0CAN029605, Forwards Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves
| ML20097G010 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 02/13/1996 |
| From: | Mims D ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 0CAN029605, CAN29605, GL-95-07, GL-95-7, NUDOCS 9602200339 | |
| Download: ML20097G010 (25) | |
Text
..
8-:-=-'.ENTERGY
' .* Entergy overations,Inc.
m asa 333 RuwMt AR 72801 ict 501858 5000 February 13,1996 OCAN029605 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station PI-137 Washington, DC 20555
Subject:
Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313 and 50-368 l License Nos. DPR-51 and NPF-6 Generic Letter 95-07,180-Day Response Gentlemen:
1 On August 17,1995, the NRC issued Generic Letter 95-07 " Pressure Locking and Thermal 3 l Binding of Safety-Related Power-Operated Gate Valves." The NRC requested that licensees )
provide the following information within 180 days of the date of the generic letter:
- 1. The susceptibility evaluation of operational configurations performed in response to (or l consistent with) 180-day Requested Action 1, and the further analysis performed in response to (or consistent with) 180-day Requested Action 2, including the bases or criteria for determining that valves are, or are not, susceptible to pressure locking or thermal binding;
- 2. The results of the susceptibility evaluation and the further analyses referred to in 1 above, including a listing of the susceptible valves identified; and
- 3. The corrective actions, or other dispositioning for the valves identified as susceptible to )'
pressure locking or thermal binding, including (a) equipment or procedural modifications completed and planned (including the completion schedule for such actions); and (b) justification for any determination that particular safety-related power-operated gate valves susceptible to pressure locking or thermal binding are acceptable as is.
The requested information is provided in the attached report. Should you have questions or comments, please contact me.
210013 9602200339 960213 PDR P
ADOCK 05000313 PDR ,
//8p g
U.S.NRC
. . Feb'ryary 13,1996 0CAN029605 Page 2 Ve truly yours, Dwightg,5 ims Director, Licensing DCM/dwb Attachment To the best of my knowledge and belief, the statements contained in this submittal are true.
Public in and for id>arv SUBSCRIBED County and the State AND SWORN this of Arkansas, TO/3dday beforeofme,
+ a Notary $dfaa*/
,1996.'
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1 ft////N/4WM Notary P'ublic /
My Commission Expires f/$a // 4'0/0 '
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1 i
cc: Mr. Leonard J. Callan Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Mr. George Kalman NRR Project Manager Region IV/ANO-1 & 2 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-H-3 One White Flint North 11555 Rockville Pike Rockville, MD 20852 -
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i Table of Contents
1.0 INTRODUCTION
.. .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...........3 2.0 SCOPE...................................................................................4 3.0 GATE VALVE SELECTION CRITERIA ... . . . ..... .. .... .. .. .... .. .. .. ... ............4 4.0 THERMAL BINDING / PRESSURE LOCKING EVALUATION METHODOLOGY ... . 5 4.1 Safety Function . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. 5 4.2 Thermal Binding Evaluation Criteria . .. . . . . . . . . . . ...6 4.3 Hydraulic Locking Evaluation Criteria....... . . .. .. . . . . . . . . . . . . . . . . .....7 4.4 Boiler Effect Evaluation ... . . ..... . . . . . . . .... . . . . . . . . . .....7 4.5 Entergy " Hub" Analysis... .. . . . . . . . . . . . . . . . . . . . . . . . . .... ..12 4.6 Surveillance Testmg.. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 5.0
SUMMARY
AND RESULTS . . . ....... ..... ..... ..... . . . .......................12 6.0
SUMMARY
TABLE OF DETAILED VALVE EVALUATIONS . . ... . 17 Appendix 1 - ANO Power-Operated Safety-Related Gate Valves Appendix 2 - ANO Hydraulic Locking Review logic Appendix 3 - Entergy Calculational Methodology
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1.0 INTRODUCTION
l l Generic Letter (GL) 95-07: Pressure locking and Thermal Binding of Safety-Related Power-
' l Operated Gate Valves requests that licensees perform evaluations of operational configurations of safety-related power-operated gate valves for susceptibility to pressure locking and thermal binding ,
and perform any needed evaluations or corrective actions.
l As part of the response to GL 95-07, the NRC requested that within 90 days ofissuance of the l generic letter, each licensee complete the following actions:
)
l
- 1. Perform a screening evaluation of the operational configurations of all safety-related ;
power-operated (i.e., motor, air , solenoid and hydraulically operated) gate valves to 1 identify those valves that are potentially susceptible to pressure locking or thermal binding.
- 2. Document a basis for the operability of the potentially susceptible valves or, where operability cannot be supported, take action in accordance with indisidual plant Technical Specifications.
Arkansas Nuclear One (ANO) responded to the 90-Day request in a letter to the NRC dated October 16,1995 (0CAN109509). Within 180 days from the date ofissuance of GL 95-07 each licensee is requested to implement and complete the following items:
- 1. Evaluate the operational configurations of safety-related power operated gate valves to identify valves that are susceptible to pressure locking and thermal binding.
- 2. Perform further analyses, as appropriate, and take needed corrective action (s) to ensure that the susceptible valves identified in 1 above are capable of performing their intended safety function (s) under all modes of plant operation, including test configuration.
Generic Letter 95-07 requested each licensee to provide a summary description of the following:
- 1. The susceptibility evaluation of operational configurations performed in response to 180-day Requested Action 1, and the further analyses performed in response to 180-day Requested Action 2, including the bases or criteria for determining that valves are or are not susceptible to pressure locking and thermal binding.
