ML20206J791

Co Program for Selected Motor- Operated Valves,Status Rept

ML20206J791
Person / Time
Site:	Maine Yankee
Issue date:	12/15/1987
From:	CONNECTICUT YANKEE ATOMIC POWER CO.
To:
Shared Package
ML20206J767	List: ML20206J764 ML20206J791
References
NUDOCS 8811290122
Download: ML20206J791 (52)

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MaineYankee ,

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l HAINE YANKEE ATONIC POWER COMPANY PROGRAM FOR SELECTED MOTOR OPERATED VALVES STATUS REPORI I

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l 8811270122 871215 PDR ADOCK 03000309 PDC O

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i TABLE OF CONTENTS MGR I. INTR 000CTION.......................................... 1 II. VERIFICATION OF COMPLETION............................ 2 A. IE Bulletin 85-03, Action Item a.............. 2 '

B. IE Bulletin 85-03, Action Item b.............. 6 C. IE Bulletin 85-03, Action Item c............. 12 D. IE Bulletin 85-03, Action Item d. . . . . . . . . . . . . 27 III. VALVE OPERABILITY.................................... 28 IV. DATA

SUMMARY

......................................... 31 V. OPEN ITEMS........................................... 40 VI.

SUMMARY

.................................. ........... 41 t VII. REFERENCES........................................... 42 VIII. ATTACHMENTS.......................................... 43 l i

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o t MaineYankee I. INTR 00lKIIM As a result of several instances of on-demand, common mode failures of motor-operated valves due to improper switch settings, IE Bulletin 85-03, Reference (a), was sent to licensees requesting that they develop a program to address the selection, setting, and maintenanct of switch settings. The development and implementation of the program was to be the result of Licensee response to the Action Items outlined in the bulletin. These Action Items

required Licensees to establish the design basis for the valves covered by the program, develep a switch setting program, stroke test each valve to determine its operability, and prepare procedures for determinatic", and maintenance of switch settings. In References (b) and (c), Maine Yankee provided the design operating conditions for the valves under this program and our schedule for completion of the Action Items in the bulletin. This schedule was to ensure completion of the Action Items within two years of the date of the bulletin.

In response to additional questions posed by the NRC, Reference (d), Maine Yankee has indicated in Reference (e) that certain portions of the program would not be completed by November 15, 1987. However, a major portion of the i

program has been completed such that a status report which provides i

information as outlined in Action Item f can be provided.

As required by Action Item f, this report presents our verification of completion for each of the individual Action Items, a summary of the as found operability of the valves, and a summary of data in the suggested data summary l format. Additionally, an Open Items section has been included to summarize j

those items remaining to be completed and to provide our schedule for l 1 completing them. Thus, this report summarizes the progress we have made

, toward completion of the program and identifies what needs to be done to bring this program to a close, i

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, i MaineYankee II. VERIFICATION OF COMPLETION Haine Yankee's plans for responding to IE Bulletin 85-03 were provided in Reference (b) and (c). This section summarizes the actions taken as a result of our plans and serves to verify that the intended actions have been completed o- identify areas where our plans changed and the completed actions  !

differ from the original plan.

II.A. IE Bulletin 85-03. Action Item a for motor-operated valves in the high pressure coolant injection / core .

spray and emergency feedwater systems (PCIC for BHRs) that are required to f

be tested for operational readiness in accordance with 10 CFR 50.55a(g),

dev21op and implement a program to ensure that valve operator switches are t selected, set and maintained properly. This should include the following components:

a. Review and docament the design basis ea the operation of each valve.

This documentation should include the u nimum differential pressure expected during both opening and closing the valve for bott, normal and abnormal events to the extent that these valve operations and events are included in the existing. approved design basis, (i.e., the design basis documented in pertinent licensee submittals such as FSAR analyses and fully-approved operating and emergency procedures, etc.). When dotermining the maximum differential pressure, those single equipment failures and inauvertent equipment operations (such l as inadvertent valve closures or openings) that are within the plant ,

i design basis should be assumed.

l tiaine Yankee Renonu Haine Yankee has completed review and documentation of the design basis j for the operation o' valves in the high pressure coolant injection function.

The results of our review are documented in References (b) and (f).

I The Maine Yankee plant is a Combustion Engineering Pressurized Water

] Reactor (PHR) and has no core recirculation or core spray systems. In addition, the Emergency Feedwater System contains no motor operated valves

! (H0Vs) which are required to operate during transients. Therefore, Maine Yankee has evaluated the high pressure coolant injecticn function which is provided by our High Pressure Safety Injection System (HPSI). The HPSI System consists of the plant charging pumps, valves and piping to enable these pumps to be changed from their normal operational duties to those required for

! accident conditions. In the recirculation mode, the Containment Spray System provides suction to the HPSI System. These systems are described in Section 6.0, "Engineering Safeguards," of the FSAR.

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i l' The HPSI System has been reviewed to identify the HOVs which are subject to the concerns expressed in IE8 85-03. All MOVs identified in response to  :

i the bulletin are shown on Figure 6.3-1 of the Maine Yankee FSAR. HOV's in the [

] HPSI System, and in the Containment Spray System which support HPSI System operation, were reviewed in accordance with the guidelines of IE Bulletin

> 85-03.

j i Table 1 lists the valves by name and number, and provides the maximum j i

differential pressure requirements. Where the numbering system used by Maine r i

Yankee differs from that used by Combustion Engineering or Stone and Hebster, both nu:nbers are given.

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, i BlaisieLiitillcene TABLE 1. MAINE YANKEE HOTOR OPERATED VALVES (HOVs) IDENTIFIED FOR IF, BULLETIN 85-03.

Maximum 01fferential Pressure Valve Type and (osid)

Valve No. Function Manufactu er_. Q21D C1011 HCV-301 HPSI Injection 1500# Globe 2,500 2700 (HSI-H-41) Header Velan Overseat Underseat HCV-302 Flow to Open or 2600 (HSI-H-42) Underseat HCV-311 HPSI to Reactor 1500# Globe 2,600 2700 (HSI-H-11) Coolant Loop 1 Velan Underseat Underseat HCV-313 Flow to Open or 2400 (HSI-H-12) Overseat HCV-321 HPSI to Reactor 1500# Globe 2,600 2700 (HSI-H-21) Coolant Loop 2 Velan Underseat Underseat HCV-323 Flow to Open or 2400 (HSI-H-22) Overseat HCV-331 HPSI to Reactor 1500# Globe 2,600 2700 (HSI-H-31) Coolant Loop 3 Velan Underseat Underseat HCV-333 Flow to Open or 2400 (HSI-H-32) Overseat LCV-204V Charging Pump 150# gate 67 (CH-H-1) Suction from Velan LCV-204S Volume (CH-H-87) Control Tank .

t H0V-204U HPSI Suction 150# Gate 67 215 (HSI-H-51) from RHST Velan HOV-204T (HSI-H-50)

H0V-3209 HPSI Suction 150# Gate 215 (HSI-H-55) from Residual Anchor H0V-3210 Heat Exchangers Darling L (HSI-H-54)

H0V-3206 Spray Pump 150# Gate 20 (LSI-H-41) Suction from Anchor (HCV- 318 K) RHST Darling HOV-3205 (LSI-H-40)

(HCV- 317 K) 9288L-LHO

I I MaineYankee TABLE 1 (Cantinuedl Maximum Differential Pressure Valve Type and (osid)

Valve No. Function _da!,facturet__ Onta Cin32 HOV-3207 Spray Pump 150# Trunnion 41 (CS-H-91) Suction fron Post-Seal (HCV- 337 K) Containment HOV-3208 Sump (CS-N-92)

(HCV-338 K)

HOV-3202 Spray Pun.p 150# Gate 21E (SIA-H-53) Recirculation Ar.chor (HCV-305 K) to RHST Ozrling HOV-3204 (SIA-H-54)

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• NRlllCYRilbCO II.B. LLBullttifL85-03. Action Ite_m_b Using the results from item a above, establish the correct switch settings. This shall include a p.ogram to review and revise, as necessary, the methods for selecting and setting all switches (i.e.,

torque, torque bypass, position limit, overload) for each valve operation (opening and closing).

3 If the licens9e determines that a valve is inoperable, the licensee shall also make an appropriate justification for continued operation in accordance with the applicable technical specification.

Maine Yankeel esRQa51 Except as described below, Maine Yankee's program for selecting and setting switches as required by this Action Item has been completed. Our schedule for completion of this Action Item is provided in Section V, of this report, In response to an NRC request for additional information, Reference (e),

4 Haine Yankee determined that valves HSI H-11, 21. -22, -31, -32, -41, and -42 will be required to both open ar d close under accid 6.t conditions.

Our response, Reference (f), ind'cated tl.at these valves will be required to

> close with 2700 psid under the sest. Since we had not considered valve closure previously, we will need to perform cciculations in accordance with this Action Item to determine if the current switch setting remains applicable. He also need to comp 11te some maximuni force calculations for stem stop assemblies, reach rods, and applicable valves. Finally, lost motion is being experienced during the operation of CS-H-91 and 92. This needs to be

evrluated to determine whether swit*h settings should be 'nodified to recover

the "t motion during design flow conditions.

I Our switch setting program which us provided in our risponse, Reference 4

(d), to an NRC request, Reference (c), ha,' been completed. The switch settings which were established for each valve followed the guidelines provided below. As a result of our expertenu in implemencing these i guidelines, some revisions have been made. These change; are noted by a vertical line in the left hand margin.

1"Ltc1LSett.lA23uideline Natti Guidances 1-6 below are for globe and gate valves which are torque closed and opened on limit.

1. Selecting

a. Open Limit Switch i

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i) 4 rotor limit switch l The open liutt will be set such that the valve does l not come in to the back seat even by momentum and <

inertia. This may initially be set at 95% and adjusted if necessary by use of information in the [

valve signatures.  ;

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11) 2 rotor limit switch (open limit coincident with l close bypass) l The open limit will be set such that the valve does  !

not come in to the back seat even by momentum and/or  !

inertia. This may initially be set at 951 and I adjusted if necessary by use of information in the  !

valve signatures.

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b. Closed Limit Switch i s 1) 4 rotor limit switch  !

4 i l The closed limit switch will be set such that the l

valve position indication indicates closed when the j J

valve is aporoximately within 1% of being in the seat, i l

l 11) 2 rotor limit switch  !

! In this case the closed limit is coincident wi3h the open bypass. The open' bypass is given precedence }

) and, therefore, the close limit is not applicable, j c) Open Bypass Limit Switch

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j i) 4 rotor limit switch

! The limit switch will be set at approximately 10% ,

1 (-2%, +5%) of valve travel beyond the valve coming  !

out of the seat.

,! 11) 2 rotor limit switch i t

In this case the open bypass simit is coincident with [

the closed limit. The open bypass limit setting is

• given precedence and will be set at approximately 10% I q (-2%, +5%) of valve travel beyond the valve coming out of the seat. l

d. Close Bypass Limit Switch

i) 4 rotor limit switch -

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d I MaineYankee The closed bypass limit switch will be set such that it covers that part of the stroke during which interrittent forces such as hammer blow occur. This may initially be set at 95% and adjusted if necessary according to valve signatures.

11) 2 rotor limit switch (close bypass coincident with open limit)

The close bypass does not take precedence over the open limit and is r.ot applicable.

e. Close Torque Switch

1) Hinimum setting The minimum setting shall be determined by the thrust or torque required to operate the valve at the design condition plus 16% margin.

The thrust will be determined as follows:

a) Calculation Required Thru11 - Differential Pressure Factor +

Stuffing Box Factor + Piston Effect Differential Pressure Factor = Differential Pressura X Seat Area X Valve factor Stuf fing Box Factor - f(stem size. packing)

(this factor may be determined by vendor tables) 03 Stuffing Box Factor - (1000 x stem dia in inches) lbs.

Piston Effect = pressure of system x area of stem MDIOR b) Testing l For detail on testing see II.C Testing Heth js

11) Maximum s; sting The maximum setting will be based on the physical limitations of the operator, valve, or unit assembly whichever is lower.

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l MaineYankee a) Operator limit That value which Limitorque (vendor) specifies as the maximum setting so as not to cause operator damage.

b) Valve lim 46 l

The value of thrust which the valve can take without exceeding 85% of the yield value of the  ;

most limiting component. This yield value '

should consider the combination of loads required by design (i.e., Seismic, End Loads, ,

Pressure, etc.) '

l EQII: 45% is an Arbitrary Safety Factor.

L EQII: .omplete calculations may not be required when the '.alve is significantly stronger than the operator or other limiting i components.

c) Unit Assembly limit This thrust value will be determined as in the va he limit above but will consider the strength of items not previously considered, such as, reach rods, valve to operator couplings, and stem stop assemblies.

f. Open Torque Switch I

The open torque switch settings will be set to maximum as determined in e.li) above. >

g. Overloads j l i) Overload selection may be according to the method i

described in Attachment (A).

