ML20116H582
| ML20116H582 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 08/06/1996 |
| From: | Wadley M NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20116H586 | List: |
| References | |
| GL-95-07, GL-95-7, TAC-M93507, TAC-M93508, NUDOCS 9608120143 | |
| Download: ML20116H582 (21) | |
Text
1
'O' Northern States Power Company Prairie Island Nuclear Generating Plant 1717 Wakonade Dr. East Welch, Minnesota 55089 August 6,1996 Generic Letter 95-07 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos.50-282 License Nos. DPR-42 50-306 DPR-60 Response to Request for Additional Information Regarding Generic Letter 95-07, " Pressure Locking and Thermal Binding of Safety-Related 4
Power-Ocerated Gate Valves"(TAC NOS. M93507 and M93508)
Generic Letter 95-07 (dated August 17,1995) was issued by the NRC requesting licensees to provide information concerning (1) the evaluation of operational configurations of safety-related, power-operated gate valves for susceptibility to pressure locking and thermal binding; and (2) analyses, and needed corrective actions, to ensure that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing the required safety function.
i By letters dated October 16,1995, with subject, " Response to Generic Letter 95-07:
Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," and February 12,1996, with subject," Response to Generic Letter 95-07:
Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," Prairie Island responded to the Generic Letter.
By letter dated July 8,1996, the NRC staff requested additional information in order to i
complete its review of the Prairie Island responses to Generic Letter 95-07. The attachment to this letter provides the information requested by the staff. This letter contains no new NRC commitments, nor does it modify any prior commitments.
9608120143 960906 PDR ADOCK 05000282 l
t
USNRC NORTHERN STATES POWER COMPANY August 6,1996 P5ge 2 j
l Please contact Jack Leveille (612-388-1121, Ext. 4662) if you have any questions related to this letter.
h MAW Michael D Wadley Plant Manager Prairie Island Nuclear Generating Plant c: Regional Administrator - Region Ill, NRC Senior Resident inspector, NRC NRR Project Manager, NRC J E Silberg Attachments:
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 95-07 (including two sets of attachments to it:16 pages of calculations,4 pages each for 4 motor valves; and the " User's Guide for PRESLOK, A Gate Valve Pressure Locking Analysis Program Using the Commonwealth Edison Model," 32 pages)
GL950702. DOC
I I
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING GENERIC LETTER 95-07 1.
Regarding valves MV-32195, -32196, -32197, -32198, Pmssurizer PORV Block Valves, the licensee's submittal states that these valves may be susceptible to pressure locking during a postulated steam generator tube rupture event, and that a bounding calculation using the Commonwealth Edison methodology was performed. Please provide this calculation for ourreview.
l
RESPONSE
The opening thrust requirements and existing margin are shown in the four attached,4 l
page calculations. Attached also is the Westinghouse Owners Group " User's Guide for PRESLOK, A Gate Valve Pressure Locking Analysis Program Using the Commonwealth Edison Model." This methodology has been discussed at a number of industry motor operated valve meetings (e.g., refer to NUREG/CP-0152, " Proceedings of the 4th NRC/ASME Symposium on Valve and Pump Testing," dated July 1996).
The following is a summary of the Limitorque actuator / valve information, assumptions, and margin results used to calculate actuator capability:
Actuator / valve: SB-00 Limitorque actuator with a 15 ft-lb,1700 RPM, AC motor, and overall gear ratio of 63.0. The stem diameter is 1.125 inches with a 2/3 lead and 1/3 pitch general purpose ACME threads. The weak link in the open direction is actuator capability.
Caoability Assumotions: Motor nameplate torque is de-rated for design reduced voltage (squared relationship) and high ambient temperature. Pullout Efficiency of 40% and application factor of 1.0 are used (design reduced voltage is less than 90% on all four valves). Stem / stem nut coefficient of friction is conservatively assumed to be 0.20 in determining stem factor (torque to thrust conversion). VOTES measurement uncertainty is applied.
Margin Summarv: The Commonwealth Edison Methodology predicts a substantial margin for each valve as follows (where margin equals actuator capability divided by total required opening thrust):
MV-32195 1,79 MV-32196 1.60 MV-32197 2.23 MV-32198 2.13 l
2.
