RAIO-0418-59424, LLC Supplemental Response to NRC Request for Additional Information No. 185 (Erai No. 8963) on the NuScale Design Certification Application
| ML18094B106 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 04/04/2018 |
| From: | Rad Z NuScale |
| To: | Document Control Desk, Office of New Reactors |
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| ML18094B105 | List: |
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| RAIO-0418-59424 | |
| Download: ML18094B106 (48) | |
Text
RAIO-0418-59424 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com April 04, 2018 Docket No.52-048 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738
SUBJECT:
NuScale Power, LLC Supplemental Response to NRC Request for Additional Information No. 185 (eRAI No. 8963) on the NuScale Design Certification Application
REFERENCES:
- 1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 185 (eRAI No. 8963)," dated August 18, 2017 2.
NuScale Power, LLC Response to NRC "Request for Additional Information No. 185 (eRAI No.8963)," dated October 17, 2017 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) supplemental response to the referenced NRC Request for Additional Information (RAI).
The Enclosures to this letter contain NuScale's supplemental response to the following RAI Questions from NRC eRAI No. 8963:
03.08.05-13 03.08.05-14 03.08.05-22 NuScale requests that the security-related information in Enclosure 1 be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390. Enclosure 2 contains a public version of the NuScale response.
This letter and the enclosed responses make no new regulatory commitments and no revisions to any existing regulatory commitments.
If you have any questions on this response, please contact Marty Bryan at 541-452-7172 or at mbryan@nuscalepower.com.
Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution:
Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A Prosanta Chowdhury NRC, OWFN-8G9A Za Z ckary W. Rad Director Regulatory Affairs
RAIO-0418-59424 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com : NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 8963, nonpublic : NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 8963, public
RAIO-0418-59424 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com :
NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 8963, nonpublic Security-Related Information - Withhold Under 10 CFR §2.390
RAIO-0418-59424 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com :
NuScale Supplemental Response to NRC Request for Additional Information eRAI No. 8963, public
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 8963 Date of RAI Issue: 08/18/2017 NRC Question No.: 03.08.05-13 10 CFR Part 50, Appendix A, GDC 1, 2, 4 and 5 provide the regulatory requirements for the
design of the seismic Category I structures. DSRS Section 3.8.5 provides review guidance
pertaining to representing the settlement of foundations.
FSAR Tier 2, Section 3.8.5.5.5, Settlement Approach, the applicant states, the soil
stiffnesses are further reduced by 50 percent to amplify the effect of differential movements or
settlements. The size of the soil included in the model is so large that the static displacements
induced by the static loads of the structures become negligible on the edges of the free field soil
model. It is not clear to the staff whether the reduced soil stiffnesses are extended to the size of
the triple building (RWB+RXB+CRB) basemats or extended for the entire soil model shown in
Figure 3.8.5-41, SAP2000 Model for Settlement. Clarify the boundary of soils with the reduced
stiffness.
NuScale Response:
As discussed, in a public meeting on February 14, 2018, a supplement to NuScale's original response to RAI 8963 03.08.05-13 is provided.
The 50 percent reduction in soil stiffness includes the areas below the triple building basemats and is extended to the entire free-field soil model. The results presented in Tier 2, FSAR Section 3.8.5, for which the soil stiffness is reduced by 50 percent include the following:
- 1) Maximum static demand forces used in the RXB foundation design check.
- 2) Maximum differential displacements within each building foundation over 50' in length.
- 3) Maximum foundation bottom tilt angle of the CRB.
- 4) Maximum static demand forces used in the CRB foundation design check.
- 5) Static demand forces in RXB design.
NuScale Nonproprietary Impact on DCA:
FSAR Tier 2, Section 3.8.5 has been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-125 Draft Revision 2 The resultant resistance to East-West overturning is:
MEW = M4 + M5 +M6 3.8.5.5.4 Bearing Pressure Approach RAI 03.08.05-22 Average Bearing Pressure RAI 03.08.05-22 Average static bearing pressure is calculated by dividing the building weight by the building footprint. Seismic average bearing pressure is calculated by the algebraic summation of reaction time histories in the rigid springs below the basemat. The springs connect the basemat with the free-field soil. The algebraic summation yields three time histories of total basemat reactions in the three global directions due to each seismic input. From the time histories, the maximum reactions can be obtained. The vertical reaction divided by the total area of the basemat yields the average bearing pressure.
RAI 03.08.05-22 Localized Bearing Pressure RAI 03.08.05-22 Localized bearing pressure under each building's basemat is calculated using the forces in the rigid springs, which connect the RXB and the CRB basemats to the excavated free-field soil (or to a fixed support for the static case). The vertical force in a spring is divided by the tributary area of the spring to obtain the localized nodal soil pressure. For the seismic case, reactions are obtained as a result of the four-step post-processing method described in Section 3.7.2.4.1.
3.8.5.5.5 Settlement Approach RAI 03.08.05-13S1 A large-scale SAP2000 finite element model is used to determine the effect of foundation differential movements. To maximize the effect of the differential movements and to have flexibility in the construction sequence, the soil is modeled using the softest soil profile, i.e. Soil Type 11. In addition, the soil stiffnesses are further reduced by 50 percent to amplify the effect of differential movements or settlements. The 50 percent reduction in soil stiffness includes the areas below the triple building basemats and is extended to the entire free-field soil model. The size of the soil included in the model is so large that the static displacements induced by the static loads of the structures become negligible on the edges of the freefield soil model. The model is analyzed for both the cracked and uncracked concrete conditions.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-126 Draft Revision 2 The size of the freefield soil block in the model is 2005.5' long, 768.5' wide, and 360' deep. Figure 3.8.5-41 shows the overall size of the freefield soil block with the three embedded buildings.
As discussed in Section 3.8.4, Load combination 10 using Equation 9-6 of ACI 349 governs U = D + F + H + 0.8L + Ccr + To + Ro + Esse For the dynamic analyses, the dead weight of the building was increased to account for the effect of live and snow loads.
RAI 03.08.05-13S1 The results presented in the NuScale Power Plant design certification application for which the soil stiffness is reduced by 50 percent include the following:
1)
Maximum static demand forces used in the RXB foundation design check.
2)
Maximum differential displacements within each building foundation over 50 feet in length.
3)
Maximum foundation bottom tilt angle of the CRB.
4)
Maximum static demand forces used in the CRB foundation design check.
5)
Static demand forces in RXB design.
3.8.5.6 Results Compared with Structural Acceptance Criteria 3.8.5.6.1 RXB Stability Factors of safety (FOS) were determined for 16 cases for the RXB. The cases include enveloping seismic loads from two RXB models (a standalone RXB model and an integrated RWB+RXB+CRB triple building model), two concrete conditions (cracked and uncracked with 7 percent damping) and four soil profiles (Soil Types 7, 8, 9, and 11) and are shown in Table 3.8.5-5. The results in this table indicate that the linear analysis for RXB sliding stability did not yield a FOS of greater than 1.
RAI 03.08.05-15 The minimum acceptable factor of safety for flotation, uplift, sliding and overturning is 1.1. This was not achieved for RXB sliding. Table 3.8.5-5 summarizes the factors of safety for the RXB.
RAI 03.08.05-15 A nonlinear analysis was performed for the RXB to show sliding was insignificant.
RAI 02.03.01-2, RAI 03.08.05-15 Bearing pressure is used to establish a design parameter for bearing capacity for site selection. The bearing capacity of the soil should provide a factor of safety of
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 8963 Date of RAI Issue: 08/18/2017 NRC Question No.: 03.08.05-14 10 CFR Part 50, Appendix A, General Design Criteria (GDC) 1, 2, 4 and 5 provide the
regulatory requirements for the design of the seismic Category I structures. DSRS Section 3.8.5
provides review guidance pertaining to maximizing the bending moments used in the design of
foundations.
Based on the staffs review of FSAR Section 3.8.5.4, Design and Analysis Procedures, the
applicant did not provide any discussion related to stiff and soft spots in the foundation soil.
Therefore, describe how the stiff and soft spots are to be considered in the basemat
evaluations of seismic Category I structures.
