IRWST Sump Strainer and Trash Rack Structural Analysis

IRWST Sump Strainer and Trash Rack Structural Analysis APR1400-E-N-NR-14002-NP, Rev.0

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IRWST Sump Strainer and Trash Rack Structural Analysis

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December 2014

Copyright ⓒ 2014

Korea Electric Power Corporation &

Korea Hydro & Nuclear Power Co., Ltd

All Rights Reserved


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REVISION HISTORY

Revision Date Page Description

0 December 2014 All First Issue

This document was prepared for the design certification

application to the U.S. Nuclear Regulatory Commission and

contains technological information that constitutes intellectual

property.

Copying, using, or distributing the information in this

document in whole or in part is permitted only by the U.S.

Nuclear Regulatory Commission and its contractors for the

purpose of reviewing design certification application

materials. Other uses are strictly prohibited without the

written permission of Korea Electric Power Corporation and

Korea Hydro & Nuclear Power Co., Ltd.


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ABSTRACT

This technical report describes the structural qualification of the floor/plenum mounted cartridges for APR1400 IRWST Sump Strainer and Trash Rack located in the entrance of HVT. The strainer design of Transco Products Inc. (TPI) is utilized and the structural qualification of APR1400 IRWST Sump Strainer was performed by Structural Integrity Associates, Inc. (SI), subcontractor of TPI. The structural analyses of IRWST Sump Strainer and Trash Rack were provided hereto.


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TABLE OF CONTENTS

1 IRWST SUMP STRAINER STRUCTURAL ANALYSIS ................................................................. 1

1.1 Introduction ...................................................................................................................................... 1

1.2 Design Input .................................................................................................................................... 3

1.2.1 Filter Cartridge CAD Geometry ................................................................................................... 3

1.2.2 Seismic Acceleration Response Spectra .................................................................................... 3

1.2.3 Hydrodynamic Drag Force .......................................................................................................... 3

1.2.4 Material Designations for Filter Cartridge Assembly Components .............................................. 3

1.2.5 Hydrodynamic and Debris Loads ................................................................................................ 4

1.3 Assumptions .................................................................................................................................... 5

1.4 Methodology .................................................................................................................................... 7

1.5 Analysis ........................................................................................................................................... 9

1.5.1 CAD Geometry and Finite Element Model .................................................................................. 9

1.5.2 Loads and Boundary Conditions ................................................................................................. 9

1.5.3 Material Properties .................................................................................................................... 10

1.6 Results ........................................................................................................................................... 11

1.6.1 Modal Analysis............................................................................................................................ 11

1.6.2 Response Spectral Analysis ....................................................................................................... 11

1.6.3 Stresses Comparison with ASME Code Allowable Stresses ..................................................... 11

1.7 Conclusions ................................................................................................................................... 17

2 TRASH RACK STRUCTURAL ANALYSIS .................................................................................. 44

2.1 Description of Trash Rack ............................................................................................................. 44

2.2 Trash Rack Analysis ...................................................................................................................... 44

3 REFERENCES .............................................................................................................................. 47


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LIST OF TABLES

Table 1-1 Load Combinations (Reference [1-2]) .................................................................................... 2

Table 1-2 Effective Material Densities for Various Components of the Filter Cartridge Assembly ................................................................................................................................ 4

Table 1-3 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level A .................................................................................... 13

Table 1-4 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level B ................................................................................... 14

Table 1-5 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level C ................................................................................... 15

Table 1-6 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level D ................................................................................... 16


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LIST OF FIGURES

Figure 1-1 Input Response Spectrum (Vertical Global Y-Direction) to GS-50873-GA Filter Cartridge Assembly .............................................................................................................. 18

Figure 1-2 Fixed Support Boundary Conditions Applied to GS-50873-GA Filter Cartridge Assembly - Response Spectral Analyses ............................................................................. 19



Figure 1-5 Geometry of GS-50873-GA Filter Cartridge Assembly......................................................... 22

Figure 1-6 Finite Element Model of GS-50873-GA Filter Cartridge Assembly ...................................... 23

Figure 1-7 Example Bonded Surface Contact Interface of Tube/Top Plate for GS-50873-GA Filter Cartridge Assembly ..................................................................................................... 24

Figure 1-8 Example Bonded Surface Contact Interface of Tube/Bottom Plate for GS-50873-GA Filter Cartridge Assembly ..................................................................................................... 25

Figure 1-9 Input Response Spectrum (Horizontal Global X and Global Z-Direction) to GS-50873-GA Filter Cartridge Assembly .................................................................................... 26

Figure 1-10 Significant Mode Shape, M1, Transverse Bending, Frequency = 52.387 Hz, GS-50873-GA Filter Cartridge Assembly .................................................................................... 27





Figure 1-15 Significant Mode Shape, M25, Vertical Displacement of Access Panel, Frequency=76.668 Hz, GS-50873-GA Filter Cartridge Assembly ........................................ 32

Figure 1-16 Significant Mode Shape, Vertical Displacement of Access Panel, Frequency =79.331 Hz, GS-50873-GA Filter Cartridge Assembly ......................................................... 33

Figure 1-17 Displacement Contour Plot, Global Y for Vertical Direction SSE Response Spectrum for GS-50873-GA Filter Cartridge Assembly ........................................................ 34

Figure 1-18 Displacement Contour Plot, Global Y for Vertical Direction OBE Response Spectrum for GS-50873-GA Filter Cartridge Assembly ........................................................ 35

Figure 1-19 Displacement Contour Plot, Global Z for Horizontal Direction SSE Response Spectrum for GS-50873-GA Filter Cartridge Assembly ........................................................ 36

Figure 1-20 Displacement Contour Plot, Global Z for Horizontal Direction OBE Response Spectrum for GS-50873-GA Filter Cartridge Assembly ........................................................ 37

Figure 1-21 Normal Stress Contour Plot for Vertical Direction (Y-Axis) SSE Response Spectrum Loading for GS-50873-GA Filter Cartridge Assembly .......................................................... 38


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Figure 1-22 Shear Stress Contour Plot for Vertical Direction (Y-Axis) SSE Response Spectrum Loading for GS-50873-GA Filter Cartridge Assembly .......................................................... 39

Figure 1-23 Normal Stress Contour Plot for Vertical Direction (Y-Axis) OBE Response Spectrum Loading for GS-50873-GA Filter Cartridge Assembly .......................................... 40

Figure 1-24 Shear Stress Contour Plot for Vertical Direction (Y-Axis) OBE ResponseSpectrum Loading for GS-50873-GA Filter Cartridge Assembly .......................................................... 41

Figure 1-25 Normal Stress Contour Plot for Horizontal Direction (Z-Axis) Hydrodynamic Drag Force Loading for GS-50873-GA Filter Cartridge Assembly ................................................ 42

Figure 1-26 Shear Stress Contour Plot for Horizontal Direction (Z-Axis) Hydrodynamic Drag Force Loading for GS-50873-GA Filter Cartridge Assembly ................................................ 43

Figure 2-1 Trash Rack Location ............................................................................................................. 45

Figure 2-2 3D view of Trash Rack ......................................................................................................... 46


