ML20206J120
| ML20206J120 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/30/1999 |
| From: | Danni Smith ENTERGY OPERATIONS, INC. |
| To: | |
| Shared Package | |
| ML20137N361 | List: |
| References | |
| ME-98-001-00, ME-98-1, NUDOCS 9905120120 | |
| Download: ML20206J120 (21) | |
Text
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CNRO-99/00006 1
Att chm:nt 3 REDACTED VERSION ENGINEERli4G REPORT ME-98-001-00 PRESSURE LOCKING AND THERMAL BINDING TEST PROGRAM ON TWO GATE VALVES WITH LIMITORQUE ACTUATORS 4
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REDACTED VERSION Engineering Report No.:
ME 98-00100 Pageiof20 ENTERGY OPERATIONS Engineering Report For "Entergy's Pressure Locking and Thermal Binding Test Program on Two Gate Valves with Limitorque Actuators" J
APPLICABLE SITES ANO Unit 1: l X l GGNS: l X l W-3: l X l ANO Unit 2: l X l RBS: l X l ECH: l l
Safety Related:
x Yes No Prepared by: Dana E. Smith Arut Date: 11/4/98 Reviewed by:
Date: // 20 /6
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///2 kf8 Reviewed by:
M
/
Date:
Supervisof/ Reviewer Y!3o/P7 Approved by:
Date:
psponsible CDE Manager (for multiple site reports only)
PROPRIETARY & CONFIDENTIAL 4
J
Engineering Report No.:
ME-98-001-00 Page 2 of 20 1.0 EX E C UT I V E S U M M A R Y........................................................................................ 3
- 2. 0 I NT R O D U CT I O N....................................................................................................... 3 3.0 I N D U ST RY B A C KG RO U N D................................................................................... 4 4.0 SCOPE OF TESTI NG (TEST PROCED URE)........................................................ 5 5.0 T E ST R E S U LT S......................................................................................................... 9 5.1 BASELINE AMBIENT FRICTION FACTOR AND ELEVATED TEMPERATURE FRICTION FACTOR (3-INCil VALVE ONLY) COMPARISON CONCLUSION....................................... 9 5.2 B YPASS LEA K AG E TESTING CONCLUSION................................................................... 9 5.3 BONN ET PRESSURE TESTING CONCLUSION............................................................ 9
- 5.4 UPSTREAM PRESSURE TESTING CONCLUSION........................................................ 9 5.5 COMBINED PRESSURE TESTING CONCLUSION..........................................................9 6.0 ANALYSIS OF ACTUAL TEST DATA AND ENTERGY'S PRESSURE LOCKING E VA L U AT I O N M ET 110 D...................................................................................... 10 7.0 OVERALL CONCLUSIONS OF TEST DATA VERSUS ENTERGY'S PRESSURE 1
)
LOC KI NG EV A L U ATI ON M ETI I O D.................................................................. 10
]
- 8. 0 R E F E R E N C E S.......................................................................................................... 1 1 9.0 F I G U R ES A N D TA B L ES................................................................... 1 1
-1 PROPRIETARY & CONFIDENTIAL 1
Engineering Report No.:
ME-98-001-00 Page 3 of 20 1.0 Executive Summary:
Binding of flexible wedge gate valves in the closed position due to bonnet pressurization is a significant safety concern for the following reasons: (1) flexible wedge gate valves are used in a variety of applications in nuclear power plant safety systems; (2) the valves may be required to open during or immediately following postulated design basis events and (3) the events that most.
severely challenge plant safety (i.e., the design basis accidents) usually involve the most rapid system ambient temperature increases, depressurization rates and possibly the largest pressure differentials in and across these valves.
Tests were designed and performed to simulate representative combinations of pressure expected to be seen under normal and design basis conditions. Both a large bore and small bore valve were tested under a broad range of pressure combinations from zero to near the P/T limit of the valves. Actual static friction factors for each test were determined while pressure and thrust measurements were taken for each of the test matrix points. The effect of elevated body / fluid temperatures on the friction factor of the smaller valve was measured. The point at which bonnet pressurization occurred due to upstream pressure against a closed disc was also determined.
The application of the Entergy Pressure Locking Evaluation Methodology with a minimum friction factor of 0.4 bounds all test results. The pullout thrust calculations performed by this method produced thrust values ranging between 3.77% to 108% greater than actual required threst values. Twenty-four pressure combination scenarios were tested for each valve. Except for two test points on each valve, the Entergy method using actual friction factors predicted greater pullout thrust than actually required to open the valve. For these two tests, the maximum under prediction of pullout thrust was less than 8% of required thrust for the small valve and less than 2.5% for the larger valve. All information is based on raw data and no attempt was made to quantify data scatter.
2.0 Introduction l
As of May 1998, Entergy's pressure locking analysis method is one of the predominant modeling
]
approaches used by utilities for Generic Letter 95-07 submittals. A 1992 test series on the
)
Powell 14" 600# valve demonstrated close agreement with the evaluation method, however, it.