NuScale Response:
As discussed, in a public meeting on February 14, 2018, a supplement to NuScale's original response to RAI 8963 03.08.05-14 is provided.
The following COL item is added to Tier 2 FSAR Section 3.8.5.4:
A COL applicant that references the NuScale Power Plant design certification will identify local stiff and soft spots in the foundation soil and address these in the design, as necessary.
Impact on DCA:
FSAR Tier 2, Section 3.8.5 has been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Interfaces with Certified Design Tier 2 1.8-3 Draft Revision 2 RAI 01-61, RAI 02.04.13-1, RAI 03.04.02-1, RAI 03.04.02-2, RAI 03.04.02-3, RAI 03.05.01.04-1, RAI 03.05.02-2, RAI 03.06.02-15, RAI 03.06.03-11, RAI 03.07.01-2, RAI 03.07.01-3, RAI 03.07.02-8, RAI 03.07.02-12, RAI 03.08.05-14S1, RAI 03.09.02-15, RAI 03.09.02-48, RAI 03.09.03-12, RAI 03.09.06-5, RAI 03.09.06-6, RAI 03.09.06-16, RAI 03.09.06-16S1, RAI 03.09.06-27, RAI 03.11-8, RAI 03.11-14, RAI 03.11-14S1, RAI 03.13-3, RAI 05.04.02.01-13, RAI 05.04.02.01-14, RAI 06.04-1, RAI 09.01.02-4, RAI 09.01.05-3, RAI 09.01.05-6, RAI 09.03.02-3, RAI 09.03.02-4, RAI 09.03.02-5, RAI 09.03.02-6, RAI 09.03.02-8, RAI 10.02-1, RAI 10.02-2, RAI 10.03.06-1, RAI 10.04.06-1, RAI 10.04.06-2, RAI 10.04.06-3, RAI 10.04.10-2, RAI 13.01.01-1, RAI 13.01.01-1S1, RAI 13.02.02-1, RAI 13.03-4, RAI 13.05.02.01-2, RAI 13.05.02.01-2S1, RAI 13.05.02.01-3, RAI 13.05.02.01-3S1, RAI 13.05.02.01-4, RAI 13.05.02.01-4S1, RAI 19-31, RAI 19-31S1 Table 1.8-2: Combined License Information Items Item No.
Description of COL Information Item Section COL Item 1.1-1:
A COL applicant that references the NuScale Power Plant design certification will identify the site-specific plant location.
1.1 COL Item 1.1-2:
A COL applicant that references the NuScale Power Plant design certification will provide the schedules for completion of construction and commercial operation of each power module.
1.1 COL Item 1.4-1:
A COL applicant that references the NuScale Power Plant design certification will identify the prime agents or contractors for the construction and operation of the nuclear power plant.
1.4 COL Item 1.7-1:
A COL applicant that references the NuScale Power Plant design certification will provide site-specific diagrams and legends, as applicable.
1.7 COL Item 1.7-2:
A COL applicant that references the NuScale Power Plant design certification will list additional site-specific piping and instrumentation diagrams and legends as applicable.
1.7 COL Item 1.8-1:
A COL applicant that references the NuScale Power Plant design certification will provide a list of departures from the certified design.
1.8 COL Item 1.9-1:
A COL applicant that references the NuScale Power Plant design certification will review and address the conformance with regulatory criteria in effect six months before the docket date of the COL application for the site-specific portions and operational aspects of the facility design.
1.9 COL Item 1.10-1:
A COL applicant that references the NuScale Power Plant design certification will evaluate the potential hazards resulting from construction activities of the new NuScale facility to the safety-related and risk significant structures, systems, and components of existing operating unit(s) and newly constructed operating unit(s) at the co-located site per 10 CFR 52.79(a)(31). The evaluation will include identification of management and administrative controls necessary to eliminate or mitigate the consequences of potential hazards and demonstration that the limiting conditions for operation of an operating unit would not be exceeded. This COL item is not applicable for construction activities (build-out of the facility) at an individual NuScale Power Plant with operating NuScale Power Modules.
1.10 COL Item 2.0-1:
A COL applicant that references the NuScale Power Plant design certification will demonstrate that site-specific characteristics are bounded by the design parameters specified in Table 2.0-1.
If site-specific values are not bounded by the values in Table 2.0-1, the COL applicant will demonstrate the acceptability of the site-specific values in the appropriate sections of its combined license application.
2.0 COL Item 2.1-1:
A COL applicant that references the NuScale Power Plant design certification will describe the site geographic and demographic characteristics.
2.1 COL Item 2.2-1:
A COL applicant that references the NuScale Power Plant design certification will describe nearby industrial, transportation, and military facilities. The COL applicant will demonstrate that the design is acceptable for each potential accident, or provide site-specific design alternatives.
2.2 COL Item 2.3-1:
A COL applicant that references the NuScale Power Plant design certification will describe the site-specific meteorological characteristics for Section 2.3.1 through Section 2.3.5, as applicable.
2.3 COL Item 2.4-1:
A COL applicant that references the NuScale Power Plant design certification will investigate and describe the site-specific hydrologic characteristics for Section 2.4.1 through Section 2.4.14, as applicable.
2.4 COL Item 2.5-1:
A COL applicant that references the NuScale Power Plant design certification will describe the site-specific geology, seismology, and geotechnical characteristics for Section 2.5.1 through Section 2.5.5, below.
2.5 COL Item 3.2-1:
A COL applicant that references the NuScale Power Plant design certification will update Table 3.2-1 to identify the classification of site-specific structures, systems, and components.
3.2
NuScale Final Safety Analysis Report Interfaces with Certified Design Tier 2 1.8-6 Draft Revision 2 COL Item 3.7-8:
A COL applicant that references the NuScale Power Plant design certification will identify the implementation milestone for the seismic monitoring program. In addition, a COL applicant that references the NuScale Power Plant design certification will prepare site-specific procedures for activities following an earthquake. These procedures and the data from the seismic instrumentation system will provide sufficient information to determine if the level of earthquake ground motion requiring shutdown has been exceeded. An activity of the procedures will be to address measurement of the post-seismic event gaps between the fuel racks and the pool walls and between the individual fuel racks and to take appropriate corrective action if needed (such as repositioning the racks or assuring that the as-found condition of the racks is acceptable based on the assumptions of the racks' design basis analysis). Acceptable guidance for procedure development is contained in Regulatory Guide 1.166 "Pre-Earthquake Planning and Immediate Nuclear Power Plant Operator Post-earthquake Actions," Rev. 0 (or later) and 1.167, "Restart of a Nuclear Power Plant Shut Down by a Seismic Event," Rev. 0 (or later).
3.7 COL Item 3.7-9:
A COL applicant that references the NuScale Power Plant design certification will include an analysis of performance-based response spectra established at the surface and intermediate depth(s) that take into account the complexities of the subsurface layer profiles of the site and provide a technical justification for the adequacy of V/H spectral ratios used in establishing the site-specific foundation input response spectra and performance-based response spectra for the vertical direction.
3.7 COL Item 3.7-10:
A COL applicant that references the NuScale Power Plant design certification will perform a site-specific configuration analysis that includes the Reactor Building with applicable configuration layout of the desired NuScale Power Modules. The COL applicant will confirm the following are bounded by the corresponding design certified seismic demands:
- 1) The in-structure response spectra of the standard design at the foundation and roof
- 2) The maximum forces in the NuScale Power Module lug restraints and skirts
- 3) The maximum forces and moments in the east and west wing walls and pool walls If not, the standard design will be shown to have appropriate margin or should be appropriately modified to accommodate the site-specific demands.
3.7 COL Item 3.8-1:
A COL applicant that references the NuScale Power Plant design certification will describe the site-specific program for monitoring and maintenance of the Seismic Category I structures in accordance with the requirements of 10 CFR 50.65 as discussed in Regulatory Guide 1.160.
Monitoring is to include below grade walls, groundwater chemistry if needed, base settlements and differential displacements.