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LIST OF APPENDICES

Appendix A Hydrodynamic Mass Calculations ................................................................................... 1


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ACRONYMS AND ABBREVIATIONS APR1400 Advanced Power Reactor 1400 ASME American Society of Mechanical Engineers CAD computer-aided design CFR Code of Federal Regulations CQC complete quadratic combination CSS containment spray system ECCS emergency core cooling system FEA finite element analysis IRWST in-containment refueling water storage tank ISRS in-structure response spectra KEPCO Korea Electric Power Corporation KHNP Korea Hydro & Nuclear Power Co., Ltd. LOCA loss-of-coolant accident NPSH net positive suction head NRC Nuclear Regulatory Commission OBE operating basis earthquake RG regulatory guide SI Structural Associates, Inc. SIS safety injection system SRP standard review plan SSC structure, system and components SSE safe shutdown earthquake TPI Transco Products Inc. US United States of America ZPA zero period acceleration


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1 IRWST SUMP STRAINER STRUCTURAL ANALYSIS

1.1 Introduction

The APR1400 has four (4) Emergency Core Cooling System (ECCS)/Containment Spray System (CSS) trains with an independent 56.14 m2 (604.27 ft2) (Reference [1-1]) strainer for each train for a total of 224.55 m2 (2,417.08 ft2) (Reference [1-1] and [1-2]). The design requires a minimum of three trains in operation (168.42 m2 (1812.81 ft2), (Reference [1-1] and [1-2])) assuming one train with a single failure. The strainers prevent debris from being ingested into the Safety Injection System (SIS) and CSS in the event of a loss-of coolant-accident (LOCA) and are located within the IRWST. If a LOCA inside the reactor building were to occur, it could generate debris that, if transported to and deposited on the recirculation sump strainers, could challenge the safety function of the recirculation sumps. Debris can block openings or damage components in the systems served by the IRWST pumps. Specifically, debris that could accumulate on the sump strainers would increase head loss across the resulting debris bed and sump strainers. This head loss might be sufficiently large such that it may exceed the net positive suction (NPSH) margin of the SIS and CSS pumps that draw from the sump. The IRWST sump (also known as the emergency or recirculation sump) is part of the ECCS. Every nuclear power plant in the United States of America (US) is required by regulation (i.e., 10 CFR 50.46, (Reference [1-3]) to have an ECCS to mitigate a design basis accident. The emergency core cooling system is one of several safety systems required by the Nuclear Regulatory Commission (NRC). The IRWST sump collects reactor coolant and chemically reactive spray solutions following a LOCA. The IRWST sump serves as the water source to support long-term recirculation for the functions of residual heat removal, emergency core cooling, and containment atmosphere cleanup. This water source, the related pump inlets, and the piping between the source and inlets are important safety components. The objective of this Technical Report is to provide the structural qualification of the floor/plenum mounted cartridges for APR1400 IRWST Sump Strainer developed by TPI. The analysis includes modal, response spectrum and static structural finite element analysis (FEA) conducted using ANSYS (Reference [1-4]), and includes the calculation of the maximum stresses of the cartridge components at critical design conditions. The strainers are evaluated for design basis conditions including seismic, and are capable of withstanding the force of full debris loading and hydrodynamic loads during an upset, emergency or faulted event. The structural qualification strategy that SI employs to address the TPI strainer configuration is to demonstrate that all of the load combinations including the worst-case loading (in this case the Service Level D load combination) meet specified acceptance criteria. The Specification provided by Korea Hydro & Nuclear Power Co., Ltd. (KHNP) (Reference [1-2]) specifies four service level conditions for the evaluation of the sump strainers: • Service Level A (Normal) • Service Level B (Upset) • Service Level C (Emergency) • Service Level D (Faulted)


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The loads for each combination are detailed in Table 1-1.

Table 1-1 Load Combinations (Reference [1-2])

Service Level Load Combination

A W+ΔP

B W+ΔP+OBE

C W+ΔP+SSE

D W+ΔP+SSE+PDE

Where,

W = Dead Weight ΔP = Differential Suction Pressure (Allowable Head Loss is 60.96 cm-water (2 ft-water) of water or 0.061

kg/cm2 (0.87 psig).) OBE = Operating Basis Earthquake SSE = Safe Shutdown Earthquake PDE = Postulated Dynamic Load i.e. Hydrodynamic Load

The Service Level A load combination is evaluated in the submerged condition (wet) with added mass effects, and the Service Levels B and C/D load combinations are evaluated in identical submerged conditions. Service Level D is the most critical in terms of high stresses. Specific documentation in Appendix A details the calculation of hydrodynamic mass values used in the Design Report. A discussion of the perforated plates used in the strainer design, as well as information regarding the area reinforcement calculation used to justify the modeling of solid plates in the subject analysis is also provided.


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1.2 Design Input

The following design input has been provided by TPI for use in the qualification of the IRWST sump strainers.

1.2.1 Filter Cartridge CAD Geometry

TPI provided a shell model (Reference [1-5]) for one of the four floor mounted filter cartridge assemblies. There are four trains (including Train A) which are mirror reflective image of the A train. Trains A through D are located at angular locations of 25°, 155°, 205° and 335° around the containment wall. Train A consists of twenty four (24) units of four tube filter cartridge sub-assemblies. A finite element model was developed for the filter cartridge assembly, in this case the TPI Train A computer-aided design (CAD) model, whose filename is as listed below. • STRAINER ASSEMBLY.SLDASM (Reference [1-5])

1.2.2 Seismic Acceleration Response Spectra

The In-Structure Response Spectra (ISRS) curves as shown in Figure 1 of Reference [1-2] for the three orthogonal directions corresponding to different damping factors (as summarized in Table 1 of Reference [1-2]) have been digitized. The strainer assembly is a welded and bolted steel structure with friction connections. A majority of the bolt holes in the strainer cartridge assembly are oversize in comparison to the bolt stud diameter. The NRC Regulatory Guide (RG) 1.61, Rev. 1 states an acceptable structural damping value of 4% for SSE and 3% for OBE. The bolts used in the strainer assembly are used for high-load connections and obtain their total strength from the shear strength across the diameter of the bolt PLUS the friction developed between the nut and joined steel surfaces. In order to achieve the friction capacity, these bolts are tensioned to at least 70% of the ultimate tensile strength of the material according to the table below. It is noted here that 3/8 inch and 1/2 inch A193 Grade B8, Class 2 bolts are used in the strainer filter cartridge assembly and Reference [1-1] provides the bolt torque recommendations. The seismic response spectral accelerations vs. frequency at a 4% damping ratio for the SSE and 3% damping ratio for OBE, as stated in Reference [1-6], are applied to the finite element models in three orthogonal directions, namely, vertical and in the two horizontal axes. For the purpose of strainer dynamic qualification, one half of SSE values shall be used for OBE (Reference [1-2]).

1.2.3 Hydrodynamic Drag Force

The strainer filter cartridge assembly is designed to withstand the hydrodynamic loads caused by the fluid discharged (water jet, air bubble transient, steam jet, etc.) into the IRWST water pool. The hydrodynamic load acts on the strainers concurrently with SSE. The total drag force of 54 kips (Reference [1-2]) is applied in both the horizontal directions (Global X and Z directions).

