ML20203B973

Rev 1 to RD-466, Test & Calculated Results Pressure Locking

ML20203B973
Person / Time
Site:	Sequoyah
Issue date:	08/05/1997
From:	Farrell J, Isbitsky S TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20203B931	List: ML20203B926 ML20203B959 ML20203B973
References
RD-466, RD-466-R01, RD-466-R1, NUDOCS 9712150197
Download: ML20203B973 (26)

Text

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O ATTACNMENT B TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 SUPPLEMENTAL RESPONSE TO GENERIC LETTER (GL) 95 PRESSURE LOCKING AND THERNAL BINDING OF SAFETY-RELATED PONER OPERATED GATE VALVES 3-INCil AND 4-INCli 1500# VELAN VALVE TEST AND CALCULATED PRESSURE LOCKING RESULTS FOR SON VALVES 4

REPORT NUMBER RD-466, DATED AUGUST 5, 1997

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9712150197 971201 PDR P

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, ..- VM R & D Department Test and Calculated Results RD 466 Pressure Locking FOB INF0By AT10F '00 RD-466 Tennessee Valley Authority Sequoyah Nuclear Plant P.O. Box 2000 - STB-4A Soddy Daisy, TN 37379 Velan P.O. No.: P9-81035-K T.V.A. Order No.: P-96N4E-176161 Velan Dwo. No.: Size and Flaure No.:

88405 2 3" B10-30548-13MS 88415-2 3" B10-3054813MS 88521-3 4" B12-20548-13M 88517-3 4" B12-3054B-13M

• \

? a.u. re r t Compiled By: / ,

/1A/W M!i.=. '

MC"

! John M. Farrell, Eng.

'Vice,-#residen , Engineering Reviewed By: ./ I~:: ~

Eemewy l

k. Isbitsky, Eng, Manager, Stress Dept. ,

DATE: bY: RE V.: PAGE No:

! Auaust 5.1997 J.M. Farroll 1 i 1 -

kYM R & D Departm:nt i

Test and Calculated Results Pressure Locking RD466 l

-nn tungppTTinpf UN'l:V l CERTIFICATE of COMPLIANCE:

We hereby certify that the following data are in compilance with the applicable purchase order:

CUSTOMER: Tennessee Valley Authority CUSTOMER P.O.: P-96N4E-176161 VELAN P.O.: P9-81035 K DESCRIPTION: Test and Calculated Results - Pressure Locking Signature. blYb/AM n u nmd l W/

John M. Farrell, Eng.

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Title:

Vice President, Engineering Date: Original: July 7th,1997 Revised: August 5th,1997 DATE: BYi REY.: PAGE No:

Auaust S.1997 J.M. Farrell 1 il

.. VVfLAN a a o oepartment Test and Calculated Results Ro46a.

Pressure Locking TOliINFliffMXTION UKY 2 PECORD of REVIS1QN1 A

Her Descriotion: Dy/Date: Cert _ By / Date:

A  %

0 Initial Release J.M. Fbr[ ell, Eng.Hsbitsky, /p/ .3Eng. -

July 7,1997 July 8,1997

.- ,/

1 Revised per J.M. F 5 rell, Eng. / sis i 5(E6g. t customer Augtist 5,1997 August 5,1997 comments, n -

e DATE: BY: REV.: PAGE No:

Auoust 5.1997 J M Farrell 1 iii

VM R & D Departm:nt Test and Calculated Results RD 466 Pressure Locking

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FOR INF0RMXTI0F0NEY 3 TABLE of CONTENISJ P_aga

1. Certificate af Compliance il

2. Record of Revision ill

3. Table of Contents iv

4. Summary of Test Pesults & Analysis 1

5. Appendix 'A' - Test Results A1

6. Appendix 'B' - Supplementary Data B1 t -

I I

DATE: BY; REY.: PAGE feo:

Auaust 5.1997 J.M. Farrell 1 iv

. VELAN R & D Departm:nt Test and Calculated Results RD-466 Pressure Locking l

1) It[TRODUCTl01h FOR INF6RMXTOW Unry Under a purchase order from T.V.A. tests were carried out on a 3" 1500 lb. Velan gate valve in order to determine the amount of pressure locking which occurred due to various cavity pressures and differential pressures. The resuits of the tests were compared with those of an analytical model with the intent of using this analytical model to evaluate the i potential for pressure socking in similar valves at the T.V.A. Sequoyah plant.