- 2. The results of the susceptibility evaluations and the further analyses referred to in 1 above, including a list of the susceptible valves identified.
- 3. The corrective actions, or other dispositioning, for the valves identified as susceptible to '
pressure locking and thermal binding, including: (a) equipment or procedure modifications completed and planned with associated schedule; and (b) justification for any determination that particular safety-related power operated gate valves susceptible to pressure locking and thermal binding are acceptable as is.
l The response to the 180-Day Requested actions is contained herein.
l
i Attachment to '
- q OCAN029605 15 age 4 of 17-
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2.0 ' SCOPE his report Wants the results of evaluations performed for pressure locking and thermal i bindmg per GL 95-07 for 214 ANO Unit 1 and 2 power-operated, safety-related gate valves. !
Dese valves represent all safety-related power-operated gate valves at ANO.
- ne eval ation encompasses all system modes of operation within the plant's design basis, he evaluations were conducted by reviewing ANO system operating and emergency operating i- procedures, system design basis documents, piping and instrumentation drawings, surveillaixe p testing and maintenance evolutions. He scenarios reviewed bound those conditions during q emergency and normal system operations, maintenance and testing with the exception of system "
hydrostatic testing, that would be governed by approved special test procedures. Rese procedures typically include controls for retuming equipment back to service.
Each valve was categorized under hydraulic locking, boiler effect o ' r thermal binding as Not l Susceptible, Potentially Susceptible, and Susceptible. Changes to any actions herein will be made
[ . consistent with ANO's Commitment Change Process which is based on the NEl document,
" Guideline for Managing NRC Commitments," which was recently endorsed by the NRC.
~3.0 GATE VALVE SELECTION CRITERIA' Of the total set of 214 valves,23 were considered to be not susceptible to binding or locking. - For L
instance, Unit 1 & 2 sluice gate valves were removed from further consideration because they have no bonnet and do not wedge the gate into the seats. Pressure locking or thermal binding of these
, valves is not possible. He list was further screened to 39 potentially susceptible valves by i considering only valves with an active safety function to open. Dough not considered active safety related valves, ANO-2 "once through cooling" valves,2CV-4698-1 and 2CV-4740-2, and the ANO-1 electromatic relief valve (ERV) block valve, CV-1000, were added to the population of potentially susceptible active valves, based on information provided in GL 95-07 regarding power-i operated relief valves (PORVs) and associated block valves. Fourteen (14) additional normally open valves were added to the scope to address concerns related to pressure locking or thermal 4
binding concems during surveillance testing. Appendix 1 lists the valves included in the ANO
~
review scope. His screening was based primarily on data obtained during the GL 89-10 program, .
but also included interviews with operations, design and system engineering and maintenance i personnel. A total of 56 valves were identified as potentially susceptible to binding or locking. i
- Appendix 2 describes the logic by which the valves were reviewed for susceptibility to bindmg w l 4
locking. Evaluations for pressure locking effects are subdivided into evaluations for 1) hydraulic {
locking, 2) ambient temperature induced (emrironmental) boiler effect locking, and 3) branch line induced (proximity) boiler effect locking. He evaluation methodology is described in Section 4.0.
Section 5.0 provides a listing of valves susceptible to binding or locking, and the corrective actions taken or proposed by ANO. Since a valve can be subject to more than one effect, several actions could be proposed for a single valve. Valves, which could not be shown to be in full compliance with the design basis were evaluated for operability through the ANO Condition Reporting process.
- A total of nine (9) valves were determined to be susceptible to pressure locking. Rese valves were determined to be dc ri.ded but operable. Two of the valves were modified during the last refueling
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page 5 of17 outage. Modifications are planned for six (6) valves during the next respective unit's refueling ,
outage. For ANO-1, two (2) valves will be modified by the end of the next refueling outage 2 (IR13). For ANO-2, four (4) valves will be modified by the end of the next refueling outage .
(2R12). ,
One (1) of the nine (9) susceptible valves was determined acceptable based on procedural controls.
In addition to any pressure locking modifications, eleven (11) valves have procedural changes in ,
place to mitigate the potential for thermal binding or pressure locking.
The evaluations are summarized in Section 6.0 of this report. ,
i 4.0 THERMAL BINDING AND PRESSURE LOCKING EVALUATION ;
l METHODOLOGY i The valves were evaluated utilizing the methodology discussed below and presented as logic diagrams in Appendix 2. The absence of a history of thermal binding or pressure locking did not i preclude the valve from being evaluated. For example, as routine maintenance is performed on l valves, the pressure-tightness of the valves may be increased. In such cases, valves which have not l experienced hydraulic locking problems in the past because the bonnet was leaking, may become l
I susceptible. Unless a valve has successfully opened cold, without damage, after closure at maximum potential temperature, the possibility of thermal binding was also considered to exist.
4.1 Safety Function All power-operated, safety-related, active gate valves were considered for binding / locking including valves with the power removed from them or in some other way disabled, valves locked in position, and keylocked valves. The first screening applied to the population of power-operated, safety-related gate valves was to eliminate those which could not physically lock or bind. Next, those valves that did not have an active safety function to open from a closed position were eliminated, based on the logic shown in Table 1 on the following page.