1.2.4 Material Designations for Filter Cartridge Assembly Components

The mechanical properties and stress allowables were obtained from the ASME Code, Section II, Part D (Reference [1-7]). For the FEA, physical properties used include density and elastic properties, which include the modulus of elasticity (E) and Poisson’s ratio. The density of water at Service Level B temperature conditions was obtained from Table 1-8 of Reference [1-8]. The filter cartridge tubes, frame support, circular/rectangular plates, attachments and other miscellaneous hardware are made of either SA-240, Type 304 or Type 304L stainless steel (Reference [1-1]). The stress allowables for each component of the filter cartridge assembly are based on the ASME Boiler and Pressure Vessel Code, Section III, Division 1. The strainer structural frame components are


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evaluated per Subsection NF (Reference [1-9]) and the stress allowables for the tube cartridges are evaluated per Subsection NC (Reference [1-10]). The stress allowable for Service Level A at 110 °C (230 °F) (Reference [1-2]) for the limiting SA-240, Type 304L stainless steel material is conservatively used.

1.2.5 Hydrodynamic and Debris Loads

The finite element analysis includes the hydrodynamic “added mass” of the cartridge tubes and frame structure due to the disturbances generated in the fluid in motion, and the debris “added mass” accumulated in the cartridge. The mass moment of inertia due to the fluid inside the concentric tube pairs of the filter cartridge and dead weight of the inner tubes are accounted for as an effective density increase across the inner tubes. The mass moment of inertia due to the added mass and dead weight of the outer tubes are accounted for as an effective density increase across the outer tubes. The added mass due to the debris is conservatively applied as an effective density increase across the tube set pairs (12.7 cm (5 inch) inner tube and 15.2 cm (6 inch) outer tube) of the filter cartridge assembly. The analysis accounts for all estimated debris being clogged on one independent safety train, in accordance with Reference [1-2]. Table 1-2 shows the modified effective material density for various components of the filter cartridge assembly. Detailed representative calculations for the hydrodynamic mass and effective material weight densities are provided in Appendix A.

Table 1-2 Effective Material Densities for Various Components of the Filter Cartridge Assembly

Component Designation Effective Material Weight Density

(gf/cm3 / lbf/in3)

Filter Module 8.03 / 0.29

Filter Tubes 17.84 / 0.64

Structural Components 8.03 / 0.29


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1.3 Assumptions

The following assumptions are used for the evaluation:

1) Under Service Level B conditions, the submerged condition affects the mass weight due to the buoyancy effect. A buoyancy factor of 0.8817 was calculated, and this value is applied to the density of the structure.

From equilibrium in the vertical direction, the resultant load R is: R = W − N Where, W = Weight and N = Buoyancy R = ms × g − mw × g = (ρs × V) × g − (ρw × V) × g = (ρs − ρw) × V × g

= �(ρs − ρw) ÷ ρs� × ρs × V × g = �1− �ρwρs�� × ms = (1 − dr) × ms = factor × ms

Where,

ms = Mass of the filter cartridge assembly structure mw = Mass of the water displaced by the filter cartridge assembly structure g = Acceleration due to gravity ρs = Density of steel structure ρw = Density of water V = Volume of the filter cartridge assembly structure dr = Density ratio factor = Buoyancy factor

2) The IRWST sump strainers will expand due to the elevated temperature of 110 °C (230 °F) for

Service Level D. However, there are no significant dissimilar metal effects since all materials are similar in terms of thermal properties (SA-240, Type 304 and SA-240, Type 304L in Reference [1-7]). As a consequence, thermal stresses are negligible, and are not considered in the analysis.

3) All welds are full penetration, so that weld joint efficiency factors applied to the allowables for

non-full penetration welds are not applicable in the analysis. 4) All welds are assumed to be volumetrically examined, so that the weld joint efficiency factor

applied to the allowables is taken as 1.0 in the analysis. 5) All pump head loss (60.96 cm-water (2 ft-water) of water or 0.061 kg/cm2 (0.87 psig)) related

pressure loads acting on the flat faces of the cartridge assembly structure (for example, cross braces, formed channels, side channels, cross braces, etc.) are in equilibrium except for the bottom plate with weld studs that are in contact with the inner and outer filter tubes. A uniform static pressure load of 0.87 psig is applied on outer diameter of the outer tube, inner diameter of the inner tube and the bottom plate and the stress is accounted for in the Service Level A through D load combination.

6) The FEA includes the hydrodynamic “added mass” of the cartridge tubes and frame structure due

to the disturbances generated in the fluid in motion, and the debris “added mass” accumulated in the cartridge. The mass moment of inertia due to the fluid inside the concentric tube pairs of the filter cartridge and dead weight of the inner tubes are accounted for as an effective density increase across the inner tubes. The mass moment of inertia due to the added mass and dead


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weight of the outer tubes are accounted for as an effective density increase across the outer tubes. The added mass due to the debris is applied as an effective density increase across the tube set pairs (5 inch inner tube and 6 inch outer tube) of the filter cartridge assembly.

7) The perforations in the filter tubes were not explicitly modeled. However, it can be shown that

the requirements for area reinforcement are satisfied (per ASME Code, Section III, NC-3332, (Reference [1-10])) for all planes through the center of the 0.0938 inch (Reference [1-1]) circular perforated holes and normal to the surface of the filter tube.

The total cross-sectional area of reinforcement, A (in2), required in any given plane for a vessel under internal pressure shall not be less than:

A = d × tr × F per ASME Code, Section III, NC-3332.2 (Reference 1-10)

where,

d = Finished diameter of the circular opening = 0.0938" (Reference [1-1]) tr = Required thickness of a shell under internal pressure F = A correction factor which compensates for the variation in pressure stresses on

different planes with respect to the axis of the vessel. A value of 1.0 is used for this analysis

tr = P×Ri

σallowable

where,

P = Internal pressure due to head loss loading across filter tubes Ri = Internal radius of inner filter tube σallowable = Allowable membrane stress for inner filter tube (Reference [1-7])

tr = 0.87×2.4375

13850= 0.0001531 inch (3.89 μm)

This implies that since the nominal thickness of the shell, 0.0625 inch is greater than 0.0003062 inch, there is enough thickness available for area reinforcement.

A = 0.0938 × 0.0001531 × 1 = 0.00001436 in2 (0.00926 mm2)

Per ASME Code, Section III, NC-3335.1 (Reference [1-10]), A = (t − F × tr) × d Therefore, A1 = Area in excess thickness in the vessel wall available for area reinforcement, in2

A = (0.0625 − 1 × 0.0001531) × 0.0938 = 0.005848 in2 (3.773 mm2)

The reinforcement required for the perforated hole opening in the shell designed for internal pressure is 0.25% of the available area in the shell, and hence the requirements of area reinforcement are satisfied.


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1.4 Methodology

The following steps are performed during the analysis of the GS-50873-GA filter cartridge assembly.