Through review of operational experience feedback, the staffis aware ofinstances where licensees have completed design orprocedural modifications to preclude pressure locking or thermal binding which may have had an adverse impact on r
Attachment August 6,1996 Page 2 plant safety due to incomplete orincorrect evaluation of the potential effects of these modifications. Please describe evaluations and training forplant personnel that have been conducted for each design orprocedural modification completed to address potentialpressure locking or thermal binding concems.
RESPONSE
MV-32064, MV-32065 [MV-32167, MV-32168): RHR to Vesselinjection (Iow head safety injection)
These flex wedge gate valves were determined to be susceptible to pressure locking in 1993 and were changed from their historical normally closed position to normally open and therefore are no longer a concem for pressure locking. Justification for the position change is provided in Safety Evaluation #351. Normal operating and surveillance procedures were changed to accomplish this activity. These non-complex procedural instructions are provided to plant operators in a concise and descriptive manner, thus no specific training beyond normal requalification training was necessary.
MV-32206, MV-32207, [MV-32208, MV-32209]: RHR to S1 Pump Suction These split wedge gate valves were determined to be potentially susceptible to pressure locking. The Unit 1 valves were modified in 1994 and the Unit 2 valves in 1995 by installation of bonnet vents with manual valves which are controlled administratively to prevent pressure locking.
Both licensed and non-licensed operators received training on this modification in 1995.
The RHR System lesson plan was changed to accommodate this modification. Normal operating and surveillance procedures were changed to cycle the bonnet vents whenever conditions occur that could introduce a pressure locking condition. These non-complex procedural instructions are provided to plant operators in a concise and descriptive manner.
MV-32075, MV-32076, MV-32077, MV-32078, [MV-32178, MV-32179, MV-32180, MV-32181): Containment Sump B to RHR Pump Suction i
These flex wedge gate valves are required to open to provide water for core cooling during the recirculation phase. Each train contains two valves in series, both of which must open to provide containment sump water to the RHR Pump. These valves were determined to be susceptible to pressure locking.
GL950702. DOC
Attachment August 6,1996 Page 3 i
The Unit 1 pumpside valves were modified in 1994 and the Unit 2 pumpside valves in 1995 by installation of bonnet vents with manual valves which are controlled administratively to prevent pressure locking.
l Both licensed and non-licensed operators received training on this modification in 1995.
The RHR System lesson plan was changed to accommodate this modification. Normal operating and surveillance procedures were changed to cycle the bonnet vents i
whenever conditions occur that could introduce a pressure locking condition. These non-complex procedural instructions are provided to plant operators in a concise and descriptive manner. These bonnet vent valves are also cycled prior to transition to the i
recirculation phase following a loss of coolant accident by the emergency operating procedures. A Job Performance Measure for local operator actions for this activity was revised to incorporate this modification. Training on this JPM is being conducted during the present operator requalification training cycle.
The sumpside valves are cycled administratively prior to leaving cold shutdown to ensure the bonnet and the pipe between the pumpside and sumpside valve is drained l
backwards to the containment sump and thus are filled with air preventing the possibility l
of pressure locking. These non-complex proceduralinstructions are provided to plant operators in a concise and descriptive manner.
General Training on Pressure Locking and Thermal Binding:
Licensed and non-licensed operators have periodically received training on MOV testing, issues (including pressure locking and thermal binding), and modifications relative to Generic Letters 89-10 and 95-07, conducted by the MOV Program Engineer.
Prairie Island Engineering and Technical Staff has received training on MOV testing, issues (including pressure locking and thermal binding), and modifications relative to Generic Letters 89-10 and 95-07, conducted by the MOV Program Engineer, j
i A reading assignment was prepared and routed for all system and program engineers i
to alert them to the nature and possibility of pressure locking and thermal binding during abnormal plant system lineups.