Valves in the decay heat removal and shutdown cooling systems were elim'mated since both ANO units are Hot Shutdown licensed plants. The ability to further cool the reactor coolant system using decay heat or shutdown cooling is not a safety-related function. Neither the decay heat or shutdown cooling systems are required to mitigate a design basis event.
nree valves that do not have an active safety function to open at ANO, the Unit-1 ERV block valve and the Unit-2 once-through cooling valves, were added to the population because of concems with PORVs, Generic Letter 90-06 and Generic issue 94 (low temperature over pressure protection [LTOP]). Fourteen (14) additional normally open valves were added to address concerns related to pressure locking or thermal binding during surveillance testing.
These valves all have a safety direction of open; however, they are periodically closed for surveillance testing. To ensure that they will perform their safety function when called upon, !
! they were evaluated for the potential to thermally bind or pressure lock during the sun'eillance l test. He listing in Appendix 1 tabulates these valves. Of the 191 physically potentially susceptible valves,56 were found to require evaluation using this first pass screening. During this process, the valves were checked by knowledgeable system / design engineers and l
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Attachment 10
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. OCAN0}9605 Page 6 of17
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- j. operators to determine if the normal. and safety direction information were correct.
Calculations 91-E-0091-01, Design Control Logic Review of Unit 1 Motor Operated Valves
, . and, 91-E-0091-02, Design Control I4c Review of Unit 2 Motor Operated Valves, were
, used extensively in these reviews. These reviews were augmented by'research of System 4-C iw. hug and E.T.c,;wy Operating Procedures, the Upper Level Document for the system, 4
the System Training Manual and the Safety Analysis Report, where necessary. The 56 valves
. which received individual pressure locking and thermal binding reviews are presented in l l: Section 6.0. ;
y .
Table 1 i
).
NORMPOSIT SAFETY DIR ACrlVE FUNCrION TO l OPENT l OPEN OPEN YEs (Surveillance Testing) 1
- OPEN CLDSED NO i CLOSED CLOSED NO i
OPEN/CIDSED CIDsED NO ,
- ' CIDSED OPEN YEs
- OPEN/CIDSED OPEN YEs
- . CLOSED OPEN/CIDSED YEs
$ OPEN/CIDSED OPEN/CIDSED YEs OPEN OPEN/CIDfED YEs
]
i l 4.2 Thermal Binding Evaluation Criteria
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'Ihermal contraction loads (body. contraction) and valve stem thermal expansion (stem elongation) effects were evaluated concurrently using the criteria defined below.
A. System Temperature: Valves located in systems with operating temperatures of 200*F or less were exempted from consideration of thermal binding. 200 F was chosen as the dividing point between a hot and cold system, based upon past evaluations of thermal binding for the Limerick Generating Station, the Perry Nuclear Power Plant and the i i Susquehanna Steam Electric Station. INPO confirmed the acceptability of the 200*F l j dividing line during the Susquehanna evaluation. The line temperatures that were used l
- during this evaluation were the maximum service condition values specified in ANO's !
line lists M-2083 R20 and M-83 R19.
B. Disc Confguration: Valve disc identification data identifying whether the valve discs
, were of solid wedge, flexible wedge, or double-disc parallel-seat construction was
! obtained. Double disc type gate valves are not considered susceptible to thermal i binding. The wedging mechanism between the discs collapses as the stem rises, allowing i the discs to move inward away from the seats. This permits the discs to be raised i i
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- OCIN029605 l Page 7 of17 regardless of the system temperatures. For the purposes of this evaluation, both solid
{
wedge and flexible wedge valves will be assumed to be susceptible to thermal binding.
1 Piping thermal expansion loads are generally not significant and, in fact, are not discussed as l a failure mechanism in SOER 84-7 or AEOD/S92-07 In addition, no documented industry )
gate valve failures attributed to piping thermal expansion were noted in Information Notice i 92-26, SER 20-84, SER 77-83 and SER 8-88. Acrefore, a review of ANO gate valves for ;
piping thermal expansion loads was not done. j 4.3 Hydraulic Locking Evaluation Criteria l
ne gate valve hydraulic locking phenomenon was evaluated using the following methods: l i
A. Disc Confguration: Solid-wedge gate valves were exempted from consideration for hydraulic locking, because it is not possible for the faces of a solid wedge to be pushed l in opposite directions against both seating surfaces. Valve disc identification data was l obtained stating whether the valve discs were of solid wedge, flexible wedge, or i double-disc parallel-seat construction. He Type i valve disc (see Figure 1) is occasionally designated on valve drawings as flexible wedge but in reality offers limited i flexibility. For the purposes of this evaluation, all flexible wedges were assumed as j solid wedge for the thermal binding evaluation and as flexible wedge for the hydraulic !
locking evaluation. His assures conservatism in the evaluation. l 1
B. Bonnet Relief! Valves with a bonnet drain, a bonnet relief valve or a hole through either side of the valve bridge or valve disc were exempted from consideration for hydraulic locking. His is acceptable because any pressure that leaks into or is trapped in the bonnet area will have an escape path to prevent hydraulic locking. If a bonnet drain was provided, it must have been connected to an open piping path (drain piping installed and in line valves open) to exempt the valve from consideration.
C. Line Pressure: If the pressure in the piping upstream or downstream of the valve is greater than or equal to the pressure in the valve bonnet, the line pressure will offset the pressure trapped between the faces of the disc. His will result in a maximum ;
differential pressure across a single face of the valve disc no greater than those analyzed ;
in the existing Generic Letter 89-10 differential pressure calculations. He upstream and l downstream piping pressures at opening will be determined using system / plant procedure l
reviews. I Results of these evaluations are provided in Section 6.0, Table 2.