1) The analysis of the floor mounted cartridge of the IRWST sump strainers was performed using a response spectrum analysis approach in ANSYS (Reference [1-4]).

2) The geometry was imported from SolidWorks 2012 as a shell model into ANSYS. As mentioned

before, the CAD model included the filter cartridge assembly and the channels that the assembly is mounted on before being bolted down to the floor using Hilti anchor bolts (Reference [1-11]). Each component of the filter cartridge assembly is assigned a shell thickness as a real constant, and each component was assigned the respective physical material properties. The geometry is meshed in ANSYS Workbench using SHELL181 (4-Node Structural Shell) elements. Surface bonded contacts are manually created between tube/plate, top plate/middle plate, side channel/bracket, base plate/Hilti anchor Attachment and many more interfaces.

3) The free vibration response of the structure and the natural frequencies of the structure are

calculated from modal analysis. An iterative Preconditioned Conjugate Gradient Lanczos solver was selected to calculate the eigenvalues and eigenvectors, which correspond to the natural frequencies and mode shapes, respectively.

4) ANSYS runs were executed to evaluate the boundary conditions at the base plate that is in

contact with the floor and is held to the L-shape brackets through Hilti anchor bolts. In this case, only one node corresponding to the Hilti anchor bolt location was pinned in the vertical direction. All other degrees-of-freedom were released. The FEA results showed that the vertical tensile reaction force in the Hilti anchor bolts was lesser than the minimum preload on the Hilti anchor bolts (calculated from the installation torque (Reference [1-1])). Therefore, there would be no risk of uplift of the bolts or increased bending stresses at the web section of the C-channels in contact with the floor. The loading condition for the test run was an equivalent static acceleration corresponding to the guidance provided in Page 3.7.2-7 of Reference [1-12] that states: To obtain an equivalent static load for an Structures, Systems and Components (SSC) that can be represented by a simple model, a factor of 1.5 is applied to the peak spectral acceleration of the applicable ground or floor response spectrum.

5) A single point spectrum analysis was performed to calculate the maximum response of the

structure to seismic loading. In a single response spectrum, the structure is excited by a spectrum of known direction and frequency, acting uniformly on all fixed support points. Refer to Figure 1-1 for an example Input Response Spectrum (Vertical Global Y-Direction) for the GS-50873-GA Filter Cartridge Assembly. The fixed support boundary condition is considered conservative based on the ANSYS test runs explained above. Refer to Figures 1-2 for a pictorial representation of the boundary conditions.

6) When performing the spectrum analysis (both SSE and OBE) that takes into account missing-

mass and rigid response effects, the following recommendations were implemented and in accordance with NRC RG 1.92 (Reference [1-13]):

a. The Zero Period Acceleration (ZPA) frequency value is defined corresponding to the input

spectrum (Reference [1-6]). This value is the beginning of the frequency range for which the acceleration remains constant and equal to the ZPA.

b. All modes in the frequency range 0-100 Hz have been included in the spectrum analysis. c. The Complete Quadratic Combination (CQC) mode combination technique is used to

correctly combine modes with closely spaced frequencies. d. The missing mass effect was included in the simulation. e. The rigid response effect using the Yindley-Yow method is also included.


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7) A hydrodynamic drag force of 54 kips is applied in both the horizontal directions i.e. Global X and

Z directions. The hydrodynamic load acts on the strainers concurrently with SSE. Figure 1-3 shows the pictorial representation of application of the total static drag force applied on the outer 6 inch tubes. This total static drag force translates to 562.5 lbf on each 6 inch outer tube. This loading condition is considered appropriate since as stated in Reference [1-2], the total volume occupied by the strainer is utilized in the computation of the acceleration drag force. Figure 1-4 shows the fixed support boundary conditions are conservatively used for all bottom faces of the C-Channels and the Hilti Anchor attachments.

8) A separate load case is analyzed in ANSY to simulate the 1G (386.4 in/s2) gravity acceleration to

satisfy the Service Level A load combination. The finite element model has all the hydrodynamic "added" mass, fluid mass inside the filter tubes and stainless steel component weight included in this analysis.


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1.5 Analysis

The following section describes the analyses performed to qualify the IRWST sump strainers.

1.5.1 CAD Geometry and Finite Element Model

As mentioned previously, ANSYS 12.1 was used to perform the finite element analysis of the floor-mounted cartridges. The geometry was imported from SolidWorks 2012 as *.SLDPRT and *.SLDASM files. The CAD model included the filter cartridge assembly and the channels that the assembly is mounted on before being bolted down to the floor using Hilti anchor bolts (Reference [1-11]). Refer to Figure 1-5 for the GS-50873-GA filter cartridge assembly. It should be noted that representative plots are shown for the GS-50873-GA filter cartridge assembly in the main body of this report. A Uniform Quad method in ANSYS 12.1 was selected to produce a uniform mesh of quadrilateral elements over the entire part of the selected body, depending on the values of element size specified for the selected geometry. Figure 1-6 shows the finite element model of the GS-50873-GA filter cartridge assembly. The finite element model has 1,078,286 nodes which amount to approximately 6.5 million degrees-of-freedom. Figures 1-7 and 1-8 show an example of bonded Contact-Target surface connections in ANSYS (Reference [1-4]).

1.5.2 Loads and Boundary Conditions

1.5.2.1 Single Point Input Response Spectrum Analysis

The inertial loads acting on the floor mounted cartridges are proportional to the masses in motion and acceleration. The dry steel masses are directly calculated by ANSYS as a function of volume and density of the material. A summary of the total effective weight densities of individual components of the filter cartridge assembly, that includes the hydrodynamic and debris “added” mass effects are shown in Table 1-2. Figures 1-1 and 1-9 provide the representative input response spectrum in vertical and two horizontal directions (ANSYS Global Y, Z and X) to excite the GS-50873-GA Filter Cartridge Assembly structure and components in the case of a SSE event. These spectral acceleration loads act uniformly on all fixed support points. The modes are combined in a separate solution phase using the CQC method. Reference [1-2] provides guidance that for the dynamic qualification of the strainer, one half of SSE values shall be used for OBE. In this case the ISRS curve with 3% damping is digitized and the seismic acceleration magnitudes are divided by two across the 0-100 Hz frequency range. The resulting seismic acceleration vs. frequency is used as input for the OBE event. Fixed support boundary conditions are used for all bottom faces of the C-Channels and the Hilti Anchor attachments as shown in Figure 1-2. As described earlier in Section 4.0, ANSYS test runs proved that there was no risk of uplift of the Hilti Anchor bolts or increased bending stresses in the web section of the C-Channels.

1.5.2.2 Hydrodynamic Drag Force Analysis

The strainer filter cartridge assembly is designed to withstand the hydrodynamic loads caused by the fluid discharged (water jet, air bubble transient, steam jet, etc.) into the IRWST water pool. The hydrodynamic load acts on the strainers concurrently with SSE. The total drag force of 54 kips (Reference [1-2]) is applied in both the horizontal directions (Global X and Z directions). Figure 1-3 shows the pictorial


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representation of application of the total static drag force applied on the outer 6 inch tubes. This loading condition is considered appropriate since as stated in Reference [1-2], the total volume occupied by the strainer is utilized in the computation of the acceleration drag force. Figure 1-4 shows the fixed support boundary conditions used for all bottom faces of the C-Channels and the Hilti Anchor attachments.

