ML20215L144
| ML20215L144 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/06/1987 |
| From: | VALTEK, INC. |
| To: | |
| Shared Package | |
| ML20215L035 | List: |
| References | |
| 34753-52-48, 34753-52-48-R02, 34753-52-48-R2, NUDOCS 8705120113 | |
| Download: ML20215L144 (34) | |
Text
. _ _ _
+
4 Rev.
2 Date M*Y b i$7 Design Report No. 34753/52-48 Seismic / Environmental Qualification Report of Purge Isolation Control Valves for Bechtel Energy Corporation Contract No. 14926-4409/8409 Bechtel Energy Valtek Tag No.
Ortler No.
A1HC-W-9776 34753-48 A1HC-W-9777 34753-48 A2HC-W-9776 34752-48 A2HC-W-9777 34752-48 a:48(4) e B705120113 870508 PDR ADOCK 05000498 A
r-TABLE OF CON 11D@S Page Title Page..................................................
i Table 6f Contents...........................................
11 Record o f Revision.......................................... iii Certificates of Compliance.................................. iv Statement of Qualified Life.................................
v Abstract....................................................
1 1.0 Introduction......................................
2 2.0 Description of Valves and Service Conditions......
2 3.0 List of Pressure Retaining and Other Important Valve Parts......................................
2 4.0 Environmental Qualification Analysis and Test.....
3 4.1 %erinal Aging Test...........................
4 4.2 Test Anomalies...............................
4 5.0 Seismic Qualification.............................
5 5.1 Description of Test Valve.....................
5 5.2 Test Anomaly.................................
6 5.3 Structural Adequacy..........................
6 5.4 Justification for Not Testing Aged Solenoid g
Valve and Limit Switches.....................
7 6.0 Body Wall h ickness...............................
7 7.0 Correlation of Analyses and Tests.................
7 8.0 Concluaions.......................................
7 9.0 Tables and Figures................................
7 10.0 Re fe rences........................................
14 Appendix....................................................
A-1 Wall thickness Calculations............................
A-2 Letter ST-VT-YB-0177...................................
B-2 Le t te r ST-YB-P2-1...................................... B-8 Post Test Seat Inspection..............................
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O Recorti of Revision Page Description Revision No.
All
. Complete Revision 1
i,1v Update to Rev 2 2
i Correct P.O. ntamber to 4409/8409 4
Para 4.1 add "See also section 5.4" 5
Para 5.0 add last 2 sentenced referencing heavier yoke.
7 Add para. 5.4 15 Add reference 23.
C1 Underline wortl " environmental" to emphasize it is correct 4
iii
e Certificate of Design Calculations and Seismic / Environmental Qualification as to Compliance with the Requirements of Eechtel Energy Corporation and the ASME Boiler and Pressure Vessel Code,Section III for Nuclear Power Plant Components.
REVISION: 2 1
SECflON III ISSUE DATE:
1980 ADDENDA:
None AND ANSI B16.34 ISSUED:
1973 CUS'IGIER P.O.:
14926-4409/8409 CUS'IU1ER: Bechtel Energy Corporation SilOP JOB ORDER NUMBER:
34752-48 TAG NO.:
A2ilC-FV-9776, A211C-FV-9777 34753-48 A1HC-FV-9776, A1HC-FV-9777 CUS'lOIER SPECIFICATION: 4Z439ZS1007 REV 8 VALVE ASME CIASS:
2 DESCRIPfION:
18 Inch, Class 150 Valdisk PREPARED BY: bM DATE: M9y 6,I4g7 VERIFIED BY:
11.h,
~QM b }
~7 DATE:
m
[
/
I certify that the valve (s) are designed and qualified (subject to the limitations listed in this report) to withstand, without loss of specified function or structural integrity, the seismic and environmental conditions given in the specification.
CERTIFIED BY: bM Registered Professional Engineer DATE:
Ai e lo;1M7 y
gOfESSlo f
[J CRA!G G.
1 S iv 5'
HAROLD 5EN k
S N
No.6314 TE op 6 1
r Statement cf Qualified Lifa h following items should be replaced during the W maintenance intervals.
~
1.
h Btma-N 0-rings in the valve actuator should be replaced at least every 5 years.
1 2.
h valve body seat, and snaket, and packing should be m pi a.
during a regular maintenance period at 5 year intervals due to the limited effects of radiation and M maintenance practices.
With the maintenance performed as'above the qualified life of the valves is 40 years in the normal envirtmeent, plus a period of 30 days at accidental conditions of temperatum, pressure, and integrated radiation da=amm that includes the 40 year normal operation exposure plus 180 daye post-eocident exposure. h non-=ntblating valves are designed for 75 open-shut cycles per year. Proper maintenance intervals must be observed in order to achieve a 40 year life. Storage / shelf life is included in the 40 year life and 5 year maintenance interval.
e V
F e
e ABS'IRACT
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'Ihis report contains or references the analyses and testing of the Valdisk Control Valves, Valtek-serial ntaber 34753/52-48, for Bechtel Energy Corporation P.O. number 14926-4409/8409, which demonstrate that the valves
{ 2 meet the specified seismic / environmental and ASME Code requirements. The valves are environmentally and seismically qualified'for a'40 year life as explained in the statement of qualified life.