3.8 COL Item 3.8-2:
A COL applicant that references the NuScale Power Plant design certification will confirm that the site independent Reactor Building and Control Building are acceptable for use at the designated site.
3.8 COL Item 3.8-3:
A COL applicant that references the NuScale Power Plant design certification will identify local stiff and soft spots in the foundation soil and address these in the design, as necessary.
3.8 COL Item 3.9-1:
A COL applicant that references the NuScale Power Plant design certification will provide the applicable test procedures before the start of testing and will submit the test and inspection results from the comprehensive vibration assessment program for the NuScale Power Module, in accordance with Regulatory Guide 1.20.
3.9 COL Item 3.9-2:
A COL applicant that references the NuScale Power Plant design certification will develop design specifications and design reports in accordance with the requirements outlined under American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section III (Reference 3.9-1). A COL applicant will address any known issues through the reactor vessel internals reliability programs (i.e. Comprehensive Vibration Assessment Program, steam generator programs, etc.) in regards to known aging degradation mechanisms such as those addressed in Section 4.5.2.1.
3.9 COL Item 3.9-3:
A COL applicant that references the NuScale Power Plant design certification will provide a summary of reactor core support structure ASME service level stresses, deformation, and cumulative usage factor values for each component and each operating condition in conformance with ASME Boiler and Pressure Vessel Code Section III Subsection NG.
3.9 Table 1.8-2: Combined License Information Items (Continued)
Item No.
Description of COL Information Item Section
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-120 Draft Revision 2 The coordinate system for the nonlinear analysis is represented by the CRB SAP2000 model as shown in Figure 3.8.5-40. The X axis points to the East, the Y axis point to the North, and the Z axis points vertically upward. The X-coordinate of the west side of the CRB tunnel is 350'-0" (4,200") in the global X-direction (East-West) from the origin of the global SAP2000 coordinate system.
RAI 03.08.05-14S1 COL Item 3.8-3:
A COL applicant that references the NuScale Power Plant design certification will identify local stiff and soft spots in the foundation soil and address these in the design, as necessary.
3.8.5.5 Evaluation Criteria for Stability Analysis 3.8.5.5.1 Flotation and Uplift Stability Analysis Approach Flotation is calculated for static conditions and uplift is calculated with the earthquake present.
The factor of safety is calculated as follows, with load combination E for flotation and load combination C for uplift:
Eq. 3.8-1 Eq. 3.8-2 Eq. 3.8-3 Where Fresisting is the resistance of the buried portion of the structure. This includes two components:
D= the weight of the building F = Vertical friction due to static soil pressure The driving forces for uplift are from groundwater and seismic motion. This includes two components:
B = the buoyant force from groundwater or floodwater at grade.
Rz = Upward inertia = Seismic vertical base reaction (when soil moves downward in the direction of gravity).
FOS Fresisting Fdriving
=
FOSflotation D
B----
=
FOSuplift D
F
+
B Rz
+
=
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 8963 Date of RAI Issue: 08/18/2017 NRC Question No.: 03.08.05-22 10 CFR Part 50, Appendix A, General Design Criteria (GDC) 1, 2, 4 and 5 provide the
regulatory requirements for the design of the seismic Category I structures. DSRS Section 3.8.5
provides review guidance pertaining to stability of foundations.
FSAR Tier 2, Section 3.8.5.6.3, Bearing Pressure, page 3.8-72, provides static bearing
pressures of 10.1 ksf and 6.42 ksf for the RXB and CRB basemats, respectively. The applicant
also provides dynamic bearing pressures of 4.6 ksf and 5.32 ksf for the RXB and CRB
basemats, respectively. Furthermore, the applicant refers to Figure 3.8.5-3, Seismic Base
Pressure Contours from SASSI 2010 Analysis, to obtain seismic bearing pressure contour for
the RXB basemat. It is not clear to the staff how the applicant determined 4.6 ksf from Figure
3.8.5-3. Therefore, address the following:
describe the reason(s) why the dynamic bearing pressures of CRB is larger than the a.
dynamic bearing pressures of RXB.
explain how the applicant determined 4.6 ksf from Figure 3.8.5-3 for the dynamic bearing b.
pressures of RXB basemat.
address and provide figures of static and seismic basemat pressure contours for the CRB c.
and CRB Tunnel.
NuScale Response:
As discussed, in a public meeting on February 14, 2018, a supplement to NuScale's original response to RAI 8963 03.08.05-22 is provided.
Miscellaneous questions Clarify/define/correct the different distances between the RXB and CRB found in 1.
FSAR Section 3.8.
Response
The RXB and CRB are separated by a distance of 34 feet between wall centerlines. The
NuScale Nonproprietary distance between wall exterior faces is 30 feet. The distance between wall centerlines will be used as the distance between the RXB and CRB. FSAR sections 3.8.4 and 3.8.5 have been revised accordingly.
- 2. Verify the dimensions of the CRB tunnel area. Is the tunnel length 25 feet or 34 feet?
Response
Figure 1 shows the partial CRB Drawing at EL.50'-0". The RXB wall can be seen on the left side. The outer walls face-to-face distance between RXB and CRB is 30' as shown in the figure.
The distance between the center lines of RXB and CRB exterior walls is 34' and is obtained by adding the half thicknesses of RXB and CRB walls:
= 30' + 5'/2 + 3'/2 = 34' The CRB tunnel foundation dimensions can be deduced from the drawing:
Tunnel NS Width = 25'-8" = 25.67' Tunnel EW Length = 19'-6" With these two dimensions, the tunnel foundation area is calculated as follows:
Tunnel Foundation Area = 25.67' x 19.5' = 500.6 ft2 In the CRB finite element model, the tunnel EW length is 25' and corresponds to the distance between the CRB wall centerline to the tunnel edge. This is also the width of the backfill soil in the finite element model. The tunnel NS width is 18-8 (distance between wall centerlines).
NuScale Nonproprietary Figure 1. Part of CRB Drawing at EL.50'-0" Showing CRB Tunnel.
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NuScale Nonproprietary
- 3. Difference in tributary area for toe pressure calculation of Reactor Building and CRB, Tables 3.8.5-14 and 3.8.5-16.
Response
The difference in tributary areas between East and West edges is due to the difference between the element sizes in the EW dimensions for the East and West edges.
Response
In Section 3.8.4.3.1.1, the concrete self-weight for the RXB and CRB are specified as 465,420 kips and 43,870 kips, respectively. These weights are calculated using the concrete volume obtained from the 3D Solid Works models and the concrete unit weight.
In Section 3.8.5.3, the Dead Loads for the RXB and CRB are specified in 587,147 kips and 45,774 kips, respectively. The Dead Load used for the RXB is the effective seismic weight, which is consistent with the weight used for the seismic analysis in SASSI and ANSYS. For the CRB, however, the dead load includes only the self-weight of the concrete and steel structures, and equipment. Therefore, FSAR section has been updated accordingly.
In Section 3.8.5.6.1.1.1, the RXB Dead Weight reaction of 471,487 kips corresponds to the self-weight of the concrete structures, equipment, and water weight.
In Section 3.8.5.6.2.1.1, the Dead Weight reaction for the CRB is specified as 45,680 kips. This is a typo. The CRB dead weight is 45,774 and corresponds to the self-weight of the concrete and steel structures, and equipment. FSAR is updated accordingly.
In Section 3.8.5.6.3, the weight of the RXB is shown as 587,147 kip. This is the effective seismic weight. The CRB seismic weight is 49,041 kips. FSAR is updated to show this seismic weight.
Response: FSAR tables in Section 3.8 have been revised with the correct weights.
Supplemental response to part a) of the question:
As stated in FSAR Section 3.8.5.5.4, localized bearing pressure under each buildings basemat is defined as the vertical force in a spring below the basemat divided by its tributary area. FSAR Section 3.8.5.6.7, basemat soil pressures along the basemat edges (toe pressures), calculates localized bearing pressures along the RXB and CRB basemat edges. The localized bearing pressures correspond to the static plus the envelope of all dynamic cases. The localized edge bearing pressures, or toe pressures, along the edges are averaged to obtain the average toe pressures shown in FSAR Tables 3.8.5-14 and 3.8.5-16, for the RXB and CRB, respectively.