1.5.3 Material Properties

The cartridge tubes, frame support and anchor attachments are made for either SA-240, Type 304 or SA-240, Type 304L Stainless Steel (Reference [1-7]). The elastic and physical material properties at an elevated temperature of 110 °C (230 °F) (Service Level D) used in FEA are as follows: • Elastic Modulus, E = 1.92E6 kg/cm2 (2.735E7 psi) (Reference [1-7]) • Poisson's Ratio, μ = 0.31 (Reference [1-7]) • Weight Density, ρ = 8.03 gf/cm3 (0.29 lbf/in3) (Reference [1-7])


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1.6 Results

Results for the analyses previously described are summarized in this section.

1.6.1 Modal Analysis

A pre-stressed modal analysis was performed to calculate the natural frequencies of the GS-50873-GA filter cartridge assembly. Because of the large mass matrix involved in the analysis, an iterative Block Lanczos solver was selected to calculate the eigenvalues and eigenvectors, which correspond to the natural frequencies and mode shapes, respectively. Figures 1-10 through 1-13 show the significant mode shapes with appreciable mass participation factors for the GS-50873-GA filter cartridge assembly. Figure 1-14 shows a directional deformation mode shape for significant mass participation factor in the horizontal (Global-Z) direction. Figures 1-15 and 1-16 show a directional deformation mode shape for significant mass participation factors in the vertical (Global-Y) direction.

1.6.2 Response Spectral Analysis

A single point spectrum analyses for both SSE and OBE events were performed to calculate the maximum response of the structures to the seismic loading. In a single response spectrum, the structure is excited by a spectrum of known direction, amplitude and frequency, acting uniformly on all support points. Displacements from the response spectrum analysis are shown in Figures 1-17 through 1-20. Please note that in the response spectrum analyses, displacements are positive magnitudes and do not represent relative displacement with respect to the global coordinate system. Figures 117 and 1-19 show the directional deformation in the direction of application of the input spectrum for the Vertical direction SSE in global Y-direction and bounding Horizontal SSE in global Z-direction. Figures 1-18 and 1-20 show the directional deformation in the direction of application of the input spectrum for the Vertical direction OBE in global Y-direction and bounding Horizontal OBE in global Z-direction.

1.6.3 Stresses Comparison with ASME Code Allowable Stresses

The maximum FEA normal stress at any node is below the minimum membrane only allowable stress from the ASME Code. Since the stresses are low and below that minimum allowable criterion, linearization was not performed to satisfy the assessment. This is conservative since the FEA stresses include both membrane and bending components, and are compared to a membrane only allowable. Figure 1-21 shows an example normal stress contour plot for the vertical direction (Y-Axis) SSE response spectrum loading for the GS-50873-GA Filter Cartridge Assembly. Figure 1-22 shows an example shear stress contour plot for the vertical direction (Y-Axis) SSE response spectrum loading for the GS-50873-GA Filter Cartridge Assembly. Figure 1-23 shows an example normal stress contour plot for the vertical direction (Y-Axis) OBE response spectrum loading for the GS-50873-GA Filter Cartridge Assembly. Figure 1-24 shows an example shear stress contour plot for the vertical direction (Y-Axis) SSE response spectrum loading for the GS-50873-GA Filter Cartridge Assembly. The tabulated data of normal stresses versus allowable stresses are shown for Service Levels A through D in Tables 1-3, 1-4, 1-5 and 1-6 for the GS-50873-GA Filter Cartridge assembly. Figure 1-25 shows example normal stress contour plot for the hydrodynamic drag force when applied in one of the horizontal directions (Z-Axis) for the GS-50873-GA Filter Cartridge Assembly. Figure 1-26 shows example shear stress contour plot for the hydrodynamic drag force when applied in one of the horizontal directions (Z-Axis) for the GS-50873-GA Filter Cartridge Assembly. It is noted here that the normal stress state in the limiting hydrodynamic drag load direction is then combined by taking the SRSS to generate one resultant stress state for Service Level D load combination. The resulting stresses are


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used as input for the total stress evaluation shown in Table 1-6. In the stress qualification of the Hilti Anchor bolts, the most limiting tensile/compressive reaction force and shear reaction force are considered in the bolt stress calculation. Section 3.3.3 of Reference [1-11] provides an allowable tensile load of 1,148 kgf (2,530 lbf) and an allowable shear load of 2,218 kgf (4,890 lbf) for Hilti HSLG-R M 12/25 Anchor Bolt. These tensile and shear reaction loads are applicable for Hilti anchor bolts installed in normal-weight concrete with an allowable compressive strength of 211 kg/cm2 (3,000 psi). The cumulative bolt reaction force for the limiting Service Level D load combination is 379 kgf (836.13 lbf) in the tension direction and 1,987 kgf (4381.56 lbf) in the shear direction. It is noted here that all sixteen Hilti anchor bolts (two Hilti anchor bolts for each attachment location) are modeled and resisting the applied load. In the scenario of any of the Hilti anchor bolts not being installed due to presence of concrete rebar in the containment floor, it is logical that the remaining Hilti anchor bolts will see an increase in both tensile/compressive and shear reaction loads. In such a case, a separate analysis for the limiting Service Level D load combination will need to be performed taking into account the missing Hilti anchor bolts. Additionally, the existing Hilti anchor bolts can be overdesigned to a Stainless Steel HSLG-R M16 Hilti anchor diameter. The M16 Hilti anchor bolt provides an allowable tensile load of 2,134 kgf (4,705 lbf) (Reference [1-11]) and an allowable shear load of 4,066 kgf (8,965 lbf) (Reference [1-11]).


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Table 1-3 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level A

Strainer Stress

Stress type Service Level A

Service Level B

Service Level C/D

Allowable Stress_Service

Level A (psi)

FEA_Peak Stress_Service Level A Load

Combination (psi)

Stress Check (Y/N)

Primary Membrane Stress, σm1 1.0×S 1.10×S 1.50×S 13,850.0000 1,905.8500 Y Primary Membrane + Bending Stress, σm + σb2 1.5×S 1.65×S 1.80×S 20,775.0000 1,905.8500 Y

Support Stress


Service Level B

Service Level C/D


Level A (psi)

FEA_Peak Stress_Service Level A Load

Combination (psi)

Stress Check (Y/N)

Plate and Shell Type Components

Primary Membrane Stress, Sm3 1.0×S 1.33×S 1.50×S 13,850.0000 1,905.8500 Y Primary Membrane + Bending Stress, Sm + Sb4 1.5×S 2.00×S 2.25×S 20,775.0000 1,905.8500 Y

Linear Type Components Tension Stress5 0.60×Sy 1.33×Level A 1.5×Level A 15,000.0000 1,137.4000 Y