9 Page i of 15 1
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1.0 Introduction 1his report represents a seimaio/ environmental qualification manlysis perfonsed on the Valtak automatic contal valves, ceder vanhae 34753/52-48 for Bechtel Ehergy Corporation P.O. v==hme 14926-4409/8409 according to the requirements of specification 4Z4392S1007 (Ref 6).
h requirement of the applicable codes, s+mdards and specifications m a met as requimd.
This aport includes a description of the valves, service anaditions, and envire==arital/seismio analysis and tests and conclusions. Tables, l
Piaures, aferences, and an appendix are also included at the end of the report.
2.0 Description of Valves and Service conditions h valves h,4 by this qualification report a n all exactly the same configuration and am all 18 inch Class 150 Valdialr control valves. h basic configumtion la +=M1=ted as follows:
18 inch Valdisk Vespel SP-1 (plaque) seat Carbon Steel Yoke and transfer case Heavy Duty Spring /200 square inch actuator 60 psi design pressure 323*F design temperatum (valve intamal parts) 298-104*F embient tempemtum (230 F max for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) i Outside Contairusent, Active ASCO 4-my solenoid Namco limit switches (3)
Radiation exposure (40 year life plus accident)1.7 X 108 RAD (actuator) 140 X 108 RAD Beta and Gamma (valve intamals only)
A mon detailed description of the valve geometry and materials is presented on Valtak assembly drawings A34753/52-48.
(Ref. 8) 3.0 List of Pressure Retaining and Other Important Valve Parts l
A list of pressure retminine parts and other important parts used in the valve along with the drawing revision raaber an as follows:.
Description Drawing No.
Revision l
Body 51308 1
Body Blanir (plate) 51311 0'
Disk 18874 3
Disk Casting 18873 3
Gasket 37634 0
Shaft flange 24440 5
Stud (shaft flange) 3258 1
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r Description D mwing No.
Revision Nut (shaft flange) 15258 0
Yoke 55290-2 Transfor Case 53826 1
0-ring 1716 0
0-ring 2525 O
O-ring 2522 0
Bmoket (1 limit switdi) 53863 1
Bracket (1 limit switches) 53950 1'
Bracket (molenoid) 53949 1
Seat 53845 1
Solenoid Valve 54968
. 1 Limit Switch 28939 0
Limit Switch 28938 0
Yoke Bolt 55550 1
hpered Dauel Washer 55295 1
4.0 kivimrumental Qualification ' Analysis and Test h environmental conditions for the valves and actuators are harsh
,enough that non-metallie or age sensitive parts will be affected. 'Ibese parts are listed as follows:
Valve Body Assembly a.
Seat Vespel SP I (Plaque) b.
n== hat Spiral woimd asbestos c.
Par *hw Grafoil GIN Actuator Assembly d.
0-rings Ben-N e.
Lubricant (cylinder)
Dow Coming 55M, Silicon Based f.
Rycon lubricant actuator Table 1 lists the==vi==
rW Operating Temperatures for con-tinuous use and the thmshold radiation levels for the materials in the lactuatorassembly. It can be seen that the materials are suitable for use in the mari== environment of 2308F and that the radiation exposure for a period of 5 years will not exceed the threshold radiation limit.
%erefom these materials are environmentally qualified for 5 years life.
Environmental qualification of the solenoid valve and limit ' switches is given in and 12.
he valve seat was environmentally qualified by test in accordance with Ref 14. See Ref 15. Seat leakage at the end of the test is shown in i
Table 3.
Seat leakage for infomation only after the test is shown in Table 4 (see Ref 15 section 4.0).
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4.1 hermal Aging nemal Aging test on the valve seat was included as a part of the environmental. qualification referenced in paragraph 4.0.
The themal aging reported in Ref 18 applies to the Actuator Assembly parts listed in paragraph 4.0 above. See also section 5.4.
l2 4.2 Test Anomalies 4.2.1 he first attempt to perfom the loss of Coolant Accident (IDCA) simulation ended with gross seat leakage as explained in section 5.5 of the Test report (Ref. 15). his leakage was caused by pipe scale lodged between the~ valve seat and disk as further explained in the test report. The fact that the leakage was not caused by the increased temperature was verified by a short test at elevated temperature after the valve and test fixtures,had been cleaned out.
At the start of the second attempt to perform the IDCA Simulation there was also gross seat leakage. Pipe scale contamination was again suspected so the valve disk was opened and steam, at 5 peig, was used to blow out the valve.
Re first transient of the IOCA Simulation was perfomed and seat leakage was within specification. h e second transient was perfomed and seat leakage (at various differential pressures) was acceptable at the end of 5000 seconds elapsed time. At the end of 1 day elapsed time the seat leakage was measured at various differential pressures, as prescribed by,
the test procedure (Ref 14 section 3.4.5.1(10) Note 2).
At 54, 45, 30, 20, 2, and 1 peig there was zero leakage.
