed their required continuing training program for Limitorque operators.
(b) All valves within the scope of IEB 85-03 have been determined to be operable and at no time were any valves considered inoperable based on bulletin requirements. If a valve is determined inoperable, an evaluation will be performed with respect to the operating license conditions and the applicable Technical Specifications. Appropriate action will be taken in accordance with Technical Specifications and other administrative and license requirements, including reports to the NRC as applicable.
(c) Differential pressure testing was conducted to the maximum expected differential pressure to the extent practical for valves within the scope of IEB 85-03. Stem thrust measurements were not taken during the differential pressure testing.
(d) valves not tested at the maximum differential pressure were identified as being of the same design and manufacturer, with the same or more conservative switch settings, and of the same system application as valves that had been tested at maximum differential pressure in a sister unit. This similarity of design and valve application was taken credit for in order to demonstrate valve operability for valves in which the maximum expected differential pressure could not be achieved due to system configuration / constraints resulting from plant operations.
(e) The differential pressures listed in Table 1 take into consideration pipe break conditions as part of their design basis events.
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TABLE 1 Design Basis Conditions /WP (PSI)
Comunorneealth Edison Company Byron - Units 1&2 Valve Taq Normal _WP Upset WP __ Ffterqency WP Faulted WP_ Design pressure (PSI) (PSI) (PSI) (PSI) 1,2AF006A,B Closed 0 Closed 0 Open 97 Open 97 150 1,2AF017A,B Closed 0 closed 0 Open 97 Open 97 150 1,2CVI128,C open 0 closed 77 Closed 77 Closed 77 200 1,2Cvil2D,E Closed 0 Open 34 open 34 open 34 200 1,2CV8105 Open 0 Closed 370 Closed 370 Closed 2620 2750 1,2CV8106 Open 0 closed 370 Closed 370 Closed 2620 2750 1,2SI8801A,B Closed 0 Open 2620 Open 2620 Open 2620 2750 1,23I8806 Open 0 Open 0 closed 32 closed 32 200 1,2SI8821A,B Open 0 Open 0 closed 0 Closed 0 1500 1,2SI8835 Open 0 Open 0 Closed 0 closed 0 2750 1,2AF013A-II open 0 Open 0 Open 0 Closed 1450 1450 (00S4r/050288)/9
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< r Commonwealth Edison Company Byron - Units 1&2 ;
Valve Tag Justification for Maximum Differential Pressure (
)
1,2AF000A,B Valve is normally closed and opens on a low-low AF pump [
suction pressure signal concurrent with automatic AF pump '
initiation. Valve must be able to open against a
. differential pressure equal to the maximum header pressure L 2
of the SX pumps (115 psi) less the static head (18 psi).
Maximum differential pressure is 97 psi.
1,2AF017A,B Valve is normally closed and opens on a low-low AF pump suction pressure signal concurrent with automatic AF pump i initiation. Valve must be able to open against a differential pressure equal to the maximum header pressure of the SX pumps (115 psi) less the static head (18 psi).
Maximum differential pressure is 97 psi.
1,2Cv1128,C These valves must close on SI signal; the maximum differential pressure 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 (approximately 2 psig), i t
1,2CV112D,E These valves are normally closed and are required to open [
against a full RWST head of water. Maximum differential pressure is 34 psig. (Upset condition.)
1,2CV8105 This valve is normally open and required to close to [
provide isolation to the RCS from the CVCS. Normal ,
operating pressure of RCS is 2250 psi and the shutoff head l cf the centrifugal charging pump is 2620 psi. Valve must close against a differential pressure of 370 psi. (Upset and Emergency conditions.) In the case of a large steam :
line break (faulted condition), the RCS pressure is O psi and the valves must close against a differential pressure equal to the shutof! head of the centrifugal charging pump, I which is 2620 psi.
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Attachment 5 i Braidwood Station Response to NRC Request for Additional Information l on IEB 85-03 submittals WRC Request #1 Has water hammer due to Valve closure been considered in the determination of pressurs differentials? If not, explain.
praidwood Response Water hammer will only be a concern for r.ormally open valves.
This question thus concerns eight motor operated valves, each of which will be discussed below:
1,2CV112B/C, 1,2CV8105, 1,2Cv8106, 1,2S18806 water hammer due to valve closure is not considered to impact operation of these valves. The valves were successfully stroke tested against maximum expected differential pressures without any water hammar effects.
1,2SI8821A/B: 1,2SI8835 These valves are only required to close when switching from cold leg to hot leg recirculation. The procedure requires that the safety injection pumps be stopped prior to any valve realignment. With no flow present during closure, water hammer is not a concern.