Shear Stress6 0.40×Sy 1.33×Level A 1.5×Level A 10,000.0000 1,835.4500 Y

Compression Stress7 0.47×Sy 1.33×Level A 1.5×Level A 11,750.0000 1,905.8500 Y

Bending Stress8 0.66×Sy 1.33×Level A 1.5×Level A 16,500.0000 1,155.4700 Y

Bolting Tension Stress10 14,489.3458 3,113.1557 Y Shear Stress11 27,894.8428 148.2591 Y For Axial Compression +Bending Stress Criteria9 Computed Bending Stress (Z Axis) 398.3750 Computed Bending Stress (X Axis) 418.4200 Computed Axial Stress (Y Axis) 1,905.8500 Equation 21 Load combination Criteria (≤1.0) 0.1766 Hoop Stress (Membrane + Bending) – Head Loss Loading Acriss filter Tubes, 2 feet of water 500.6500 Notes:

S: Allowable Stress Sy: Yield strength Su: Tensile strength 1. Table NC-3321-1. S defined in Section II, Part D, Subpart 1, Table 1A 2. Table NC-3321-1. S defined in Section II, Part D, Subpart 1, Table 1A 3. Subsection NF-3251.1 Eq. 1. S defined in Section II, Part D, Subpart 1 Table 1A 4. Subsection NF-3251.1 Eq. 2. S defined in Section II, Part D, Subpart 1 Table 1A 5. Subsection NF-3322.1 Eq. 1 6. Subsection NF-3322.1 Eq. 3a 7. Subsection NF-3322.1 Eq. 6a 8. Subsection NF-3322.1 Eq. 15b 9. As per NF 3322.1, Equation 21 10. Section 3.3.3 of Reference [1-11], Allowable Tensile Load of 2540 lbf for Hilti HSLG-R M 12/25 Anchor Bolt, FEA

cumulative bolt reaction force is 545.74 lbf, Ultimate Tensile Strength for Hilti HSLG-R M 12/25 Anchor Bolt used is 102 ksi (Reference [1-11])

11. Section 3.3.3 of Reference [1-11], Allowable Shear Load of 4890 lbf for Hilti HSLG-R M 12/25 Anchor Bolt, FEA cumulative bolt reaction force is 25.99 lbf, Ultimate Tensile Strength for Hilti HSLG-R M 12/25 Anchor Bolt used is 102 ksi (Reference [1-11])


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Table 1-4 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level B

Strainer Stress


Service Level B

Service Level C/D


Level B (psi)

FEA_Peak Stress_Service Level B Load

Combination (psi)

Stress Check (Y/N)


Support Stress


Service Level B

Service Level C/D


Level B (psi)

FEA_Peak Stress_Service Level B Load

Combination (psi)

Stress Check (Y/N)







Bolting Tension Stress10 14,489.3458 3,915.1010 Y Shear Stress11 27,894.8428 4,402.5934 Y For Axial Compression +Bending Stress Criteria9 Computed Bending Stress (Z Axis) 694.5800 Computed Bending Stress (X Axis) 694.5800 Computed Axial Stress (Y Axis) 2,376.8900 Equation 21 Load combination Criteria (≤1.0) 0.1824 Hoop Stress (Membrane + Bending) – Head Loss Loading Acriss filter Tubes, 2 feet of water 500.6500 Notes:





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Table 1-5 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level C

Strainer Stress


Service Level B

Service Level C/D


Level C (psi)

FEA_Peak Stress_Service Level C Load

Combination (psi)

Stress Check (Y/N)

Primary Membrane Stress, σm1 1.0×S 1.10×S 1.50×S 20775.0000 3206.1213 Y Primary Membrane + Bending Stress, σm + σb2 1.5×S 1.65×S 1.80×S 24930.0000 3206.1213 Y

Support Stress


Service Level B

Service Level C/D


Level C (psi)

FEA_Peak Stress_Service Level C Load

Combination (psi)

Stress Check (Y/N)







Bolting Tension Stress10 14,489.3458 4,769.6582 Y Shear Stress11 27,894.8428 4,402.5934 Y For Axial Compression +Bending Stress Criteria9 Computed Bending Stress (Z Axis) 1,300.2713 Computed Bending Stress (X Axis) 1,300.2713 Computed Axial Stress (Y Axis) 2,710.6300 Equation 21 Load combination Criteria (≤1.0) 0.2255 Hoop Stress (Membrane + Bending) – Head Loss Loading Acriss filter Tubes, 2 feet of water 500.6500 Notes:





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Table 1-6 ASME Code, Section III, Division 1 Stress Qualification for the GS-50873-GA Filter Cartridge Assembly, Service Level D

Strainer Stress


Service Level B

Service Level C/D


Level D (psi)

FEA_Peak Stress_Service Level D Load

Combination (psi)

Stress Check (Y/N)


Support Stress


Service Level B

Service Level C/D


Level D (psi)

FEA_Peak Stress_Service Level D Load

Combination (psi)

Stress Check (Y/N)







Bolting Tension Stress10 14,489.3458 4,769.6582 Y Shear Stress11 27,894.8428 24,994.4637 Y For Axial Compression +Bending Stress Criteria9 Computed Bending Stress (Z Axis) 12,111.8400 Computed Bending Stress (X Axis) 8,366.4000 Computed Axial Stress (Y Axis) 2,710.6300 Equation 21 Load combination Criteria (≤1.0) 0.9479 Hoop Stress (Membrane + Bending) – Head Loss Loading Acriss filter Tubes, 2 feet of water 500.6500 Notes:


cumulative bolt reaction force is 836.13 lbf, Ultimate Tensile Strength for Hilti HSLG-R M 12/25 Anchor Bolt used is 102 ksi (Reference [1-11] )

11. Section 3.3.3 of Reference [1-11], Allowable Shear Load of 4890 lbf for Hilti HSLG-R M 12/25 Anchor Bolt, FEA cumulative bolt reaction force is 4,381.56 lbf, Ultimate Tensile Strength for Hilti HSLG-R M 12/25 Anchor Bolt used is 102 ksi (Reference [1-11] )


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1.7 Conclusions

Stress results from response spectrum and static structural finite element analyses for the GS-50873-GA filter cartridge assembly shows that all the components structurally meet the requirements for stress qualification per ASME Code, Section III, Division 1, Subsections NC and NF (Reference [1-9] and [1-10]), as appropriate.