1 1 11) 11 the data required to size the overload by the method in (a) aboya is not available, ihtn the  !

overload should be sized to trip for 10 seconds of locked rotor motor current, t l

h. Gate or Globe Valves That Close on Limit Switch settings for these valves will be the same as 1.a l through 1.g. above uttat as noted below: I I

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1) Closed Limit Switch i a) 4 rotor limit switch The closed limit switch will be set such

' that the valve seats closed. (Probably by momentum). '

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The closed limit switch will be set such that th6 valve stops when goroximately within 1% of being in the seat. t The above choice will most likely be determined by whether tightness of the valve is important. L b) 2 rotor limit switch f The closed limit switch will be set such that l the valve does not seat. This is because there t

, is no torque bypass function available, f

11) Maximum Torque Switch Setting (Open or Close)  !

1 The valve does not have the stress produced by torque  !

i during normal operation of the plant. Therefore  !

seismic loads for these valves need not be included  ;

b the combination of loads as in e.11) b) above. ,

1. Butterfly Valves t i

1) Butterfly valvt switch settings will in geteral be t the same as in ).a through 1.h. above. Hevever, i differences may occur due to the function and/or 6 tonstruction of the valve. These differei.ces follow: l l

a) Limit Stated Butterfly (CS-M-91. 92) (Two Rotor l Limit Switch) j The function of these valves in the close f direction is to provide containment isolation. [

The expected condition of operation is no flow i and no pressure. These valves open on RAS and since they close on limit, there is no torque bypass. Manufacturer's information indicates that this function is not needed to overcome unseating forces, j i

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MaineYankee b) High Velocity Butterfly The "high velocity" refers to the fluid passing 2

through the valve. A high velocity butterfly may have maximum force required for operation at other than the near full closed porition.

Switch settings for valves of this type should be considered on a case by case basis and will be primarily concerned with preventing inadvertent torque switch operation at the point of maximum force.

2. Setting

a. The sotting of limit switches will be done using approved orocedures. Use of valve signature traces will be used, t when available, te help accomplisn the switch setting in accordance with the guidelines set forth in 1.a through 1.1.

b. The setting of torque switches will be done as in a) above with the following differences:

Measured values of thrust or torque fer the design condition of the valve will take precedence over calculated thrust or torque values. Subsequently these values will be used to determine the minimum torque switch setting.

c. Thermal overload protection devices shall be fleid vertfled to be the correct size as determitied in 1.g.

3. Maintaining Sw!tch Settings

a. All limit switch settings, once completed, are not subject to drift and, therefore require checking or resetting on')

siter the following maintenance activities:

1) Removal of operator from valve

11) Removal of limit switch 111) Removal of stem nut

tv) Any repair requiring removal of any gearing during some part of the maintenance evolution l

b. Torque switch settings should be checked by calibration once every 10 years,

c. The determination of whether the valve can still properly perform subsequent to minor maintenance such as packing adjustment, is made as follows:

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! i) The thrust or torque at which the valve operator

( trips due to actuation of the torque switch will be l measured during initial testing.

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11) The thrust or torque due to design forces will be determined by taking the design thrust or torque and subtracting the thrust or torque measured during a stroke with no pressure or flow in the valve.

l l 111) The thrust or torque due to design force will be ,

I subtracted from the value in 1) above. This value l will be the maximum acceptable running load, iv) A value of motor load or current will be correlated I with the maximum acceptable running load. This value l of motor load or current minus some safety factor I will be used as a "go-no go" value for the maintenance technicians.

v) Whenever minor maintenance is accomplished the valve

. will be stroked subsequert to the maintenance. A 1

value for motor load or c e rent will be measured at the appropriate Motor Control Center. If this value is less than the "go-no go" value then the Motor Operated Valve is acceptable.

d. Motor overloads, if replaced, will normally be replaced by

[ the same size overload device. If a different type or I different manufacturer is used for overloari protection ihtn the method of 1.g. will again be used to assure that the proper size is chosen.

II.C ILB111e.tifLB5-0L Aution Iteste

! Individual valve settings shall be changed, as appropriate, to those l established in item b, above. Whether the valve setting is changed or i not, the valve will be demonstrated ta be operable by testing the valve at the maximum differential pressure determined in item a above with the

exception that testing motor. operated valves under conditions simulating I a break in the line coitaining the valve is not required. Otherwise,

* ification should be provided for any cases where testing with the l 'm differential pressure cannot practicably be performed. This I

(cation should include the alternative to maximum differential re testing which will be used to verify the correct settings.

l l m: This bulletin is not intended to establish a requirement for i valve testing for the condition simulating a break in the line containing the valve. However, to the extent that such valve operation is relied upon in the design basis, a break in the line containing the valve should be cor.*1dered in the analyses l

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settings for pipe break conditions should be vertfled, to the extent practical, by the same methods that would be used 'o verify other settings (if any) that are not tested at the maximum differential pressure.

Each vahe shall be stroke tested, to the extent practical, to verify that the settings defined in item b above have been properly implemented i even if testing with differential pressure can not be performed.

Maine YankJ A Rupn ig '

Haine Yankee has addressed this Action Item in two phases. First, we have implemented the switch setting guidelines as outlined in our response to Action Item b. Second, we evaluated the available testing methods and valve data to determine the testing necessary to verify that the switch settings were appropriate. At this time a significant portion of this Action Item has been completed. However, as our letter, Reference (f), in response to an NRC request for additional information, Reference (e), indicated some of our plans for the program had to be revised. Thus, se may be unable to fully complete this item until the next schedulM refueling outage. Our actions .oward completion of this item are presented below.

Calculated target thrusts / torques were based on the switch setting guidelines which were a result of Action Item b of the bulletin. Tables 2a and 2b provide summaries of the calculated target thrusts and torques and the measured as found and as left values. Target thrusts for the H0Vs not d'fferential pressure tested were determined by selecting the most r nservative value available at the time of testing. Target thrusts /to:1ues l or valves that were differential pressure tested were equal to or greater chan 115% of the measured thrust at worst case differential pressure. In general, target thrusts were assumed not to conflict with maximum settings based on valve limit since these were not known at the time of testing.

Limit switch settings were also determined using the switch setting guidelines. During the testing an adjustment was made to section 1.c of the guideline to specify that "The limit switch will be set at approximately 10%

i (-il, +5%) of valve travel beyond the valve coming out of the seat." This switch setting guideline for limit switch bypass was slightly different than the policy prior to the bulletin. Therefore, valves that had not been worked on prior to testing for the bulletin were usually found to be "out of adjustment." Valves that had been worksd on were often very close (<1%) to the desired setting. Thus, HOVfTS testing seemed to be unnecessary for successful limit switch setting. Table 3 is a summary of the open bypass limit switch settings and st,'oke time for computation of percent bypass. None of the as found or as left open limit switch settings allowed the valves to coast in to the backseat. The only gate valves which had a close limit setting, HSI-H-50 and -51, were set close to seating as shown an Table 2a.

The 0% bypass of CS-N-91 and -92 is not cri+1 cal to the valves' op3rability since the torque switch is set higher than the design differential pressure unseating forces.

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TABLE ta

Calculated and Measured Thrust Values

_ Calculated Target Thrust (1bs) As Found Thrust (Ibs) As Left Thrust (los) _

valva Limitorcue 8 MOVATS Open Close Open Close Open Close Switch Total Switch Total Switch Total Switch Total Trio Trio Trio Trio JSL-M 21.706 10.520 13.930 24.22.0 26.280 29.100 30.560 ._ 22.020 24.000 21.180 23.820__

_HSLd-12 21.706 IDJZO 13.980 17.040 20.000 30.300 32.300 _21.500 _24.380 22.840 24.780_.

HSI-M-2? 21.706 10.6Z0 13.930 36.300 44.000 24.100 26.150 24.000 26.135 21.250 23.500 1151- % 22_. 21.205 10.6ZD__ LL.930 40.030 41.750 32.150 41.800 23.350 24.540 20.500 23.450

_BSI-%31 21.706 10.62D_ 13.980 _

46.650 49.900 29.650__32.100 21.300 24.000 21.'450 24.000_

JSI-M-2 21.706 1DJ20 13.980 51,200 60.900 37.550 39.650 21.850 23.780 21.800 23.400

_BSI-M-4! 37.422 16.590 21.620 37.950 40.750 38.450 42.150_ 39.550 43.450 36.450 40.750 JSI-M 42 37.422 16.590 21.620 26.550 34.900 34.800 39.650 39.050 45.250 39.400 43.600 JE%50- 8dO7 7.150 4.580 6.650 18.750 0' 0'- 26.900 37.750 0* 10.000

_H;I-M-51 8.407 7.150 4.530 23.600 40.000 0* 0** 28.600 40.250 0* 7.650 JSI-M-54 3.537 4.810 3.D95 NA+ NA+ 1.216 L 670 v 5.000+ 3.118 3.659_.

ESI-%55 3.537 4.810 3.095 NA+ NA+ 2.660+ " 5.000+ 3.423 3.613

_SIA-M-53 3.537 4.810 3.095 NA+ NA+ 2.776+ ~ 5.000+ " 5000++

JIA-M-54 3.537 4.810 3.095 NA+ NA+ 1.749+ ~ 5.000+ " 5000++

_CH -M- 1 1.3D5 335_ _ Z6_0 3cC_ 1900 3.900 4.500 4.140 6.340 1.420 2.640

_CH -M-87 1.305 336 260 966 1.156 878 10J0 926 1.120 520 4.240

_LSI-M-40 4.081 3.Z_10 1.900 lbs 5.150 7.150 8.244 8.570 8.050 8.350 a 7000++

_LSI-M-41 4.081 3.210 1.900 lbs 9.180 10.720 _Z.580 -

9.180 10.720 " 7000++

Closes on Limit Valves not seating

+ The use of the SST on reach rodded valves limited car ability to gather data

++ Thrust values resulting from torque switch adjustments subsequent to MOVATS testing are based on the "three point graph" provided by MCVATS 9334L-LM0

1 TABLE 2b Calcula*ed and Measured Torque Values

_Calculited Ictque_ ASl0Madl0LQue_ ALLt ?t Torque Valve (ft-lhs) (fl}t1) (ft-lbn)_

Jpen Targtt Optn i Clou _J pen _ Close JS-M-9L J 37 450' >1000+ _ > 1000n 665 SQ L 35-B-9L_._317 3M >1000_ _ 2.1000 460 760_ L Based on calculations for CS-N-92

+ Torque switch wired backwards l

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TABLE 3 Summary of Stroke Times and Limit Switch Settings Stro h l.1me Qggn_Jlypu;.I Valve _Open Cloit___ _Sec__ _ _L_ _

jiSI-M-11 5.2L 5.47 9L _]SL

,__1151-11-12 _ -_ 4 . 8_0_ 4.97 . 81__ 10A, liSI-M-21 4 . 3L ._4. 59 . 97-- __10 . 0 _

_jiSL-Ji.22 _3.82 _. 4 . 0 9 _ .77 _1A1.

__HSI-M-31 4.40 _ L86 .8L_1QA.

_}iSI-M-32 4.13- 4.30_ m B6_ _ _10_. 0 _

HSI-M-4! _10.23_ _10Ji9 14L _10 A  :

. JfSI-h 42 10 5L _LQ.s85__ _ L4 L __102 L

_liSL-M-50 8.89 8.95 . 9L s.6 HSI-M-51_ _ 8.17 __ 8 . 23, = 1.34_ 11.9 '

_ jiSI-M-54 _ 31.72_ _32J2 4.2L 9.9

_JiS L-M-55_J210L _32.1B__ _adL_1015_

._.51 A-H-5 3__ ._3.2. 7 7 32.95 __L60__104 L

._SIA-M J4 ,_3011L_30.25 _4.73 _1 1. 4 --

,__CS..-M 91_ 29.90 _30104 _ .18_ 01__

,_CS- M-92 _31_.63 31.75 .17 0*

CH- M-1 _10.20_ 10.26 1.79 9.L

_CH-_M-87 8 . 2 5_.__L35 1.60 _,l.1.0_

, LSI-M-40 95.35= 94.60_ 12.35 10.4_ i l_ LSI-M-41 96.60_ 96.95 12.10 10 2_

Two rotor limit switch MOV that closes on limit l

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i All of the calculated and actual torque switch settings are cummarized in Table 4. This taMt shows that the torque switch cettings based on field measurements are often different from the calculated settings. In these l cases, the torque switch settings wera revised.