I did not include sufficient data points to establish the applicability of the model to variations in the upstream / downstream pressures. To better support the methodology, additional testing was performed in October / November,1997 on this valve and on a 3" 900# Velan valve.
This report documents the October / November,1997 test results.
PROPRIETARY & CONFIDENTI AL 1
i
Engineering Report No.:
ME-98-001-00 '
Page 4 of 20 3.0 Industry
Background:
INPO SOER 84-7 reported a number of events involving flexible wedge gate valves that failed to' open, These failures have prevented safety-related systems from functioning.when called upon; Binding of the valve disc in the closed position due to high pressure water trapped in the bonnet cavity (i.e, pressure locking) represents a potential common mode failure mechanism for this type of valve.
In GL 89-10, the NRC licensees were asked to provide additional assurance of the capability of-safety-related MOVs and certain other MOVs in safety-related systems to perform their safety-related functions. In GL 89-10 licensees were asked to review MOV design basis, verify MOV '
switch settings, test MOVs under design-basis conditions, improve evaluations of MOV failures and trend MOV problems. Supplement 6 to GL 89-10 described an acceptable approach to
' address pressure locking of motor-operated gate valves.
GL 95-07 required licensees to take actions as necessary to ensure that safety-related power operated gate valves susceptible to pressure locking are capable of performing their required safety functions.
Significance:
Binding of flexible wedge gate valves in the closed position due to bonnet pressurization is a significant safety concern for the following reasons: (1) flexible wedge gate valves are used in a variety of applications in nuclear power plant safety systems: (2) the valves may be required to open during or immediately following postulated design basis events; (3) the events that most severely challenge plant safety (i.e., the design basis accidents) usually involve the most rapid system ambient temperature increases, depressurization rates and possibly the largest pressure differer.tials in and across these valves. Valve operators were not originally sized to open the valves with high pressure fluid trapped in the valve bonnet or when excessive binding forces are
~
applied to the disc. Pressure locking is a phenomenon that can cause the unseating thrust for a gate valve to increase significantly above levels expected for design basis DP conditions. This can result in the valve actuator having insufficient capability to open the valve. In addition, this can result in valve damage in cases where the actuator capability exceeds the valve structural j
limits.
PROPRIETARY & CONFIDENTIAL J
Engineering Report No.:
ME 98-001-00 i
Page 5 of 20 i
4.0 Scope of Testing (Test Procedure)
Test Specimen
Description:
The test specimens were two flexible wedge gate valves equipped with Limitorque actuators.
The 14-inch specimen was a Powell 600# class valve equipped with a SB-3 actuator. The valve was equipped with a Teledyne Smartstem. The disc angle was 5 degrees. The maximum pressure value for testing considerations was 1080 psig.
The 3-inch specimen was a Velan 900# class valve equipped with an SMB-00 actuator. The disc angle was 3.5 degrees. The maximum pressure value for testing considerations was 1500 psig.
Test Setup Description The valves were installed horizontally in mounting stands. Blind flanges with pressurization and instrumentation ports were installed on the upstream and downstream ends. High pressure water was supplied from a pressure vessel pressurized with a nitrogen blanket. The water was supplied independently to each of the specimen's upstream ports, down stream ports, and bonnet cavities.
For the 3-inch valve, a steam supply line allowed high temperature water / steam to be circulated through the specimen to facilitate heating for the high temperature friction factor testing.
Test Program Summary:
Quality Assurance:
All work performed on the Entergy pressure locking test was completed in accordance with Wyle laboratories' Quality Assurance Program, which complies with the applicable requirements of i
ilydrostatic Leakage Testing:
PROPRIETARY & CONFIDENTIAL
Engineering Report No.:
ME-98-001-00 Page 6 of 20 liaseline Ambient Temperature Friction Factor Testing e
l I
I l
Elevated Temperature Friction Factor Testing (3-Inch Valve Only)
Ilypass Leakage Testing Bonnet Pressure Testing PROPRIETARY & CONFIDENTI AL
Engineering Report No.:
ME-98-001-00 Page 7 of 20 Upstream Pressure Testing
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f i
m PROPRIETARY & CONFIDENTIAL
Engineering Report No.:
'ME-98-001-00 Page 8 of 20 Combined Pressure Testing I
N Test Equipment:
All instrumentation, measuring, and test equipment used in the pressure locking test program were calibrated in accordance with Wyle laboratories' Quality Assurance Program, which complies with the requirements of ANSI /NCSL Z540-1, ISO 10012-1, and military Specification MIL STD-45662A.