2) IEST EQUIPMENT:

The tests were carried out on a Velan 3" 1500 lb. t; ate valve with a configuration corresponding to Velan drawing No. BR415 2 which is the drawing number for one of the valves under !nvestigation at T.V.A. As back-up data he results of a previous test performed on a 10" 1500 lb. Velan gate valve (Dwg. Nc 88802-1) are presented to substantiate the analytical model used. The results from a (Urd test, on a Velan 10" 300 lb. API 600 gate valve are also reviewed.

All valves are clamped in a fixture and pressurised by means of a hydraulic pump connected to the bonnet of the valve. Details are given in report RD 459.

3) TEST RESULTS:

The test results for the 3" valve are given in RD-459 (Appendix 'A'). The results of the tests on the 10" 1500 lb. and 10" 300 lb. valves are also included in Appendix 'A'.

4) ANALYSIS of TEST RESULTS Nomenclature:

The following nomenclature is used:

T,, = Total opening load - Ibf. from tests.

Tw = Static unwedging load - Ibf. from tests, gf = Gland friction load - Ibf. from tests.

Pe

= Stem piston effect Ibf.

Pt = Pressure locking load - Ibf.

Po = Differential pressure load -Ibf.

X = Difference between test and calculated loads - Ibf.

oATE: en REY.: PAGE No:

Atmst 5,1997 J M. Farrell 1 1 of 3

7VfLAN a a o oepartm:nt Test and Calculated Results Pressure Locking RD46

4) musis of Test assutrs remem FOR INFORMATION ONEY Inillally the intention was to use the analytical method of Com. Ed. given in Nureg/CP-0152 for evaluating the pressure locking load. However, it had been found in the test on the 10" 1500 lb. Velan gate valve that no seat loading due to deflection of tha wedge plates in the axis of the valve bore centerline was detested. (Rnf. Nureg/CP-0146 Velan paper), in the results of the tests on the 3" 1500 gate valve, again no significant effect of wedge plate deflection could be seen.

Therefore it was decided that the deflection of the wedge plate would be ignored, and only the downward force component due to the cavity pressure acting on the wedge would be considered. In the equation that is used, an unknown factor X is used which shows the deviation of the calculated from the test results.

The equation used is then:

T,, = Tw & gf - Pc + Pt + Po + X (1)

IIIII Using the following dimensional data: fliw '

g i d, = Valve stem diameter -ins, ddb - + D D = Valve mean seating fall diameter - ins. - -

0 = Valve' seat angle - degrees. , ,

Y p = Valve seating / unseating factor - 0.3 assumed. ggg p = Cavity pressure - psig. p delP = Differential pressure across wedge - psi.

2 T,, = Tw + gf - 0.785 d,2 p + 2 x 0.785 D pSinD + 0.765pD2 delP + X.~(2)

Using the above equation and the results of the tests on the 3" and 10" 1500 lb. valves the results shown in Table 1 were obtained. it will be seen from Table 1 that the variation between test and calculation is not large, sometimes positive and sometimes negative.

This suggests that the method of calculation is reasonable.

A possible cxplanation of this is that, for this particular valve design, the wedge is relatively much less flexible than the body. That is, the assumption that the seats are fixed is overly conservative.