4.4 Boiler Effect Evaluation (Environmental and Proximity)
Gate valves were screened for susceptibility using the following criteria:
A. Gas Systems: Valves which are part of gas or steam systems were not considered for boiler effect if their valve stems were oriented above the horizontal. It is highly unlikely
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l^ !
l that the valve bonnet contains liquid in these orientations. Unless the bonnet contains a i l significant amount ofliquid, it is not possible to build up the high pressures in the bonnet l that arise from heating an incompressible fluid. If the local piping configuration will not ;
collect coi4c.a te and the valve stem is horizontal, then the valve was not considered '
capable of collecting sufficient liquid for boiler effect.
I B. Bonnet Relief Valves with a bonnet drain, a bonnet relief valve or a hole through either one side of the valve bridge or the valve disc were exempted from consideration for boiler effect locking, because any pressure that leaks into the bonnet area will have an escape path to prevent locking. If a bonnet drain is provided, it must be connected to an ,
open piping path (drain piping installed and in line valves open) to exempt the valve i from consideration.
C. Valve Heat-up: Valves which have water in their bonnets experience the boiler effect phenomenon only when the trapped water is heated. For this criterion to apply, the valve {
must be in the closed position when the heat source is applied. 'Ihe potential heat i sources that were considered for this evaluation are listed below.
Normal ambient enadit ians: Normal ambient conditions were typically not i expected to cause bonnet pressurization since the normal ambient temperature swmgs are small enough and gradual enough not to cause binding. If binding were to occur, the condition would become apparent during periodic system ;
surveillance testing and would be corrected. -l 1
Accider.t ambient conditions: . Accident ambient conditions potentially impact i the fluid if they elevate the area temperature around a closed valve for a J significant period of time (several hours) before the valve must open j (environmental boiler effect). Valves which are required to open within minutes 1 I
of an accident would not be impacted by the elevated ambient conditions and were not evaluated. Accident ambient conditions were determined from ANO Technical Standard NES-13, " Environmental Qualification - Emironmental i Service Conditions," and its associated sources. i Fluid Temperatures: If the closed valve is located in a stagnant branch of a hot system, there is the potential that heat will be conducted through the fluid and/or the piping (proximity boiler effect). As the distance from the hot piping ,
increases, the heat lost to the atmosphere increases and the potential for bonnet I pressurization decreases Based on thermal gradient calculations for similar nuclear power plant applications,20 feet was used as the cutoff beyond which the heat input to the bonnet would be insignificant. This 20 foot distance must be outboard of another closed valve, a vertical drop of piping, or a restricting orifice so convection currents in the fluid are not created (see Figure 2).
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l 3
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He maximum theoretical valve internal pressure due to " boiler effect" can be .
determined by the Bulk Modulus of Elasticity Equation ' or by interpolation of specific volume data from the Steam Tables:
Pressu% = 319,000 [(Vr# - Vr%)/ Vw)
Where: V% = Specific volume ofwater at the hot temperature as found in the .
Saturated Steam Table (Temperature). I r
Vw = Specific volume ofwater at the cold {
temperature as found in the Saturated Steam Table (Temperature).
D. Disc Confguration: Solid wedge gate valves were exempted from consideration for 'I boiler effect locking, because it is not possible for the faces of a solid wedge to bc )
pushed in opposite directions against both seating surfaces. He Type 1 valve disc (see l Figure 1) is occasionally designated on valve drawings as flexible wedge but in reality ;
offers limited flexibility. For the purposes of this evaluation, all flex wedges, including q Type 1, were assumed as solid wedge for the thermal binding evaluation and as flexible wedge for the boiler effect locking evaluation for conservatism.
l 8
Reference Standard Handbook for Mechanical Engineers, Eighth Edition, pages 3 - 35
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i Figure 1 GATE VALVE DISC CONFIGURATIONS l l
i , I M h . -- - i
- }.1 l l v,,,,
d ,,---n 11,-,, 11--, c .
Double Disc, Solid Wedge Parallel Seat l
1 l
l N .
M ,
s%
v"" ,,,,,
l v'n< /,/i:3 i
i Type 1 Flexible Wedge Type 2 Flexible Wedge l
. . . _ .. .~. . . . . . . . . . . . - - . . . . . . - . . . . - . . - - - _ _ . _ _
j Attachment to OCAN029605 Page 11 of17 Figure 2 THERMAL CONDUCTION
- l r- 20' -> g RPV I h W -
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O MD y , '20 + 1 1
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4.5 Entergy" Hub" Analysis 1 I
Valves not elimmated from consideration by the above screenmg for pressure locking were funher evaluated using the Entergy " Hub" analysis method (see Appendix 3).
l
(- 4.6 Surveillance Testing i
If a system (train) is to be considered operable during the conduct of a surveillance test, then 1 safety-related valves in the system (train) must be capable of repositioning, as necessary, in response to an engmeered safeguards signal. To assure that these systems remain operable at ANO, safety-related power-operated normally open valves with a safety position of"Open", '
that are closed during a surveillance test were evaluated for susceptibility to pressure locking )
or thermal binding during the test. Because of the shon time during the test that the valves l l~ are actually closed, the, mal binding was not considered to be a concem. The valve would not I have sufficient time to change temperature by more than a few degrees. Therefore, no solid :
disk valves were considered for thermal binding or pressure locking during surveillance i testing. A listing of the flexible wedge valves evaluated for pressure locking is shown in l - Appendix 1.