The data used to calculate thermal overload sizes using the method shown ,

in Attachment A is summarized in Table 5. Additionally, the results of the J calculations and the present heater size is presented in the table. In accordance with Table 5, the thermal overload devices have been replaced on all valves except valves CH-H-1 and -87. The thermal overload devices on i

, these two valves will be replacid by the end of the next scheduled refuelir.D

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Maine Yankee had several test methods available to verify that the switch  ;

settings were correctly set to allow the valves to perform their required >

function during design basis differential presture conditions. These test methods were provided in Reference (d) and received further clarification in i

Reference (f). The test methods for verification of switch settings are

, summarized below.

TESTING HETH005 2

1. This test method applies when a valve is identical, or has 1 sufficiently similar valve-operator combinations to a reference valve that has been testea usin) method 3 below. The valve is i

stroked in the required direction (s) with minimal differential pressure or flow applied across the valve. The data is compared to that for the reference valve to determine the correctness of the

, torque switch settings. The limit switch settings can be verified j without data comparison.

2. If the valve is identical, or has valve-ope ator combinations sufficiently similar, to a reference valve that has been tested

! using methods 4 or 5 balow, its switch settings can be verified i using the method outlined here. The valve is stroked in the

required direction (s) with minimal differential pressure or flow

! across the valve. The test data is then compared with the data for the reference valve to verify the correr.tness of the torque switch aettings. The limit switch settings can be vertfled without soeparing the data with that of the reference valve.

1 3. Valves that have adequate supporting celculations or test data for torque swita.h settings can be tested using this method. Examples of

supporting calculations are

.

Required Thrust = Delta P Factor + Seat Area x Valve Factor u

1

, 9288L-LHO l

s .s s

d TABLE 4 Torque Switch Settings Summary Calculated Sentings Actual Settinas o e' Limit 0Igye Settinas Movats Settings Oriainal Modified Open Close As Found As f. eft Valve _ Min / Max MinLMax Max Max _00en Close Ooen Close HSI-M-11 2.5/3.5 2.75**/2.75+ 1.4 1.2 _ 1.5 1.5 1.25 1.1 15 HSI-M-12 2.5/3.5 2.75**/2.75+ 1.75 2.125- 1.5 _2.25 1175 2.0 HSI-M-21 2.5/3.5 2.75**/2.75+ 2.4 2.5 3.5 2.5 2.125 2.25 HSI-M-22_ _2.5/3.5 2.75**/2.75+ 2.125 2.25 _3.5 2.75 2.1 2.0 HSI-M-31 2.5/3.5 2.75**/2.75+ 1.75 1.875 3.5 2.0 1.75 1.75

!!SI-M-32 2.5/3.5 2.75**/2.75p 1.25 1.25 3.5 2.0 1.125 1.125 HSI-M-41 2.25/2.75 2.5/2.5*" 2.2 2.2 1.75 1.815 2.0 1.875  !

HSI-M-42 2.25/2 25__

t 2.5/2.5** 3.0 2.75 2.0 2.5 2.5 2.5 HSI-M-50 1.0/2.75 2.0/2.75** 3.75 4.3 2.5 1.5 2.5 2.0 HSI-M-51 1.0/2.75 2.0/2.75** 3.4 3.6 2.5 1.5 2.5 1.5 '

__HSJ-M-54 2.5/4.0 2.5/4.0 Not Given Not Given 4.5 2.0 4.0 2.0 l

_B3J-M 2.5/4.0 2.5/4.0 N/A N/A 4.0 2.0 4.0 3.0 SIA-M-53 2.5/4.0 2.5/4.0 Not Given Not Given N/A 3.0 4.0 4.Q__

SIA-M-54 2.5/4.0- 2.5/4.0 Not Given Not Given 2.5 2.5 3.25 4.0 '

__CS -M-91 4.0/4.0 1.0/1.0* Not Given Not Given 3.0 2.0 1.0 1.0 ,

CS -M-32__4dL' O 1.0/1.0* Not Given Not Given 3.0 3.0 1.5 1.0 CH -M-1 '.25/3.0 1.0/3.0** N/A N/A 2.75 2.75 3.0 1.25 CH -M-87 1.23/3.0 1.0/3.0** 3.6 4.2 2.25 2.75 2.75 1.0 t LSI-M-40 1.5/2.25 3.0/2.25** 3.3 3.3 2.0 2.0 2.25 2.125 LSI-M-41 1.5/2.25 1.0/2.25** 3.0 3.3 2.25 0.25 2.25 3.125

• New Spring Pack ** Different differential pressure + original setting invalid Note: The HOVATS settings aie calculated based on field measurements.

,i W

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. -. .- - - -. ~

.= c

• w .

TABLE 5 MOV Data LRA Present New Item Valve Time Heater

_HQ. Desio. HE. Duty ELA LEA . Withstand Time Stroking Time Heater Size Size 1 .CH-M-1 1.33- 15 min. 2.3 14.0 10 sec 10 sec H27 FH21 (LCV-204S) 2 CH-M-87 0.66 15 min. 2.3 14.0 10 sec 10 sec H30 FH21 (LCV-204V) 3 CS-N-91 0.133 15 min. 0.95 5.0 10 sec 30 sec H17A FH12 (MOV-3207) 4 CS-N-92 1.33 15 min. 0.95 5.0 10 sec 30 sec FH18 FH12 (H0V-3208) 5 HSI-M-11 2.59 15 min. 5.75 50.0 10 sec 10 sec H37 FH35 (HCV-311) 6 HSI-H-12 2.59 15 min. 5.75 50.0 10 see 10 sec H37 FH35 (HCV-313) 7 HSI-H-21 2.59 15 min. 5.75 50.0 10 see 10 sec H37 FH35 (HCV-321) 8 HSI-H-22 2.59 15 min. 5.75 50.0 10 sec 9 sec H36 FH35 (HCV-323) 9 HSI-H-31 2.59 15 min. 5.75 50.0' 10 sec 9.5 see H37 FH35 (HCV-331) 10 HSI-H-32 2.59 15 min. 5.75 50.0 10 sec 9.5 sec H36 FH35 (HCV-333) 11 HSI-H-41 3.9 15 min. 6.1 59.7 10 see 11.8 see H39 FH36 (HCV-301) (7.8) 12 HSI-H-42 3.9 15 mine 6.1 59.7 10 sec 11.2 see H38 FH36 (HCV-302) (7.8) 13 HSI-H-50 3.2 15 min. 5.2 36.0 10 sec 20 see FH36 FH33 (HCV-2040) 14 HSI-H-51 3.2 15 min. 5.2 36.0 10 see 19 sec H36 FH33 (HCV-204T) 9334L-LHO

'i i TABLE 5 (Continued)

MOV Data LRA Present New Item Valve Time Withstand Stroking Heater Heater

_Hg2 Desia. HE Duty ELA LEA Time- Time Size Size 15 HSI-H-54 0.32 15 min. 0.95 5.0 10 sec 30 sec H17A FH12 (HOV-3209) 16 HSI-H-55 0.32 15 min. 0.95 5.0 10 sec 30 see H19 FH12 (H0V-3210) 17 LSI-d-40 0.5 15 min. 2.3 12.3 10 sec 100 see H27 FH21 (H0V-3206) 18 LSI-H-41 0.32 15 min. 2.3 12.3 10 sec 100 sec H27 FH2' (H0V-3205) 19 SIA-N-53 0.32 15 min. 0.95 5.0 10 sec 32 sec H18 FH12 (HOV-3202) 20 SIA-k-54 0.32 15 min. 0.95 5.0 10 sec 31 sec H18 FH12 (HOV-3204) 1 3

9334L-LHO

MaineYankee  !

l Delta P Factor - Delta P x Seat Area x Valve Factor l

Stuffing Box Factor - f(stem size, packing) [This function is  !

usually tabulated]

Piston Effect - pressure of system x area of stem The valve is stroked in the required direction (s) with the maximum available differential pressure across the valve. The measured

.. values are compared to the values predicted by the calculations for the given test pressure. This should verify the correctness of the i calculations. If the measured values do not agree with the predicted values, an extrapolation technique is used to determine the value of thrust required for design differential pressure.

This technique requires that test data be used to generate a line of the form y - mx + b which relates target thrust to differential pressure. The resulting line is then used to give values of target i thrust for selected differential pressures. Test data for measured i thrust are compared to predicted thrust for design condition l differential pressure to verify the correctness of the torque i switch setting. l l 4. This method involves design differential pressure testing of the valve. The valve is stroked in the required direction (s) with the calculated design differential pressure applied across the valve. l The test data are used to verify the correctness of all current '

switch settings and are used to determine the adequacy of future switch settings. l

5. This method is used for valves that can be removed and shipped ,

offsite. The valve is installed in a qualified test facility and i stroked in the required direction (s) with t h calculated design l

differential pressures applied across the valve. The data are then  !

used to verify the correctness of current switch s9ttings and used to determine the adequacy of future switch settings. ]

For each of the above test methods, Maine Yankee used a test system

, provided by MOVATS, Inc. The stroke tests were monitored and the data were recorded using the system. Depending on the valve configuration, either a load cell, a stem strain transducer (SST) or a torque measuring system (THS) was used to determine the thrust values. The SST was used for valves HSI-H-54. -55, and SIA-H-53,- 4 because of their reach rodded configuration.

In order to obtain torque values for CS-N-91 and -92, the TMS was used. All other valves used the load cell to measure the thrust values.

All of the testing performed at Maine Yankee was organized around a i database developed by H0 VATS Incorporated. This database provides the

reference valve data necessary for testing methods 1 and 2. Because this database has been used by a large segment of the industry in their programs l

l l 9288L-LHO l -

MaineYankee for this bulletin, Maine Yankee assumes thht the NRC is fainiliar with the .

, database and has not included a descriptior, of it here. Cete.minatic.n of  ;

4 which valves required differential pressure testing was based on Noverrher 1985 ,

correspondence with MOVATS Incorporaced Since then, it nas been determined that the database cannot be applied to certain valves. Therefore, for differential pressure testing, the valvas have been organized aroLnd their applicability to the MOVATS database. The */alves fall into the following four categories: '

1. Valves which ' :tinue to be covered by the H0 VATS database. ,

2. Valves which ,,vre thought to have been covered by the database in  :

November 1986, but have since been determined to be beyond its ,

scope.

3. Valves which were thought to be beyond the scopo of the database in .

hovember 1986, but have since been determined to be within its scope.

i

4. Valves which were assumed to be. and remain, beyond the scope of '

i the MOVATS database.

Each valve category is discussed separately below. i Category 1 '

This category includes valves 3 through 16 of Table 6. Table 6, which was provided by H0 VATS, Inc., is a summary of how H0 VATS database  !

, oresentiv apolies to Maine Yankee. Maine Yankee has concluded that i

these valves are part of a sufficient data base and therefore differential pressure testing is not necessary.  ;

The minimum target thrust only is considered. Actual thrusts greater than H0 VATS maximum target thrusts are considered conservative as long r as they are less than the maximum vaiue determined according to the ,

I switch setting policy described previausly in response to Action Item b ,

of the bulletin, i Valves 3 through 8 (Table 6) have the following additional  ;

l considerations:

1) These valves were found to be thrusting more than the design I maximum. This high thrust may be the result of variations on the friction factor, spring pack constant, or contactor dropout time. This overthrust condition has been corrected as a result of this Bulletin. The effects of repeated overthrusts during their operating history are still being evaluated.

2) These valves are routinely stroked against full pump flow and ,

head as part of Maine Yankee plant surveillance procedure. .

L 9288L-LHO

TABLE 6 Diftsrential Pressure Thrust Calculations for Mains Yankee Atomic Power Company ..

"0 VATS CALC THRUST -DP DP DP LINE ORIFICE STEM CO DP OC DP TARGET THRUST RANGES- TEST. .-.

CO OC PRESSURE DIA DIA THRUST THRUST CLOSE-TO-OPEN CPEN-TO-CLOSE REQ'D Valve ID Size Type Manuf Actuator (PSI) (PSI) (PSI) (IN.) (IN.) (LBS) (LBS) MIN MAX MIN .. MAX CO OC NOTES.