NuScale Nonproprietary FSAR Section 3.8.5.6.3 is updated to include the correct weight of the CRB and resulting basemat pressure.
Supplemental response to part c) of the question:
C1. Describe analysis, design and associated tables and figures for the CRB tunnel basemat The analysis and design of the CRB basemat under the tunnel follows the same approach explained in the FSAR for the entire CRB basemat, except that the seismic bending moments are also obtained from an alternative approach, as explained below. The maximum of the moments from the two approaches is used for the design of the tunnel basemat.
Seismic demand General approach for the CRB basemat The seismic demand for the CRB tunnel basemat is calculated by post-processing the seismic stresses at the centroid of the solid elements, obtained from SASSI2010. The stresses of a solid element are converted to axial and shear forces per unit length of the solid element. For the conversion, the in-plane normal stresses xx, yy and shear stress, xy are multiplied by the thickness of the basemat to obtain the in-plane axial forces per unit length. Similarly, the out-of-plane shear forces are obtained by multiplying the out-of-plane shear stresses by the basemat thickness.
The bending moments are calculated using a separate SAP2000 shell element basemat model.
In this model, the nodes along the base of the concrete walls are fixed and the soil pressure from the SASSI analysis results are applied as out-of-plane pressure to the basemat shell elements. The resultant bending moments across the CRB Basemat are shown on new FSAR figures 3.8.5-6a and 3.8.5-7a, respectively. Mxx is the moment along the X (E-W) axes,. Myy is the moment along the Y (N-S) axes. For design of the shell elements along the perimeter of the basemat, the end moments of the perimeter walls, obtained from SASSI results, are used instead.
Alternate approach for CRB tunnel basemat The bending moments at the center of the spans between the CRB tunnel walls are also estimated by considering the tunnel basemat as a one-way slab (foundation strip) spanning between the exterior and middle tunnel walls (see Figure 2). The moments at the middle of the foundation strip, between two walls, are calculated as described below.
The moments at both ends, say, M1 and M2, where the walls are located, are obtained from the shell elements modeling the walls in SASSI2010.
NuScale Nonproprietary Figure 2. CRB Tunnel showing foundation and walls To obtain the moment at the middle, the soil pressure obtained from SASSI2010 is first averaged over the foundation strip. The average soil pressure, designated as, acts as uniform distributed load upward on the bottom of the tunnel basemat. The moment due to the uniform soil pressure, designated a M3 is calculated assuming a simply supported beam between walls as follows:
M3= xL2/8 The moments at the ends are averaged and added to the moment due to the soil pressure. That is, the moment at the middle of the strip, designated as M, is calculated using the following formula:
M = (M1+M2)/2 + M3 During the calculation of M1 and M2, the larger wall bending moment between Mxx_wall and Myy_wall are used. The twisting moment Mxy_wall is also added.
M1 or M2= Max (Mxx_wall, Myy_wall) + Mxy_wall
NuScale Nonproprietary Conservatively, the out-of-plane moments calculated using basemat strips are used for bending about the two horizontal axes, i.e.
MX = MY = M The moments, MX and MY, are bending moments about the global X-and Y-axes, respectively.
The larger of moments MX and MY is used as the seismic moment about both horizontal directions. This moment represents the maximum seismic moment of the CRB tunnel area from the two approaches explained above (i.e., standalone CRB basemat model and foundation strip).
The maximum seismic results enveloping all seismic analysis cases for the CRB tunnel foundation are shown on Table 1. The seismic forces and moments presented in this table are the final seismic results including the results of both the standalone and combined SASSI models.
Static Demand The static demand for the CRB basemat, including tunnel, is calculated by post-processing the nodal forces at the solid elements modeling the basemat in the SAP2000 model.
The SAP2000 program calculates the nodal forces at all eight nodes of each solid element. A typical solid element showing the SAP2000 nodal force output components is shown in Figure
- 3. The local axes of each solid element are aligned with the global coordinate directions. The response nodal forces of basemat solid elements are converted into axial and shear forces, and moments. The procedure is explained below.
Forces and moments are obtained along the positive X and positive Y faces of each solid element (i.e., shaded faces on Figure 3).
Normal forces and shear forces along each face are obtained by summing up the corresponding nodal forces of the four nodes at that face. For example, to obtain the axial load at the X positive face, the F1 forces of nodes 3, 4, 7, and 8 are summed up.
The moments along a face are calculated with respect to the centroid of that face of the solid element. Three moments (MX, MY, and MZ) are obtained, due to the nodal forces at a node (F1, F2, and F3), by the vector product of the position vector and the nodal force vector of that node (Equation 1). The position vector at a node is the vector containing the x, y, and z distances from the centroid of the face to the node, where a nodal force vector applies. The moments due to nodal forces of pertinent nodes are summed together to obtain the total moment along the face.
NuScale Nonproprietary Figure 3. SAP2000 Solid Element Nodal Force Output.
For Positive X-Face The moments along the positive X face are calculated with Equation 1, setting xi to zero, and the summation is performed for nodes i = 3, 4, 7, and 8 for the positive X-face. In this case, the moments that are obtained are:
Moment about X-axis (twisting moment along X-face):
NuScale Nonproprietary Mxy =
Moment about Y-axis (bending moment along X-face):
Mxx =
Moment about Z-axis:
This is the in-plane moment which is not used.
For Positive Y-Face:
The moments along the positive Y face are calculated with Equation 1, setting yi to zero, and the summation is performed for nodes i=2,4,6, and 8 for the positive Y-face. In this case, the moments that are obtained are:
Moment about X-axis (bending moment along Y-face):
Myy =
Moment about Y-axis (twisting moment along Y-face):
Myx =
Moment about Z-axis:
This is the in-plane moment which is not used.
The calculated forces and moments are divided by the element width to obtain the forces and moments per unit length.
Conservatively, the twisting moment is added to the bending moments. The final bending moments are:
Resultanat bending moment about X-axis:
MX = Myy + Mxy
NuScale Nonproprietary Resultant bending moment about Y-axis:
MY = Mxx + Myx The procedure explained above is used to obtain the forces and moments from all four SAP2000 models: standalone and combined models with crack and un-cracked concrete conditions, using the controlling load combination for calculating structural forces for design, corresponding to ACI349 Equation 9-6.
From the four set of results, the maximum and minimum forces and moments are obtained. The maximum and minimum static results are shown on Table 2.
Total Demand for Design The seismic forces and moments across the CRB basemat, including the tunnel, are combined with their static counterparts to obtain the design forces and moments. For the final design, the CRB basemat is divided in three regions: exterior basemat perimeter, interior basemat, and tunnel foundation. The maximum forces and moments from each region are used for the design of that specific region. The maximum design forces and moments along the three CRB basemat regions are shown on FSAR Tables 3B-36 through 3B-38.
FSAR Section 3.8.5.4.1.3 is updated with more explanation on the CRB basemat design.
C2. Provide figures showing static base pressure contour, moment contours, etc., for the CRB basemat including tunnel The envelope of maximum static pressure (compression) contours on the CRB basemat, including the tunnel, is shown on new FSAR figure 3.8.5-2a. This figure is obtained by selecting the maximum vertical stresses of the solids elements across the CRB basemat, from both the standalone and combined SAP2000 CRB models.
New FSAR figures 3.8.5-4a and 3.8.5-5a show the static out-of-plane moment contours Myy and Mxx, respectively. These are obtained by post-processing the nodal forces of the solid elements modeling the CRB basemat in SAP2000, as explained before. For these plots, the standalone CRB SAP2000 model with cracked concrete is used. As indicated above, four SAP2000 models (standalone and combined models with cracked and un-cracked concrete condition) are used to obtain the maximum forces and moments for design.
C3. For consistency, include the units in the titles of figures FSAR figure titles have been changed for Figures 3.8.5-2, 3.8.5-3, 3.8.5-4, 3.8.5-5, 3.8.5-6, and 3.8.5-7 to include the correct units in the titles.