However, at 10 peig leakage ues 4285 cc/ minute and at 5 psig leakage was 1935/ minute compared to a maximun allowable leakage of 1327 cc/ min.
h e test was continued. After 5 days and 33 days elapsed time the seat leakage was again measured at the same differential pressures as before and there was zero leakage.
It was decided to continue the test. n e leakage in excess i
of the specification was attributed to contamination which l
was still present in the valve.
i
(
These anomalies point out the fact that th'e valve seat leakage is affected by contamination. Nomal dust and rust particles and minor damage to the seat can be tolerated and will not cause leakage which exceeds specification (see Appandix C).
However, gross contamination such aa w urred during the IDCA Simulation may cause excessive leakage.
Normal periodic maintenance, i.e. replacement of the valve seat and cleaning the valve at 5 year intervals as required in the Statement of Qualified Life, will alleviate this Page 4 of 15 l
problem. In addition, the high flow rate through the valve during accidental conditions will effectively blow out any gross contamination. his is supported by the fact that blowing out the valve with.5 psig steam through only a 2-inch inlet pipe cleaned out the contamination which occurred at the second attempt to perfom the IOCA Simulation.
4.2.2 After the valve was irradiated to accidental dosage there was an anomaly in the seat leakage. % e first seat leakage test which was performed after irradiation showed zero leakage. Subsequent tests showed leakage rates which i
exceeded the specification. See section 5.6 of Ref 15. %e last seat leakage test data is shown in Appendix F of Ref 15 and is duplicated in Table 3 of this Design Report.
h e valve was later examined by Valtek and Bechtel personnel. The cause of the leakage was determined to be a relaxation of the clamping force on the valve seat due to flange gasket relaxation. h e flange bolting was tightened in accordance with the procedures explained in the Valve Assembly Drawing (Ref 8) and the valve Maintenance Bulletin (Ref 23). H e seat leakage was tested and was within specification. See Appendix B of this report for details.
5.0 Seismic Qualification Seismic qualification by static analysis proved to be inadequate due to natural frequencies of vibration of the actuator being less than 33 Hz.
A dynamic seismic qualification test was therefore required. The test procedure is Ref 16 and the test report is Ref 17. The test procedure contains 2 separate procedures for perfoming seismic tests on the valve with 2 different yokes. However, only the heavier yoke was actually tested (see Appendix A of Ref 16). The heavier yoke is supplied to 1
Bechtel on the referenced valves for the South Texas Project. All documents and drawings have been updated to show the use of the heavier yoke.
5.1 Description of Test Valve The valve / actuator was the same valve / actuator which was used for the environmental qualification test (Ref 14 and 15) with the following exceptions:
a.
Flange gaskets were changed because the valve test flanges had to be changed for the seismic test.
b.
Actuator solenoid valve and air filter were changed. This was necessary in ortier to achieve 5 seconds maximum closure time with no air supply (fail-safe spring only).
c.
New position indicating switches were installed.
d.
New yoke was installed. The new yoke was stiffer and stronger than the original yoke, e.
New yoke bolts and taper dowel washers were required for the new yoke.
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h is valve / actuator is identical in design and materials to the 4 valves supplied to Bechtel. It was installed in the test fixture with the shaft horizontal, spring up, which simulates actual installation.
5.2 Test Anomaly At the end of the OBE portion of the test 3 of the 4 yoke bolts which attach the actuator to the body had vibrated loose.
ne large lateral loads caused by the CBE caused the threads of the ha dened bolts (SAE Grade 8) to embed into the softer tapered dowel washers (carbon steel). See Figure 1.
This allowed the bolts to rotate as the actuator vibrated. n e problem was resolved by installing haMened tapered dowel unshers, tightening the yoke bolts to a predetermined torque (350 foot pounds) and installing safety lock wire on the bolts to prevent bolts rotation. The OBE test was repeated and the rest of the test was successfully-completed.
R ese equipment modifications have been made on the 4 valves supplied to Bechtel and all doctment have been updated to show the correct parts, materials and procedures.
5.3 Structural Adequacy he seismic qualification test was conducted in accoMance with the procedure in Ref 16. He acceleration levels were 3 G horizontal and 2 G vertical (plus 10% margin) in acco Mance with Bechtel specification 4A479ES1019.
Structural adequacy of the valve and actuator, including fail-safe spring, was verified by closing the valve, using the fail-safe spring only, during each OBE sine sweep and during each SSE sine beat test at resonant frequencies. he time to close, recoded during each closure during SSE tests, was consistent and showed there was not binding due to deflection of the actuator. The valve body was not pressurized during the tests because flow or pressure in the valve body dies not increase operating forces on the actuator. See Ref 22.
h e bracket mounted actuator solenoid valve was tested by de-energizing it to allow the fail-safe spring to close the valve once during each OBE sine sweep and once during each SSE sine beat test at resonance frequencies. h e solenoid valve operated properly, as detennined by measured closure time during the SSE tests and after the SSE tests. Also see Ref 11.