1 HSI-M-41 4 GLS VELAN 1 2600 - -

2.500 1.375 13780 -

15847 17225 Y - 1,4,6 2 HSI-M-42 4 GLS VELAN 1 2600 -- -

2.500 1.375 13780 -

15847 17225 -- Y - i,4,6 3 HSI-M-11 3 GLB VELAN 0 2400 - -

?.000 1.125 7659 -

8808 9574 -- N > 3,4,6 4 HSI-M-12 3 GLS VELAN O 2400 - -

2.000 1.125 7659 - 8808 9574 N - 3,4,6 5 HSI-M-21 2 GLB VELAN O 2400 - -

2.000 1.125 7659 -

8808 0574  ; - 3,4,6 -

6 HSI-M-22 3 GLS VELAN C 2400 - - 2.000 1.125 7659 -

8808 9574 -- - N - 3,4,6 7 HSI-M-31 3 GLB VELAN O 2400 - - 2.000 1.,1?S 7659 - 8808 9574 N - 3,4,6 8 HSI-M-32 3 GLS VELAN 0 2400 -- -

2.000 1.12.5 7659 -

8808 9574 N - 3,4,6 9 CH-M-1 4 FWG VELAk 00 67 67 3.063 1.000 1877 2252 2440 -- *! 2,4.5,7 ,

10 CH-M-87 4 FWG VELAN 1.000 2252 2440 00 67 67 3.063 1877 - N 2,4,5,7 1 11 CH-M-50 10 FWG VELAN 1 67 215 215 7.875 1.500 3476 6111 4171 4519 7023 7639 N N 2,4,5 12 CH-M-51 10 FWG grLAN 1 67 215 215 7.875 1.523 3476 6111 4171 4519 7023 7639 N N 2-4,5 13 HSI-M-54 6 FWG ANC DART 00U 215 - -

6.094 1.125 4888 5621 6110 N - 2.4,6 14 HSI-M-55 6 FWG ANCP DARL 000 215 - -

6.094 1.125 4838 5621 6110 N - 2,4,6 15 SIA-M-53 6 FWG ANCH DARL G00 - 215 215 6.094 1.125 4261 -

4900 5326 - N 2,4,5,7

16 $!A-M-54 6 FWG ANCh DARL 000 - 215 215 6.094 1.125 4261 -

4900 5326 - N 2,4,5,7 17 LSI-H-40 18 FWG ANCH DARL 00 -

20 20 17.303 1.750 3452 - 4142 4488 - N 2,4,5,7 2 18 LbI-M-4i IS FWG ANCH DARL 00 -

20 20 17.303 1.750 3452 4142 4488 - N 2,4,5,7 ABBREVIATIONS DE7INITIONS CO - CLOSE-TO-OPEN TARGET THRUST RANGE MIN - 1.15 m DP THRUST FOR DP THRUST > 4000 LBS OC - OPEN-10-CLOSE TARGET THRU5f RAEE MAX - 1.25 m DP THRUST FOR DP THRUST y 4000 LBS DP - DIFFERENTIAL PRESSURE TARGET THRLST RANGE MIN - 1.2 m DP THRUST FOR GP THRUST 44000 LBS 1 FWG - FLEX WEDGE CATE TARGET THRUST RA E E MIN - 1.3 m DP THRUST FOR OP THRUST < 4000 LBS I

! GLS - tME VALVE I

1 l THRUST CALCULATION METH00 THRUST REQUIREMF4TS WERE CALCULATED STATISTICALLY USING DATA POINTS FOR VALVES OF THE SAME TYPE FROM THE MOVATS DP DATA BASE.

LINEA?. REGRESSION MAS PERFORMED ON THE DATA POINTS TO FIND THE EQUATION FOR THE "BEST4IT" LINE THROUGH THE POINTS. AFTER f A THRUST VALUE WAS PREDICTED FOR THE VALVE USING THE "BEST-FIT

• EMTION, A 907. CONFIDENCE 8AND, OR TOLERANCE, WAS ADDED TO j THE PREDICTED THRUSf TO OBTAIN THE THRUST REQUIREMENT.

{ ALL CALCULATEL THRUST VALUES PRG.' ICED ARE BASED ON THE MDYATS DP DATA BASE AS OF THE DATE ON WHICH THE CALCULATIONS WERE

PERFORMED. NOTE THAT BECAUSE THE DATA BASE CHANGES AS NEW TEST DATA 15 ADDED THE CALCULATED THRUST VALUES CAN CHANGE.

1 i

?

9334L-LMO i

, - - _ . _ m , _ - - , _ . - . . .m. - _ ~ . - - - , . - - - . , , .._ - . , . . _ . . . - . . , . - - - . .- - - , - , - _. - . - . - _ . . .

's '.

TABLE 6 DIFFERENTIAL PRESSURE THRUST CALCULATIONS FOR MAINE YANKEE AT0 HIC POWER COMPANY N

. O.. T. ES. .: . . . . . . . . . .

1. Thrust values shown for this valve are included for information only.

These thrust values were calculated using an empirical equation based on globe valves with orifice diameters in the 1.75-2.00 inch range. Since the orifice diameter for this valve is not in that size range, it is recommended that these valves be tested under pressure in order to determine the actual required DP thrust,

2. Opening and/or closing thrust values for this valve are based on test data from more than 20 valves of the same type, therefore based on the Callaway IEB 85-03 response, there is sufficient data to justify using these calculations in place of OP testing.

3. Opening thrust values for this valve are based on 4 data points from Velan globe valves of the same size, therefore, based on the Callaway IEG 85-03 response, there is sufficient data to justify using these calculations in place of OP testing.

4. The DP open and close thrust values represent the thrust, above running load, that is required to operate the valve against the given DP. The minimum target thrust includes the possibility of inaccurate thrust measurement due to torque switch repeatability and instrument accuracy.

The maximum target thrust is only provided so that there is a range to set the torque switch to. The true Limitation on the thrust is the capability of the actuator or the maximum allowable thrust for the valve or actuator.

5. The Line pressure (or system pressure) is assumed to be equivalent to the greatest (open or close) maximum differential pressure provided.

6. Since only an oper. differential pressure was provided, it was assumed

- that this valve's safety function is to open. Opening thrust values only are provided.

7. Since only a close differential pressure was provided, it was assumed that this valve's safety function is to close. Closing thrust values only are provided.

l 9334L-LHO

A 4 MaineYankee Valves 13 through 16 (Table 6) have actual thrusts that are slightly less than the minimum target thrusts. Maine Yankee has a high confidence in these valves for the following reasons:

1) A test was performed on August 29, 1985 to stroke test HSI-H-54 under Recirculation Flow Conditions (RAS) to demonstrate operability of HSI-H-54 under accident conditions. The test results were recorded informally as follows:

"August 29, 1985: HSI-H-54 timed open under flow in'31 seconds. Hould not fully close under flow. 35 amps on PGis i and 125 GPM HPSI flow" '

The required safety function is to open, which the valve did, indicating that it was "operable" against differential pressure.

2) This successful test was conducted prior to spring pack replacement which improved the valve's operability margin. '

a Category _2 This category includes HSI-H-41 and HSI-H-42. Maine Yankee did not differential pressure test these valves because at the time the testing program was planned we expected that the HOVATS database would cover these valves.

. Temporary justification is based on the following three factors:

1. The current thrust settings are conservative with respect to the d!,ta generated by the MOVATS database by over 200%.

2. These valves are routinely stroked against full pump flow and head as part of standard Haine Yankee plant surveillance procedures.

3. Maine Yankee has committed to test these valves during the next refueling outage if they have not been covered by the database at  !

3 that time.

Catesory 3 This category includes valves LSI-H-40 and -41. In response to an NRC  !

request for additional information, Reference (e), Maine Yankee reported that these valves were found to be within the scope of the HOVATS database. Therefore, the switches have been set in accordance with values calculated from the database. As part of our earlier plans to complete this Action Item, Maine Yankee had conducted a differential pressure test on LSI-H-40 at greater than design differential pralsure.

This valve was tested to open against 25 psid and found to require 6100 i

9288L-LHO

4  :

MaineYankee

• i Ibs of thrust to perform its function. Even though opening ths valve against differential pressure 's the more conservative operation, both valves were set to close at 7000 lbs of thrust. The final se'; tings for these valves were based on tha individual three point test graph generated by H0 VATS, Inc. ,

Cateaorv 4 This category includes CS-N-91 and CS-H-92. These two valves are 16" butterfly valves made by FvSI-SEAL International, Inc. I'. was not l' expected that the MOVATS .fatabase would cover these valves. Therefore, we felt that it was necer,sary to differential pressure t9st one of these  !

two valves (same age, maintenance, valve, operation, etc.). Also, both '

valves were fully H0 VATS tested at zero pressure provideng additional  ;

assurance of similar performance.  ;

CS-N-92 was selected because its test could be coordirated with that of l LSI-H-40. Although not specifically addressed by the Bulletin, we  ;

believe flow can be respecially important with butter',1y valves (See high j velocity butterfly valves, Section 9.a.11 of the switch setting s guideline). Maine Yankee ascertained from the valve manufacturer that for the following expected design condition the hignest required torque was for unseating the valve:

Shut off pressure - 41 PSID Inlet pressure at full open - 41 PSID Flow rate of wide open - 3700 GPM l According to the manufacturer's calculations ths resulting critical angle is about 20' and requires about 801. of the ur.aating torque.

I The differential pressure test revealed that these valves take 30 to 32 seconds to open or close. Of this time,12 seconds were necessary for unseating the valve. Visual observation at the valve revealed that this "lost" motion was recovered after the valve unseated. However, the i

manufacturer's data indicates that with flo',s through these valves, the I

close torque is always greater than the open torque. Therefore, the i lost motion may not be regained in an actual design condition. Since

this represents as much as 35' of 90' of potion Maine Yankee will have

to evaluate the applicability of the curriant switch settings for these

, valves.

1 CS-N-92 was tested at 35 psid, 41 psid, and 45 psid. At 41 psid, 396 ft.-lbs. of torque was required to unseat this valve. The torque switch was then set to 460 ft-lbs. CS H-91 was set at 665 ft-lbs because it could not be set lower.

Supporting manufacturer's data and differential pressure data is i provided in Attachment 8.

l l 9288L-LHO i

MaineYankee II.D. IE Bulletin 85-03. Action Item d Prepare or revise procedures to ensure that correct switch settings are determined and maintained throughout the life of the plant *. Ensure that applicable industry recommendations are considered in the preparation of these procedures.

Maine Yankee Resoonse Activities associated with this Action Item are still underway. Maine Yankee procedures have been revised to ensure that switch settings are correctly determined and maintained throughout the life of the plant, and to include applicable industry recommendations. However, additional procedures for using HOVATS motor load equipment for valve testing and for a valve stem cleaning and lubricating program are currently under development. Upon completion of these procedures, Maine Yankee will have completed its respense to this Action Item.

The applicable procedutes have been revised to include the switch setting guidelines developed in response to Action Item & The proredures have also been revised to allow the use of H0/ATS or similar equipment for determining torque switch settings.

Maine Yankee is currently developing an additional procedure for valve testing which will use H0 VATS motor load equipment. This procedure will

utilize data being developed specifically for this method of valve testing. Once these data are obtained, this procedure will be implemented as part of Haine Yankee's post maintenance testing program.

! Haine Yankee has investigated other aspects of valva maintenance that may affect the switch settings. As a result, Maine Yankee believes that

a formal valve stem cleaning and lubrication program would help ensure l that correct switch settings are maintained throughout the life of the plant. This program is currently in the process of being developed and will be implemented once it has been completed.

l This item is intended to be completely consistent with action item l 3.2, "Post-Haintenance Testing (All Other Safety-Related Components)," of Generic Letter 83-28, "Required Actions Based on i

Generic Implications of Salem ATHS Events". These procedures i should include provisions to monitor valve performance to ensure the switch settings are correct. This is particularly important if i

the torque or torque bypass switch setting has been significantly l

raised above that required.

)

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\ 9288L-LHO t

MaineYankee III. VALVE OPERMILIll Maine Yankee has completed the evaluation of switch settings which were calculated in response to Action Item b for the twenty motor operated valves which are subject to this bulletin. As a result of our evaluation, Maine Yankee has determined that all of the valves were operable in their "as found" condition. Maine Yankee's determinations of valve operability were based on information generated through the Action Items and the operating history of the valve. The data that resulted from the Bulletin and the Bulletin itself have not changed Maine Yankee's definition of operability.

Instead, they provide additional information for making our determination.

A summary of our evaluation of the "as found" operability of the valves follows. This summary has been organized around seven groups of valves. Each group contains valves that are essentially identical in design. Thus, the valves in a group will have similar operability considerations. The groupings for the valves are as follows:

1. HSI-N-11, HSI-H-12, HSI-H-21. HSI-H-22, HSI H-31, HSI-H-32

2. HSI-H-41. HSI-H-42

3. HSI-H-50, HSI-H-51

4. HSI-H-54, HSI-H-55, SIA-H-53, SIA-N-54

5. CS-N-91, CS-N-92

6. CH-H-1, CH-H-87

7. LSI-H-40, LSI-H-41 As stated above, Maine Yankee has determined that all twenty valves evaluated in response to this Bulletin were operable in their as found condition. A group by group summary of our operability determinations follows.

Group 1:

The valves in Group I were all found to be operable prior to switch adjustments made as a result of the Bulletin. He found that the limit switches settings were in agreement with the calculated values. Also, the torque switch settings exceeded the values needed to meet the design requirements for these valves. This information, combined with their operating history enabled us to determine that these valves were operable.

Group 2:

The Group 2 valves were determined to be operable in their as found condition. The limit switch settings were found to be in agreement with the calculated values. The values for the torque settings on valve closure were also set correctly. The open torque settings.