l l
atesovoa.noe
1
- Com Ed Model to Provide Open Thrust Requirement for Pressure Locking - MV-32195 INPUTS:
Bonnet Pressure Pbonnet - 2235 psi Assume Normal Operating Pressure i
Upstream Pressure Pup - 1000 psi Conservative upstream pressure after SGTR Downstream Pressure Pdown : 0 psi PRZR PORV leaks by Disk Thickness
- 0.966 in EPRI PPM ((B1-K1)/D+(D1/2)*cos(theta)
Seat Radius a ' : 1.2813 in Velan: ((2.75+2.375)/2)/2 Hub Radius b = 0.8125 in Velan: 1.625/2, Dimension M1/2 Hub Length L : 0.125 in EPRI Dimension K1 Seat Angle theta : - 5 deg Velan Poisson's Ratio (Disk) v:-0.3 Typical of SS 6
Modulus of Elast. (disk)
E 27.610. psi Typical of SS, Marks p. 5-5 l
Static Pullout Force Fpo :: 5443.21.073 Ibf Votes test 1/10/96 x VOTES UN Stem Diameter Dstem : - 1.125 in From Eng-ME-046 Coefficient of friction between disk and seat (open):
mu = 0.4 per table 2-3. p. 2-37 EPRI Gate Valve Model Report mu ' : 0.4 l
l PRESSURE FORCE CALCULATIONS Average DP across disks:
l DPavg : Phonnet "El DPavg = 1735 psi CE-PL195.MCD 1
i 4
Disk Stiffness Constants:
6
~[{,~ ~ 2}
D = 2.278*!0 lbf in
- b- -
7 G
G = 1.06210
- psi 2-(1 t v)
Geometry Factors:
C2 :- 1 + 2 in "
C2 = 0.058 C3 =
+1 In
- t 1
C3 = 0.006 C8 = I-1 + v t (1 - v) 5 C8 = 0.791 2
a In "-\\ +
1 fb\\
C9 -
C9 = 0.254 a
2 bi/
4
\\a/
Inf"\\ + " - 1 L3 : ---*- -
t1 L3 = 0 4a af
\\a/
al I4V L9 : "
...ln " e -- N L9 = 0 a
2 a
4 a
4 2
2' Lil=11+45)2-55-45 2i In
- Lil = 0.00063 64 a
a a
b Ll7 = -
1-1 1 + ( l + v) In "
b Ll? = 0.053 Moment:
Mrb E*18'*- - -
9-(a - b ) -- L17 2
2 Mrb =-239.635 albf C8 2ab Qb E "18-(a - b )
2 2
Qb = 1.048 10'
- CE-PL195.MCD 2
Deflebion due to pressure and bending:
Mrb "2-C2 4 Qb *- C3 - -
E'"
L11 ybq = - 5.022* 10
- in 3
4 6
ybq D
D D
Deflection due to pressure and shear stress:
Ksa 0.3 2 in "
l+
Ksa = - 0.094 2
K5"'DPavg a 5
ysq ysq = - 2.609* 10
- n tG Deflection due to hub stretch (from center of hub to disk):
2 2
Pforce ' : x-(a -- b ) DPavg Pforce = 5.35 10' *1bf "I'* E 6
ystretch -
ystretch = 5.842* 10
- in 2
n-b 2E Total Deflection due to pressure forces:
i yq :- ybq t ysq - ystretch yq = -3.696* 10' *in Deflection due to seat contact force and shear stress (per Ibf/in):
- 1.2-In " a f
8 ysw -
ysw = - 6.83* 10 in Deflection due to seat contact force and bending (per Ibf/in):
ybw-fb\\ f*E!\\L9-f"\\C3iL3 ybw = - 1./67* 10 8
I"
- - ~
\\D)
\\C8/ \\b/
\\b/
lbf in Deflection due to hub compression (per Ibf/in), (from center of hub to disk):
ycompr = - 8.79* 10' * " -
ycompr.