5.0
SUMMARY
AND RESULTS This section summarizes valves determined to be susceptible to pressure locking / thermal binding.
Evaluations and/or corrective actions taken to resolve binding or locking concerns are listed.
Valve required thrust values were determined by utilizing the " Hub" analysis method (see L Appendix 3) developed at the Grand Gulf Nuclear Station. The required thrust values were compared to the weak link and operator capability. Conservative design basis assumptions were used as inputs to the calculation of expected margin. A test performed by Wyle Laboratories
} demonstrated good agreement between the required force predicted by the " Hub" analysis and the l- required thrust to open a test valve.
The probabilistic safety assessment (PSA) ranking process utilized for GL 95-07 was similar to the process used in ranking motor operated valves (MOVs) for GL 89-10. The subject MOVs were j initially placed into one of four priority categories based on PRA analyses: high, medium, low, and low-low (see Appendix 1).
l l The PSA ranking process involved a series of" screening" calculations using the existing ANO IPE/PSA models. Because these priorities were established in a sequential process, they will be defined in the same order as they were assessed.
High High Priority MOVs were identified in the first screening. High Priority MOVs are those which have a single Functional Failure Mode (FFM) which, when assumed to i- occur (i.e., set to TRUE), doubles the nominal core damage frequency (CDF).
l Thus, the given failure results in a Risk Achievement Worth (RAW) which is equal
- to or greater than 2.0. The RAW value is defined as the CDF calculated with the MOV FFM failed divided by the nominal CDF.
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l l Att;chment to
't 0CAN029605 Page 13 of17 Low-Low The Low-Low Priority MOVs were identified in the second screening. Low-Low Priority MOVs are those whose combined FFMs, which when assumed to occur concurrently (i.e., all set to TRUE), result in a CDF which is less than twice the nominal CDF.
Low The Low Priority MOVs were identified in the third screening.. Low priority valves ;
are those whose combined FFMs, which when all are assumed to have a bounding l high failure probability (i.e., all set to 8.7 E-2), result in a CDF which is less than l twice the nominal CDF.
l Medium 'Ihe Medium priority MOVs were identified in the last screening. Medium Priority ;
l MOVs are those which are not in either the High, Low-Low, or Low categories.
l L
The following valves were determined to be susceptible to pressure locking or thermal binding: I i: 1 Pressurizer ERV Isolation Valve CV-1000 A. Susceptible to ThermalBinding
- Corrective Action
- To eliminate thermal binding as a concern, when CV-1000 has been isolated at normal operating temperatures,
- plant cooldown procedures have been revised to require ,
! that CV-1000 be opened at the start of the cooldown and !
! left open. As an alternative to this, the valve is allowed to be cycled approximately every 100 *F during the l- cooldown to LTOP conditions. i l 1 l l 1
B. Susceptible to Environmental &
Prox. Boller Effect i
Corrective Action: Procedural heatup guidance has been established to require that CV-1000 remain open following steam J bubble formation. The valve can be opened and closed while the plant is at normal operating temperature without declaring it inoperable. " Operability" of the valve is not required as part of the ANO-1 licensing basis, since the valve has no active credited safety function. The valve is part of a redundant RCS vent path l as described in ANO-1 Technical Specification 3.1.1.7. !
l LPI/DH Loop Isolation Valves CV-1400, CV-1401 A. Susceptible to ThermalBinding Corrective Action The operating procedures have been revised to add a caution stating that the valves should remain open above 200* F, since they are potentially susceptible to thermal binding. If they are closed while above 200* F, an engineering evaluation is required.
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/ OCdN029605 Page 14 of 17 RB Sump Isolation Valves CV-1405, CV-1406 A. Susceptible to ThermalBinding Corrective Action: To preclude the potential for thermal binding, procedural requirements exist to ensure the lines are filled with water to act as a buffer. Procedures have been revised to require water filled sump suction lines any time the reactor coolant system ternperature is above 200 F.
EFW Valves CV-2620, CV-2626, CV-2627, CV-2670 A. Susceptible to ThermalBinding Corrective Action: Procedures caution against thermal binding and require an engineering review of the valves before they are placed back in senice following such an event. The valves are shut during plant cooldown. To avoid thermal binding, procedural guidance cautions against shutting the valves hot and cooling down. Engineering analysis is currently required if this situation occurs.
EFW P7A/B SW Suction Isolation Valves CV-2803, CV-2806 A. Susceptible to Environmental Boiler Efect Locking Margin: 0% (both valves)
Corrective Actions: Night orders have been issued to inform operators of the potential of these valves to bind, and provide methods of dealing with the occurrence should it happen. The valves will be modified by the end of refueling outage IR13.
Steam to EFWP K-3 and 2K-3 Turbine CV-2613, CV-2663,2CV-0340-2 A. Susceptible to ThermalBinding Documentation Results: These valves are stroked monthly and have been closed hot and opened cold successfully. Maintenance inords were examined to demonstrate that the valves have not suffered damage during previous cycles
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.* OCEN029605 l Page 15 of 17 SW to EFW Pump Isolation Valves 2CV-0711-2,2CV-0716-1 )
A. SuseeptibletoEnvironmental l Boller EfectLocking l Margin: 0%(both valves) l Corrective Actions: Night orders have been issued to inform operators of the l potential of these valves to bind, and provide methods of 1 dealing with the occurrence should it happen. The valves 1 will be modified by the end of refueling outage 1R13 EFW 2P7A to A/B Steam Generators 2CV-1026-2,2CV-1076-2 l
A. SusceptibletolhermalBinding Corrective Action: To eliminate binding due to back leakage of feedwater j through the check valves, procedures were revised to I require opening the valves successfully following an event )
of this type. Engineering is required to be notified if the valve body temperature exceeds 200 *F. .