9288L-LHO

MaineYankee although less than the calculated values, were sufficient to meet the design basis conditions. The torque switch settings are overconservative by up to 200%. Our determination is supported by the results of standard Maine Yankee surveillances on these valves which include routine stroke testing under full pump flow conditions. From this information, Maine Yankee has determined that these valves were operable in their as found condition.

Group 3:

Haine Yankee has determined that the Group 3 valves were operable in their as found condition. The safety function for these valves is to open. However, they were found not to be seating. Because these valves have a two rotor design, the guideline requires that they not seat. This ensures that the valves do not exceed the torque switch setting upon actuation. He have evaluated the as found limit and torque switch settings and determined that they are in agreement with the calculated values. Therefore, these valves were found to be operable.

Group 4:

Based on informal tests conducted prior to the Bulletin, Maine Yankee has determined that the valves in Group 4 were operable in their as found condition. All of the valves were found to have torque switch settings less than the values calculated for the Bulletin. However, the limit switch settings were properly set for bypassing the torque switch for the first 10% of the valve stroke beyond the valve coming out OP the seat. When the torque switch is made effective by the limit switch, the thrust requirements become significantly less than the original torque switch setting. Thus, the valves could meet the design basis differential pressure. Valve operability is further supported by an August, 1985 stroke test of HSI-H-54 under Recirculation Flow Conditions (RAS) to demonstrate that this valve could operate under accident conditions. The test showed that the valve was able to perform its safety function by opening against differential pressure. Therefore, we have concluded that the valves in Group 4 were operable in their as found condition.

Group 5:

The valves in Group 5 were found to be operable prior to any adjustment as a result of the Bulletin. The limit switch settings on both valves were found to be in agreement with the values calculated for Action Item b. Although the torque switch settings did not agree with the calculated values, the valves would not have stopped on inadvertent torque switch operation. Valve CS-H-92 was found to have an installed spring pack that was stiffer than that used for the calculations. The torque switch for CS-H-91 was improperly installed so that it would not actuate. Thus, the torque switch settings in one case were found to be appropriate and in the other it was found to be irrelevant to valve operatia.

l i l 9288L-LHO l

i

I MaineYankee Group 6

,

The valves in Grtup 6 were determined to be operable in their as found condition. The limit switch settings were found to meet the values '

calculated for Action Item b. The torque switch settings fcr opening 4

and closing the valves exceeded the values necessary to meet the target thrusts. By combining this information with the prior operating history of these valves, Maine Yankee concluded that these i valves were operable in their as found condition.

Group 7:

In their as found condition, the Group 7 valves were all determined to i be operable. Both the limit switch and torque switch settings were in agreement with the calculated values. Also, the prior operating history indicated the valves were operable. Therefore, Maine Yankee has determined that these valves were operable.

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MaineYankee ,

t I

IV. DATA

SUMMARY

l This section provides a summary of the differential pressure, switch setting, "as found" operability, test method description, and operability  :

justification for each of the valves in the program. T1bles 7 and 8 present the data in a manner similar to the suggested format provided in Table 2 of Action Item f of the bulletin. Additional information on limit switch and thermal overload settings can be found in section III.c. of

this Report. i I

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!  ; 9288L-LHO l  !

TABLE 7 Data Summary Torque Switch Settings .-

Design Basis Test

• Prior to Ad- Final Torque Differential Differential justments as Switch Settings ,

Pressure Pressure a Result of In Response To '

(osid) (osid) Bulletin Bulletin Valve Valve Doerator Valve Function Ooen Close Doen Close Oosn Close Open Close HCV-311 (HSI-M-11)

Manufacturer:Velan Manufacturer:Limitorque High Pressure 2,600 2,700 0 0 1.5 1.5 1.25 1.125 Type: Globe Model:SMB-0 Safety Injection Underseat Under-Mod 2l: Motor RPM:1732 to Reactor Cool- or 2,400 Sa'+

Size:3" Output Speed (RPM):61 down Loop 1 Oversest Ratino:1500#

HCV-313 (HSI-M-12)

Manufacturer:Velan Manufacturer:Limitorque High Pressure 2,600 2,700 0 0 1.5 2.25 1.75 2.0 Type: Globe Model:SMB-0 Safety Injection Underseat Under- t Model: Motor RPM:1732 to Reactor Cool- or 2,400 Seat l Size:3" Output Speed (RPM):61 down Loop 1 Overseat Ratina:1500#

HCV-321 (HSI-M-21)

Manufatt~2er:Velan Manufacturer:Limitorque High Pressure 2,600 2,700 0 0 3.5 2.5 2.125 2.25 Type: Globe Model:SMB-0 Safety Injection Underseat Under-Model: Motor RPM:1732 to Reactor Cool- or 2,4GO Seat Size:3" Output Speed (RPM):61 down Lcop 2 Overseat RTtina:1500#

HCV-323 (HSI-M-22)

Manufacturer:Velan Manufacturer:Limitorque High Pressure 2,600 2,700 0 0 3.5 2.75 2.1 2.0 Type: Globe Model:SMB-0 Safety Injecilon Underseat Under-Model: K, lor RPM:1732 to Reactor Cool- or 2,400 Seat

$1ze:3" Output Speed (RPM):61 down loop 2 Overseat Ratina:1500#

HCV-331 (HSI-M-31)

Manufacturer:Velan Manufacturer:Limitorque High Pressure 2,600 2,700 3.5 2.0 1.75 1.75 Typ2: Globe Model:SMB-0 Safety Injection Underseat Under- 0 0 Modal: Motor RPM:1732 to Reactor Cool- or 2,400 Seat Size:3" Output Speed (RPM):61 down Loop 3 Overseat Ratina:1500#

• An entry of 0 indicates that testing was performed on the absence of flow and differential pressure.

, TABLE 7 (Cont d)

Data Summary Torque Switch Settings ..

Design Basis Test

• Prior to Ad- Final Torque

. Differential Differential justments as Switch Settings I Pressure Pressure a Result of In Response To (osid) (osid) Bulletin Bulletin Valve Valve Ooerator Valve Function Open Close Open Close Ooen Close Open Close HCV-133 (HSI-M- 32)

Manufacturer:Velan Manufacturer:Limitorque High Pressure 2,600 2,700 3.5 2.0 1.125 1.125 Typ2: Globe Model:SMB-0 Safety Injection Underseat Under- 0 0 Model: Motor RPM:1732 to Reactor Cool- or 2,400 Seat Size:3" Output Speed (RPM):61 down Loop 3 Overseat Ratina:1500#

l HCV-301 1 (HSI-H-41) l Manufacturer:Velan Manufacturer:Limitorque HPSI Injection 2,500 2,700 1.75 1.875 2.0 1.875 l Type: Globe Model:SMB-1 Header Overseat Under- 0 0 Hodel: Motor RPM:1675 or 2,600 Seat

, Size:4" Output Speed (RPM):59 Underseat Ratina:1500#

HCV-302 (HSI-M-42)

Manufacturer:Velan Manufacturer:limitorque HPSI Injection 2,500 2,700 2.0 2.5 2.5 2.5 Type: Globe Model:SMB-1 Header Overseat Under- 0 0 Model: Motor RPM:1675 or 2,600 Seat Size:4" Output Speed (RPM):59 Underseat Ratina:1500#

MOV-204T (HSI-M-50)

Manufacturer:Velan Manufacturer:Limitorque HPSI Suction 67 215 0 0 2.5 1.5 2.5 2.0 Type: Gate Model:SB-1 from RHST Size:10" Motor RPM:3600 Ratina:150# Outout Speed (RPM):167 MOV 204U (HSi- M-51)

Manufacturer:Velan Manufacturer:limitorque HPSI Suction 67 215 0 0 2.5 1.5 2.5 1.5 Type: Gate Model:SB-1 from RHST Size:10" Motor RPM:3600 Ratina:150# Outout Soeed (RPM):167 An entry of 0 indicates that testing was performed on the absence of flow and differential pressure.

9334L-LHO i

TABLE 7 (Cont'd)

Data Summary lTorqueSwitch Settings .-

Design Basis Test

• Prior to Ad- Final Torque l

l Differential Differential justments as Switch Settings Pressure Pressure a Result of In Response To (osid) (osid) Bulletin Bulletin Valve Valve Operator Valve Function Open Close Doen Close Ooen Close Ooen Close MOV-3210 (HSI-M-54)

Manu: Anchor Darling Manufacturer:limitorque HPSI Suction 215 NA 0 0 4.5 2.0 4.0 2.0 Typt: Gate Model:SMB-000 from Residual Size:6" Hotor:1800 RHST Ratina:150# Outout Speed (RPM):46.5 MOV-3209 (HSI-M-SL) '

Manu: Anchor Darling. Manufacturer:Limitorque HPSI Suction 215 NA 0 0 4.0 2.0 4.0 3.0 Typ2: Gate Model:SMB-000 from Residual Size:6" Motor RPH:1800 RHST Ratina:150* Outout Speed (RPM):46.5 MOV-3202 (SIA-M-53)

Manu: Anchor Darling Manufacturer:Limitorque Spray Pump NA 215 0 0 Not 3.0 4.0 4.0 Typ3: Gate Modal:ShB-000 Recirculation Re-Size:6" Motor:1800 to RHST corded Ratina:150# Culput Soeed (RPM):46.5 MOV-3204 (SIA-M-54)

Manu: Anchor Darling Manufacturer:Limitorque Spray Pump NA 215 0 0 2.5 2.5 3.25 4.0 Type: Gate Model:SMB-000 Recirculation Size:6" Hotor:1800 to RHST Ratina:150# Outout Soeed (RPM):46.5 MOV-3207 (CS-M-91)

Mane: Post-Seal Manufacturer:Limitorque Spray Pump 41 NA 0 0 3.0 2.0 1.0 1.0 Type: Butterfly Model:SMB-000/HOBC Suction from Modal: Trunnion Motor:1800 Containment Size:16" Output Speed (RPM:35.5/90* Sump Rating:150# l An entry of 0 indicates that testing was performed on the absence of flow and differential pressure.

9334L-LHO

TABLE 7 (Cont'd)

^ ' -

Data Summary Torque Switch Settings .-

Design Basis Test' Prior to Ad- Final Torque.

Differential Differential justments as Switch Settings Pressure Pressure a Result of In Response To (osirf) (osid) Bulletin Bulletin Valve ._ V:1ve Operator Valve Function Open Close Open Close Open Close Open Close MOV-3208 (CS-N-92)

Manu: Post-Seal Manufacturer:Limitorque Spray Pump 41 NA 41.5 0 3.0 3.0 1.5 1.0 Type: Butterfly 'Model:SMB-000/H00C Suction from Model: Trunnion IMotor:1800 Containment Size:16" Output Speed (RPM:35.5/90* Sump Ratina:150#

LCV-204V (CH-M-1)

Manu:Velan Manufacturer:Limitorque Charging Pump NA 67 0 0 2.75 2.75 3.0 1.25 Type: Gate Mt nl:SMG-00 Suction from s Mode:h Mttor:1800 Volume Control

} Size:4" Output Speed (RPM):47 Tank i

Ratina:150# ,

i LCV-2045 (CH-M-87)

Manu:Velan Manufacturer:Limitorque Charging Pump NA 67 0 0 2 . .'5 2.75 2.75 1.0 ~

T)pe: Gate Model:SMB-00 , Suction from

, Mod 21: Motor:1800 Volume Control

Size

4" Outpat Speed (RPM):47 Tank Patina:150#

M I (OV-3205 LSI-M 40) j Manu: Anchor Darling Manufacturer:Limitorque Spray Pump NA 20 25 0 2.0 2.0. 2.25 2.125 l

Type: Gate Model:SMB-00 Suction from j Model: Mator:180G RNST l Size:18" Output Speed (RPM):22 l Eatina:150s _

MOV-3206 *

. (LSI-M-41)

] Manu: Anchor Darling' Manufacturer:Limitorque Spray Pump NA 20 0 0 2.25 2.25 2.25 2.125 i

Type. Gate Model:SMB-00 Suction from Medal: Motor:1800 RMST '

i Size:18" Output Speed (RPM):22

, Ratina:150s

• An entry cf 0 indicates that testing was performed on the absence u flow and differential pressure.

j L - -. - . - - _ _ . . -

TABLE 8 Data Summary Valve Component As found Valve 10 Operability Test Method Descriottoii/ Justification .-

Test Method 1 or 2 As Left Thrusts: Switch Trip Total Open 22.020 24.000 Close 21.180 23.820 HSI-M-11 Operable The remainder of the data for justification is available for review at HQVATS in Marietta. Georaia Test Method 1 or 2 As Left Thrusts: Switch TriD Total Open 21 500 24,3B0 Close 22.840 24.780 HSI-M-12 Operable The remainder of the data for justification is available for review at MOVATS in Marietta. Geqrg13__