1 Further discussion of this conclusion if given in Appendix 'B'. -

DATE: SY: REV.: PAGE No:

Atpst 5,1997 JM Farrell 1 2 of 5

, VfM R & D D:partm:nt Test and Calculated Results RD-466 Pressure Locking FOR INFORM ATION ON1.Y

5) P_REf}1GIl_QR Q of OPENING LOAD includina PRESSURE LOCKING:

Using the equation (2), the calculated opening loads for the T.V.A. valves are given in Tabia 2.

i The pressures are taken from Attachment 1 in Appendix 'B'. The data were supplied by T.V.A It is assumed that the unwedging load includes the packing friction; therefore gf is shown as zero in the table.

6) CONCLUSlDNS1 For the particular design of valve analysed, Vs'an 3" and 4" 1500 lb. gate valves, the amount of pressure locking which occurs due to cavity pressure is reasonably predictable by assuming that only the downward component of the cavity pressure load on the wedge (reverse piston effect) is effective.

In other designs, this assumption may not be valid. In fact the results obtained on a 10" t 300 lb. Velan gate valve showed considerable effect due to the deflection of the wedge plates. The conclusion is that the relative flexibilities of the wedge and the body must be taken into account and the assumption of fixed seats is valid only in some cases, in most cases a simple analysis of the relative flexibilities would not be very accurate, end finite element methods would be recommended.

i DATE: BY: REV.: PAGE No: )

August 5, 1997 J.M Farrell 1 3 of 5 l

PRESSURE LOCKING FORCE ( Ref. RD459)

Test Valves Valve No. 88415-2 (3*) 88802-1 (10")

test no. b1 c1 b2 c2 Tr0 1915 2216 2423 2715 15292 Opening Thrust Unwedging Thrust Tw 994 994 1440 1440 7634 gf 900 900 900 900 800 Gland Friction ds _ 1.125 1.125 1.125 1.125 2.25 Stem Dia.

p 2500 2500 2500 2500 2000 cavity pressure Mean Seating Dia. D 2.735 2.735 2.735 2.735 7 delP O 300 0 300 0 Differential Press.

Residual Pressure Locking Force X

- 54 -282 8 - 229 1396

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Z3 E-T1 O

23 EE TABLE 1 ->.

--4 3f 2 g

• O 2

A r-

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l CALCULATED OPENING FORCE Site Valves -T1' l 88415-2 p') 88405-2 (3*)

D Drawing No. ~23]

Tag No. 2-FCV-68-332, -333 1 & 2 -FCV-62-138 gi

~11 Unwedging Thrust Tw 5228 5228 3300 3300 ,

d, Gland Friction gf 0 0 0 0 y Stem Dia. ds 1.125 1.125 1.125 1.125 g I cavity pressure p 2250 2235 220 120 p Mean Seating Dia. D 2.735 -

2.735 2.56 2.56 33 Q---t Differential Press. delP O 300 102 C")

Z Opening Thrust Tr0 5296 5824 3436 3339 d, 88521 -3 (4') 88517-3 (4'L 4 Drawing No. 88405-2 '(3')

Tag No. 1-FCV-68-332 & 333 1 & 2 --FCV-63-152 & 153 1 & 2 -FCV-63-156 & 157 Tw 5228 5228 5645 9630 Unwedging Thrust gf 0 0 0 0 Gland Friction ds 1.125 1.125 1.375 1.375 Stem D!a.

cavity pressure p 2250 2235 1520 2235 Mean Geating Dia. D 2.56 2.56 3.53 3.53 Differerdial Press. de!P O 300 0 25 Tr0 5010 5475 5981 10197 Opening Thrust 5 s 2

w R TABLE 2 w

[ -. - _ _ - _ .

VVfLAN a a o Departmsnt

( '

Test and Calculated Results RD-466 Pressure Locking APP.A

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FOR INF0RM ATl0N '0NEY APPENDIX 'A' ,

This appendix contcins:

(a) The test report on the 2" 1500 lb. Velan gate valve.

(b) The test results on the 10" 1500 Velan gate valve.

(c) The test results on the 10" 300 lb. Velan gate velve.