I l
RB Spray Header Isolation Valves 2CV-5612-1,2CV-5613 2 A. Susceptible to Hydraulic Locking 1 Margin: 0% (both valves) 1 Corrective Action: Implemented short term action to stroke the valves prior j to entering MODE 3 in order to relieve any trapped <
bonnet pressure. These valves will be modified by the end of refueling outage 2R12.
B. Susceptible to Proximity ,
Boiler Efect Locking l Corrective Action: Same as above Sump Recirculation Outside Isolation Valves 2CV-5649-1,2CV-5650-2 A. Susceptible to Environmental BoilerEfect Locking Corrective Action: Bonnet pressure relief valves were installed on these valves during refueling outage 2RI1 in 1995.
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SUMMARY
TABLE OF DETAILED VALVE EVALUATIONS l Table 2 summarizes the results for each of the 56 valves requiring detailed evaluation for potential susceptibility to binding / locking.
TABLE 2 ARKANSAS NUCLEAR ONE DETAILED VALVE EVALUATION
SUMMARY
Suarentible to: Minknum Corrective Action:
Boiler Boiler Requina l Valve Tag No. Thenna: Ilydraalle Effect f,ged Doc't l Bindina 14cidna EEL) (Presi Use Asis Modify Cliannes i i
CV 1000 Yes No Yes Yes - - Yes l CV 1276 No No No No . - -
CV-1277 No No No No - - -
l CV 1400 Yes No No No - - Yes CV 1401 Yes No No No - - Yes CV 1405 Yes No No No - - Yes CV 1406 Yes No No No . - Yes CV 1407 No No No No - - -
CV 1408 No No No No - - -
CV 1414 No No No No . - -
CV 1415 No No No No - - -
CV 1436 No No No No - - -
CV 1437 No No No No - - -
CV 1616 No No No No - - -
CV 1617 No No No No . - -
CV-2613 Yes No No No Yes - -
CV 2617 No No No No - - -
CV 2620 Yes No No No - - Yes CV 2626 Yes No No No - - Yes CV 2627 Yes No No No - - Yes CV 2663 Yes No No No Yes - -
CV 2667 No No No No . - -
CV-2670 Yes No No No - - Yes CV 2803 No No Yes No - Yes -
CV 2806 No No Yes No - Yes -
Attachment to
. OCAN029605 Page 17 of 17 Suscestible to: Minimuss Corrective Action:
Bouer Bollgg Required Valve Tag No. Thernaal flydraube Effect Egggi Doc't Bindian Locidna Env.) &ros.) he As Is Modify Chena em CV 3806 No No No No - - -
CV-3807 No No No No - - -
CV 3812 No No No No - - -
CV-3813 No No No No - - -
CV 3850 No No No No . - -
CV 3851 No No No No - - -
2CV-0205-2 No No No No . - -
2CV4340-2 Yes No No No Yes - -
2CV-07112 No No Yes No - Yes -
2CV 0716-1 No No Yes No - Yes -
2CV 1026 2 Yes No No No - - Yes 2CV 1036 2 No No No No - - -
2CV 10371 No No No No - - -
2CV-1038-2 No No No No - - -
2CV-1039-1 No No No No - - -
2CV-1076-2 Yes No No No - - Yes 2CV 15015 No No No No - - -
2CV-46981 No No No No . - -
2CV-4740-2 No No No No - - -
2CV-4950-2 No No No No - - -
2CV 56121 No Yes No Yes - Yes Yes 2CV-5613-2 No Yes No Yes - Yes Yes 2CV-5630-1 No No No No - - -
2CV-56312 No No No No - - -
2CV 5647-1 No No No No - - -
2CV-5648-2 No No No No - - -
2CV 5649-1 No No Yes No - 2Ril' -
2CV-5650-2 No No Yes No - 2Ril' -
2CV 56571 No No No No - - -
2CV-5667 2 No No No No - - -
2CV-82331 No No No No . - -
- Completed during 1995
Appendix 1 to l
, OCAN029605 l Page1Of2 l
APPENDIX 1 1
VALVES IN THE ANO GL 95-07 REVIEW SCOPE (POWER-OPERATED; i SAFETY. RELATED, PIIYSICALLY POTENTIALLY SUSCEPTIBLE, ACTIVE SAFETY FUNCTION TO OPEN/ADDED SCOPE) 2C,y-0205,2 ,, .
E.M,. PUMP,pIEAM,B,yP.,, ,jMQy ., ,,,iH. . ,,,j E 1,.. ,,,j 2CV 0340-2 EFW MS ISOLATIONL !MOV !H E1
.EbEhI.i hk.. ..h.k.i.kkkk. UMP,1,SQLAllpM(,, ,[hUY[,', ,,,{((,, .j{,','
2CV 0716-1 SW ISOLATIONL FROM EFW MOV lLL E1
'56E-'1656 2 2Ef " die 65 ido E56""""~ M6E" ~ll"" EI"
.Nkh.).0fk(,','
EMjh.'5jk,',',',
~
iU4j~ $ E,j,"
.2CV-1501-5 2VUC7C ISOLATION lMOV !LL !O3 2.bkNI YIkIbEI UUk. U UU 2CV-4740-2 LTOP ISOLATIONL MOV lH lC4 2d23ssi" "kWiii6EXfi65~ U6v id ~ iXi 2Cv-56121 RB, SPRAY HDR,lSOLATIONL,., MOV !G,1 j 7
[H 2C.v-5613-2 RB SP, RAY _HDR _lSOLATlONL _ MOV i H ,, !G1 2Cv:5648.t... . ,
RB,, SUMP, PUTS!DE,,lSOLAI!QN MOV [H,, 181, 2Cv-5650-2, RB SUMP OUTSIDE ISOLATION MOV. !H i81, 29V:5657,1,,,7 ,.