NuScale Nonproprietary Table 1 Maximum Seismic Forces and Moments in CRB Tunnel Foundation.
Force/Moment FX(Sxx)
FY(Syy)
Sxy Vxz Vyz MX MY Unit k/ft k/ft k/ft k/ft k/ft k-ft/ft k-ft/ft Maximum 425.3 398.4 205.6 247.8 139.7 357.4 357.4 Elem.no.
550 547 547 550 548 397 397 Table 2. SAP2000 Maximum and Minimum Static Results for CRB Tunnel Area.
Comp FX(Sxx)
FY(Syy)
Sxy Vxz Vyz MX MY Unit kip/ft kip/ft kip/ft kip/ft kip/ft kip-ft/ft kip-ft/ft Max 379.9 26.1 77.6 105.3 103.3 339.3 167.3 Elem.no.
547 398 400 516 485 488 519 Min 209.8
-153.9
-72.0 18.8
-95.0
-101.7
-398.0 Elem.no.
487 486 397 549 488 485 486 For SAP2000 Static analysis, the results carry signs. A positive FX or FY is in tension; negative compression.
Impact on DCA:
FSAR Tier 2, Section 3.8.5 has been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-110 Draft Revision 2 3.8.5 Foundations 3.8.5.1 Description of Foundations RAI 03.08.05-22S1 The Seismic Category I Buildings are the Reactor Building (RXB) and the Control Building (CRB). These buildings are approximately 340 feet apart between centerlines of walls, and are connected by a tunnel. The Seismic Category II Radioactive Waste Building (RWB) is approximately 25 feet from the RXB. The RXB, CRB and RWB are described in Sections 1.2 and 3.8.4. The foundations of the RXB and CRB are described below.
Reactor Building Foundation The RXB basemat foundation is 10 feet thick. The basemat is larger than the building and measures approximately 358 feet by 163 feet. The foundation top of concrete (TOC) elevation is 24'-0". The foundation for the refueling pool area has a top of concrete elevation of approximately 19 feet. Similarly, the elevator has a TOC of approximately 17 feet and sumps have a TOC elevation of approximately 20 feet. For the locations where the top of concrete is less than 24'-0" the foundation depth is increased to maintain the 10 foot minimum thickness.
The basemat reinforcement pattern is 6 layers of #11 bars at 12" centers each way (i.e.,
north-south and east-west) top and bottom for main reinforcing steel, and 2-legged stirrups of #6 bars at 12" centers each way at the perimeter of the basemat, extending 15 feet from the centerline of the exterior walls. The interior section of the basemat is 4 layers of #11 bars at 12" centers each way top and bottom for main reinforcing steel, and 1-legged stirrups of #6 bars at 12" centers each way.
Control Building Foundation The CRB basemat foundation is 5 feet thick, with dimensions of approximately 130 feet by 91 feet with TOC at 50'-0".
The reinforcement pattern for the basemat is 3 layers of #11 bars at 12" centers each way top and bottom for main reinforcing steel, and 2-legged stirrups of #6 bars at 12" centers each way. The perimeter of the main slab contains 4 layers of #11 bars at 12" centers each way top and bottom for main reinforcing steel, and 2-legged stirrups of #6 bars at 12" centers each way.
3.8.5.2 Applicable Codes, Standards and Specifications The codes, standards, and specifications that are used to design and construct the RXB and CRB are identified in Section 3.8.4.2. These codes are applicable to the foundations as well.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-111 Draft Revision 2 3.8.5.3 Loads and Load Combinations The loads and load combinations used for the design of the RXB and CRB, including the design of the foundations, are discussed in Section 3.8.4.3.
Stability Load Combinations The load combinations used for the assessment of stability (flotation, uplift, sliding, overturning) are discussed below.
Five load combinations are considered:
A. D + H + EOBE B. D + H + W C. D + H + ESSE D. D + H + Wt E. D + B Load case A is not analyzed. The OBE is defined as one-third of the SSE and analysis is not required. In addition, the wind loads are bounded by the seismic loads as discussed in Section 3.8.4. Therefore load cases B and D are also not analyzed.
The loads are discussed in Section 3.8.4.3, but are summarized below:
RAI 03.08.05-22S1 D is the dead load. This is the seismic weight for the RXB equal to 587,147 kips. For the CRB, this is the self-weight of the concrete and steel structures, and equipment, equal to 45,774 kipsequal to 587,147 kips for the RXB (equipment and water weight) and 45,774 kips (includes equipment weight) for the CRB.
B is the buoyant force generated by the water table. This is equivalent to the embedded volume of the building times the weight of water. This load is +279,445 kips for the RXB and 40,500 kips for the CRB.
ESSE is the seismic load generated by the CSDRS or CSDRS-HF.
H is the lateral static soil pressure.
Wt = Loads generated by the design basis tornado that cause tornado wind pressure, tornado-created differential pressures, and tornado generated missiles.
3.8.5.3.1 Lateral Soil Force and Seismic Loads The RXB and CRB are embedded structures and, therefore, the surrounding soil contributes significantly to the stability of the structures. The surrounding soil
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-117 Draft Revision 2 on Figure 3.8.5-11 and Figure 3.8.5-12. There were a total of three time histories for each soil type considered.
RAI 03.08.05-10S1 Rather than directly applying the SASSI accelerations to the RXB and backfill soil, coincident nodes were created. Nonlinear node-to-node CONTA178 elements were defined between the coincident nodes as shown in Figure 3.8.5-13 and Figure 3.8.5-14. Figure 3.8.5-15 illustrates the CONTA178 definition wherein forces are transferred between the end node-I and node node-J only when the gap is closed, i.e., transmitting compression but not tension. The elements directly under the RXB basemat have a coefficient of friction of 0.58 defined to resist sliding.
RAI 03.08.05-10S1 A pressure of 36.92 psi was applied to the bottom of the basemat to account for buoyancy effects as shown on Figure 3.8.5-16. The static surcharge effects from the backfill soil against the RXB outer wall are ignored.
Table 3.8.5-6 shows the number of elements in the ANSYS structural analysis model including joints, frame elements, shell elements, solid elements, and links/supports.
RAI 03.08.05-10S1 East-west and north-south unidirectional, horizontal time-history analyses were performed for each of the surrounding Soil Types 7, 8, and 11. For all cases, the respective acceleration time-history from the SASSI representative skin node 946 was applied uniformly to all the boundary nodes in the ANSYS model, while the displacements in the other two directions were constrained.
Thus, for each soil type, the cases performed were acceleration time history in the east-west direction, with the displacements in the vertical and north-south directions fixed and acceleration time history in the north-south direction, with the displacements in the vertical and east-west directions fixed.
RAI 03.08.05-10S1 Figure 3.8.5-17 through Figure 3.8.5-19 show the input acceleration time histories for each of the Soil Type 7 cases.
RAI 03.08.05-10S1 Figure 3.8.5-20 through Figure 3.8.5-22 show the input acceleration time histories for each of the Soil Type 8 cases.
RAI 03.08.05-10S1 Figure 3.8.5-23 through Figure 3.8.5-25 show the input acceleration time histories for each of the Soil Type 11 cases.
3.8.5.4.1.3 Analysis of Control Building Basemat RAI 03.08.05-12S1, RAI 03.08.05-22, RAI 03.08.05-22S1
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-118 Draft Revision 2 The static load results are obtained from the SAP2000 model of the CRB. Both the stand-alone and the combined CRB SAP2000 models are used to obtain the static forces and moments in the basemat, using the most critical static load combination for the calculation of structural responses. Bending moments, axial and shear forces in the basemat are extracted from the SAP2000 CRB global model. To do this, the foundation's solid elements' nodal forces from the CRB model are converted into axial and shear forces, and moments, by applying equilibrium along the solid faces perpendicular to the X and Y directions. Final bending moments include the effect of the twisting moments.
RAI 03.08.05-22S1 The envelope of maximum static pressure contours on the CRB basemat, obtained from both the standalone and combined SAP2000 CRB models, is shown on Figure 3.8.5-2a.
