GTSTRUDL User

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GTSTRUDL Users Group
Annual Meeting - 2011
Dynamic Analysis of Service Water Pump
for Seismic Restraint
June 24, 2011Parimal Gandhi, PE Sr. Engineer
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PURPOSE

• Dynamic Analysis of Service Water Pump to
  Evaluate Seismic Loads on the Restraint.
• AND
• NRC Reg. Guide 1.92 NRC Gupta Method for
  Missing Mass Impact on Seismic Loads.

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AGENDA

• Background of Plant Service Water System, Pump,
  and Seismic Restraint.
• Failure of Seismic Restraint.
• Dynamic Analysis of SW Pump With and Without
  Seismic Restraint.
• Impact of NRC Reg.Guide 1.92, Rev. 2 on SW Pump
  Dynamic Analysis.
• Conclusion.

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BACKGROUND PLANT SERVICE WATER SYSTEM

The Service Water Pond covers approximately 94
surface acres, and is required to provide
adequate cooling for 30 days following an
accident.
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BACKGROUND PLANT SERVICE WATER SYSYEM

• The Plant Service Water System is designed to
• Withstand the design basis earthquake (DBE)
  without impairing its function.
• Have sufficient capacity and redundancy to
  provide reliable cooling.
• Be operable during loss-of-offsite power

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BACKGROUND SW PUMP
The SW pumps' capable to withstand a design basis
earthquake (DBE) without a loss of function.
If the seismic restraints are degraded to the
point that their design function can-not be met,
then the associated SW pumps may not be able to
withstand a DBE.  
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BACKGROUND SW PUMP
PUMP MOTOR
DISCHARGE HEAD ASSEMBLY
PUMP BASE PLATE
COLUMN ASSEMBLY
SEISMIC RESTRAINT
BOWL ASSEMBLY
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BACKGROUND SEISMIC RESTRAINT
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FAILURE SEISMIC RESTRAINT
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FAILURE SEISMIC RESTRAINT

• CORROSION
• MAINTANCE LOAD (VERTICAL)
• ZERO GAP FOR LATERAL RESTRAINT

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EXAMPLE STRUDL Math Model For Pump With Seismic
Restraint
20- FLOOR PUMP BASEPLATE
17- UPPER SEISMIC RESTRAINT
12 - LOWER SEISMIC RESTRAINT
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DYNAMIC ANALYSIS
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DYNAMIC ANALYSIS
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EIGENPROBLEM SOLUTION
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DYNAMIC MASS PARTICIPATION FACTORS
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RESPONSE SPECTRA CURVE EAST-WEST
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STORING RESPONSE SPECTRA EAST-WEST
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RESPONSE SPECTRA CURVE VERTICAL
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STORING RESPONSE SPECTRA VERTICAL
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RESPONSE SPECTRA CURVE NORTH-SOUTH
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STORING RESPONSE SPECTRA NORTH-SOUTH
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RESPOSNSE SPECTRUM LOADING
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Reg.Guide Rev.1 TOTAL (LOAD1-Z) 2 (LOAD2-X)
2 (LOAD3-Y) 2 1/2
NRC REG. GUIDE 1.92 Rev.1 LOADING
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SUPPORT REACTIONS DISPLACEMENT WITH SEISMIC
RESTRAINT
Reg.Guide Rev.1 TOTAL (LOAD1-Z) 2 (LOAD2-X)
2 (LOAD3-Y) 2 1/2
UNITS FORCE ? LBS, MOMENT? IN-LBS
UNITS DISPACEMENT ? INCH, ROTATION ? RAD
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STRUDL MATH MODEL FOR PUMP WITHOUT SEISMIC
RESTRAINT
20- FLOOR PUMP BASEPLATE
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SUPPORT REACTIONS DISPLACEMENT WITHOUT SEISMIC
RESTRAINT
Reg.Guide Rev.1 TOTAL (LOAD1-Z) 2
(LOAD2-X) 2 (LOAD3-Y) 2 1/2
UNITS FORCE ? LBS, MOMENT? IN-LBS
UNITS DISPACEMENT ? INCH, ROTATION ? RAD
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PUMP STRESSES DISPLACEMENT
Check Pump Base Plate Stresses Check Pump Base Plate Stresses Check Pump Base Plate Stresses
Forces At Pump Base Plate Due to Seismic Condition With Seismic Restraint Without Seismic Restraint Remarks
Fx (kips) 2.21 2.67
Fy (kips) 2.05 2.05
Fz (kips) 2.26 3.0
Mx (in-kips) 161.9 1065.6
My (in-kips) 0 0
Mz (in-kips) 158.2 843.4
Bolt Tensile Stress with Nozzle Seismic Loads 10.0 ksi 20.2 ksi Allowable 19.2 ksi for 1 ¼ Bolts A-307