2P136 SUPT,10N, ,,.MQ,y !LL. .. ,,.! F 1,,, .. ;
'26E5235i' NAOH SUCTION MOV lLL iF1 'i H2 PUR ISOLAti6N MOV iLE" lF5~ i 1
'6E5500"""" P 5'ENYi56E fi65~ "UOV~ ~YM"" '"iDi '"l
'6Y-I515~ '
65[66F6i5di65UFUUE"
. MOV lLL ! T' ~i
'CV-i277 DA'E66E Di5C."f6'M0"PUUE"' "7MOY" "'!L[" 'i3" 1 69I4U0 iNilD5166P 5IS6[ Vid5"~ M6E iE' !AI 1 kh. .g j[P,5h,',(6pyf,',)Sy,EI,yidN~ "kyf$ ~i(,',', l hj,',',, ',',',) j CV-1405 RB SUMP ISOLATION MOV lH iA3 ~j i k .!.M... bkkUUk.)khEIY! .U.......... . Ukk... b _ 3,[ l SYr.192... .B.WSI.pyTLETISO,LATION , ,,,jMOV,,, ,,,[H ,,, .,,%1,, .,,j j
,$Mr.1408., BW!I,9,yI(E.I,ljplATION. MOV, i H. ,,, ;A1_
' Cy,1,6.16,,, ,,,MApH,I,1,0.JSplATJpy,,, ..MQy,,. ,,,{((,, ,,j F1 CV ,16,1,7,_
7 NAOH,T-10 lSOLATION MOV j LL,,, ,,j F1_
pW2613,,, ,,,MS 10 EFW IURB,,K-3.,,,, ..... .. ,,
, ,,,;MQy,,, ,[(,. . ..!E1, CV-2620 EFW DISCHARGE ISOLATION lMOV !LL !E1
'6V-5625" !5EMI6i5ds'5EG5'i56E II65" 'M6E" '!LL'" IE1" CSh,262.( lE@,',y,ijcHN,'E,j{65IiOEl G MOS,'," "IL(, ]Ei.', ]
CV-2663 MOV !L iE1 : )
'Cv 26f6" '"fMS TO EFW TURB. K-3EF5"Di5d5 "UOV"' "' EE"R6EiN6ENii6E" "iEi" "l ;
CV266 i EEWif559[5U6iiUSI56E fi65'"'U6V ld !Ei
- y2j28d6.__
CV-3806 E M,@ lp jUyj,ijd{sp @Ti6N~Mpj EDG C(R SW ISOk ,,,,,,,,,,, ... . .,, MQy ilE'
!H,,,
iEj jo1,
]j CV73807 SW TO EDG E20B,,lSOLATION MOV iH i01 i Cv-3812 RB EMER CLR,1N(ET,,, MOV {(_ jpl j Cv7.3813 RB.EMER CLR,JNLET ,,,,,,,,,,,,,_ _ MQV !L ,,.jpl i
Cv-3850 EFW P7B SW SUCT!ON JSOLAT!ON,, MOV ,,
. ,,,$L , !E3,,
CV 73851 EFW P7A SW SUCTION ISOLATION MOV j tL ,. ,,j E3,.
l SIMS QFUNC Codes ending in 1,2, or 3 are considered to be active valves.
1 l
Appendix 1 to l
.- OCAN029605 l Page 2 of 2 )
VALVES ADDED FOR SURVEILLANCE TESTING CONCERNS i
li$d.'%1: 2 %$h%#2' d %205(ilBWhlll 0 M '~60lKll.C C M W,10 E 0 l2CV ,1,pp,2, I EFW BL_OCK TO SG- [LL_ jE1 j 12CV-1037-1 IEFW BLOCK TO SG- lLL lE1 i
[5CV-1038-2 YEFW BLOCK TO SG- j
!LL jE,1__
I2CV 1039-1 [EFW BLOCK TO SG- !LL !E1 f56V-5630-1 BS SUCTION ill,_ jA1_ .
i 12CV-56312 BS SUCTION iLL iAt l l I5dV-5647-1 ,RB SPRAY SUCTION jLL jB4__ _j f2CV-5648-2 !RB SPRAY SUCTION !LL iB4 i
[CV,,1414 YRB SUMP ISO jL,L j B,4 _ _ j l CV-1415 RB SUMP ISO !LL iB4 i CV-1436 DH SUCTION ill, jB3 j i CV-.1437 DH SUCTION lLL iB3 1 j CV-2617 EFW MS ISOLATION !LL !E1 i (EE555f MS TO EFW TURB ISOL EL }51 l SIMS QFUNC Codes ending in 1,2, or 3 are considered to be active valves.
l l
)
l I
Il l
l l
Appendix 2 to
. OCAN029605 Page1of3 APPENDIX 2 ANO HYDRAULIC LOCKING REVIEW LOGIC DOES VALVE NO S VALVE REQ REVIEW SYSTEM PERFORM AN ACTIVE TO BE ADDRESSED NO AND %
SAFETY FUNCTION TO FOR 011IER REASONS VALVE DATA OPEN7 I.E., GL 95-07?