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Figure 1-1 Input Response Spectrum (Vertical Global Y-Direction) to GS-50873-GA Filter Cartridge

Assembly


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Figure 1-2 Fixed Support Boundary Conditions Applied to GS-50873-GA Filter Cartridge Assembly - Response Spectral Analyses


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Figure 1-5 Geometry of GS-50873-GA Filter Cartridge Assembly


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Figure 1-6 Finite Element Model of GS-50873-GA Filter Cartridge Assembly


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Figure 1-7 Example Bonded Surface Contact Interface of Tube/Top Plate for GS-50873-GA Filter Cartridge Assembly


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Figure 1-8 Example Bonded Surface Contact Interface of Tube/Bottom Plate for GS-50873-GA Filter Cartridge Assembly


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Figure 1-9 Input Response Spectrum (Horizontal Global X and Global Z-Direction) to GS-50873-GA Filter Cartridge Assembly


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Figure 1-10 Significant Mode Shape, M1, Transverse Bending, Frequency = 52.387 Hz, GS-50873-

GA Filter Cartridge Assembly


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Figure 1-11 Significant Mode Shape, M3, Transverse Bending, Frequency = 56.57 Hz, GS-50873-GA Filter Cartridge Assembly


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Figure 1-14 Significant Mode Shape, M21, Transverse Bending, Frequency = 64.569 Hz, GS-50873-

GA Filter Cartridge Assembly


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Figure 1-15 Significant Mode Shape, M25, Vertical Displacement of Access Panel, Frequency=76.668 Hz, GS-50873-GA Filter Cartridge Assembly


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Figure 1-16 Significant Mode Shape, Vertical Displacement of Access Panel, Frequency =79.331 Hz, GS-50873-GA Filter Cartridge Assembly


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Figure 1-17 Displacement Contour Plot, Global Y for Vertical Direction SSE Response Spectrum for GS-50873-GA Filter Cartridge Assembly


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Figure 1-18 Displacement Contour Plot, Global Y for Vertical Direction OBE Response Spectrum for GS-50873-GA Filter Cartridge Assembly


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Figure 1-19 Displacement Contour Plot, Global Z for Horizontal Direction SSE Response Spectrum for GS-50873-GA Filter Cartridge Assembly


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Figure 1-20 Displacement Contour Plot, Global Z for Horizontal Direction OBE Response Spectrum for GS-50873-GA Filter Cartridge Assembly


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(a) Isometric View

(b) Close-Up View of Peak Normal Stress at Angle between C-channel and transverse I-beam

Figure 1-21 Normal Stress Contour Plot for Vertical Direction (Y-Axis) SSE Response Spectrum Loading for GS-50873-GA Filter Cartridge Assembly


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(a) Isometric View

(b) Close-Up View of Peak Shear Stress at Bottom plate weld stud location

Figure 1-22 Shear Stress Contour Plot for Vertical Direction (Y-Axis) SSE Response Spectrum Loading for GS-50873-GA Filter Cartridge Assembly


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(a) Isometric View

(b) Close-Up View of Peak Normal Stress at Angle between C-channel and transverse I-beam

Figure 1-23 Normal Stress Contour Plot for Vertical Direction (Y-Axis) OBE Response Spectrum Loading for GS-50873-GA Filter Cartridge Assembly


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(a) Isometric View


Figure 1-24 Shear Stress Contour Plot for Vertical Direction (Y-Axis) OBE ResponseSpectrum Loading for GS-50873-GA Filter Cartridge Assembly


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(a) Isometric View

(b) Close-Up View of Peak Normal Stress at Bottom plate weld stud location

Figure 1-25 Normal Stress Contour Plot for Horizontal Direction (Z-Axis) Hydrodynamic Drag Force Loading for GS-50873-GA Filter Cartridge Assembly


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(a) Isometric View


Figure 1-26 Shear Stress Contour Plot for Horizontal Direction (Z-Axis) Hydrodynamic Drag

Force Loading for GS-50873-GA Filter Cartridge Assembly


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2 TRASH RACK STRUCTURAL ANALYSIS

2.1 Description of Trash Rack

The In-containment Refueling Water Storage Tank (IRWST) spillways allow accumulated water in the adjacent Holdup Volume Tank (HVT) to spill into the IRWST thereby replenishing the IRWST water volume. The spillways are adequately sized to allow the maximum flow into the HVT to be returned to the IRWST after filling. The vertical screen, which is trash rack, is provided at the entrance of the HVT to prevent debris from entering the HVT and thus the IRWST.

Following an accident, water introduced into containment drains to the HVT. Debris that may exist in containment may be transported to the HVT with this fluid. Debris greater than 101.6 mm (4 inch) diameter is prevented from entering the HVT by a vertical trash rack, which is located at the entrance to the HVT (Figure 2-1). A trench exists at the base of this trash rack to prevent high density debris that may be swept along the floor by fluid flow toward the HVT from reaching the trash rack. The vertical orientation of the trash rack will help impede the deposition of debris buildup on the strainer surface. Particles that are smaller than the trash rack mesh will enter the HVT. The figure 2-1 shows the location of trash rack and the figure 2-2 shows the 3D view of trash rack.

2.2 Trash Rack Analysis

The trash rack is designed with grating mesh. The both sides of grating mesh are supported by steel and concrete structures as shown on Figure 2-2.

As the trash rack is designed to prevent debris larger than 101.6 mm (4 inch), water flow blockage will not happen even though the grating mesh is blocked by debris. Therefore the hydraulic-pressure load due to blockage will be negligible. But the trash rack is designed to resist the hydraulic pressure load of 2.3 m (90.5 in) water depth assuming hydraulic water pressure buildup due to grating mesh blockage. In addition, the trash rack is designed considering seismic load due to self weight excitation of grating mesh. But, the seismic load is negligible since the self-weight of grating mesh is very small compared to the assumed hydraulic pressure load.


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Figure 2-1 Trash Rack Location

Trash Rack


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Figure 2-2 3D view of Trash Rack


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3 REFERENCES

1-1 TPI Drawing No. GS-50873-GA (ANALYSIS), “APR 1400 STRAINER GENERAL

ARRANGEMENT,” Transco Product Inc. 1-2 Technical Specification, (Document No. 1-447-N206), KHNP, 2013. 1-3 10 CFR Part 50.46, “Acceptance criteria for emergency core cooling systems for light-water

nuclear power reactors”. U.S. Nuclear Regulatory Commission, 1-4 ANSYS Workbench Mechanical APDL and PrepPost, Release 12.1 x64, ANSYS, Inc., November

2009. 1-5 TPI Design Input - APR1400 IRWST Strainer, Shell FEA Model, STRAINER

ASSEMBLY.SLDASM (DCM No. 50873-003-CL), Transco Product Inc. 1-6 Regulatory Guide 1.61, “Damping Values for Seismic Design of Nuclear Power Plants”, Rev. 1,

U.S. Nuclear Regulatory Commission, March 2007. 1-7 ASME Boiler and Pressure Vessel Code, Section II, Part D, “Material Properties,” The American

Society of Mechanical Engineers, the 2010 Edition. 1-8 Nicholas P. Cheremisinoff, Heat Transfer Pocket Handbook, 1984 Edition. 1-9 ASME Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NF, Supports, “Rules

for Construction of Nuclear Facility Components,” The American Society of Mechanical Engineers, the 2010 Edition.

1-10 ASME Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NC, Class 2 Components, “Rules for Construction of Nuclear Facility Components,” The American Society of Mechanical Engineers, the 2010 Edition.

1-11 HSL Heavy Duty Expansion Anchor Technical Specification Datasheet, Hilti Mechanical Anchoring Systems, Section 3.3.3.

1-12 NUREG-0800, Standard Review Plan, Section 3.7.2, “Seismic Systems Analysis,” Rev. 3, U.S. Nuclear Regulatory Commission, March 2007.

1-13 Regulatory Guide 1.92, “Combining Modal Responses and Spatial Components in Seismic Response Analysis”, Rev. 3, U.S. Nuclear Regulatory Commission, October 2012.