NRC Request #2 The response of 05-15-86 does not include the maximum differential pressures expected during opening and closing valves for both normal and abnormal events. Revise the response to include differential pressures, as required by Action Item (a) of the bulletin.
Braidwood Response The maximum expected Jifferential pressures were provided in Enclosure 6 of Commonwealth Edison's January 15, 1988 response and envelope the opening and closing differential pressures for the subject valves. Further review of the design basis event and system configura: ions for the Auxiliary Feedwater (AP) and High Pressure Safety Injection (HPSI) Systems have yielded revised differential pressures. These revised differential pressures are based on events up to but not including the transfer to cold leg recirculation and excludes gross check valve failure. The revised differential pressures and their bases are provided in Tables 1 and 2. Attachment A provides the description and function plant specific design basis. of each valve and defines the
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Th3 revissd differentici pressures imptet ths test results for 1,2AF00GA/B; 1,2AF017A/B; 1,2CVll2B/C and 1,2CV112D/E. The following justification is provided for the acceptability of the testing conducted:
1,2Ar006A/3: 1,2AF017A/B The revised differeritial pressure of 104 psi considers the Essential Service Water (SX) pump to be running at shutoff head when the normally closed AF pump suction to SX supply isolation valves receive a signal to open. Due to the large number of cooling loads supplied by the SX System, operation at or near ahutoff head pressure is not considered to be a credible assumption. The normal operating pressure of the SX system downstream of the pump discharge valve is 106 psig. The 25 psi elevation head loss between the pump discharge and the AF valves is accounted for, the tested differential pressures are representative of pressures the valves are required to open against. Furthermore, these pressures could be considered as a worst case scenario since in an accident, increased demand would be placed on the SX System lowering pump discharge pressure as well as pressure at the AF valves.
1,2CV112B/C The Unit Two valves were tested at the maximum differcntial pressure practical and credit was taken for the Unit One valves due to the similiarity between units. The revised differential pressure of 77 psi considers the VCT pressurized to the relief valve setpoint and 2 psi elevation head. plant procedures limit the maximum VCT pressure to less than or equal to 65 psig. The required test pressures for the valves would be 67 psi when elevation head is accounted for with the 65 psig l administrative pressure limit. The 67 psi pressure is comparable to the 64.6 psi and 63.6 psi actual test pressures
, plus the 2 psi elevation head. Considering the valve is l
designed for a 200 psi differential pressure, adequate margin exists to ensure that the valve can function against the worst case 77 psi differential pressure.
! 1,2CV112D/E The test pressures attained in the field are comparable to the l revised maximum differential pressure of 34 psi. Considering l the valves are designed for a 200 psi differential pressure, and the open torqu3 switch by-pass setpoint set beyond the diff. pressure region adequate margin exists to ensure that the
- valves can function against the worst case 34 psi differential l
pressure.
NRC Request #3 l
l l The following MOVs of the HPSI System are not included in l Attachment A of the response of 05-15-86. However, these 140Vs are included in the NOG Report of March 1986. Revise Attachment A to include these MOVs, or justify their exclusion. As required by Action Item (a) of the bulletin,
, assume inadvertent equipment operations.
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o (a) MOVs SI8814 and SI8920 are shown normally open in the SI pump miniflow lines in zones F-6 and E-6 of Drawing M-61 Sheet lA Revision AH (Unit 1), and in cones D-4 and C-4 of Drawing M-136 Sheet 1 Revisien AH (Unit 2). These valves are shown as HV-8814-A and -B on Page 25 of the WOG Report.
(b) MOVs SI8923A-1 and SI8923B-2 are shown normally open in the SI pump suction lines in. zones E-3 and C-3 of Drawing M-61 Sheet lA Revision AH (Unit 1), and in zones C-5 and B-5 of Drawing M-136 Revision AH (Unit 2). These valves are shown as MV-8923-A and -B on Page 25 of the WOG Report.
(c) MOVs CV8111-2 and CV8110-1 are shown normally open in the CCP miniflow lines in zones A-5 and A-3 of Drawing M-64 Sheet 3A Revision AM (Unit 1), and in zones A-3 and A-5 of Drawing M-138 Staet 3A Revision AL (Unit 2). These valves are shown as HV-8110 fnd HV-8111 on page 24 of the WOG Report.