Test Method 1 or 2 As left Thrusts: Switch Trio Total Open 24.000 26.135 _

Close 21.250 23.500 HSI-H-21 Operable The remainder of the data for justification is available for review at MOVATS in Marietta. Georaia Test Method 1 or 2 As left Thrusts: Switch Trio Total Open 21.350 24.540 Close 2Q,500 23.450 HSI-M-22 Operable The remainder of the data for justification is available for review at MOVATS in Marietts1._ Georgia Test Method 1 or 2 As left Thrusts: Switc.i Trio Total Open 21.300 24.0DQ__

Close 21.350 24.000

HSI-M-31 Operable

! The remainder of the data for justification is available for review at i

l MOVATS in Marietta. Georgia Test Method 1 or 2 As Left Thrusts: Switch '-10 Total Open __ 21.85v 23.78.0__

Close 21.800 23.400 ,

HSI-H-32 Operable The remainder of the data for justification is available for review at MOVATS in Marietta. Georata 9334L-LMO

TABLE 8 (Continu:d)

Data Summary Valve Component As Found Valve j 10 Coerability Test Method Descrio_tjpn/ Justification .-

Test Method 1 or ? As Left Thrusts: Suiten Trio Total Open 39.550 43.450___

Close 36.450 40.750 HSI-W41 Operable Test Method 1 or 2 As Left Thrusts: Switch Trio Total Open 39.050 45.250 _

Close 39.400 43.600 HSI-M-42 Operat;1e Test Method 1 or 2 As left Thrusts: Switch Trio Total

, Open l ~ 5.000 - -

HSI-W 54 Cperable Close l 3.118 3.650.__

The remainder of the data for justification is available for review at MOVATS in Marietta. Georata Test Method 1 or 2 As left Thrusts: Switch Trio Total Open ~ 5.000 -

HSI-W55 Operable Close 3.423 3.613 The remainder of the data for justification is available for review at M0 VATS in Mariett Georata Test Method I or 2 as Left Thrusts: Switch Trio Total Open ~ 5.000 -

SIA-N-53 Operable Close ~ 5.000 -

The remainder of the data for justification is available for review at M0 VATS in Marietta. Georola Test Method 1 or 2 As Left Thrusts: Switch Trio Total Open ~ 5.000 -

SIA-W 54 Operable Close ~ 5.000 -

The remainder of the data for justification is available for review at MOVATS in Marietta. Georata 9334L-LMO

TABLE 8 (Contitred)

.~

Data Summary Valve Component As found Valve ID OpfrabilitY Test Method Description / Justification .-

Test Method 1 or 2 As Left Torques: . Switch TriD Open 665 CS-M-91 Operable Close 509 See Attachment 8 for additional iustification Test Method 1 or 2 As Left Torques: Switch Trio _

Open 460 __

CS-N-92 Operable Close 760 See Attachment B for additional iustification Test Method 1 or 2 As Left Thrusts: Switch Trio Total Open 4.140 6.340___

CH-M-1 Operable Close 1.420 2.640 The remainder of the data for justification is available for review at H0 VATS in Marietta. Georaia Test Method 1 or 2 As left Thrusts: Switch Trio Total Open 926 1.120 CH-M-87 Operable Close 520 4.240 The remainder of the data for justification is available for review at HOVATS in Marietta. Georata __

Test Method 1 or 2 As Left Thrusts: Switch Trio Total Open _8.050 8.350 .

LSI-M-40 Operable Close -7.000 -

The remainder of the data for justification is available for review at H0 VATS in Marietta. Georaia Test Method 1 or 2 As Left Thrusts: Switch Trio Total Open 9.180 10.720 LSI-M-41 Operable Close - 7.000 -

The remaindar of the data for justification is available for review at H0 VATS in Marietta. Georata 9334L-LM0

TABLE 8 (Continued).

Data Summary Valve Component As Found Valve 10 Orerability Test Method Descriotion/ Justification' ..

Test Method 1 or 2 As Left Thrusts: Switch Trio Total Open 26.900 37.750 HSI-M-50 Operable Close 0 10.000 The remainder of the data for justification is available for review at MOVATS in Marietta. Georcia Test Method 1 or 2 As Left Thrusts: Switch Trin Total Open 28.600 40.250 HSI-M-51 Operable Close 0 7.650 The remainder of the data for justification is available for review at M7(ATS in Marietta. Georata

.li t

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9334L-LM0

!.______-________..__--____ --__... . - - - - _ - _ _ _ _ _ _ . _ - _ . . . _ _ _ , _ , _ _ . , _ _ . . _ - . . _ . . - - . - ~ . . . - . . . _ - , . - . . . _ _ . .

MaineYankee V. OPEN ITEMS Maine Yankee has completed a significant portion of the Action Items from IE Bulletin 85-03. However, there are still a few remaining items to be completed. The activities which must be performed to close out each open Action Item are summarized below.

In order to complete Action Item b. Maine Yankee must perform additional calculations and evaluations. In Reference (f), Maine Yankee determined that valves HSI-H-11, -12, -21, -22, -31, -32. -41, and -42 will be required to close against 2700 psid under the seat. Therefore, additional switch setting calculations must be done to determine if the existing settings are still appropriate. He also need to complete some maximum force calculations for the stem stop assemblies, reach rods, and appitcable valves. Finally, the lost motion experienced during operation of CS-H-91 and -92 must be evaluated to determine whether switch settings need to be modified to recover that lost motion during design flow conditions.

In reference to Action Item c, Maine Yankee must complete three activities. First, valves HSI-H-41 and -42 will need to undergo full differential pressure testing unless the H0 VATS database is expanded to include these valves. Second, the thermal overload devices on valves CH-H-1 and -87 have to be replaced. Finally, as necessary, the switches for valves HSI-H-11. -12, -21, ~22, -31, -32. -41, and -42 may need to be reset to ensure that the valves can close against 2700 lbs under the seat. Once these activities are finished, Action Item c will be complete.

The following three activities must be completed under Action Item d. The use of motor load thresholds as part of the post maintenance testing process has to be implemented. In order to complete our evaluation of valves experiencing overthrust, HSI-H-32 should be examined using nondestructive techniques. Also, a formal stem cleaning and lubrication program will be implemented to help ensure that correct switch settings are maintained throughout the life of the plant.

These open items as listed above by Action Item constitute the unfinished portion of the IE Bulletin 85-03 program at Maine Yankee. Our schedule for completion of the program is as follows:

1. Hithin 60 days after the next scheduled refueling outage Maine Yankee will have completed the open items listed above. Currently j the next refueling outage is scheduled to begin in October 1988.

2. As required by Action Item f of the Bulletin, Maine Yankee will j submit a final report sixty days after completion of the program.

i l

1 i

9288L-LHO

MaineYankee VI.

SUMMARY

In 1984, Maine Yankee implemented a valve maintenance program based on Institute of Nuclear Power Operations Report 83-037, "Assessment of Motor Operated Valve Failures". The program which was developed to rebuild motor operators also included maintenance procedures for switch setting verification, evaluation of the conditions of motor operator parts, periodic

lubrication changes, tightening bolts, and post-maintenance testing with strictor acceptance criteria. This program was evaluated by the NP.C in 1985 as part of their Performance Appraisal Inspection, Reference (g). The Inspectors observed that the program had significantly improved HPSI system limitorque valve operability since its implementation during a 1984 refueling outage. Maine Yankee believes that this program was successful.

Although the progr > vas successful, it was not easy to implement because it relied upon a quali .tive evaluation of test results. As a result of the

Bulletin, Maine Yankee's program for HOVs has become a more quantitative i

program. He can now specify the operating requirements, evaluate the design i requirements, and then verify the design through field measurements. From these measurements, detailed information on valve operation was obtained.

With this valuable information on valve operation, Maine Yankee believes that our program has become stronger.

j Haine Yankee's activities in response to the Bulletin tsve improved the

< operability margin for HOVs in the HPSI system. He determlied that all twenty j valves were operable in their as found condition based on pitor operating history and calculated switch settings. Where necessary, swii'-h settings were reset in accordance with the switch setting guideline. These new attings

further increase the valves' reliability. Valves have been stroke tested to verify correct switch settings using met,%ds develn,ned for the Bulletin. The data which resulted from the tests provioed detailed information for assessing the operation of each valve.

Although Haine Yankee's program for HOVs has been i.mproved, we have not

fully completed the Action Items as required by the Bulletin. With the i exception of Action Item a which has been completed, Maine Yankee has i identified activities to be performed to complete the remaining Action Items.

A summary of the open items and a schedule for their completion were provided l in the previous section.

i 9288L-LHO

MaineYankee VII. REFERENCES (a) USNRC IE Bulletin 85-03: Motor Operated Valve Comm,n-mode Failures Durino Plant Transients Due to Improper Svitch Settings dated November 15, 1985 (b) HYAPCo Letter to USNRC dated June 4, 1986 (HN-86-66)

(c) USNRC Letter to HYAPCo dated September 3, 1986 (d) HYAPCo Letter to USNRC dated December 22, 1986 (HN-86-162)

(e) USNRC Letter to HYAPCo dated July 29, 1987 (f) HYAPCo Letter to USNRC dated October 2, 1987 (HN-87-109)

(g) USNRC Letter to HYAPCo dated August 8, 1985 l

[

[

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9288L-LHO

MaineYankee 1

)

l VIII. ATTACHMENTS j

i f

a i

i a

h l

i i

d 9288L-LHO

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. . Attachment A IEEE Transactions on PIser Apparat s and Systems, Vol. PAS M. NA 5 Nov/Dec 1980 THE DApe3tAs Or STPASSING THERMAL OvtAlcAD m

1. . A21,AYS IW IrUC12AA PCertR PthrF MOTOR OPERATED VALVE CIRCUITS rarout D. Santer, senior s' ember, ItrE Yankee Atnote Electric Company westboro, Massachusetts Abs t r ac t . A situation may esist where a control ,

circuit modi fic ation de signed to enhance sa f ety and (* "" - ** "" - - - - - - - ,.E q

reliability may actually jeopardise the integrity of l g the very system (L to trying to protect. r* ne such 8 Power g sit ua tion involves ac and oc Motor opo r t . es e n te { gggy g r% mit s in nuclear power plants which have bee n g g deal see with t%!r thermal ovettoad protection g g bypassed or altogethat ellei ns t ed . The purpose of this paper is tos g y -) }rircuit Breaker g

g l

(a) Point ou t the danger e of this design l l Philosophy. l op n ce tacy r y (b) Show that the tPereal overioed relay c.a play an important pett in improving overall iT -

Ciere ci ta<prlI nuclear plank saf ety. l l I l (s) Provide reconsondations on the selection of l Thermal over!Ja4 thereat overload relays. l h h h polay Fenelnr1 l tiesont i k- ... .-!

Mctot Operated Valver (MOV's) in truclear Power plants are usually powered froe Motor Control Centers MOV (MCC's) as illuettsted in F.gute 1.

Short circuit protection of the MOV circuit is typically provided by a m>1ded case ettcuit breakers overload protection is accomplished with thereal Figure 1. Line Distrae Showing ove rload relays installed in e reversing contactor. Typical MCC Internate when the breaker opera t e s, it opens up the power otteult directly: when the there41 overleed heater reaches its trip point, it activates a relay which (b) thereal owirtoad relays are designed de.energises the control nitcuit, thus dropping out primarily to protect continuous dety motore the contestor and deenergining the power circuit. In and are not sett.d to intermittent duty t

attempting to increase the overall settability of the estore.

l MOV when pe r f orming a sa f ety function, it has been ceasesa practice to either bypass the output coatsete (c) It is difficult to acewrately select thermal of the thereat overload teley, et use an oversteed overload relays for motor operated valves.

thermat overload element each that it become s 1 unresponalve to circuit overloads. (d) Tempe r a ture wartettons at the Mov and the Soth of these practices may result in a doctease MCC unde r different ope r a ting corstilloes in overall nu dle e t plant safety erstes reliabilitys mate ope r a tion of an overload relay l nonethelese, argumente and justifications continue to unpredictable and erratic.

l be of fered for this action. Soes of these arguments are listed belows (e) Accuracy and repeatability of the thereat overload relay le unknown.

let the saf ety function raast to perfetsed even ,

at the riot of desaging or de st roy1 rug the AustYpff actor.

the yteceo4 4 mg a rgvee nt s are unfortunately based Firstly, on mi sconc ep tions of the f ond ame nt at e involved, and secondly, en oretelsplification af the MW and its a ppur te na nce s. 14 le hope $ that the oweseeding paragraphe will help clarify t he s e eleconceptions.