I h e bracket mounted position indicating switches were tested by monitoring the one limit switch which will be used for computer data acquisition. Contact chatter was monitored during the SSE l
l Esge (o of LS I
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tests arei never exceeded the specified 0.002 sec limit. Also see Ref 12.
5.4 Justification for Not Testird Aged Solenoid Valve and Limit Swtiches l
h e solenoid valve and position limit switches were not aged 7
prior to the seismic test. Justification for not testing aged components is given in Ref. 23 which concludes that there is no correlation between aging and the ability of equipment to perfom properly during and after a seismic event.
6.0 Body Wall Thickness (see p. A-2)
Wall nickness
.708 in Code Required Minimun Wall hickness
.50 in Actual Bore Wall h ickness
.31 in Code Required Mini =_= Bore Wall nickness
.22 in 7.0 Correlation of Analyses and Tests h e following table correlates the analyses and tests used to qualify the valve and actuator.
VALVE /ACWNIOR COMPONENTS DWIRONMENTAL SEISMIC OR DESIGN ASPECT QUALIFICATION QUALIFICATION Valve Seat Test -Ref. 15 Test - Ref. 17 Valve Packing Analysis-Table 1 N/A (Test-Ref.19 Analysis-Table 1";
N/A ActuatorAgeSensitive]
Components J
(
b Solenoid Valve Test - Ref. 11 Test-Ref. 11, 17 Limit Switch Test - Ref. 12 Test-Ref. 12, 17 Valve and Actuator Analysis-Table 1 Test-Ref. 17 Valve Operability N/A Analysis-Ref 22 Test-Ref. 22, 17 8.0 Conclusions Tests and analyses which demonstrate the operability, environmental qualification, and seismic qualification of the valves, included or referenced in this report, demonstrate that the valves meet the environmental and seismic requirements stated in the referenced specifications. h e valves are, therefore, seismically and environmentally qualified and meet the requirements of the ASME code.
9.0 Tables and Figures Page 7 of M~
Table 1 - Age Sensitive Materials in Valves 34753/2-48'and W inn Ethvirnnemtal Properties.
Max 1hreshold Part Oper.
Radiation Deso.
hterial Rmetion Temp.(*F)
Ref.
(RADS)
Ref.
Notes 0-Rings Buna-N Sealing 300 2,p.4-2 108 1 p.3-28 Compression set Cospoimd 1050 Imb.
Dow Coming Silicon 350.
4 los-10r 1 p.3-37 ring 55M Molycote Based Painn Grafoil
% 11an 4000 9
1.5I108 13 (GIN)
Imb.
A=nnn-Ryken 350 5 p.38 3.sx10' s p.38
- 2EP 9
e I
Page % of IS
Table 2 - Stmotural Phterials cf Constructions and.All-hla Stress Values.
AIJDNABLE 1mtBBS ALIDWABLE S'11tESS VAWES (PSI)
VAWES (PSI)
T11M MATERIAL AT ROCM '11pF.. AT DESICM '11D9. (32PF)
Body SA-516-70 17,500*
17,500*
From Table I-7.0, A! DER B & PV Code, See,. III D
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e 6
Pageg of 15 8
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Tablo 3 - Seat Imakage Test Data - After accidental Doense Irradiation (See Ref.15 AWir F).
Pressure imakage Rate (psig air)
(std. oc/ min)
Mar 18,~1987 Mar 18, 1987 Mar 19, 1987 (2):
1 465 365 2
820 723 5
2540 3317 10 (1)
(1) 20 (1)
(1) 30 (1) 1441 45 470 400 54 360 235 54 325 235 225 45 300 275 250 30 1463 1219 843 20 8754 8824 3765 10 (1)
(1) 21600 5
4862 3608 9118
- s' 893 1021 2294 1
365 280 1108 NOTES:
(1) Gross leakage,'ot measu n d n
(2) Valve a s left pressurised overnight and seat leakage was measured as pure was deemasing.
1 Page 10 Of IS
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Tablo 4 - Seat Imakage Test Data - 1%rformance '1h'. for Information only (See Ref 15 Section 4.0).
Tests M M hrch 19, 1987 at American Erwimuments Company Inc. Data recorded in Valtek Imboratory Notebook #31' page 64.
Pressure f =hara Rate (psig air)
(std oc/ min)
(1)
(2) 1 240 555 2
755 1273 5
12876 11176 10 28110 37756 20 (3) 70792 30 (3) 103829 45 7214 5284 54 2890 2703 45 2355 2553 30 4970 5275 20 65129 68433 10 36340 37756 5
13911
,14641 2
4209 2982 1
2370 1641 (1) After opening and closing valve disk one time.
(2) After opening and closing valve disk a second time.
'(3) Gross leakage, not measured.
l l
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1 TAPERED DOWEL 4
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WASHER
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YOKE PLATE 2
i A/
)
FORCE s.
t 2
1 2
l 2:
V AL VE. B D DY.
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O FIGURE 1 YOKE PLATE / VALVE BODY BOLTED CONNECTION
)
q
4 3
9 D
/
N H
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VALVE BODY SEAT RETAINER r
SEAT 2
ss.