Braidwood Response A
(a) The original selection of the valves for IEB 85-03 were from those valves tested per 10CFR 50.55a(g), the Inservice Testing (IST) Program and as specified in the bulletin. At the time of the May 15, 1986 submittal, the Safety Injection Pump miniflow valves, 1,2SI8813, 1,2SI8814 and 1,2SI8920, were not included in the IST program and thus were not considered within the scope of IEB 85-03. These valves were added to the IST program on October 8, 1986. The valves are excluded from the requirements of IEB 85-03 based on being required to isolate safety injection pump miniflow during transfer to cold leg recirculation. Per the Westinghouse Owners Group report of March 1986 paragraph III. A.3, only those portions of high pressure injection required during the safety injection phase, up to but not including the manual or partial auto transfer to recirculation are considered.
(b) Valves 1,2SI8923A/B are not part of the IST program and thus t are not within the scope of IEB 85-03. These valves are not l required to change position operated during any design basis event.
! (c) At the t:me of the May 15, 1986 submittal, valves 1,2CV8110 and l 1,2CV8111 were not part of the IST program and thus were not I considered within the scope of IEB 85-03. These valves were l added to the IST program on October 8, 1986. The valves are l excluded from the requirements of IEB 85-03 based on being l active during transfer to cold leg recirculation. Per the
! West'inghouse Owners Group report of March 1986 paragraph III.
( A.3, onli those portions of high pressure injection phase, up
! to but not including the manual or partial auto transfer to recirculation are considered.
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g NRC Rrquest #4 o
MOVs AF-013A-1, -013B-1, -013C-1, -013D-1, -013E-2, -013F-2,
-013G-2, and -013H-2 are shown normally open, on the left side of Drawing M-37 Revision AF (Unit 1), and on the right side of Drawing M-122 Revision AE (Unit 2), in the AFW pump discharge lines to the steam generators. Four of these valves are in discharge lines from the motor-driven pump; the other four are in discharge lines from the diesel-driven pump. They are not included in the response; however, equivalent velves ar3 shown on page 27 of the WOG Report. Explain this exception to the Westinghouse recommendation that "all MoVs within the AFW system should be included on the list of valves to be examined for maximum differential pressure", as stated on page 5 of the WOG Report. Revise Attachment A cf the response of 05-15-86 to include these MOVs, or justify their exclusion.
Braidwood Response As stated in the response to Item 3, the original selection of valves for IEB 85-03 were drawn from the IST program. Valves 1,2AF01,3A through H were not in the IST program at the time of the May 15, 1986 submittal and thus were not considered within the scope of IEB 85-03. The valves were added to the IST program on October 8, 1986.
Subsequent evaluation of the 1,2AF013A through H valves n&s found that the valves should be included in the scope of IEB 85-03. These valves are non-active and are maintained in the open position and can only be closed by operator action to
. isolate AF flow to a damaged or depressurized steam generator.
The maximum differential pressure and applicable justification for these valves has been included in Tables 1 and 2. The valves are to be tested at the next available outage and are l considered operable based on section 10.4.9.3 of the Braidwood Final Safety Analysis Report (FSAR) which states that the
! valves are not necessary to isolate flow to a faulted steam ,
generator. A restricting flow orifice is provided in each feed line and the pumps are sized so that an auxiliary feedwater pump can deliver the required flowrate for plant cooldown with the three u.: faulted steam generators, if the required AF013 valves shoulu fail to isolate flow to the associated faulted steam generator. The testing of these valves will be tracked with Action Item 456-101-85-00302.
NRC Request #5 According to the second paragraph of the response of 05-15-86, demonstration of operability for normal system operating loads is proposed. Include abnormal loads, as required by Action Item (a) of the bulletin.
Braidwood Response l
The revised differential pressures given in Table 1 take into l
consideration abnormal events within the plant design basis.
Table 2 provides justification for the maximum differential ,
l pressures of Table 1.
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NRC Request #6 According to the response of 05-15-86 to Action Item (b), the valve supplier must certify compliance with the requirements established by the plant designer, and "therefore, no further review of the method for establishing torque switch settings is necessary or practical". Verify that the pressures used in setting the switches envelope the maximum pressures determined in Action Item (a) and that additional factors such as friction, margin of safety, degradation and wear are addressed.
Byron Response Table 1 verifies that the design pressure is equal to or exceeds the maximum differential pressure the valve would experience during both normal and abnormal events within the plant design bases.
Additional factors such as friction, margin of safety, degradation and wear are addressed in the original design calculations.