YES ,
3, YES IS VALVE LOCKEDIN POSmON YES .
ORIIAVE ITS POWER REMOVED 7 NO 1r IS VALVE YES A SOLID WEDGE TYPE? ?
NO 1r IS VALVE ygg PROVIDED WITH A m BONNET PRESSURE RELIEF?
NO 1r IS VALVE NO QUIRED TO OPENIN m A DP CONDmON7 i
! YES 1r If VALVE VALVE IS NOT POTENTIALLY NO IS PIPING YES SUSCEPTIBLE SUSCEl'11BLE TO PRESSURE PRIOR TO ; TO IIYDRAULIC liYPRAULIC LOCKING OPENING 2 BONNET LOCKING "GL95-07" PRESSURE 7
i 4
Appendix 2 to
'.' OCAN029605 Page 2 of 3 j i
)
ANO THERMAL BINDING REVIEW LOGIC I
DOES VALVE 0 1 REVIEW SYSTEM NO VALVE REQUIRED PERFORM AN ACRVE TO BE ADDRF3 SED VALVE DATA NGW TO FOR ODER MMS 1 OPEN? 1.E. GL 95-077 )
YES YES IS VALVE YES l LOCKEDIN POSITION '
ORllAVE POWER REMOVED?
NO u
)
IS YES I VALVE TIIE DOLTLE -
DISK TYPE 7 1
NO U
IS NO OPERATING TEMP -
200*F OR GREATER? )
s YES U
DOES YES ALVE CLOSE WiiILE IIOT - ALLOWED TO OOL TIIEN REQUIRED {
TO OPEN7 NO U U VALVE VALVE IS NOT POTENHALLY YES IS VALVE NO SUSCEPTIBLE SUSCEPTIBLE TO c CLOSED TIIEN TO TIERMAL TIIERMAL BINDING 1EATED UP? BINDING
Appendix 2 to
- ' OCAN029605 Page 3 of 3 ANO AMBIENT / PROXIMITY HEATUP EFFECT LOCKING REVIEW LOGIC REVEW SYSTEM DOES VALVE NO S VALVE REQUIRE NO AND PERFORM AN ACTIVE TO BE ADDRESSED VALVE DATA SAFETY FUNCTION TO FOR OTIER REASONS OPEN7 I.E. GL 95-077 YES _
y YES IS VALVE YES A SOLID WEDGE TYPE 7 ?
NO u
IS VALVE NO NEAR AIEAT SOURCE -
WIUCH COULDIEAT BONNET 7 YES u
IS VALVE YES PROVIDED Wmi A m BONNET PRESSURE RELEF7 NO u
WS 3 WS IS VALVE VALVE BONNET IN GAS OR STEAM ABOVE HORIZONTAL SERVICE? POSmON7 NO NO u
VALVE NO IS PIPING YES VALVE IS NOT POTrxnALLY SUSCEPTIBLE TO PRESSURE PRIOR TO y SUSCEPTIBLE PRESSURE LOCKING OPENING Jt BONNET TO PRESSURE
.TsL95-07" PRESSURE? LOCKING
I Appendix 3 to l
. OCAN029605 Page1of1 APPENDIX 3 l
Entergy Calculational Methodology
{
A calculational methodology referred to,as the " Hub analysis" was developed by Entergy based on "first pdnciple" analysis (i.e., forces applied and basic trigonometric evaluation of valve i discs / seats) as suggested in NUREG/CR-5807 " Improvements in Motor Operated Gate Valve Design and Prediction Models for Nuclear Power Plant Systems." These calculations were 3
used to evaluate valve operability under combination loading ofpressure locking and design basis conditions.
1 On December 28 and 29,1992, Wyle Labs performed pressure lock testing on a Grand Gulf Nuclear Station Unit 2,14" - 900 # flexible wedge gate valve. The test simulated the accident conditions associated with the LPCI/LPCS Injection Valves (IE12-F042A, IE12-F042B and IE21-F005). One of the goals of the test was to substantiate the calculational methodology !
and results which were used in the Operability Resolution of GGNS's Material Non- l Conformance Report 0270-92. The report stated under accident conditions, the required thmst to open the referenced injection valves would be 82,645 lbs., 87,724 lbs., and 76,822 lbs, respectively. The variance in opening thrusts is attributed to the differences in the as-tested static opening thrust values. By utilizing the results of the Wyle test, the GGNS calculation yields 87,297 lbs required to open the test valve vs. 87,000 lbs noted during the test. This i value is based on information (90,000 lbs closing, 55,000 lbs static opening,452/1080/320 psig !
accident conditions test pressures) provided in the trip report after witnessing the Wyle test.
As evidenced by these results, one could conclude that the methodology used in determining operability of the low pressure injection valves is acceptable and sound. This methodology was presented dudng an NRC public workshop on Febmany 4,1994, which was summarized in NUREG/CP-0146.
To support this methodology, Entergy Operations' sites (Grand Gulf and Waterford 3) have i reviewed dynamic test data from their GL 89-10 programs Review of the data suggests that the hub analysis is conservative in its ability to estimate total required thrust for pressure locked valves. Therefore, the Hub analysis was used as the standard methodology to estimate thmst requirements for pressure locked valves.
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