6 OUTSIDE CONTAINMENT CONTAINMENT SIDE SIDE VALVE DISK N
/
N N~ _ __
FIGURE 2 CROSS SECTION OF VALVE SEAT PAGE _!)
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IS
10.0 References 1.
M.B. Bruce and M.V. Davies, ' Radiation Effects on Organic h terial in Nuclear Plants,* Electrical Power Research Institute (EPRI) Report No.
NP-2129 (Nov. 1981) 2.
1985 Materials Selector issue, Materials Engineering, Dec 1984.
(Magazine) 3.
IEEE Standart1344-1975 - IEEE Rec==mded Practices for Seimmic Quali-fication of Class IE Equipment for Nuclear Power Generating Stations.
4.
Product Information Sheet on Dow Corning Holycote 55M laabricant Foria No 71-274C-82.
6.
Valtek Qualificaticn Procedure #34753-WI Rev 4 for South Texas Project
)
thits 1 and 2.
6.
Bechtel Energy Corporation Specification South Texas Project, thits 1 and 2 - 4Z4392S1007 Rev 8 with attehmts 1 and 2.
7.
S.P. Carfago and R.J. Gibson, 'A Review of Equipment Aging 'Ibeory and Technology,' Electrical Power Research Institute (EPRI) Report No. NP-
{
1558 (Sept. 1980).
8.
Valtek assembly drawings No. A-34753/52-48, Rev 6 and Bill of N terial V-34753/52-48 Rev 4.
9.
Technical Bulletin No. 524-207, thion Carbide Corporation.
10.
IEEE Standard 382-1980-IEEE Standarti for Qualification of Safety-Related Valve Actuators.
- 11.. Autamatic Switch Co. (ASCO), Test Report No. AQS21678/IR, Rev A.
- 12. Namco Controls Report No. QIR 105. Rev.1.
13.
IEEE Standard 323-1974-IEEE Standard for Qualifying Class IE Equipment for Nuclear Power Generating Stations.
- 14. American Environments Co. Inc. " Qualification Test Procedure on Valve and Actuator for Valtek Inc." STP-33186-1 Rev A.
- 15. American Environments Co. Inc. " Qualification Test Report on Valve and Actuator for Valtek Inc.", SIR-33186-1 Rev 0.
- 16. Wyle laboratories Test Procedure No. 4470," Test Procedure for Seismic Qualification of 18-inch Control Valve for Valtek for use in Houston Lighting and Power Courpany South Texas Generating Station."
- 17. Seismic Qualification Test of One 18-inch control Valve and Actuator for Valtek Inc., Wyle laboratories Report No. 53640.
Page 14 of 15
18.
R. Barbarin, " Selecting Elastomeric Seals for Nuclear Service," Power Engineering, December 1977. pp 58-61.
- 19. 'lhemal Aging and Accidental Temperature Testing of Mark One and Valdisk Valves TT-34752 for Bechtel Energy Corp., Rev. 3.
20 NUREG 0588 NRC Interim Staff Position on Environmental Qualification of Safety-related Electrical Equipnent, Rev.1.
21 Natural Frequencies of Vibration of Valve Disk / Shaft Assembly and Valve Body,.Rev 1.
- 22. Operability Analysis and Test Report 34753/2-48 Purge Containment Isolation Valve, Rev 1.
23.
EPRI NP 3326, " Correlation Between Aging and Seismic Qualification for 2
Nuclear Planta Electrical Components."
Page II of 15
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Appendix...............................,,,,,.,,,,,,,,,,,,,,,
g_3 kil thicimens calculations............................ A-2
'14rtter SF-VT-YB-0177...................................
~B-2 Letter ST-W P2-1......................................
B-8 Post Test Seat Inspection..............................
C-1, 9
9 9
9 9
g 9
9 9
9 9
e PAGE AI 0F
^2
BGW WAIL SIIGNIIBS CAUXIATIQ4S PGt 34753/52-48 RUUIS:
ANSI B16.34-1973 (Ref also AISI B16.34 1981 Par 6.7 and 6.1.3(b))
Body Drawing No.
- 51308 Rev. 1 Body Blank No.
- 51311 Rev. O Class Rating'
- 150 Bats:
7he diameter at ends: d a 19.585 Code required minima = thir*====: t. =.50 inrh a Required minimum thicimens on drawing: a.708 i W GALulRY:
Diameter on drawing:
d'= 2.25 inch =
Cods required miniana thir4m===: t' = 0.22 inches Required mici== thir*n=== on drawing: 0.31 inches NtyrilS:
1.
Interpolation, if required, done by following formula d -da t = ta + (
) (te - ta) de-da e
O i
i l
Page AZ of A3 G
iMiv B fl SI.terFr-VF-YB-0177 B2 Letter ST-YB-P2-1 B8-o O
O e
Page BI of Bio
VALTEK M
March 26, 1987 ST-VT-YB-0177 Robert Fatheree/ Robert Witthauer Bechtel Energy Corporation 5400 Westheimer Court P.O. Box 2166 Houston, Texas 77252-2166
SUBJECT:
EnvironmentalQualificationTestofValveSeatofPuhrge containment Isolation Valve PO 14926-4409/8409, Item 38.