PROPRIETARY & CONFIDENTI AL
r-Engineering Report No.:
ME-98-001-00 Page 9 of 20 5.0 Test Results:
5.1 Baseline Ambient Friction Factor and Elevated Temperature Friction Factor (3-incia valve only) Comparison Conclusion S.2
. Bypass Leakage Testing Conclusion 5.3 Bonnet Pressure Testing Conclusion 1
1 i
S.4 Upstream Pressure Testing Conclusion S.S Combined Pressure Testing Conclusion j
PROPRIETARY & CONFIDENTI AL J
Engineering Report No.:
ME-98-001-00 Page 10 of 20 6.0 Analysis of Actual Test Data and Entergy's Pressure Locking Evaluation Method Application of the Entergy pressu'e locking evaluation methodology with a minimum friction factor of 0.4 hounds the test results in all cases. The pullout thrust calculations resulted in thrust values ranging between 3.77% to 108% greater than actual required thrust values.
7.0 Overall Conclusions of Test data verses Entergy's Pressure Locking Evaluation Method The EOl method, when used in accordance with the application guidelines, conservatively bounds the required pullout thrust for valves in pressure locking situations. The Entergy Pressure Locking Evaluation Method predicts the relationship between increasing upstream pressure and required pullout thrust in the range shown in Figure 5. Elsewhere it provides a conservative value for design purposes. For increasing upstream pressure the Entergy method produces an increase in the predicted pullout force while actual test results show the opposite.
This is expected since pressurization and expansion of one end of the valve under increasing DP tends to move the seats away from the disc.
To ensure the conservative application of the methodology, a friction factor of 0.4 should be used in the predictive range as described in Figure 5. In the conservative range, actual friction factors may be used, if available, since the assumption that bonnet pressurization forces remain constant with increasing DP introduces considerable conservatism r. demonstrated by test results.
PROPRIETARY & CONFIDENTI AL
i Engineering Report No.:
ME-98-001-00 Pagei1of20 8.0 References 8.1 L Wyle Laboratories Test Report 45161-0' dated December 15,1997, " Pressure Locking and ~
Thermal Binding Test Program on Two Gate Valves with Limitorque Actuators for-Entergy Operations", Vendor Doc # M-J5.08-Ql-45161-0-8.0-1-0.
8.2 Engineering Report ME-98-002-00,"Entergy's Pressure Locking Thrust Evaluation Methodology for Flexible Wedge Gate Valves".
9.0 Figures and Tables.
9.1 Table 1: Predicted Unseating Thrust and Measured Unseating Thrust for 14"- 600#'
Powell Valve Using Actual Pressure and Actual Friction Factor -
9.2 Figure 1: Predicted Unseating Thrust Vs. Measured Unseating Thrust for 14- 600#
Powell Valve Using Actual Pressure and Actual Friction Factor 9.3 Table 2: Predicted Unseating Thrust and Measured Unseating Thrust for 14"- 600# -
Powell Valve Using Actual Pressure and 0.4 Friction Factor 9.4 Figure 2: Predicted Unseating Thrust Vs. Measured Unseating Thrust for 14"- 600#
Powell Valve Using Actual Pressure and 0.4 Friction Factor 9.5 Table 3: Predicted Unseating Thrust and Measured Unseating Thrust for 3"- 900# Velan Valve Using Actual Pressure and 0.4 Friction Factor i
9.6 Figure 3: Predicted Unseating Thrust Vs. Measured Unseating Thrust for 3"- 900# Velan Valve Using Actual Pressure and 0.4 Friction Factor 9.7 Table 4: Predicted Unseating Thrust and. Measured Unseating Thrust for 3"- 900# Velan Valve Using Actual Pressure and Actual Friction Factor 9.8 Figure 4: Predicted Unseating Thrust Vs. Measured Unseating Thrust for 3"- 900# Velan Valve Using Actual Pressure and Actual Friction Factor -
{
l 9.9 Figure 5: Predictive Vs. Conservative Range Application Guide j
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. PROPRIETARY & CONFIDENTIAL I
Engincering Report No.:
ME-98-001-00 Page 12 of 20 Table 1: Predicted Unseating Thrust and Measured Unseating Thrust for 14"-600# Powell Valve Using Actual Pressure and Actual Friction Factor -
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Engineering Report No.:
ME-98-001-00 Page 14 of 20 Table 2: Predicted Unseating Thrust and Measured Unseating Thrust for 14"-600# Powell Valve Using Actual Pressure and 0.4 Friction Factor REDACTED INFORMATION 4
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i Engin:ering Report No.:
ME-98-001-00 Page 16 of 20 Table 3 : Predicted Unseating Thrust and Measured Unseating Thrust for 3"-900# Velan Valve Using Actual Pressure and 0.4 Friction Factor REDACTED INFORMATION PROPRIETARY & CONFIDENTIAL
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Engineering Report No.:
ME-98-001-00 Page 18 of 20 Table 4 : Predicted Unseating Thrust and Measured Unseating Thrust for 3"-900# Velan Valve Using Actual Pressure and Actual Friction Factor REDACTED INFORMATION I
PROPRIETARY & CONFIDENTI AL
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Engineering Report No.:
ME-98-001-00 Page 20 of 20 Predictive vs Conservative Range I
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Figure 5 PROPRIETARY & CONFIDENTIAL