gtstrudl user’s group

GTSTRUDL User’s GroupGTSTRUDL User’s Group

Dynamic Analysis of

Service Water Pump for

Seismic Restraint

June 24, 2011Parimal Gandhi, PE

Sr. Engineer1

Annual Meeting - 2011Annual Meeting - 2011

PURPOSE

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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.

AGENDA

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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.

BACKGROUNDPLANT SERVICE WATER SYSTEM

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

BACKGROUNDPLANT SERVICE WATER SYSYEM

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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

BACKGROUNDSW PUMP

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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

COLUMN ASSEMBLY

BOWL ASSEMBLY

DISCHARGE HEAD ASSEMBLY

PUMP BASE PLATE

SEISMIC RESTRAINT

BACKGROUNDSEISMIC RESTRAINT

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FAILURESEISMIC RESTRAINT

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CORROSION

MAINTANCE LOAD (VERTICAL)

ZERO GAP FOR LATERAL RESTRAINT

FAILURESEISMIC RESTRAINT

EXAMPLE: STRUDL Math Model For PumpWith Seismic Restraint

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20- FLOOR PUMP BASEPLATE

17- UPPERSEISMIC RESTRAINT

12 - LOWERSEISMIC RESTRAINT

DYNAMIC ANALYSIS

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DYNAMIC ANALYSIS

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EIGENPROBLEM SOLUTIONEIGENPROBLEM SOLUTION

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DYNAMIC MASS PARTICIPATION FACTORSDYNAMIC MASS PARTICIPATION FACTORS

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RESPONSE SPECTRA CURVEEAST-WEST

RESPONSE SPECTRA CURVEEAST-WEST

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STORING RESPONSE SPECTRAEAST-WEST

STORING RESPONSE SPECTRAEAST-WEST

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RESPONSE SPECTRA CURVEVERTICAL

RESPONSE SPECTRA CURVEVERTICAL

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STORING RESPONSE SPECTRAVERTICAL

STORING RESPONSE SPECTRAVERTICAL

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RESPONSE SPECTRA CURVENORTH-SOUTH

RESPONSE SPECTRA CURVENORTH-SOUTH

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STORING RESPONSE SPECTRANORTH-SOUTH

STORING RESPONSE SPECTRANORTH-SOUTH

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RESPOSNSE SPECTRUM LOADINGRESPOSNSE SPECTRUM LOADING

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NRC REG. GUIDE 1.92 Rev.1 LOADINGNRC REG. GUIDE 1.92 Rev.1 LOADING

Reg.Guide Rev.1: TOTAL = [(LOAD1-Z) 2 + (LOAD2-X) 2 +(LOAD3-Y) 2 ]1/2

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SUPPORT REACTIONS & DISPLACEMENTWITH SEISMIC RESTRAINT

SUPPORT REACTIONS & DISPLACEMENTWITH 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

STRUDL MATH MODEL FOR PUMPWITHOUT SEISMIC RESTRAINT

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20- FLOOR PUMP BASEPLATE

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SUPPORT REACTIONS & DISPLACEMENTWITHOUT SEISMIC RESTRAINT

SUPPORT REACTIONS & DISPLACEMENTWITHOUT 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 & DISPLACEMENTPUMP STRESSES & DISPLACEMENTCheck Pump Base Plate Stresses

ForcesAt Pump Base

PlateDue to Seismic

Condition

With Seismic Restraint

Without Seismic Restraint

Remarks

Fx (kips) 2.21 2.67Fy (kips) 2.05 2.05Fz (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 DisplacementDisplacement At

Lower end of Pump

Due to Seismic Condition

With Seismic Restraint

Without Seismic Restraint

Remarks

Δ x ( inch) 1.51 4.27Δ y ( inch) 0.0 0.0Δ z ( inch) 1.55 5.51

`

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NRC Reg Guide 1.92, Rev 1 Missing Mass Positions

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

1/2n2

k kii=1

R = R , for k = ground motion directions 1, 2, 3

n = number of "significant" modes used in solution

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Frequency1F 2F

ZPAF

Low FrequencyOut-of-PhaseResponse

Mid FrequencyTransition fromOut-of-Phase toIn-Phase Response

High FrequencyIn-Phase Rigid StaticResponse

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

NRC GUPTA METHODMissing Mass Positions

NRC Reg Guide 1.92, Rev 2

NRC GUPTA METHODMissing Mass Positions

NRC Reg Guide 1.92, Rev 2

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

rki ki ki

2 1/2pki ki ki

ki

2 2 1/2ki rki pki

R = R (rigid modal response)

R = (1 - ) R periodic modal response

where 0 1 and k = 1, 2, 3

R = (R + R )