2 2E lbf 4 g.b j
in Total deflection due to seat contact force (per ibf/in):
8 yw ybw + ysw + ycompt yw = 9.4 /610 in CE-PL195.MCD 3
1 1
J i
I i
)
Seat Contact Force for which deflection is equal previously calculated deflection from pressure i
j forces:
i J
i Fs:=2 na N Fs = 3139.9*1bf 1
y*
4
}'
UNSEATING FORCES i
Fpacking is including in measured static pullout force 2
Fpiston :r-Dstem -Pbonnet Fpiston = 2221.6*1bf 4
I Fvert := E a sin (theta)-(2 Pbonnet - Pup-Pdown)
Fvert = 1559.8 *1bf 2
Fpreslock := 2 Fs-(mu cos(theta)- sin (theta))
Fpreslock = 1955.1 *1bf 1
i Flotal.= Fpiston + Fvert + Fpreslock + Fpo Fpo = 5840.6*1bf j
Flotal = 7133.8 *1bf This is the total unseating force under pressure lock conditions Margin Calculation:
Thrust capability at RV and cof = 0.20:
ST := 12789.lbf From Eng-ME-046 ST Margm.. = - -
Ftotal Margin = 1,793 Open Margin at Design RV and cof = 0.20 I
i i
CE-PL195.dCD 4
r i
I
' Com Ed Model to Provide Open Thrust Requirement for Pressure Locking - MV 32196 i
INPUTS:
Bonnet Pressure Phonnet = 2235. psi Assume Normal Operating Pressure I
Upstream Pressure Pup := 1000 psi Conservative upstream pressure after SGTR Downstream Pressure Pdown :' O. psi PRZR PORVleaks by l
l t
Disk Thickness t := 0.966 in EPRI PPM ((B1-K1)/2)+(D1/2)*cos(theta)
Seat Radius a :: 1.2813 in Velan: ((2.75+2.375)/2)/2 l
Hub Radius b := 0.8125 in Velan: 1.625/2, Dimension M1/2 i
Hub Length L :: 0.125 in EPRI Dimension K1 i
(
Seat Angle theta := 5 deg Velan j
l Poisson's Ratio (Disk) v : 0.3 Typicalof SS l
(
Modulus of Elast. (disk)
E ::27.610 psi Typical of SS, Marks p. 5-5 l
6 Static Pullout Force Fpo := 6241.91.073 Ibf Votes test 1/11/96 x VOTES UN
)
Stem Diameter Dstem : ' l.125 in From Eng-ME-046 i
Coefficient of friction between disk and seat (open):
mu = 0.4 per table 2-3. p. 2-37 EPRI Gate Valve Model Report mu : 0.4 PRESSURE FORCE CALCULATIONS Average DP across disks:
DPavg : Pbonnet -
- 1 *"
P DPavg = 1735' psi 2
l CE-PL196.MCD 1
l l
Disk stiffness Constants:
3 D-Et- - - ~
D = 2.278* 10 *1bf in 6
2 12 1 - v G-G = 1.06210'
- psi 2-(1iv)
Geometry Factors:
b 2r C2 = I - -
' I + 2 in,
C2 = 0.058 4
a
(
b i
I-- f+1 Inf"\\ t fb\\
l C3 :
C3 = 0.006 4a
\\a/
\\b/ \\a/
2 C8 -I I + v i (1 - v) b C8 = 0.791 2
a Inf"/\\t- --1-fb\\
C9 C9 = 0.254 a
2
\\b 4
\\a/
L3 - - - - - ")2 2
i1 In *
+ - -
-1 L3 = 0 4a a
a a
L9 "
M"+i~v--- 1f" l'v Md a
2 al 4
\\a
-)- It4N\\
5f
-45\\
2 + I\\
Inf"\\
Lil L1I = 0.00063 64 af
\\a/
ul af
\\bj L17 1-1 1 e (l i v) In Ll7 = 0.053 l
l Moment:
2 Mrb :iDPavg a,
C9_. 2 2
- b ) - L 17 Mrb = -239.635 *1bf C8 2ab Qb ~
" 8 (a - b I
- 2 2
Qb = 1.04810 ',5 3 '
i m
i CE-PL196.MCD 2
i l
f i
l l
l Deflection due to pressure and bending:
6 ybg ~ Mrb " C2 + Qb " C3
"*E'" Li l ybq = - 5.022 10
- in D
D D
i Deflection due to pressure and shear stress:
5 Ksa '
O.3-2 in " -It Ksa = -0.094 b
a ysq Ksa DPavgd
-5 ysq = - 2.609* 10
- in tG Deflection due to hub stretch (from center of hub to disk):
Pforce := n-(a - b ) DPavg Pforce = 5.35 10' *1bf 2
2 ystretch - -
-b-ystretch = 5.842* 10 * *in 2
g.b 2E i
Total Deflection due to pressure forces:
5 yq
>by 4 ysq - ystretch yq = - 3.696 10
- in Deflection due to seat contact force and shear stress (per Ibf/in):
- 1.2. " In " a ysw. -- '"'-- --
ysw = - 6.83* 10' 8 *,
i Deflection due to seat contact force and bending (per Ibf/in):
1
[a y bw -
fC2} [aC9}
8
- d"-
9 C3 t L3 ybw = - 1.767 10 (D)
\\C8/ \\b/
\\bj
[lbf I
\\iE/
Deflection due to hub compression (per Ibf/in), (from center of hub to disk):
I an L I ycompr yeompr = - 8.79* 10 2
-9 in
)
2 2E lbf gx.b j
l in Total deflection due to seat contact force (per Ibf/in):
yw : ybw t ysw t ycompr yw = 9.47610' 8 lb in CE-PL196.MCD 3
- -. _. _. _. ~.... _ - -.