NRC Request #7 The proposed program for action items (b), (c) and (d) of the bulletin is incomplete. Provide the following details as a minimum:
(a) Commitment to a training program for setting switches and maintaining valve operators, (b) Commitment to justify continued operation of a valve determined to be inoperable (for Braidwood Unit 1 and Byron Units 1 and 2 only),
(c) Description of a method possibly needed to extrapolate valve stem thrust measured at less than maximum differential pressure, (d) Justification of a possible alternative to testing at maximum differential pressure at the plant, and (e) Consideration of pipe break conditions as required by the bulletin.
Braidwood Response l
l (a) plant procedures are in place to ensure that the material
! condition of motor operated valves is maintained at the highest l standards. Procedural compliance is required in all aspects of plant maintenance and operations. In addition, all maintenance personnel receive continuing tcaining. Trainirg topics are selected and reheduled by management based on uycoming activities, maintenance personnel experience, an! methodology improvements.
(p, 4
t-0 (b) All valves within the scope of IEB 85-03 have been determined to be operable and at no time were any valves considered inoperable based on bulletin requirements. When a valve is determined inoperable, an evaluation will be performed with respect to the operating license conditions and the applicable Technical Specifications. Appropriate action will be taken in accordance with Technical Specifications and other administrative and license requirements, including reports to the NRC as; applicable.
(c) Differential pressure testing was conducted to the maximum expected differential pressure to the extent practical for valves within the scope of IEB 85-03. Stem thrust measurements were not taken during the differential pressure testing.
(d) Valves not tested at the maximum expected differential pressure were identified as being of the same design and mar.ufacturer, with-the same or more conservative switch settings, and of the same system application as valves that had beer tested at maximum expected differential pressure.in a sister unit. This similarity of design and valve application was taken credit for in order to demonstrate valve operability for valves in which the maximum expected differential pressure could not be achieved due to system configuration / constraints resulting from plant operations.
(e) The differential pressures listed in Table 1 take into consideration pipe break conditions as part of their deeign basis events.
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a'? y TABLE 1 page 1 of 2 commonwealth Edison Company Braidwood - Units 1&2 Valve Tag Normal $P Upset _ dP _ Emergency JRP_ Faulted AP Design pressure (PSI) (PSI) (PSI) (PSI)'
1,2AF006A,B Closed 0 Closed 0 open 104- open 104 150 1,2AF017A,B Closed 0 Closed 0 open 104 open 104 ~150 1,2CVll28,C open 0 closed 77 Closed 77 Closed 77 200 1,2Cvil2D,8 Closed 0 open 34 open 34 open 34 200 1,2CV8105 open 0 Closed 370 closed 370 closed 2620 2750 ;
I 1,2CV8106 open 0 Closed 370 Closed 370 closed 2620 2750 1,2SI8801A,B Closed 0 open 2620 open 2620 open 2620 2750 1,2S18806 open 0 open 0 Closed, 32 Closed 32 200 1,2S18821A,B open 0 open 0 Closed 0 Closed 0 1500 1,2SI8835 open 0 open 0 Closed 0 Closed 0 2750 1,2AF013A-ll open 0 open 0 open 0 Closed 1450 1450 t
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e TABLE 2 Commonwealth Edison Company Braidwood - Units 1&2 valve Tag Justification for Maximum Differential pressure 1,2AF006A,B Valve is normally closed and opens on a low-low AF pump suction pressure signal concurrent with automatic AF pump initiation. Valve must be able to open against a differential pressure equal to-the shutoff head of the SX pump (129 psi) less the static head (25 psi). Maximum differential pressure is 104 psi.
1,2AF013A-H Valve is normally open and only required to close and isolate flow to a faulted steam generator.
1,2AF017A,B Valve is normally closed and opens on a low-low AF pump suction pressure signal concurrent with automatic AF pump initiation. Valve must be able to open against a differential pressure equal to the shutoff head of the SX pump (129 psi) less the static head (25 psi). Maximum differential pressure is 104 psi.
1,2CVll2B,C These valves must close on Si signal; the maximum differential pressure 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 (approximately 2 psig).
1,2CVll2D,E These valves are normally closed and are required to open against a full RWST head of water.
Maximum differential pressure is 34 psig. (Upset condition.)
1,2CV8105 This valve is normally open and required to close to provide isolation to the RCS from the CVCS.
Normal operating pressure of RCS is 2250 psi and the shutoff head of the centrifugal charging pump is 2620 psi. Valve must close against a differential pressure of 370 psi. (Upset and Emergency conditicns.) In the case of a large steam line break (faulted condition), the RCS pressure ir 0 psi and the valves must close against a differential pressure equal to the shutoff head of the centrifugal charging pump, which is 2620 psi.
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