Dear Sirs:
Valtek has examined the 18-inch purge containment isolation valve and has identified the cause of and the solution to the seat leakage which occurred at the end of the qualification test of the valve seat.
The solution has been tested and witnessed by representatives of Bechtel Energy corporation.
Based on the demonstrated solution to the seat leakage, Valtek recommends that the leakage be treated as an anomaly in the qualification test which has-been resolved.
Valtek is proceeding
- with preparations for further dynamic testing of the valve which has been previously scheduled, but this is contingent on ap-proval, by Bechtel and other concerned parties, of the solution to the seat leakage.
The valve seat qualification test was conducted according to l
American Environments Test Procedure STP-33186-1 Rev A.
The l
complete sequence of environmental tests was completed, the last of which was irradiation of the valve seat (to simulate radiation exposure during an accident) followed by a seat leakage test at various prescribed pressures.
A seat leakage test prior to the irradiation showed the seat leakage was well below the specified-limit of 1327 standard cubic centimeters per minute (cc/ min) but the seat leakage test after the irradiation showed seat leakage i
in excess of the specified limit.
The leakage.was measured on March 17-19, 1987, in accordance with the Test Procedure and the data was given to Bechtel verbally via telephone conversations which are documented in Bechtel Telephone Notes TN #5134.
On March 19 the test was concluded.
The valve disk was then opened S
1 l
PAGE S1 0F 8'
P.O. Box 2200 i Mountain Springs Parkway 1 Springville, Utah 84663 2200 USA Telex 388-458 i Fax 801489 3719 i Phone 801489-8611
+
and cloogd two ticco end the coat leakage was measured after each closure.
This was done'for information purposes only and was not part of the qualification test.
has not yet been completed.
The Qualification Test Report The valve was returned to Valtak for examination on March 23.
Before any changes or. adjustments kere made to the valve. a series
~
of seat leakage tests were conducted.
Seat leakage was con-sistent with the leakage measured at American Environments.
Following these tests the flange bolt torque was checked and found to be 375 foot-pounds.
The valve assembly drawings for the valve (A34752-48 Rev. 6 and A34753-48 Rev. 6) state that the flange bolting torque must be between 500 and 600 foot-pounds.
This torque is important because it produces the clamping force necessary to hold the valve seat and seat retainer in place in the valve body.
Reduced flange bolting torque results in increased seat leakage.
The flange bolting torque was not checked prior to the conclusion i
of the qualification ~ test because the necessary equipment was not available at the American Environments Company facility.
Had the flange bolting been re-tightened the qualification test would have been successfully completed.
The bolting was tightened to 500 foot-pounds on March 24 and the seat leakage was tested again.
The results are shown in Table 1.
The leakage was less than the specified limit at all test pressures except 10 psig, where leakage as high as 2000 cc/ min was measured.
At this point Robert Fatheree (Bechtel Houston) and George i
Baenteli (Bechtel Norwalk) arrived at Valtok and the tests were discussed.
The decision was made to visually examine the valve seat and disk by removing a blind flange from the test fixture.
This did not. affect the flange bolting or the valve seat.
i In addition, the actuator spring was removed for safety reasons.
After the blind flange had been removed the valve disk was opened, allowing visual examination of the valve disk and the seating edge only (inside diameter) of the valve seat.
There was no evidence of any. damage to the valve seat-no cracks, pits, scratches, etc.
i Seat leakage was observed by closing the valve disk, pressuring the opposite side of the valve (5 psig only), and pouring water around the edge of~the disk.
The areas of the disk and seat where leakage was observed were again examined and no cracks or other damage was found.
The valve seat had not suffered any significant damage during the series of environmental tests.
The blind flange was replaced and three sets of seat leakage tests were performed with the assistance of Mr..Fatheree and Mr.
Baenteli.
The valve disk'was opened and closed at the start of 2
PAGE 63 0F S
ccch cct of tocto.
Tho first and second tests were performed with the test pressure increasing from zero to 54 psig and then decreasing to zero.
The third test started with the test prescure at 54 psig and decreasing to zero.
The results of these tests are shown in Table 2.
The seat leakage ne'sured.on increasing pressure was generally a
higher than on decreasing ~ pressure at any particular test pressure.
This is consistent with all the seat leakage tests.
The leakage was measured using a flow meter with a maximum reading of 850 cc/ min.
Seat leakage greater than 850 cc/ min was measured with 'a second flow meter with a range of 500 to 24,000 cc/ min.
As before, the maximum seat leakage occurred at approximately 10 psig and was measured at 1800 cc/ min (on the second meter) with pressure increasing.
The seat leakage with decreasing pressure for all three tests was less than the specified limit at all test pressures.
Several points should be considered in connection with the seat leakage test data in Table 2.
First, Valtek's understanding of the operation of this valve is that it will close much more rapidly than the corresponding valve inside containment.
Therefore this valve will be subjected to the full accidental pressure, with the pressure slowly decreasing.