RAI 03.08.05-12S1, RAI 03.08.05-22S1 For dynamic loads, the basemat solid element stresses obtained from the SASSI analysis are used. The axial and shear forces are obtained by multiplying the axial and shear stresses by the solid element thickness. The bending moments are calculated using a separate SAP2000 shell element basemat model. In this model, the nodes along the base of the concrete walls are fixed and the soil pressure from the SASSI analysis results are applied as out-of-plane pressure to the basemat shell elements. For the shell elements on the perimeter of the basemat, the end moments of the perimeter walls, obtained from SASSI results, are used.
RAI 03.08.05-22S1 For the tunnel basemat, the bending moments are also estimated by considering the tunnel basemat as a simple-supported one-way slab spanning between the exterior and middle tunnel walls. Conservatively, the ends moments of the exterior and middle walls are averaged and added to the simple-supported moments at the center of the span. The resultant moment is used for both X and Y directions.
RAI 03.08.05-10S1, RAI 03.08.05-22, RAI 03.08.05-22S1 The seismic forces, moments, and stresses in the structural elements, such as walls, beam elements, and basemat, are calculated using the stand-alone and combined SASSI2010 models. The enveloped seismic pressures contours on the CRB basemat are shown in Figure 3.8.5-3a. The enveloped seismic pressures are obtained as a result of the four-step, post-processing method described in Section 3.7.2.4.1. These maximum pressures are loaded into an SAP2000 model of the CRB basemat from where the seismic forces and moments for the basemat design are obtained. Absolute values of the responses obtained by applying base pressures from SASSI2010 are used to arrive at the total seismic demands.The solid element seismic stresses are calculated using the stand-alone and combined SASSI2010 models. The enveloped seismic pressures contours on the CRB basemat are shown in
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-119 Draft Revision 2 Figure 3.8.5-3a. The enveloped seismic pressures are obtained as a result of the four-step, post-processing method described in Section 3.7.2.4.1. Absolute values of the responses are used.
RAI 03.08.05-22 Control Building Basemat and Stability Linear Analysis Acceptance criteria for flotation/ uplift, sliding, and overturning is based on a factor of safety (FOS) determined from the ratio of the driving force to the resisting force. These analyses are performed statically using the maximum forces from the combinations of soil profiles, time histories, and cracked/
uncracked conditions discussed in Section 3.7. The FOS performed for the CRB yielded unacceptable results (less than 1.1 FOS) for uplift stability; therefore, the uplift, sliding and overturning of the CRB is determined by a nonlinear sliding and uplift analysis.
3.8.5.4.1.4 Control Building Basemat Nonlinear Analysis Model Description For the nonlinear analysis, the ANSYS CRB model with fixed-base boundary sliding and uplift conditions was changed to:
1)
Provide independence of the building and soil domain by establishing coincident joints/nodes for the building and soil in the finite element mesh.
2)
Define a nonlinear frictional contact region with the coincident nodes as shown in Figure 3.8.5-26. A coefficient of friction of 0.5 (between the CRB walls and soil) was used so that the tangential force required to overcome the resistance from any compressive normal force is equal to half the normal force, allowing the building to slide and uplift relative to the soil.
3)
Obtain, at a typical skin node near the CRB basemat, the seismic input acceleration time histories in the three orthogonal directions for the Soil Type 11 backfill in combination with the surrounding Soil Type 7 and Soil Type 11. Three time histories for each soil type were considered by uniformly applying the time histories from the typical skin node to the CRB and backfill soil nodes, as shown in Figure 3.8.5-27, which are in contact with the in-situ soil. The SASSI time histories for the Capitola input case were selected since that case produced the largest horizontal base reactions, as shown in Table 3.8.5-3. The three time histories are shown in Acceleration time history for each of the Soil Type 11 cases (Figure 3.8.5-28 through Figure 3.8.5-30)
Acceleration time history for each of the Soil Type 7 cases. (Figure 3.8.5-31 through Figure 3.8.5-33) 4)
Create coincident nodes and define nonlinear node-to-node CONTA178 elements as shown on Figure 3.8.5-34 and Figure 3.8.5-35 to accurately model the contact gap between CRB and soil. The typical definition of CONTA178 elements is shown in Figure 3.8.5-15, where forces are transferred between node-I and node-J only when the gap is closed. The
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-120 Draft Revision 2 elements directly under the CRB foundation have a coefficient of friction of 0.55 defined to resist sliding, i.e., transmitting compression but not tension.
The elements on the sides of the CRB have a coefficient of friction of 0.50 defined to resist sliding.
- 5) Account for buoyancy effects by applying a pressure of 29.399 psi to the bottom of the basemat, as shown in Figure 3.8.5-36. The buoyancy pressure was determined as follows:
RAI 03.08.05-22S1 Total modeled area = basemat area + tunnel area = 78' x 116.667' + 25' x 18.667'
= 9,100 ft² + 466.67 ft² = 9,566.67 ft² Buoyancy pressure = 40,500,000 lbs / (9,566.67x144) in² = 29.399 psi
- 6) Include Poisson's ratio effect in the static soil pressure profile due to the deadweight of the backfill soil on the CRB walls as a conservative measure.
The pressure profile is shown in Figure 3.8.5-37. The Poisson's ratio effect produces a complex pressure distribution depending on the local flexibility of the walls (Figure 3.8.5-38 and Figure 3.8.5-39).
RAI 03.08.05-4, RAI 03.08.05-11, RAI 03.08.05-24 The model summary showing quantity of elements in the ANSYS structural analysis model including joints, frame elements, shell elements, and solid elements is shown in Table 3.8.5-11. A comparison of the SAP2000, SASSI2010, and ANSYS models also is shown in Table 3.8.5-11.
The coordinate system for the nonlinear analysis is represented by the CRB SAP2000 model as shown in Figure 3.8.5-40. The X axis points to the East, the Y axis point to the North, and the Z axis points vertically upward. The X-coordinate of the west side of the CRB tunnel is 350'-0" (4,200") in the global X-direction (East-West) from the origin of the global SAP2000 coordinate system.
RAI 03.08.05-14S1 COL Item 3.8-3:
A COL applicant that references the NuScale Power Plant design certification will identify local stiff and soft spots in the foundation soil and address these in the design, as necessary.
3.8.5.5 Evaluation Criteria for Stability Analysis 3.8.5.5.1 Flotation and Uplift Stability Analysis Approach Flotation is calculated for static conditions and uplift is calculated with the earthquake present.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-127 Draft Revision 2 3.0 for the static bearing pressure and a factor of safety of 2.0 for dynamic bearing pressure. The maximum allowable tilt settlement for the Reactor Building is 1" total or 1/2" per 50 feet in any direction at any point in the structure. The maximum allowable total settlement at any foundation node is four inches.
3.8.5.6.1.1 RXB Uplift RAI 03.08.05-3 As shown in Section 3.8.5.5.1, The FOS for flotation is shown in Table 3.8.5-5 for each of the 16 cases considered, including cracked and uncracked conditions, Soil Types 7, 8, 9 and 11, and for RXB model and the triple building model. For each of the cases, an acceptable FOS for overturning was met.
3.8.5.6.1.1.1 Dynamic RXB Uplift Ratio The effect of foundation uplift has been evaluated for the RXB. The linear SSI analysis methods are acceptable if the ground contact ratio is equal to or greater than 80 percent. The ground contact ratio can be calculated from the linear SSI analysis using the minimum basemat area that remains in compression with the soil. The seismic total vertical base reactions are calculated by the time step-by-time step algebraic summation of all nodal vertical reactions of the nodes of the RXB basemat. The maximum seismic vertical reactions for the cracked and uncracked concrete conditions for the two models are summarized in Table 3.8.5-4. The base vertical reaction results for the uncracked condition are similar to those for the cracked concrete condition.
RAI 03.08.05-22S1 As shown in Table 3.8.5-4, the seismic reactions are much less than the total dead weight reaction over the rectangle basemat area of 471,487 kipsof 471,487 kips over the rectangle basemat area. The dead weight reaction corresponds to the self-weight of the concrete structures, equipment, and water weight. Thus, the net reactions are always in compression.