DATE: DY: REV.:

l PAGE No:

Auaust 5.1997 J M. Farrell 1 i A1 of A9

YhN R & D DEPT.

Investigation of Pressure Locking in Gate Valves RD-459

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1. Purcose of Testi F0R' it'F0RM ATIOR ~0NCY To investigate whether pressure locking would occur in 3" & 4" 1500 gate valves due to locked pressure in the bonnet and if pressure locking occurs, determine the thrust required to overcome this condition.

2. Valve Tested:

The tests were conducted on a 3" 1500 lb. similar to 88415-2 carbon steel bolted bonnet gate valve. The valve was checked for seat tightness by pressurizing the bonnet to 1500 psi with nitrogen. There was no loss of pressure after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and soap and water solution test indicated

'O' leakage through the seats.

3. Test Conditions:

Test Media: Water Upstream Pressure: 300 psig Temperature: Ambient Downstream Pressure: 0 psig Pressure in bonnet: 2500 psig Tests were conducted under extreme pressure conditions. If the pressure locking does not occur under these conditions, it will not occur at lower pressures.

4. Signifiennt To t Results and

Conclusions:

4.1 Closing thrust: 7500 - 7600 lbs. Thrust required to pull out the wedge from seats:

a) With 'O' pressure in bonnet: -

2075 lbs.

b) With 2500 psi of pressure locked in bonnet: 1915 lbs.

4.2 Closing thrust: 10,200 - 10,400 lbs. Thrust required to pull out the wedge from seats:

a) With '0' pressure in bonnet: 2525 lbs.

b) With 250 psi of pressure locked in bonnet: 2423lbs.

The above results indicate that the thrust needed to pull the wedge flom the seat, with or without the locked pressure in the bonnet cavity is nearly the same. This suggests that no stem load due to spreading of the wedge faces occurs in this design of valve.

The downward component of the pressure load on the we.dge (reverse piston effect) is almost exactly balanced by the piston effect of the stem.

DATE: BY: REV.: PAGE No; Augusc 5, 1997 M. Abbas 1 A2 of A9

YEbM R & D DEPT.  ;(

Investigation of Pressure Locking in Gate Valvea RD-459

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FOR INF0'RMXTION MCY Therefore the actual stem load was almost the same with und without pressure in the valve cavity.

5. Test Plan:

5.1 Determiv the packing friction load.

5.2 Close the valve using the following closing torques;

a. 75 ft.lb. (8000 lb. thrust)

b. 100 ft. Ib. (10,700 lb. thrust) and determine the following:

a. Torque required to unlock the stem thread.

b. Torque and thrust required to pull the wedge from the seats under following conditions:

5.1 a With packing loose (i.e. with no packing friction) and 'O' pressure inside the valve.

5.2b Packing tightened and 'O' pressure in the valve.

5.2c With 2500 psig in the bonnet cavity and 'O'_ differential pressure.

5.2d 2500 psig in the bonnet cavity and 300 psig differential pressure across the wedge.

6. Instrumentation:

6.1 Toroue Measurernent:

Closing and opening torque shall be measured with the torque wrench.

BY; REY.:

lOATE: PAGENo:

August 5, 1997 M. Abbas 1 1 A3 of A9

,k_ __ ____ _ _ _ _ - - - _ - - - - - - - - - - - - - - _ - - - - - - - - - - - - -- -- --

VELAN R & D DEPT.

Investigation of Pressure Locking in Gate Valves RD-459

6. imon,meut2iion < cont dn 95NNNENNU 6.2 Stem Thmst Mensurement-Stem thrust shall be calculated from the strain readings of the two (2) strain gages fixed on <

diametrically opposite ends of the stem. Strain due to bending is equal and opposite at the two diametrically opposite locations. Therefore, taking the average of the two strain gage readings eliminates the effect of any bending and gives a fairly accurate estimate of axial strain in the stem, 6.3 Stem thrust is calculated as follows:

4 Strain gage reading of gage #1 = q x 10 in.

4 Strain gage reading of gage #2 = e2 x 10 in, e

The area of stem at the location of gages = A in.