This means that the seat leakage tests with decreasing test pressure are more representative of the conditions that the valve may experience and Valtok recommends that seat leakage tests be performed with decreasing pressure only.
In Table 2 the seat leakage measured with decreasing pressure was always less than the specified limit of 1327 cc/ min.
Second, the specified limit of 1327 cc/ min is actually one-half of the leakage' allowed by ASME Section XI IWV-3000 for this valve.
Even if the'first point (testing with decreasing test pressure only) is discarded, the tests show that the seat leakage with increasing test pressure did not exceed the full leakage allowed by IWV-3000.
The reduction in the flange bditing torque is attributed to two causes.
First, the flange gaskets relaxed over the period of
' time that they have been compressed. Second, the flange bolting may have loosened due to vibration during transportation to and from the subcontractor which performed the irradiation of the valve.
This would have occurred after the seat leakage test which was performed prior to irradiation, but before the final seat leakage test.
The solution to the problem of reduced flange bolting torque is two-fold.
First, retighten the flange bolting as part of
, preventive maintenance.until the flange gaskets no longer relax.
3 PAGE B+_
0F 8m
- VoltOk MaintCnenc3 Bulletin 10 fcr valve S/N 34753/2-48 (written
- specifically for these valves and submitted to Bechtel on December 5, 1986 Bechtel package #18'223, sequence log #00277VT, 00279VT) recommends this be done at least once every six months (see step 1 of Preventive Maintenance in the bulletin).
Bechtel Telephone Notes TN 95134 indicates that the valves are to- -
- However, be tested once every three months to demonstrate operability.
The flange bolting should be checked and tightened on the same, l
schedule until the flange gaskets no longer relax between maintenance, and then checked at less frequent intervals.
humber of variables which will affect the gasket. operating expe Actual
- second, vibration will be eliminated by the use of lock-wire or otherthe
~
positive anti-rotation devices.
torque as the cause'of theIn conclusion, Valtak has identified reduced flange b seat leakage, has demonstrated that does bring the seat leakage within specification, and hasre-ti recommended procedures that will prevent recurrence of reduced flange bolting torque.
Valtok believes the information provided in this letter is sufficient to close the issue of seat leakage during the qualifi-cation test.
Lynn Larson or Craig Haroldsen.Please direct any questions or comments to either Craig G. Haroldsen, P.E.
Nuclear Project Coordinator CGH:mks cc:
George Baenteli Roger Barnes a:bech-let.ch i
l i
4 PAGE B5 0F N
TABLE l'.
Seat Leakag3 After Tightening Flanga Bolting to 500 Foot-Pound] T rquo.
March 24, 1987 Pressure (Psig)
Seat Leakage (cc/ min)
- 1
- 2 1
not measured 80 2
not measured 205 5
not measured 630 10 1700 2000 20 450 395 30 215 190-45 100 90 54 80 80 54 90 45 120 50 30 245 155 20 485 365 10 1600 745 5
600 350 2
215~
245 1
120 130 s
PAGE e' 0F B "'
TABLE 2.
Seat Leakago Aft r Tightening Flanga Bolting to 500 Foot-Pounds Tcrquo March 24, 1987 (Witnessed by Robert Fatheroe and George Baentali)
Pressure Seat Leakage-
~
(Psig)
(cc/ min)
- 1(1)
- 2(1)
- 3 (1) 1 not measured 22 2
100 80 5
270 285 10 1800(2)
(3) 20 600 485 30 350 385 45 340 400 54 310 385 270(4) 45 285 340 360 30 270 300
'245 20 350 370 260 10 700 440 285 5
190 140 190 2
75 80 60 1
30 10 25 (1)
Valve opened and closed before each of the thr.ee tests.
(2)
Measured with second meter.
(3)
Off scale with first meter (>850 cc/ min Test #3 started at 54 psig with pressure)., not measured.
(4) decreasing.
e e
lp e
6 6
p,,gg B7 0F 8'
n
e*
w Bacht:1 En:rgy Corporation bh bbiv D Egim Cones
/\\\\8((.3 ll ((}87 P. O. Box 2166 Houston, Texas 77252 2166 retas mme VALTEK INC.
ST-YB-HS-388
, iST-YB-HL-13920 ST-YB-P2-1 CONFERENggNfgES NO: 1579 SOUTH TEXAS PROJECT FILE NO:
BECHTEq JOB NO.14j26 PAGE OF
^ " '
DATE OF CONFERENCE:
March 24,1987 LOCATION:
Valtek - Springville, Utah ATTENDEES:
Valtek Bechtel
~
C. Haro1dsen G. Baenteli L. Larson*
R. Fatheree
- Parttime
SUBJECT:
18" Supplementary Purge Containment Isolation Valve Environmental Qualification
'A meeting was held on March 24, 1987 at Valteks' Springville, Utah manufacturing facility in order to witness the Environmental post test inspection of the 18" Supplementary Purge Containment Isolation Test Valve.
This meeting was necessary due to the failure of the test valve to maintain its seat leakage integrity after being subjected to.the accident radiation dosage.