RAI 03.08.05-16 The typical total basemat vertical reaction time histories are shown in Figure 3.8.5-42 through Figure 3.8.5-47. Figure 3.8.5-42 and Figure 3.8.5-43 show the reactions for comparison between the cracked and uncracked concrete conditions. Each of the CSDRS-and CSDRS-HF-compatible seismic inputs contain three acceleration components, X (EW), Y (NS), and Z (vertical).
FOS Fresisting Fdriving
=
FOSflotation D
B----
=
FOSuplift D
F
+
B Rz
+
=
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-130 Draft Revision 2 magnitude of this displacement is insignificant. Thus, the potential for uplift is insignificant.
3.8.5.6.2.1.1 Dynamic CRB Uplift Ratio The effect of the foundation uplift has been evaluated for the CRB. The linear SSI analysis methods are acceptable if the ground contact ratio is equal to or greater than 80%. The ground contact ratio can be calculated from the linear SSI analysis using the minimum basemat area that remains in compression with the soil. The seismic total vertical base reactions are calculated by the time step-by-time step algebraic summation of all nodal vertical reactions of the nodes of the CRB basemat. The maximum seismic vertical reactions for the cracked and uncracked concrete conditions are summarized in Table 3.8.5-15. The base vertical reaction results for the uncracked condition are similar to those for the cracked concrete condition.
RAI 03.08.05-22S1 As shown in Table 3.8.5-15, the seismic reactions are much less than the total dead weight reaction over the rectangle basemat area of 45,680 kips45,774 kips. The dead weight reaction corresponds to the self-weight of the concrete and steel structures, and equipment (based on SAP2000 calculations). Thus, the net reactions are always in compression.
RAI 03.08.05-16 The typical total basemat vertical reaction time histories are shown in Figure 3.8.5-77 through Figure 3.8.5-82. The first two show the reactions for comparison between the cracked and uncracked concrete conditions.
Others are all for the cracked concrete condition for the CSDRS Capitola input and CSDRS-HF Lucerne input. As can be seen in these figures, the total reactions are always in compression. Each of the CSDRS-and CSDRS-HF-compatible seismic inputs contain three acceleration components, X (EW), Y (NS), and Z (vertical).
The cracked and uncracked total reactions can be compared using Figure 3.8.5-77 for the cracked reaction and Figure 3.8.5-78 uncracked reaction due to Capitola input for Soil Type 7. The differences in total reactions are small because the differences between the cracked and uncracked seismic reactions are small as shown in Table 3.8.5-15.
Based on the examination of the total vertical reaction force underneath the basemat, all net vertical reactions are in compression. Thus, the basemat is 100 percent in contact.
3.8.5.6.2.2 Control Building Sliding Figure 3.8.5-51 shows the relative sliding between the nodes at location A. In contrast to penetration compatibility, sliding can exhibit both positive and
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-131 Draft Revision 2 negative values equally since the nodes could move away from each other, towards one side or the other. Maximum sliding at A is approximately 0.006".
RAI 03.08.05-20, RAI 03.08.05-21 A summary of the results is provided in Table 3.8.5-13. The magnitudes of these displacements are insignificant. Thus, the potential for sliding is insignificant.
3.8.5.6.2.3 Control Building Overturning RAI 03.08.05-21 The results provided in Table 3.8.5-13 show that the deeply embedded Control Building experiences less than 1/10" of sliding displacement and less than 1/64" of total vertical uplift displacement. The magnitudes of these displacements are insignificant. Thus, the potential for overturning is insignificant.
RAI 03.08.05-22 3.8.5.6.3 Average Bearing Pressure RAI 03.08.05-22 As stated in Section 3.8.5.5.4, the average static bearing pressure is the dead load of the building divided by the footprint.
RAI 02.03.01-2, RAI 03.08.05-22S1 The weight of the RXB is 587,147 kips and the calculated footprint is 58,175 ft2. This results in an average pressure of 10.1 ksf. This results in a factor of safety of 6.9 to the minimum soil bearing capacity of 75 ksf specified in Table 2.0-1.The seismic weight of the RXB is 587,147 kips and the calculated footprint is 58,175 ft2. This results in an average pressure of 10.1 ksf. This results in a factor of safety of 7.4 to the minimum soil bearing capacity of 75 ksf specified in Table 2.0-1. The weight of the CRB (based on static vertical gravity reaction (1GZ) and soil weight) is 75,779 kips with a base area of 11,800 ft2. This results in a static bearing pressure of 6.42 ksf. This value for the CRB static bearing pressure provides a factor of safety of 10.9 to the minimum soil bearing capacity of 75 ksf in Table 2.0-1.The seismic weight of the CRB, including the tunnel, is 49,041 kips. The rectangular basemat area is 11,800 ft2, the tunnel area is 501 ft2, which makes a total area of 12,301 ft2. This results in an average static bearing pressure of 4.0 ksf. This provides a factor of safety of 19 to the minimum soil bearing pressure of 75 ksf provided in Table 2.0-1.
RAI 03.08.05-22, RAI 03.08.05-22S1 The average dynamic bearing pressure is obtained as described in Section 3.8.5.5.4, with the vertical reaction for the entire basemat computed at each time step. The RXB foundation average dynamic pressure is 4.6 ksf. The CRB average foundation dynamic pressure is 2.3 ksf.The RXB foundation average dynamic pressure is 4.6 ksf.
The CRB average foundation dynamic pressure on the rectangular basemat is 2.3 ksf. The average dynamic pressure on the tunnel area is not calculated.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-132 Draft Revision 2 Maximum dynamic pressures across the entire CRB basemat, including the tunnel basemat, are shown on Figure 3.8.5-3a. These pressures are obtained by the post-processing approach indicated in Section 3.7.2.4.1.
3.8.5.6.4 Settlement RAI 02.03.01-2 Displacement values are provided for selected nodes in the foundation in Table 3.8.5-8. The location of these nodes is shown in Figure 3.8.5-10. As can be seen from the values in Table 3.8.5-8, total settlement at any foundation node, tilt settlement, and differential settlement are minimal. The maximum allowable differential settlement between the RXB and CRB, and between the RXB and RWB is 0.5 inch.
RAI 02.03.01-2 The RXB settles approximately 13/4 inch on the west end and approximately 2 inches on the east end. The tilt settlement of 0.25" is less than 1" as cited in Section 3.8.5.6.1. There is negligible tilt north to south. The east end of the building contains the pool and the NPMs.
RAI 02.03.01-2 The CRB settles approximately 13/4 inch on the west end and approximately 1 inch on the east end. The tilt settlement of 0.75" is less than the 1" limit cited in Section 3.8.5.6.2. North to south tilt is negligible. The CRB tilts toward the RXB.
Differential settlement between the two buildings is on the order of 1/4 inch.
The Seismic Category II Radioactive Waste Building settles approximately 1/2 inch on the west end and approximately 11/2 inch on the east end. The RWB tilts toward the RXB. The RWB tilts approximately 1/5 inch in the north-south direction. Differential settlement between the RWB and the RXB is also on the order of 1/4 inch.
3.8.5.6.5 Thermal Loads During normal operation, a linear temperature gradient across the RXB foundation may develop.
An explicit analysis considering these loads has not been performed, as thermal loads are a minor consideration. Thermal loads are, by nature, self-relieving by means of concrete cracking and moment distribution. This is especially true of the NuScale RXB, as it is not a traditional pre-stressed/post-tensioned, cylindrical containment vessel, but, rather, a rectangular reinforced concrete building with several members framing into the roof, external walls, and basemat.
3.8.5.6.6 Construction Loads The entire RXB basemat is poured in a very short time. The building is essentially constructed from the bottom up. The main loads (the reactor pool and the NPMs) are not added until the building is complete. Therefore, there are no construction-
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-133 Draft Revision 2 induced settlement concerns. The CRB basemat is much smaller and will be poured later than the RXB basemat in the construction sequence.