l h
l
'I Seat Contact Force for which deflection is equal previously calculated deflection from pressure forces.
i Es =2 x a I9 Fs = 3139.9 *1bf yw UNSEATING FORCES Fpacking is including in measured static pullout force 1
x 2
Fpiston := -Dstem Phonnet Fpiston = 2221.6*1bf 4
2 Fvert = x a sin (theta)-(2 Pbonnet-Pup-Pdown)
Fvert = 1559.8'Ibf Fpreslock := 2 Fs-(mu cos(theta) - sin (theta))
Fpreslock = 1955.l *1bf Ftotal : = - Fpiston + Fvert i-Fpreslock + Fpo Fpo = 6697.6 *1bf Ftotal = 7990.8 lbf This is the total unseating force under pressure lock conditions Margin Calculation:
Thrust capability at RV and cof = 0.20:
ST := 12759 lbf From Eng-ME-046 Margin := E---
Flotal Margin = 1.597 Open Margin at Design RV and cof = 0.20 l
1 CE-PL196.MCD 4
I l
t Com Ed Model to Provide Open Thrust Requirement for Pressure Locking - MV-32197 4
i INPUTS:
Bonnet Pressure Pbonnet := 2235 psi Assume Normal Operating Pressure
{
Upstream Pressure Pup := 1000-psi Conservative upstream pressure after SGTR Downstream Pressure Pdown : 0 psi PRZR PORV leaks by Disk Thickness t :: 0.966 in EPRI PPM ((B1-K1)/2)+(D1/2)*cos(theta)
Seat Radius a :: 1.2813 in Velan: ((2.75+2.375)/2)/2 Hub Radius b :: 0.8125 in Velan: 1.625/2, Dimension M1/2 Hub Length L := 0.125 in EPRI Dimension K1 I
i Seat Angle theta: 5 deg Velan Poisson's Ratio (Disk) v : 0.3 Typicalof SS 6
Modulus of Elast. (disk)
E := 27.610. psi Typical of SS, Marks p. 5-5 Static Pullout Force Fpo :: 4233.41.073 lbf Votes test 6/3/95 x VOTES UN Stem Diameter Dstem : = 1.125 in From Eng-ME-046 Coefficient of friction between disk and seat (open):
mu = 0.4 per table 2-3. p. 2-37 EPRI Gate Valve Model Report mu : 0.4 PRESSURE FORCE CALCULATIONS Average DP across disks:
P*
DPavg ? Phonnet DPavg = 1735 psi 2
CE-PL197.MCD 1
- Disk Stiffness Constants:
6
',}~, _ 2j D = 2.278* 10 lbf in E--
7 G
G = 1.06210
- psi 2-(1 v)
Geometry Factors:
C2 :-
1-1 i 2 in
- C2 = 0.058 C3 -
4-1 In "
t I
C3 = 0.006 2
C8 I - 1 + v t (l v) b C8 = 0.791 2
a
In f * \\ t
~Y l!