F to 260 0 A paper reseenended and approved by the H) Interoitteet ever Mg3 . The thereal i litt Mwelear Power Engineering Commf

• tee at the litt Powe, ovetteed relays erg deeigned to Le Engineering gestegy for presentamien at the !!!! FL5 toponsin to t>s heat predaced by the flew Winter Meeting New Terk, lef, Fr euety 3 8. 1980, of currents whethH this current le drawn by

' kanuscript oubeltted September

• 19ff;made avail.nle * ***'l ** ddtf " ' ' ' ' ' ' ** IM A'^'

l for printing Deceeter 5,1979. duty motos to immaterial se far 0018-9910/ 60/ l 100,1287W.? J C i gs0 I E E C

- - . _ - _ - - =- _-_ - - - _ - .- _

j ,

• 1 1288 as the tneraal overload relay is concerned. (4) Dejggs, - The reauns why bypa s sing of sy e Ung the correct techniques c.nd trip thirsal overload relays results in a characteristic curves, the overload relay decrease in overall nuclear plant safety are can be eised and used ef fectively to protect illustrated by analysing moV operation under l intermittent duty motor s with all various abnormal conditions sach as frozen h bea r ing , tight pacting, aid-travel  !

. uncer.atnties r e solved . It should however a

obstruction, torque switch fatture, Itait be post ted out that manufacturer sopp11es >

selection tables for thermal ovectoad relays switch fatture, and pet.aecident l are intended to be used on continuous dJty operation. First, a brief esplanation of [

motors therefore, use of these tables for molded ease citeult breakers is in ordet. r interuittent duty motors constitutes a 14oided circuit brJakers are of two basic types aisapplication which could result in errors. (This appears to be the 4 " comme Magnetic Only, and f overload relay l cause for thermal saloperation and also, the most popular Thermal-Magnetic reason for advocating their bypass.) (

Both types of breakers have a magnetic trip; (

12) variations in mater tablent - The mov shocid the magnetic trip is an instantaneous device be designed to ope r a te in the sanims that trips without time delay once a predeter-  !

l e nvir onse nt which is espected: therefore* mined setting has been reached. The thermal = i the mtor will have no problem operating in magnetic circuit breaker differs from the  !

J temper ator es lower than this mani= n. magnetic in that 8.t has arl inve r s e-tirae r J

(Admittedly, by this de sign the Mov vill thermal element to provide some degree of over*

have unutt11:ed thermal capability at any load protection. The minimum trip point of temperature lower than its design mast =m.) the thermal e leraent is usually unadjustable Under a given operating condition. the mov and factory set at approximate)"# 300% of  !

will essentially draw the sa 4 corrent breaker continuous current. ,

j whether its ambient is 400C or 150*C# f f or example, if the f all load current is 10 In selecting a circuit breaker cae must ensure 3

A at 40'C, it will for all practical that it has a continuous currect rating greater ,

o yurposes, be 10 A at 150*C. (Although than the full load current rating of the HoV, I j totor winding resistance will increast with and that it has a magnetic trip setting i a a ncr easing tosperatwee, this will have a greater than the locked rotor current. (Since l sinimal of fect on the cuttent drawn) . Now, the rnagnetic trip is instrntaneous, it must J if ,the rewtely locates thermal overload be set abovs locked rotor current to allow the i j relay is set to trip at say 10 A, it will raotor to start).

t trip at this current tegardless of the f tosperature of the sotot . Clearly, rator j sabient tesMrature variations do not (a) Prote Searls " if a safety related ,

influence the trip setting of the thermal valve ha s a frosen bearin1, the motor J j overload relay be:aase these vettations do will not move and will draw lo:ted  ;

not have any ef f ect on the eutrent pe a s 1M rotor cuttent. If the circuit breater f

through the overload relay. is of the thereat.sagnetic type, then j

' the thereal eleme nt in the circuit .

i Varlstions in MCC A.ebl e nt a Temper atur e breater will sense the locted rotor =

i variations at the MCC are of concern because current and open the circuit [

these affect the operation of she overhad therefore nothing has been gaines by  ;

relay. Most aanufacturers ses9me a 400C etteinsting the thetsal overload j asaient when providing relay time-cu t t e n t relay. In fact, there is a serious l

concern that the etor sight esceti its l cMaracteristicar however, as pointed out in paragraph (11 above, the overloas relay thereal withstans limit beroe, the I the* mal ele *ent actuates. }

responds to heat which is normally grodsees j bv the flow of certent theat.C I ), any l other source of heat will also af fect the if the oltcait breater is esinetic only, the locsed tetot cwtrent it is relay, ine h 81n1 significant changes in r

] the re. carrying is welt aeove na entinuous sebient te M ratete at if j teeMrature variations in MCC ambient are a rating and yet below the instantaneows f concern, the eolwtion is to use seateat telp setting. FallJre of tne siteuit ,

j coe ensated overload relays, !! it can be breater er motor is now t emian t . If l l the circuit breater et motor faits, a I datermined that the MCC is locatei in a snott el cait will tesJ1t w% tem w!!!

controllet environannt area, the ambient

{ now Pave 'o be cleared by the incoetM l < aepensated totsys may be unnecessary Mfea W $ the MCCf t%le setton will Steady state teofersteres above et bet w t e au ~e all pnwer to other safety eget su. t en tme 69s. The reliability 40% ca9 *>e coeM nsated by t ecngnis ing the ,

decreasef or increases thereal estability of of the .afety systee has been decreasei  ;

by elleinstan1 the t%ersal overload the teley to s ecovr>ia te 13 meetiM Prior I to teley setuation. telay.

I I

' i (b) That P a" l *1

• the valve may  ;

f th A*evrag a Tse acewracy of thereal overload

' relays is know9 and ns availabit free th* edMenence Pe r t t e t bin 84M (that is. [

bindant 4de to tight paettagl. tAat l

1. 4mefacturers' publieked data. Ms t ti me *c wt r e nt charatteristle eweves indicate permits testfiete.$ movement of the l f valve. T** e* t >t est dr8e a current [

the oferatlM band of the beater and relays the met eoneesvallee valve of the canj anyw*ere froe fdl tesi eartent to l shale M willises. loce d roter everent 4 re nd t M an t%e (

i l

F e _ _ -

2244 degree of btMing.

If the circuit breaker is of 't should be clear from the above discveston thethereal-sagnette type, then the t>at the thermat over ad relay is invr* sble in thermal element ray or may not see the providing ctreult proseutton for all sy pe s of increased current, sattunctions end ope r o .ing modes that may be eFPer f anced it is also vital in enhancing the

!! the thermaa-*agnetic elemnt sensee cont. 444 safety of the nuclear power plant, the current and opens the circuit, tilatnating or over s t eing the thermal overload relay then nothtM has been gained by appears to be a practice for which there is no

,1tmanating the thermal overload relay. tachrical basis or justification.

If, however , the thermal elesent doe s  ;

not sense the increased current, the orcom reAftow current wt11 exceed the continuous rating of the circuit breater by a ?n order to assist engineers and designers in factor up to 3004. Fattore of the correctly string thermal overload relays, certain circuit breaker or motor can be steps are suggested an esemple of an actual erpected in time with results staller calculation is also providad, to that desettbed in paragraph (4ae above. The rettattit'/ of the safety The first step to to obtain the followthg infirmatinni system has bee n decr ea s ed by e11str: sting the thermal overload relay. sa nd motor full load current r Rated motor locked rotor current (c) Mid-Travel obetruetton and Torque mtor service factor  ;

$witen retlure - if a safety related m tor thermal stee liais for carrying valve encounters an obstruction dating locked rotor current travel and the torque produced escoede Stroting time of MOV when performing its the setting of its torque evitch, the design fonction switcP will actuate to instantaneously Time-current trip curve of thermal de-Snergise the etreutt. Since the overload relay thermat overload relay has Overtoed heatet selection tables '

inverse-time characteristics, it would MCC ambient temperature not have responded as fast as the ,

torgae switch in tais s itua tion, d'he selection of the thermal overload relay for a ,

therefore, nothing is gained by given application should be based on the following  ;

I ellatnating the thermal overload relay, cetteria If, however, the torque switch had 1. When ca r r ying locked rotor current, the failed to ope r ate and the thermal thermal overload relay should actuate in a ove r load relay had been bypassed, the stan within the motor's Itatting time for t W would have drawn locted rotor carryte locked rotor current.

cur ent. The conseque neea would be similar to the massive fattere 2. When carrying a curren*, equal to nameplete described in paragraph 4s. full load current times the service tactor. -

I the notor should not trip in a tire period I

!! a valve encounters en obstruction less than twice the MOV stroting time.

and the torque g raduced does not e xceed the setting of its torque s.fje, switch, the nuation and consequences  ;

would be s e i ., to those deset tbed in 1. Civen Cata i paragraph 4 b. ,

rutt lead current 5.0 A [

18.5 4 (d) Qtt Switch ratture reaches the end of stroke

- if a valve and its tacted rotor current service factor 1.15

[

ltatt evitch f at j e to oper a te, the MOV Trernal time limit k I

will drew lected rotor current. It for estrying locked the thermal overload relay has been rotor current 15 seconde i bypassed, the consequence s would be Stroking time 15 seconds i atollar to the maestre fattore Time. current trip  !

de scr ibed in Pa r a g r a ph 4. 4. curve rtgare 2 4 eater selection (e) fo,sj-Acejdeat eteration - by table Ftgure 3 et6atnattng the thersat ovetload MCC aanieat tesp. 300 c to 500C relay, the MOV or its circuit may te  ;

damaged or destroye$ while trying to 2. Seleet ten Procedare [

perform tte safety function. It is  !

obv ious that firstly, the MOV say not a. on rigure 3 drav e %ortiontal Itae at  ;

be in its desired position when it 15 seconds to indleate tne thermal .

fatist and secondly, the MOV may be t t sk, 1 tent for "arrying locked ro t or incapsele of teing moved subseque ntly current.

if it to in a high ra$tation or other inacc e ss ible area. Inclusion of the b. This !!ne intersects the relay curve  ;

thermal overlead relay in the circuit at both 3.1 and 6 ti me s the trip could provide for r epea ted strating ewerent r e t i ng . If we choose 3.5 t i me s . we oeserve that, dwe to attempts even Lt the relay act ua ted .

_ .m ..# 1

2290 sti:rance, the esty may Oso trip in 40 seconde. This ?,e unacceptable se l Adjusteele raate of it etolates criterton 1. Choosing 6 **'C"'

times results in a nautsun trip time Cat. no. sta. l maa.

of 15 secoe.de and a minimas of 6

" ' i 1.92 f.10 teou locked rotor current e 6 times t 2.11 f.*1 c.

relay trip current, or relay trip 3 ,, 3, ,,,,

current a 38.5/6 = 6.4 A. 2.00 4 1.54 (

d. The note on Figure 3 states that the 5 2.81 3.07 relay trip current is 125% of the rates relay settings so relay minimum 4 3.00 3.30 l

eurtent

• 6.4/1.25 = 5.10 n,, , g 3.44 4.19 I

e. The nearest rated relay else from 8 Figure 1 to Beater too. 11 with a ' O II sinime corrent rating of 4.99 A.

10 4.64 4.94

f. rising neater too. 11 the trip curren'. 8' i le now 4.99 a 1.2$ a 4.25 A.

3I

?!

8f r 5.42 l.09

(

g. tecked rotor current le 36.1/6.25, or 5.90 6.44 13  ;

6.2 times the trip corrent.

totee . 14 6.45 f.03 I l i g'It the everent et matte t*e beate* .411 stee trip the everload relay is tilt of t>e am utstet.

Figure 3 Overload Relay Selection Table i

t i

seet ,

' M ferring back to Figure 2, we note h.

f that 6.2 times trip current results in [

'"' k s trip time of 14 seconde aanteus and l.1 seconde minimum, both of which g

meet c 1 and are therefore accepte.ritrrien 1o.

see To determine if criterion 2 to met, we

• • • ( t.

dielde the full load current times the i J g i '

k eereice factor by the relay trip

) \ corr ut Htep f), t.o. S.0 a 1.15/6.15 see 7

• 0.92. This indleates that the full l [

loaJ current to 0.92 times the trip i

' l current. Referring to Figure 2, we i see  ;

I note that 0.92 times trip current ,

results in a etnimum trip time of 1000 ,

seconde and a sutwa of infinity.  :

s sine. th. aircung o.e of the esov is

\

3% seconde, criterio,4 2 is also f

\ t satisfied. r' go ). The correct heater to established as [

us. 11. l

\

< is

" ColecLUSf As_9 g

j \'

h The proceeding r a r ag r aph s have analysed the s '

operation of pe0V'e under var tous abnormal candit '.ons 3 each as froten bearing. tight pacting, std-travel e obstraction. torgoe switch falle , iteit switch 3 -

3 fatture, and post-accident operation. Each condition '

I j has been reviewed to show that an adverse attuatim "8 g reeg1te if the thermal overload relays in the circuit t r e bypa s s ed. In concleston, there appears to he no f technical basis for bypassing or oversialmq the t

' thermal overload relay provided it to selectea i

i e a e s o r s e io ao correctly. Correct selection beeones eleple once the

', "w1;tples of Oserload lieta, frif C.rrent ope r a ting f undame nt ale and characteriettee of circett treakers, thersal overload relays, and ie0V' s are Figure 2. Overload Relay Time Current understood, to aid in the prope r seleetton of Characteristic 5 fdjustabit thermal overload relays, certain recommendations nave Wient Cce"centstelt Type

c

• 2291 bee n Ed s . Ynssa reemsene t tons should hsip eltsinate all unce r t a t nt ie s le6 d s rig to unrettable safety related MOV circuits .n nustear generstmg facditres, cierload relays are either bypa**ed or over4sted to prevent operation of the MOV, and adotttonally, shou 1J result userload relos to unnecenary inp MOVs due to small over-in 49 increaseJ *argin of safety at nuclear power load eo.hhisons plants. C8h3(S. in this case, edi het to be taken into special considera-tions when bemg sized At' normal luked rotor current of short circuit condit on is beyond the bearable condition and should be isolated as ptrrerg soon as possible.