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

1/2n n

pk kij pki pkji=1 j=1

ZPA

R = R R ,k = 1, 2, 3,

and where n = number of modes below F

NRC GUPTA METHODMissing Mass Positions

NRC Reg Guide 1.92, Rev 2

NRC GUPTA METHODMissing Mass Positions

NRC Reg Guide 1.92, Rev 2

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

n

rk rki missingmasski=1

ZPA

R = R + R , k = 1,2,3,

and where n = number of modes below F

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

1/22 2k rk pkR = R + R , k = 1, 2, 3

NRC GUPTA METHODMissing Mass Positions

NRC Reg Guide 1.92, Rev 2

NRC GUPTA METHODMissing Mass Positions

NRC Reg Guide 1.92, Rev 2

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NRC Reg.Guide Rev.2: TOTAL+MM = [(‘LOAD1-Z’+’Z-MAS’) 2 + (‘LOAD2-X’+’X-MAS’) 2 +(‘LOAD3-Y’+ ‘Y-MASS’) 2 ]1/2

Missing MassNRC Reg Guide 1.92, Rev 2

Missing MassNRC Reg Guide 1.92, Rev 2

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NRC Gupta Method Reg Guide 1.92, Rev 2NRC Gupta Method

Reg Guide 1.92, Rev 2

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NRC Gupta Method Reg Guide 1.92, Rev 2NRC Gupta Method

Reg Guide 1.92, Rev 2

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NRC Gupta Method Reg Guide 1.92, Rev 2NRC Gupta Method

Reg Guide 1.92, Rev 2

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NRC Gupta Method Reg Guide 1.92, Rev 2NRC Gupta Method

Reg Guide 1.92, Rev 2

‘GUP-ZT’= [(‘ZR’+’ZPMM’) 2 + (‘Z-PERDC’) 2]1/2

‘GUP-XT’= [(‘XR’+’XPMM’) 2 + (‘Z-PERDC’) 2]1/2

‘GUP-YT’= [(‘YR’+’YPMM’) 2 + (‘Z-PERDC’) 2]1/2

‘GUP-TOTL’= [(‘GUP-ZT’) 2 + [(‘GUP-XT’) 2 + (‘GUP-YT’) 2]1/2

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Reg.Guide Rev.1: TOTAL = [(‘LOAD1-Z’) 2 + (‘LOAD2-X’) 2 +(‘LOAD3-Y’) 2 ]1/2

NRC Reg.Guide Rev.2: TOTAL+MM = [(‘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’) 2]1/2

Missing Mass PositionsNRC Reg Guide 1.92, Rev 1 & 2

NRC Gupta Method

Missing Mass PositionsNRC Reg Guide 1.92, Rev 1 & 2

NRC Gupta Method

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FREQUENCY SPECIFICATONS O TO 900

NUMBER OF MODES 50

NRC Reg Guide 1.92, Rev 1, 2 & Gupta Method Missing Mass Positions

NRC Reg Guide 1.92, Rev 1, 2 & Gupta Method Missing Mass Positions

Frequency

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NRC Reg Guide 1.92, Rev 1 & 2 Missing Mass Positions

NRC Reg Guide 1.92, Rev 1 & 2 Missing Mass Positions

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DYNAMIC MASS PARTICIPATION FACTORSDYNAMIC MASS PARTICIPATION FACTORS

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Reg.Guide Rev.1: TOTAL = [(‘LOAD1-Z’) 2 + (‘LOAD2-X’) 2 +(‘LOAD3-Y’) 2 ]1/2

NRC Reg.Guide Rev.2: TOTAL+MM = [‘(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’) 2]1/2

Missing Mass PositionsNRC Reg Guide 1.92, Rev 1 & 2

NRC Gupta Method

Missing Mass PositionsNRC Reg Guide 1.92, Rev 1 & 2

NRC Gupta Method

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Reg.Guide Rev.2: TOTAL-X = [(X LOAD2) 2 + (MM LOAD2) 2]1/2

NRC Gupta Method: GUP XT = [(X RIGID+MM-XPERD) 2 + ( X PERDC) 2]1/2

Reg. Guide 1.92, Rev. 1: X LOAD 2

Missing Mass PositionsNRC Reg Guide 1.92, Rev 1 , 2 & NRC GUPTA Method

Missing Mass PositionsNRC Reg Guide 1.92, Rev 1 , 2 & NRC GUPTA Method

CONCLUSION

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Seismic Restraint : To Reduce Pump Deflection

and Stresses

No Impact of NRC Reg.Guide 1.92, Rev.

2 on Pump Dynamic Analysis

Questions?Questions?

Thank you.Thank you.

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