1-14 Robert D. Blevins, Ph.D., Formulas For Natural Frequency And Mode Shape (Robert E. Krieger Publishing Company, Reprint Edition 1984).


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Appendix A

Hydrodynamic Mass Calculations


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The objective of this appendix is to provide an estimate of the hydrodynamic mass of a strainer cartridge for use in the response spectrum analyses. Because the strainers must resist specific seismic accelerations, the mass of the assembly for use in the dynamic analysis must include not only the intrinsic mass of the material, but also the hydrodynamic “added mass” due to the disturbances generated in the fluid (both inside and surrounding the tubes) when the tubes are in motion in the fluid. The hydrodynamic mass is significant, and in this subject case where you have an accelerating motion, it exceeds the mass of the materials of the strainer cartridges themselves. An unperforated circular cylinder immersed in and filled with fluid has a hydrodynamic mass equivalent to that of a volume of fluid equal to twice the volume of the cylinder. This accounts for the mass of the fluid inside the cylinder and for the “virtual inertia” of the surrounding fluid which is forced to accelerate because of the motion of the cylinder. Strictly, this value occurs in two-dimensional (2-D) flow, for example where the length of the cylinder is considerably greater than the diameter so that end effects can be considered small, or where the flow around the ends is effectively constrained by end plates. For a perforated cylinder, however, the nature of the flow is different than for an unperforated surface. Of primary importance is the fact that fluid can flow “through” the surface of the cylinder. The fluid encounters resistance to this passage into and out of the cylinder, so the pressures acting on the body are substantially different from those generated when fluid cannot pass through the boundary at all, and consequently must stagnate at some points on the body. It is noted here that when the displacement of the strainers is of large amplitude with respect to the surrounding fluid, the hydrodynamic mass of the perforated strainer tubes also becomes large, in fact considerably greater than the intrinsic mass of the cartridge components. By contrast, when the displacement is of small amplitude the hydrodynamic mass of the strainer tubes rapidly decreases, and in fact approaches zero. For this analysis the hydrodynamic mass calculations consider the filter tubes to be unperforated, which provide a conservative estimate for the “added” hydrodynamic mass for all components of the individual filter cartridge assembly. The filter cartridge assembly is made up of a row of vertical concentric pairs of tubes, fabricated of perforated stainless steel sheet. Depending on the installations required to suit the geometry of various plants, cartridges of different heights are designed. The hydrodynamic mass calculation is described below for the filter cartridge assembly GS-50873-GA. In the case of the GS-50873-GA filter cartridge assembly, it consists of four concentric tube pairs arranged in a row. The nominal diameters of outer and inner strainer tubes are 15.2 cm (6.0 inch) and 12.7 cm (5.0 inch), respectively. The tubes are thin walled, with a sheet thickness of 1.59 mm (0.0625 inch).


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Assumptions:

1) The FEA includes the hydrodynamic “added mass” of the cartridge tubes and frame structure due to the disturbances generated in the fluid in motion, and the debris “added mass” accumulated in the cartridge.

2) The mass moment of inertia due to the fluid inside the concentric tube pairs of the filter cartridge

and dead weight of the inner tubes are accounted for as an effective density increase across the inner tubes.

3) The mass moment of inertia due to the added mass and dead weight of the outer tubes are

accounted for as an effective density increase across the outer tubes. 4) The added mass due to the debris is applied as an effective density increase across the 12.7 cm

(5 inch) inner tube and 15.2 cm (6 inch) outer tube of each of the filter cartridge assemblies since it causes the most conservative bending moment for a lateral spectral acceleration.

5) The 'filter module' consists of cross-braces, cross-brace gussets, bottom support, bottom support

outer channel, exposed cross brace arm, tie rods and sleeves. 6) The 'filter tubes' consists of the inner and outer filter tubes within the filter cartridge assembly. 7) The 'structural components' consist of the C-Channel in contact with the floor, I-beams that run

longitudinally across the filter cartridge assembly and end support brackets.

Table A-1 Inputs

Outer Diameter of Outer Filter Tube (Reference [1-6]) 15.2 cm (6 inch)

Outer Diameter of Inner Filter Tube (Reference [1-6]) 12.7 cm (5 inch)

Shell Thickness of Outer Filter Tube (Reference [1-6]) 1.59 mm (0.0625 inch)

Height of the Outer/Inner Filter Tube (Reference [1-6]) 67.6 cm (26.628 inch)

Density of water at Service Level B Condition Temperature (Reference [1-14])

0.949 g/cm3 (0.0343 lb/in3)

Total Debris Mass (including coatings, latent fiber and latent particulate) (Reference [1-2])

114.5 kg (533.192 lbm)

Cumulative CAD Volume for all tubes within the 4 filter module 1.06x10-2 m3 (645.84 in3)

Cumulative CAD Volume for all twenty-four top plates in GS-50873-GA filter cartridge assembly

9.41x10-3 m3 (574.13 in3)


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Table A-2 Calculations

Inner Diameter of Inner Filter Tube (Di) = �5 − 2 × (0.0625)� = 4.875 inch

Fluid Mass Inertia inside the inner tube

=π4

× Di2 × H × ρ

=π4

× (4.875)2 × (26.628) × (0.03429398)

= 17.04494 lbm

Fluid Mass Inertia inside the inner tube for one filter module

= 17.04494 × 4 = 68.17978 lbm

Fluid Mass Inertia inside the annulus =3.1416

4× (5.8752 − 52) × 26.145 × 0.03429398

= 6.77908 lbm Fluid Mass Inertia inside the annulus for one filter module

= 6.77908 × 4 = 27.11632 lbm

"Added" Hydrodynamic Mass per unit length for a cylindrical cross section [14]

= π × ρ × D02 × H

= 3.1416 × 0.03429398 × (62

)2 × 26.628

= 25.81956 lbm

Total Fluid Mass = (4 × 25.81956) + 27.11632 + 68.17978 = 198.5743 lbm

Effective Adjusted Material Density of Filter Tubes

= 0.29 × 0.8817 + �198.5743

645.84 × 0.29� × 0.03429398

+�25.81956 + �533.192

96 �25.81956

� × (0.29 × 0.8817)

+�25.81956 + �533.192

96 �25.81956

� × 0.034294

= 0.6444 lbf/in3

Effective Adjusted Material Density of Filter Module = (ρsteel × Buoyancy Factor) + ρwaterServiceLevelD = (0.29 × 0.8817) + 0.03429398 = 0.2899 lbf/in3

The weight density used for 18Cr-8Ni stainless steel is 8.03 gf/cm3 (0.29 lbf/in3). The effective material density of 17.84 gf/cm3 (0.64 lbf/in3) is conservatively applied to both the inner and outer filter tubes.


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Table A-3 Effective Material Densities for Various Components of the GS-50873-GA Filter Cartridge Assembly

Component Designation Effective Material Weight Density (gf/cm3 / lbf/in3)

Filter Module 8.03 / 0.29

Filter Tubes 17.84 / 0.64

Structural Components 8.03 / 0.29

Documents

IRWST Sump Strainer and Trash Rack Structural Analysis