The modulus of elasticity (E) for stem = 29.2 x 10'lb./in.2 for stem material 13% Cr. steel at 70 'F.

Stem thrust = Axial strain x E x A

= , 29.2 (si A .2Lx A lbs.

2 6.4 Calculation of stem torque required to produce the required thrust:

Required stem torque (ft.lbs.) = Stem Thmst (lbs.) x T.F.

T.F., the thread factor is the mechanical advantage ratio for the type and size of stem thread. '

7. Valve Datn:

Seat Bore = 2.63 in.

Stem Thread = 1 1/8 - 5 ACME T.F. = .00936 Stem area at the location of gages = n (11/8)2/4 = 0.994 in.: .

Wedge Angle = 10' OATE: BY: REV.: PAGE Ho:

August 5, 1997 ,

M Abbas 1 A4 of A9

. VELAN R & D DEPT.

Investigation of Pressure Locking in Gate Valves RD 459

8. Test Results: F0n INFliRMXTION ~0EY 8.1 Test #1:

Thrust required to pull the wedge from seats with packing loose and '0' (zero) internal pressure:

Closing Strain Cage reading closing Torque to Torque to puli Strain gage reading Wedge Torque a 10

• inch Thrust unlock stem out wedge a 10 Pull out ft.lten Qae il Cace f7 h Threads.ft.lb. ft. Its Caan #1 Cace f2 t hru s t 75 -260 -291 8,040 25 10 0 + 70 1015 100 -362 -416 11,290 40 18 0 + 120 1752 8.2 Ten #2:

Packing stud tightened to 25 ft.lbs. packing stress == 4000 psi.

Wedge pull test: a) With '0' pressure in the bonnet and 'O' differential pressure across g wedge, b) With 2500 psi in the bonnet and 'O' differential pressure across wedge, c) With 2500 psi in the bonnet and 300 psi differential across the wedge. ,.

a.1 75 -246 -278 7,604 30 20 +50 + 70 2075 75 -258 -264 7,575 b.1 -255 -264 7,532 30 20 +68 + 64 1915 75 -258 -271 7,692 c.1 -258 -269 7,648 35 20 +78 + 82 2219 a.2 100 -332 -380 10.333 45 25 +72 + 102 2525 100 -340 -370 10,304 b.2 -338 -365 10,202 45 25 + 64 + 103 2423 100 -350 -378 10.565 c.2 -347 -376 . 10,492 45 25 +68 + 118 2715 CATE: B Y; REY.: FAGE Nm Atmust 5,1997 M Abbas 1 A5 of A9 -

_ _ _ _ _ _ _ _ . _ _ - _ - _ - _ _ _ _ _ . - . - _ _ - - - - - . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - '- - - - - - - - - - - - - - - ' - ~ ^ ^ " - ^ ^ ^ ^ ~

. VVELAN R & D DEPT.

Investigation of Pressure Locking in Gate Valves RD-459 F0FiiNFURNinTION UffCY

)

8. Test Results (Cont'd) '

8.3 Packing Friction Load:

Measured Running Strain gage 104 and Packing Friction Load (lbs.) ,

Iproue (ft. Ibst Gage #1 G2&cf2 . Average of 3 rendingst Opemng -16 +42 6-8 + 18 +42 880

+ 20 +46 Closing -18 -42 6-8 -19 , -46 924

-20 -46 l _

DATf; ) BY REV.: PAGE No; August 5, 1997 l M Abbas __

1 A6 of-A9

RD-459

,p F0FiINFliifNiATI0F MY r a T  !