C9 C9 = 0.254 a
2
\\b]
4
\\a/
L3 f*
t Inf"\\ t f*
1 1
L3 = 0 4a
\\a/
\\a/ \\a/
9. _a
[a} l;v
[a}2 1iv L9 = 0 a
2
\\al 4
\\al 2
d 2
~
2' Lil I It4b 5b 4b 24 In,
Lil = 0.00063 64 a
a a
a b
Y l
1 + ( 1 + v) In '
Ll?
I-Ll7 = 0.053 l
Moment:
Mrb : ~
"* E' "
- 2 2
2 a b (a - b ) Ll7 Mrb = -239.635 *1bf C8 Qb
- E(a-b)
Qb = 1.04810' *!,
- 2 2
m CE-PL197.MCD 2
Deflection due to pressure and bending:
ybq : Mrb
- C2 e Qb " C3 -
"?8'"
Lil ybq = - 5.022 10
- in
~6 D
D D
Deflection due to pressure and shear stress:
5 Ksa :
0.3-2 in "
l+
Ksa = - 0.094 b
a
"$E"*E1" 5
ysq ysq = ~ 2.609* 10
- in tG Deflection due to hub stretch (from center of hub to disk):
2 2
3 Pforce : n-(a - b ) DPavg Pforce = 5.35* 10 *1bf
-6
"?
ystretch = 5.842* 10 ystretch :
2 2E nb Total Deflection due to pressure forces:
-5 yq - ybq t ysq ~ ystretch yq = -3.696* 10
- in Deflection due to seat contact force and shear stress (per Ibf/in):
1.2f"'In"a ysw.
-- '" -- ' k' -
~8 ysw = 6.83* 10 tG lbf in Deflection due to seat contact force and bending (per Ibf/in):
ybw f
f"S\\ - L9 f"\\ C3
~8
- b-
+ L3 ybw = ~ 1.767* 10 (D)
\\C8/ \\b/
\\b/
lbf in Deflection due to hub compression (per Ibf/in), (from center of hub to disk):
I 2anL I
-9 in ycompr.
yeompr = - 8.79* 10 2
g g.b 2 Ej lbf in Total deflection due to seat contact force (per Ibf/in):
yw ybw t ysw t ycompr yw = - 9.476 10' 8 in CE-PL197.MCD 3
Seat Contact Force for which deflection is equal previously calculated deflection from pressure forces:
Fs 2 n a #9 Fs = 3139.9 lbf yw UNSEATING FORCES Fpacking is including in measured static pullout force 2
Fpiston - - Dstem Pbonnet Fpiston = 2221.6*1bf 4
2 Fvert = x a sin (theta)-(2 Pbonnet - Pup-Pdown)
Fvert = 1559.8 lbf Fpreslock : 2 Fs-(mu cos(theta)- sin (theta))
Fpreskick = 1955.1 lbf Ptotal -- Fpiston t Fvert e Fpreslock & Fpo Fpo = 4542.4 *1bf Flotal = 5835.7 lbf This is the total unseating force under pressure lock conditions Margin Calculation:
Thrust capability at RV and cot = 0.20:
ST ~ 12994 lbf From Eng-ME-046 Margin : --
Flotal Margin = 2.227 Open Margin at Design RV end cof = 0.20 CE-PL197.MCD 4
i
i i
1
- Com Ed Model to Provide Open Thrust Requirement for Pressure Locking - MV-32198 INPUTS:
Bonnet Pressure Pbonnet r 2235 psi Assume Normal Operating Pressure Upstream Pressure Pup ' ~ 1000 psi Conservative upstream pressure after SGTR Downstream Pressure Pdown := 0 psi PRZR PORV leaks by Disk Thickness t - 0.966 in EPRI PPM ((B1-K1)/2)+(D1/2)*cos(theta)
Seat Radius a - 1.2813 in Velan: ((2.75+2.375)/2)/2 n
Hub Radius b u 0.8125 in Velan: 1.625/2, Dimension M1/2 Hub Length L = 0.125 in EPRI Dimension K1 j
Seat Angle theta ' - 5 deg Velan Poisson's Ratio (Disk) v:-0.3 Typical of SS l
6 Modulus of Elast. (disk)