Failure of fuses or 4en to open a fault mill result m a com.

(1) p. c. ritepatetet, ' Standard Control Circuitry plete isolation of the MCC, however redunJant equipment are therefore for Motor Operated valves.* Yankee Atomic required and are fed from an independent so irce.

tiectric Cca pany peport No. yatC-1066, October 31. 1972.

hianunenpt recein4 Fet>ruary 25. luo.

[2] A. W. ple ards. C. D. Forstea, ' Motor overload Protection for Mtor Act ua t ed Valves." Itt!

Pa per No. F 79 649.) presented at ! ff t pts Summa: Meeting, Vancouver, July 1979. Farouk D. Banter: I would like to thank Mr. Duong for taking the time to comment on my paper. I wdl dtseuss his comments in the order

[3] tJ . S . Nucle a r Regula tory Coemission Pequlatory listed in hts analynas.

Guide 1.106

• Thermal overload Protection for 1, I agree that thermal-magnetic breakers are n,n recommended for tiectric mtore on Puter Operated valves.* rnotor operated valve circuits, this ta because it may be difficult to provide adeqt, ate protection against oserload heater burnout with ra r os.t D. Sauter (M'63.sM'77) thermal-magntic breakers. The uw of magnetic only breakers are i was born in Poona, India in preferred because they can trnprove heater prctection.

. 1937. Me received the S. Tech. Hometer, the practice of using thermal-magnetw br.kers ts q Segree in tiectrical taq1neering quite prevalent in the industry, and for this reanod l.att addreswd 4 *rca the indian Institute of them. My point was to emphante that eith or without *.hermal-

• echnology, theragpur, India in magnetic breakers, nothirig is gained by bypasatts the thermal 1943, overload relay, a of his 17 years 2. The dangers addrened in the paper edl esist whether circuit

[ ,erofesetonal e ape r tence , all breakers or fuses are used. If fuwt arg used, the fuse must be sued t have teen associated with power to be unresponsne to locked rotor current drama donns motor seneratton, 15 yeare of these starting; therefore, when carr)ing a sustained locked rotor current, sith the engineering, licensing, it remains questionable if the fase would blow before the motor and operation ot nuclear power plants. Since 1969. failed The use of fuses does not eliminate the dangers assocsated ne has been with Yantee Atomic tiectrte company where with the bypatung of thermal oserload relays.

he currently holds the posLtion of Manager of AdditionaHy, she use of fuses mtroduces yet another hasard; Electrical Engineering. Rio responeintlities cover that of single phasms ,%fter the 1968 San Onofre ftre mhuh was the full erectr um of electrical engineering ( pcwe r ) attnbuted to singje phastng, many utthties have avoided uses as they a;9ly to and interface with nuclear power fusestn i t ue h circuits plante. 3. If locktu rotor current is allowed to perstat,one can espect burn-Mr. Santer to a registered profeestonal engineer out or faJures of the thermal oserload heaters, the motor. the in the states of Massachusette and New nampshire. No contactor, cr the circuit breakea because thtse equipments may to a member of the Itzt Pts nuclear Power engineering not be capable of operating continuously whde carryirs locked Committee (NPEC) as well as VLCe*ChairSan of the NPEC rotor current. Unfortunately, the failure or burncut may not be Aust11ery Power Subcoanittee. in faAl-safe mode, and if not, the conseque sces could resu!! tr decreased safety by now requinns the mcomms aupply breaker to the MCC to open.

Discussion 4&$.Taktng credit for the MCC incorntr.: supply breaker inp results in a totady unacceptable design for the follooms reasons.

Quang H. Duong (The Detroit LJtson Co.. Detroit, Mit The fo!!owing a. A!! other safety related equ2pment on that MCC edt now be are comments on the anal)s.s of the dangers de+,ergued due to a localued esent on a branch circuit.

I

1. No mal practxe is io use either magneticenly ')pe cateuit b. Since the reJundant MOV. powered from an independan' breakers or fuses and thermal overload relays to protect source, rs des:gned to the Sarre cntena, it must also be MOV actuators. Thermal <nagnet>c breakers are not recom- assurned to fad in the same mode, that is, by enrpmg the mended to be used an cosvunction with thermal overload MCC mcoming breaker. A common mode design fadure has relays, therefore the analysts is unnecessary. now been mtroduced in the redundant component whxh as

2. In case overload relays are b) passed; If fuses are utthaed, contrary to the omgje fadure entenon(see IEEE 379L locked <otor current whan perststs long enough edl be in conclusion,it is the obrctne of my paper to try to rotat out cleared by fuws, la case magnet.conly type breakers are the dangers of this towa!!ed normal practxe"of bypassms or over-utdited, locked rotor current ed! Wentuat/ damage the sizmg thermal oserload relays Regulatory Guide 1.106 posmon C.1 motor. Utdtastion of fuses therefore is preferable clearly states that *rwiJed that r4e cumpletion of r4e saferr funct,og 3 In case overload relays are overmaed Locked totor current u nor /topJrJceJ or r4Jr other Jefer) 3 Bre9t! era Mor degredad Ia) the when perststs longer than allow' d, mitt be cleared by over- thermal overload prct ec tion de,1ce should be contmuously b y-load relays passed .** It should be quite (lear twm this position that the NRC is

4. Breakers or fows are utdiaeJ to mterrupt and isolate a fault concerned with indsnminate bypassing of thermal overloaJ relays shoJJ a short strewit occur. If they fad to tnp open, art- whwh coulJ result in a decrease of overall nuclear plant safety. W ith coming breaker feedmg the MCC is nest to inp Overload the help of my paper, Aensees can now make a determination .hether re!ays, as the name represents, are not designed to operate on or not they shoulJ ta) pass thermal overload rela): Furthermore, te-a short circuit. Contactors are not rated or des:gned to inter- cause of the recognard dangers of bypasses thermal overload relays, rupt short orcuit currents the NRC have pronJed in their Regulatory Guide 1.106, an alternatat The rehabihty of the safety system =di not be decreased poution C: whwh advocates the use of thermal oserload relays for both as e ntten in 44, by thmanatms the thermal overload relay, normal and safety functions

5. In eenclusion. oserload heaters are normally selected to operate at 1:51 FLA at its normal ambent temperature. In uncanra rect =4 aPol 2,1980

MaineYankee '

ATTACHMENT B Justification for Not Differential Pressure Testing (CS-N-91)

The same methods of signature analysis (Interactive use of a computer) errployed by MOVATS Inc. cannot readily be used in an effective hardcopy prosentation. Although the following analysis may be similar, 6here are some numerical differences due to the accuracy of each method.

The objective of this attachment is to present sufficient justification for not differential pressure testing CS-H-91. This is based on testing a sister valve CS-N-92 at or above design differential pressure, comparing operation of both valves at zero ps!d and no flow, and conservatively setting the valves based on the test results.

Most of the measurements are done using a measuring device called the THD which senses spring pack movement (l" - 10V). Conversion to enginaering units (ft-lbs) is done by comparing TH0 and TMS voltages. The TMS voltage that results is converted to engineering units by the following formula:

l Torque (ft-Ibs) - TMS (volts)

• 833 (Ibs/ volt) * .583 (ft)

The spring pack displacements resulting from valves CS-N-91 and -92 with no flow and no differential pressure are shown in Figures B-1 and B-2 respectively. Figures B-3 and B-4 provide comparison curves for TMS and THD 4

voltages for valves CS-N-91 and -92. The running load for both valves can be determined from these curves. These loads were found to te approximately 178.7 ft-lbs for CS-N-91 and 138.4 ft-lbs for CS-N-92. Thus, evaluation of l these four figures can show that the operating condition for these identical valves is quite similar. He expect these valves can operate similarly under design differential pressure.

In order to determine the settings for CS-M-91, the operation of CS-N-92 under design differential pressure has to be evaluated. The spring pack i displacement resulting from operating CS-N-92 with 41.5 psid and no flew is shown in-Figure B-5. From this figure, the peak unseating force was found to

be 0.49 volts less the end of valve stroke va!ue of 0.079 volts. The i resulting value of 0.390 volts is then found on the TMS-THD comparison curve shown in Figure B-6. The corresponding TN value of 0.845 volts can then be i

converted into the value for maximum unseating force of 410 ft-Ibs.

The switch settings for CS-N-91 provided a value of G65 ft-Ibs. Since this value is conservative compared to the value of 410 ft-Ibs determined for

, unseating CS-N-92, Maine Yankee feels that this value is a # auate justification for not conducting full differential pressure tests.

l l

9288L-LHO I -

~

XX 1 FIGURE B-1 hk fh

• QQ

_g864g Close to Open Valve Stroke of CS-M-91 at Zero PSID Y0lts TMD

. .. ... . . . . . . . . . .. . .. . ... a. a .

eg,y. m ,, , , , mv . : - . ; - - .-

-v -. -,-

9.915 tt Beoinning

~ of U0lts Valve Stroke This *. race shows that during a % psid valve stroke that the running load is always less than the l spring pack preload and there is no spring pack gap.

29,929 Seconds Erid of Valve Stroke

FIG'JRE L-2 XX 1 .

Close to Open Valve Stroke of CS-M-92 at Zero PSID g 4

-0.675 Ynlts i

TMD

^

_ 7, Spr1ng pack -

e a a ion

• N # - N e bb Beginning of U0lt5 Valve Stroke This trace shows dat during a d psid valve stroke that the running load is always less than the spring g'gg pack preload and that there is a spring pack gap of hgCQP,d5 approximately .003" (1" = 10% on TMD) Running load produces less than 10MV of displacement.

End of Yalve Stroke

l FIGURE 3-3 TMS-TMD Comparison Curve for CS-N-91 at TMD Voltage of 0.015 Volts.

BX 1 '

s ms UX 1

. -0.368 a hlts l

l l 0.015 Volts s

TMD anseenwimmmuse.-. _m.- u_ .-

e

Seconds I

This trace shows by comparison what the running load of CS-M-91 is [(.368)(833)(-583) = 178.7 ft-lbs]

- . _ . - - . - - . - . -- ~ . . _ . - . . . . - - _ __ - . - _ - . = .. .. .. .. ._

FIGURE B-4 TMS-TMD Comparison Curve for CS-M-52 at TMD Voltage of 0.006 Volts .

m,__.- TMS XX 1

_ . yy 1 ,

-0.285

• Yolts 6.996 Volts i

TMD 1,689 we m - wr vs,-,ws-ener w Seconds This trace shows by comoarison what the running load of CS-N-92 is (running load appears to be <10Mv): 3

[(.735) (833) (.583) = 1.38.4 ft-lbs) j

FIGURE C-5 Close to Open Valve Stroke of l{ {

CS-M-92 at 41.5 psid UN 1h '

.ggg Yelts TMD 7

e a N l Yolts I

?

Spring pack gap ,

and relaxation :.f . 1 g .

Ip. q, AW ve Beginning Stroke y qqq

(.079 Volts) 10s6dW of -l (31.95 Vaive Stroke ( Seconds

)

$e008 (0 Volts, 9 Seconds) )2 9.465

~ _ _ . _ _ . _ _ _ _ _ _ _ _ . _ . _ _ - . _ . - -

FIGURE B-6 TMS-TMD Comparison Curve forl CS-M-92 at TMD Voltage of 0.390 Volts

'.r' o

jllX 1 i TMS

. , ny i rl

-0,845 f+

Volts 1

l

, 0.3'30 iVolts i

I I

e j

I TMD '

g rio o.31c This trace shows by comparison what the l unseating force of CS-M-92 was at 41.5 psid:

(.845) (833) (.583) = 410 ft-lbs

' _ ,._- _ _ _, _ . , - - , _ .. _ . - -- ~ .- .. - _ ,_ _ . _ .-..-_ .- .. . .. _ ._.. _ _ _ . _ ._ . _ .-_- - - - _ . - .