I STRAIN GAUGET l

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t- ~[ -iPRESSURE GAUGE l l -

-- n

-f r ,- i CAVITY PRESSU9E FROM HYDRO PUMP l l g i I I/

% Ds c"'"

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{

aP FROM HYDRO PUMP

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- - d - -

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TIE BOLTSI lENO CLAMPS l Page A7 of A9

VVELAN R & D Departm:nt Test and Calculated Results RD-466 Pressure Locking APP.A

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r0g INF0RM ATIOR MCY (b) Test Results on 10" 1500 lb. Gate - Dwa.' 88802-1 Initial 1 Cavity Calculated Actual Value Closing Press.p Ooenino Load Ooenino Load of X Load 0 7634 -355 24500 1000 10264 9909 24800 1500 12530 12234 -296 23700 2000 13895 15292 +1397 24800 Using equation 2 the values of the calculated opening lead and the actual opening load are plotted in graph 1. !! appears as if some wedge spreading effect is present at 2000 psig, (c) 10" 300 lb. Gate Valve: , _

Cavity Calculated Actual. Value Closing Press. o Ooenina Load Ooenino Load of X Load 0 8000 14000 500 14460 21000 +6540 14000 in this case the calculated figure for opening load is 6540 lbs. too low suggesting wedge plate deflection loading over seat.

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DATE: gY: REV.: PAGE No:

Auaust 5.1997 J.M. Fanell 1 A8 of A9 l

OPENING LOAD / CAVITY PRESSURE . .

10 in. VALVE - 2.25 dio. STEM 16 r1 15 '

p 14

[ 20 E

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l<n ' */

S8 12 J'

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o8 Zm b$ 1;- ,!

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to 3 10 - Jcf

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7 _ --

0 0.2 0.4 0.6 0.8 j j*p 1.8 2

@ (Thousands)

PRISSURE ffJ VALVE CAVITY-PSI s 5 A " FOR INFORMATION ONLY >m 3 x 'c*ut". c GC4Dt1 [.

VVELAN R & D Departmant Test and Calculated Results RD 466

' Pressure Locking APP.B

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F0fi INF0RM ATION '0KY APPENDIX 'B' This appendix contains:

(a) Data supplied by T.V.A.

(b) Calculation of the pressure locking load due to deflection of the wedge plates and assuming fixed seat for the 10" 1500 lb. gate, 3" 1500 lb. gate and 10" 300 lb. gate.

DATE: DY: REv.: ' PAGE No:

Auaust 5.1997 J.M. Farrell 1 B,1 of B6 __

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n J0R INFORMATION 0'NiiY = AL

/* . APP. B ATTACH?ENT 1 - /

y&

Please determine whether pressure locking would occu:, at the conditions listed below, for the subject Velan motor operated valves. If you deter =ine that pressure locking would occur, provide the thrust required to overcome the pressure locking conditi-on.

VLV No. Size Drawino Press Uo/In Bonnet /Down Unwedoinc 1&2-FCV-62-138 3" 88405-2 102 220 0 3300 /

1&2-FCV-62-138 3" 88405-2 50 120 17 3300 /

1-FCV-68-332,333 3" 88405-2 300 2235 0 5228 /

1-FCV-G8-332,333 3" 88405-2 0 2250 0 5228 v 2-FCV-68-332,)33 3" . 88415-2 300 2235 0 5:28 s 2-FCV-68-332,333 3" 88415-2 0 2250 0 5228 /

1 & 2 --FCV- 63 -15 2 ,15 3 4" 88521-3 0 1520 0 5645 1&2-FCV-63-156,157 4" 88517-3 25 2235 0 9630 Press up = Pressure in the upstream piping Press down = Pressure in the downstream piping Press in Bonnet a Pressure assumed to be trapped in the Bohnet The unwedging loads, shown above, were taken fro:a the most recent diagnostic tests data.

The deter =ination of susceptability and the thrust required to overcome pressure locking will be used to satisfy concerns of NRC Generic Letter 95-07., Any calculated values must be supported by test data.

Calculation methodologies and associated test dat; must be provided to TVA.