3.8.5.6.7 Basemat Soil Pressures along Basemat Edges (Toe Pressures)
RAI 03.08.05-22S1 The static deadweight reaction at an edge node is added to the seismic reaction of the node to calculate the total reaction. The bearing pressure is calculated by dividing the total reaction by the tributary area of the node.The seismic reaction is obtained with the approach shown in Section 3.7.2.4.1, for combining seismic analysis results. The bearing pressure is calculated by dividing the total reaction by the tributary area of the node (i.e., localized bearing pressure). The edge bearing pressures, or toe pressures, along the edges are averaged to obtain the average toe pressures of the basemat. The average toe pressures for the RXB and CRB are shown in Table 3.8.5-14 and Table 3.8.5-16, respectively. The values shown in these tables indicate that two times the maximum toe pressure is less than the minimum soil bearing pressure capacity of 75 ksf as specified in Table 2.0-1.
3.8.5.6.8 Leak Detection Groundwater has the potential to leak through the RXB exterior walls through microscopic concrete cracks. Due to the exterior concrete wall thickness, these leaks will be very slow (<<1 gallon per day (gpd)). This leak rate through the wall is not enough to cause an interior flood in any of the rooms that share an exterior wall. Leaks of this nature will be discovered and dealt with in accordance with plant concrete maintenance specifications. Further reduction of groundwater seepage can be accomplished with a building dewatering system surrounding the RXB.
A leak chase system is provided in the RXB basemat to detect any leakage from the reactor pool.
3.8.5.7 Materials, Quality Control, and Special Construction Techniques Section 3.8.4.6 describes the materials, quality control, and special construction techniques applicable to the RXB and CRB including the foundations.
3.8.5.8 Testing and Inservice Inspection Requirements Section 3.8.4.7 identifies the testing and inservice surveillances applicable to the RXB and CRB including the foundations.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-138 Draft Revision 2 RAI 03.08.05-22S1 Table 3.8.5-1: RXB Stability Evaluation Input Parameters Data Description Value RXB DeadSeismic Weight (kips) 587,147 RXB East-West Length (ft)
(between exterior faces of walls) 346 RXB North-South Length (ft)
(between exterior faces of walls) 150.5 RXB Height (ft) 167 RXB Embedment Depth (ft) 86 Foundation East-West Length (ft) 358 Foundation North-South Length (ft) 162.5 Foundation Area (ft2) 58,175 Soil Density, soil (pcf) 130 Coefficient of Friction between Wall and Soil 0.5 Coefficient of Friction between Basemat and Soil 0.58 Effective Soil Density, eff = soil - water (pcf) 67.6 Angle of Internal Friction 30º Soil Coefficient of Pressure at Rest, Ko 0.5 Surcharge (psf) 250
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-147 Draft Revision 2 RAI 03.08.05-8, RAI 03.08.05-22S1 Table 3.8.5-9: CRB Stability Input Evaluation Parameters Data Description Value CRB Seismic Weight (kips) 45,77449,041 Buoyancy Load (kips) 40,500 CRB East-West Length (ft) (between exterior faces of walls) 81-0 CRB North-South Length (ft) (between exterior faces of walls) 119-8 CRB Height (ft) 95-0 CRB Embedment Depth (ft) 55-0 CRB Main Foundation East-West Length (ft) 91-0 CRB Main Foundation North-South Length (ft) 129-8 Main Foundation Area (ft²)
11,800 CRB Tunnel Foundation East-West Length (ft) 19'-6" CRB Tunnel Foundation North-South Length (ft) 25'-8" Tunnel Foundation Area (ft2) 500.6 Soil Density, ysoil (pcf) 130 Soil Coefficient of Pressure at Rest, Ko 0.5 Ground water level Less than plant elevation 98-0 Flood level Less than plant elevation 99-0 Surcharge (psf) 250 Coefficient of Friction between Wall and Soil 0.5 Coefficient of Friction between Basemat and Soil (static analysis) 0.58 Coefficient of Friction between Basemat and Soil (nonlinear analysis) 0.55 Buoyancy load based on the water level at Elevation 100'-0" for conservatism.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-153 Draft Revision 2 RAI 03.08.05-22S1 Table 3.8.5-15: Seismic Vertical CRB Base Reactions and Dead Weight Concrete Soil Seismic Load Cracked Seismic Vertical Reaction Uncracked Seismic Vertical Reaction Dead Weight Case Type Case (kips)
(kips)
(kips)
Cracked 7%
Damping S7 CSDRS Capitola 22,228 23,455 45,68045,774 Chi Chi 26,415 26,333 45,68045,774 El Centro 27,118 26,885 45,68045,774 Izmit 24,628 25,146 45,68045,774 Yermo 26,253 26,015 45,68045,774 S8 CSDRS Capitola 22,129 22,284 45,68045,774 Chi Chi 26,196 26,074 45,68045,774 El Centro 26,565 26,562 45,68045,774 Izmit 24,857 25,868 45,68045,774 Yermo 26,284 26,267 45,68045,774 S11 CSDRS Capitola 20,173 20,103 45,68045,774 Chi Chi 24,121 23,885 45,68045,774 El Centro 24,400 24,413 45,68045,774 Izmit 21,793 21,150 45,68045,774 Yermo 24,260 24,132 45,68045,774 S7 CSDRS-HF Lucerne 18,371 19,126 45,68045,774 S9 CSDRS-HF Lucerne 21,209 20,637 45,68045,774 S7, S8, S9, S11 designate Soil Types 7, 8, 9, and 11, respectively.
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-157 Draft Revision 2 RAI 03.08.05-11S1, RAI 03.08.05-22S1 Figure 3.8.5-2: Static Base Pressure Contours for American Concrete Institute Load Combination 9-6 in the Reactor Building Basemat (psi)Governing Load Combination in the Reactor Building Basemat Model (Lb, in Units)
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-158 Draft Revision 2 RAI 03.08.05-22S1 Figure 3.8.5-2a: Static Base Pressure Contours for American Concrete Institute Load Combination 9-6 in the Control Building Basemat (psi)
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-159 Draft Revision 2 RAI 03.08.05-11S1, RAI 03.08.05-22S1 Figure 3.8.5-3: Seismic Base Pressure Contours from SASSI2010 Analysis in the Reactor Building Basemat Model (Lb, inch Units)(psi)
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-161 Draft Revision 2 RAI 03.08.05-11S1, RAI 03.08.05-22S1 Figure 3.8.5-4: M22 due to Static Base PressureMyy due to Static Base Pressure on Reactor Building Basemat (kip-ft/ft) in the Reactor Building Basemat Model
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-162 Draft Revision 2 RAI 03.08.05-22S1 Figure 3.8.5-4a: Myy due to Static Loads on Control Building Basemat, Stand-Alone SAP2000 Model (kip-ft/ft)
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-163 Draft Revision 2 RAI 03.08.05-11S1, RAI 03.08.05-22S1 Figure 3.8.5-5: M11 due to Static Base PressureMxx due to Static Base Pressure on Reactor Building Basemat (kip-ft/ft) in the Reactor Building Basemat Model
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-164 Draft Revision 2 RAI 03.08.05-22S1 Figure 3.8.5-5a: Mxx due to Static Loads on Control Building Basemat, Stand-Alone SAP2000 Model (kip-ft/ft)
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-165 Draft Revision 2 RAI 03.08.05-11S1, RAI 03.08.05-22S1 Figure 3.8.5-6: M22 due to Seismic Base PressureMyy due to Seismic Base Pressure on Reactor Building Basemat (kip-ft/ft) in the Reactor Building Basemat Model
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-166 Draft Revision 2 RAI 03.08.05-22S1 Figure 3.8.5-6a: Myy due to Seismic Base Pressure on Control Building Basemat (kip-ft/ft)
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-167 Draft Revision 2 RAI 03.08.05-11S1, RAI 03.08.05-22S1 Figure 3.8.5-7: M11 due to Seismic Base PressureMxx due to Seismic Base Pressure on Reactor Building Basemat (kip-ft/ft) in the Reactor Building Basemat Model
NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-168 Draft Revision 2 RAI 03.08.05-22S1 Figure 3.8.5-7a: Mxx due to Seismic Base Pressure on Control Building Basemat (kip-ft/ft)