E ' 27.610 psi Typical of SS, Marks p. 5-5 Static Pullout Force Fpo - 4391.21.073 lbf Votes test 6/3/95 x VOTES UN Stem Diameter Dstem : = 1.125 in From Eng-ME-046 Coefficient of friction between disk and seat (open):
mu = 0.4 per table 2-3. p. 2-37 EPRI Gate Valve Model Report mu' O.4 PRESSURE FORCE CALCULATIONS Average DP across disks:
l DPavg Pbonnet - "El DPavg = 1735 psi CE-PL198.MCD 1
Disk Stiffness Constants:
6
'~12-(1 V l 2\\
D = 2.278 10 lbf in 7
G=
G = 1.062 10 psi 2-(l i v)
Geometry Factors:
C2 -
1-I t 2 In "
C2 = 0.058
]
C3 - f4 Inf*\\ + fb\\ - 1 1
C3 = 0.006 4a
\\al
\\bj \\al C8 I t v t (1 v) fb\\
C8 = 0.791 2
\\al C9 =
- In "-
-Y t
I-C9 = 0.254 L3
- - - f"\\t Inf"\\ t f*\\ - I L3 = 0 1
4a
\\al
\\al \\al L9 *-
inf"\\ t --
1-f"\\
~
L9 = 0 a
2
\\al 4
\\al 2
d 2
2 Lil
-I - 14 4 b - 5 b\\
4b 2+
In Lil = 0.00063 b
64 a
a a
a Ll7 1
- Y I
1 i (1 + v) In b
Ll? = 0.053 Moment:
N"3EE"
-(a - b ) - Ll7 Mrb = -239.635 lbf 2
2 Mrb C8 2ab E (a - b )
- 2 2
Qb 3 '
Qb = 1.04810 ',
in CE-PL198.MCD 2
Deflection due to pressure and bending:
hirb "2-C2 t Qb "- C3 -
"JE'*
L11 ytx] = ~5.02210
- in 3
4
-6 ybq D
D D
Deflection due to pressure and shear stress:
Ksa - 0.3-2 in "
It Ksa = 0.094 Ksa DPavg:a[
ysq = -2.60910' 'in y3q -
tG Deflection due to hub stretch (from center of hub to disk):
2 2
3 Pforce : n-(a - b ) DPavg Pforce = 5.35* 10 *1bf ystretch ' ' N *
ystretch = 5.842 10
- in
-6 2 2E xb Total Deflection due to pressure forces:
5 yq = ybg e ysq - ystretch yq = -3.69610 in Deflection due to seat contact force and shear stress (per Ibf/in):
- 1.2-In " a
~8 ysw ysw = 6.8310 tG lbf Deflection due to seat contact force and bending (per Ibf/in):
ybw.
fb \\ f"'b!\\ - L9 f"\\ C3 8
- 1"-
t L3 ybw = 1.76710 (D/
\\C8/ \\b/
\\b/
lbf in Deflection due to hub compression (per Ibf/in), (from center of hub to disk).
-}
ycompr = - 8.79 10'
- I"-
~ '"'
ycompr -
2 2E lbf (nb j
in Total deflection due to seat contact force (per Ibf/in):
a in CE-PL198.MCD 3
Seat bontact Force for which deflection is equal previously calculated deflection from pressure 1orces:
Es = 2 n a I9 Fs = 3139.9'Ibf yw UNSEATING FORCES Fpacking is including in measured static pullout force 2
Fpiston :- Dstem Pbonnet Fpiston = 2221.6'Ibf 4
2 Fvert x a sin (theta)-(2 Pbonnet-Pup - Pdown)
Fvert = 1559.8'lbf Fpreslock = 2 Fs-(mu cos(theta)- sin (theta))
Fpreslock = 1955.1 *1bf Flotal : - Episton + Fvert + Fpreslock + Fpo Fpo = 4711.8'Ibf Frotal = 6005'lbf This is the total unseating force under pressure lock conditions Margin Calculation:
Thrust capability at RV and cot = 0.20:
ST : - 12789.lbf From Eng-ME-046 I-Margin :
Ftotal Margin = 2.13 Open Margin at Design RV and cof = 0.20 CE-PL198.MCD 4
l l
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