.l

.i g

Page B2 of B6 g'

.. VEM R & D Dopartm:nt Test and Calculatect Results RD-466 -

Pressure Locking APP.B

, Calculation of oressure Iqpkina load. assumina seats are fixed FOR' INFORM ATION '0NEY The following calculations are made to see what the pressure lock ng load would be if the seats were considered fixed.

The Roark Case No. 2d is used, as shown below, using the Roark nomenclature:

+ (9 &

N* #y j' / s.

I$2rJWp(Ng_CQ,C,

'Jb

. . . Q.

(a) 10" 1500 Valve:

q = 2000 psi a = 3.5 , _.

b = 1.9 = r, Kas = 0.4 Q, = qxax0.4 Q4 = Q, x b _q. (a2 - b 2) a 2a

= 2000 x 3.5 x 0.4 x 1.9 - 2000 (3.5 2 3,9 )

2 3.5 2 x 3.5

= -948 lb.lin.

DATE: BY: REV.: PAGE No:

August 5, 1997 J M Farrell 1 B3 of B6

VEM

. R & D Department Test hnd Calculated Results PD-466 Pressure Locking APP.B l FOR'INFORMA~ TION TfNTY (a) 10" 1500 Valve (Cont'd):

Total Seat Load = 2 x 2na x Q,

= 2 x 2n x 3.5 x (-948)

= -41674 lbs.

Assuming a seat factor of 0.3 Pt = -41,674 x 0.3

= -12,502 lbs.

This value of pressure locking due to wedge plate deflection is far too large to have been missed in the test.

(b) 3" valve; a = 1.36 b = 0.875 q = 2500 Kaa = 0.25 Q, = q x a x 0.25 DATE: BY: REV.: PAGE No:

Anaust 5.1997 J . A Farrell 1 B4 of B6

VfLAN R & D Departmsnt Test and Calculated Results RD-466 Pressure Locking APP.B F0fiINFlijnMTTON tiEY (b) 3" Valvg_(Cont'd)

Ox = 0, x k .g_ (a2 - b 2) a 2a 2 2

= 2500 x 1.36 x 0.25 x 0.875 - 2500 (1.36 -0.875 )

1.36 2 x 1.36

= 546.8 - 996.3 i

= -449 lb.lin.

Total Seat Load = 2 x 2na x 0 4

=

2 x 2n x 1.36 x (-449)

= -7,678 lb.

Using 0.3 seat factor i _

Pt = 0.3 x -7678

= -2303 Again this load is too large to have been missed in the tests.

DATE: BY: REV.: PAGE No; Auaust 5.1997 J.M Farrell 1 B5 of 86

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VVELAN R & D D partment

. Test and Calculated Results RD-466 Pressure Locking APP.B

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F0fiINFliRM ATION ~0NI'Y (c) 10" 300 lb. Valve:

q = 500 a = 5.18 b = 3.125 Q, = q x a x 0.25 2 2 Q3 = 0, x b __q. (a - b )

a 2a 2

= 500 x 5.18 x 0.28 x 3.125 - 500 (5.18 -3.1252) 5.18 2 x 5.18

= 437 - 823

= -385 Total Seat Load = 2 x 2n x 5.18 x (-385)

= -25,080 Assuming a seat factor of 0.3 Pt = -25080 x 0.3

= -7524 lbs.

This is consistent with the test value of 6540 lbs. giver, in Appenaix 'A'.

DATL BY; REV.: PAGE No:

Auaust 5.1997 J M Farrell 1 _

B6 of B6 l

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ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 SUPPLEMENTAL RESPONSE TO GENERIC L2TTER (GL) 95 PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED PONER OPERATED GATE VALVES TVA Commitment 1

TVA will implement design changes to eliminate the potential for pressure locking for the following valves:

' FCV-63-25 FCV-63-26 FCV-72-2 FCV-72-39 FCV-72-40 FCV-72-41 The design changes will be completed prior to startup from the Cycle 9 refueling outage for both units.

5

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