Check Pump Displacement Check Pump Displacement Check Pump Displacement
Displacement At Lower end of Pump Due to Seismic Condition With Seismic Restraint Without Seismic Restraint Remarks
? x ( inch) 1.51 4.27
? y ( inch) 0.0 0.0
? z ( inch) 1.55 5.51
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NRC Reg Guide 1.92, Rev 1 Missing Mass Positions
All modes are assumed to be out-of-phase with the
ground acceleration and out-of-phase with each
other
All modes having frequencies significant
frequency
If frequencies are not closely spaced SRSS Mode
Combination Method
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NRC GUPTA METHOD Missing Mass Positions NRC Reg
Guide 1.92, Rev 2
F1 frequency at which peak spectral
acceleration is observed F2 frequency above
which the SDOF (modal) oscillators are in-phase
with the transient acceleration input used to
generate the spectrum and in phase with each
other FZPA frequency at which the spectral
acceleration returns to the zero period
acceleration maximum base acceleration of
transient acceleration input used to generate the
spectrum
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NRC GUPTA METHOD Missing Mass Positions NRC Reg
Guide 1.92, Rev 2

• For each mode i, in each ground motion
  direction k, the response is separated into a
  periodic part and a rigid part

• The periodic modal response portions are
  combined using a double sum rule

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NRC GUPTA METHOD Missing Mass Positions NRC Reg
Guide 1.92, Rev 2

• The rigid modal responses are combined
  algebraically,
• including the residual rigid contribution from
  the missing mass

• The total response in each ground motion
  direction is computed from the SRSS of the modal
  combinations of the periodic and rigid responses

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Missing Mass NRC Reg Guide 1.92, Rev 2
NRC Reg.Guide Rev.2 TOTALMM
(LOAD1-ZZ-MAS) 2 (LOAD2-XX-MAS) 2
(LOAD3-Y Y-MASS) 2 1/2
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NRC Gupta Method Reg Guide 1.92, Rev 2
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NRC Gupta Method Reg Guide 1.92, Rev 2
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NRC Gupta Method Reg Guide 1.92, Rev 2
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NRC Gupta Method Reg Guide 1.92, Rev 2
GUP-ZT (ZRZPMM) 2 (Z-PERDC) 21/2

GUP-XT (XRXPMM) 2 (Z-PERDC) 21/2

GUP-YT (YRYPMM) 2 (Z-PERDC) 21/2

GUP-TOTL (GUP-ZT) 2 (GUP-XT) 2
(GUP-YT) 21/2
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Missing Mass Positions NRC Reg Guide 1.92, Rev 1
2 NRC Gupta Method
Reg.Guide Rev.1 TOTAL (LOAD1-Z) 2
(LOAD2-X) 2 (LOAD3-Y) 2 1/2
NRC Reg.Guide Rev.2 TOTALMM (LOAD1-Z
Z-MAS) 2 (LOAD2-X X-MAS) 2
(LOAD3-YY-MASS) 2 1/2
GUP-TOTL (GUP-ZT) 2 (GUP-XT) 2
(GUP-YT) 21/2
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NRC Reg Guide 1.92, Rev 1, 2 Gupta Method
Missing Mass Positions
FREQUENCY SPECIFICATONS O TO 900 NUMBER
OF MODES 50
Acceleration
Frequency
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NRC Reg Guide 1.92, Rev 1 2 Missing Mass
Positions
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DYNAMIC MASS PARTICIPATION FACTORS
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Missing Mass Positions NRC Reg Guide 1.92, Rev 1
2 NRC Gupta Method
Reg.Guide Rev.1 TOTAL (LOAD1-Z) 2
(LOAD2-X) 2 (LOAD3-Y) 2 1/2
NRC Reg.Guide Rev.2 TOTALMM (LOAD1-Z
Z-MAS) 2 (LOAD2-X X-MAS) 2 (LOAD3-Y
Y-MASS) 2 1/2
GUP-TOTL (GUP-ZT) 2 (GUP-XT) 2
(GUP-YT) 21/2
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Missing Mass Positions NRC Reg Guide 1.92, Rev 1
, 2 NRC GUPTA Method
Reg. Guide 1.92, Rev. 1 X LOAD 2
Reg.Guide Rev.2 TOTAL-X (X LOAD2) 2 (MM
LOAD2) 21/2
NRC Gupta Method GUP XT (X RIGIDMM-XPERD) 2
( X PERDC) 21/2
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CONCLUSION

• Seismic Restraint To Reduce Pump Deflection and
  Stresses
• No Impact of NRC Reg.Guide 1.92, Rev. 2 on Pump
  Dynamic Analysis

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THE END
Questions? Thank you.