The following coments are applicable to the meeting:
1.
Valtek measured the seat leakage for repeatability with American Environments test data after the valve was received from AE and found that the results were approximately the same (Reference TN Number 5134 dated March 23, 1984).
FACE 88 0F "'
l l
sTP 1170 (12421 l
9242c/0365c
..a s eane rnwsus BECHTEL JOS NO HB28 PAGE 2 0F 3
DATE: April 15, 1987 CONFERENCE NOTES NO: 1579 FILE NO:
J37.14 ST-YB-HS-388 ST-YB-HL-13920 ST-YB-P2-1 2.-
Line flange bolt torques were checked and retorqued to 500 ft-lb.
The outline dimensional drawing requires that the bolting be torqued to 500-600 f t-lbs (measured torque was 375 ft-lbs).
Probable cause for the reduced torque values was attributed to the line flange gaskets,taking a set during the accident radiation dosage.
3.
Valtek rechecked the seat leakage after Item 2 and found that the seat leakage had been substantially reduced.
PRESSURE TEST #1 TEST #2 (PSIG)
(SEAT LEAKAGE STD. CC/ MIN) 1 80 2
205 5
630 10 1700 2000 20 450 395 30 215 190 45 100 90 54 80
.80 54 90
~
45 120 50 30 245-155 20 485 365 10 1600 745 5
600 350 2
21 5 245 1
120 130 5.
Bechtel requested that Valtek stroke the valve and remeasure the seat leakage several times in order to gain confidence in the valves ability to consistently achieve tight shut-off.. The following results were obtained:
PRESSURE SEAT LEAKAGE (STO CC/ MIN)
(PSIG)
STROKE #1 STROKE #2 STROKE #3 1
2 2
100 80 5
270 285 10 1800 20 600 485 30 350 385 45 340 400 54 31 0 385 270 45 285 340 360 l
l PAGS 89 0F 9242c/0365c y
g SECHTEL JOS N0.14828 PAGE 3 0F 3
OATE: April 15, 1987 CONFERENCE NOTES NO: 1579 ST-YB-HS-388 FILE NO:
J37.14 ST-YB-HL-13920 ST-YB-P2-1 PRESSURE SEAT LEAKAGE (STD CC/ MIN)
(PSIG)
STROKE #1 STROKE #2 STROKE #3 30 270 300 245 20 350 370 260 10 700 440 285 5
190 140 190 2
75 80 60 1
30 10 25 NOTE: LARGEST SEAT LEAKAGE WAS DETECTED IN THE 10-15 PSI RANGE.
In sumary, the failure of the. test valve to maintain its leakage integrity was attributed to the relaxation of the line flange bolting torque.
It was mutually agreed that the seismic test scheduled for the week of March 31, 1987 was contingent upon Valtek successfully addressing the American Environments test anomaly concerning excessive seat leakage. Valtek to submit a letter to Bechtel by March 26, 1987.
Recorded by AM
- n. ratneree Reviewed by g A. Matiuk AM/DHA/RHP/RCF/ bib cc: Attendees E. W. Dotson (HL&P - 5) (3 copies)'
W. H. Kinsey (HL&P - NPOD)
B. Tandy (HL&P)
~STP-DC-SRC(1) i l
PAGE 8' 0F
'S 'O 9242c/0365c
O 4
Appendix C Post-Test Valve Seat Inspection n e valve was disassembled after the seismic test had been completed. The valve seat was examined and the following items were noted. The locations on the valve seat.noted here refer to the valve oriented with shaft vertical, actuator up, as it was oriented during,the environmental qualification test.
l2 it is viewed from the disk side, or outside containment side. See Figure 2.
1.
The surface labeled 1 on Figure 2 has mat deposits from 4 o' clock to 8 o' clock. Burnishing, caused by contact with the seat retainer, is evident all around the seat.on surface 1.
2.
Surface 2 has rust deposits from 5 o' clock to 7 o' clock.
3.
Surface 3 also has rust deposits from 5 o' clock to 7 o' clock despite being clamped against the metallic seat retainer. The opposite side of the disk, clamped against the body, did not show any rust deposits.
~
4.
Surface 4 has rust deposits from 3 o' clock to 8 o' clock.
5.
Surface 5 has rust deposits from 5 o' clock to 7 o' clock.
6.
The corner between surface 4 and 5 has rust deposits all around which are worst from 4 o' clock to 8 o' clock.
7.
n e sealing corner, labeled 6 on Figure 2, has some scratches at about 7:30. It is slightly rounded and burnished.
8.
n e rust deposits are very abrasive. n e boric acid spray from the ioCA simulation probably left deposits on the seat which are mixed with the rust deposits.
9.
The rust deposits were cleaned off with alcohol. This left very hard deposits on surface 1 from 3 o' clock to 5 o' clock and on surface 4 and 5 from 3 o' clock to 9 o' clock. These deposits could only be scraped off.
- 10. D e seat remains flexible.
The seat suffered very little damage as a result of the tests perfomed on the valve.
Page C\\ of c.\\
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