ML18120A261

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LLC Response to NRC Request for Additional Information No. 110 (Erai No. 8932) on the NuScale Design Certification Application
ML18120A261
Person / Time
Site: NuScale
Issue date: 04/20/2018
From: Rad Z
NuScale
To:
Document Control Desk, Office of New Reactors
References
RAIO-0418-59757
Download: ML18120A261 (127)
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Text

RAIO-0418-59757 April 30, 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 Response to NRC Request for Additional Information No.

110 (eRAI No. 8932) on the NuScale Design Certification Application

REFERENCES:

1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 110 (eRAI No. 8932)," dated July 30, 2017 2 . NuScale Power, LLC Response to NRC "Request for Additional Information No. 110 (eRAI No.8932)," dated September 27, 2017 3 . NuScale Power, LLC Response to NRC "Request for Additional Information No. 110 (eRAI No.8932)," dated December 21, 2017 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).

The Enclosure to this letter contains NuScale's response to the following RAI Question from NRC eRAI No. 8932:

03.07.02-4 The responses to RAI No. 110, eRAI No. 8932, questions were previously provided in Reference 2 and Reference 3. The response to question 03.07.02-5 will be provided by November 29, 2018 and the response to question 03.07.02-6 will be provided by May 31, 2018.

This letter and the enclosed response 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 Di Director, R l Regulatory Aff i Affairs NuScale Power, LLC Distribution: Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A Prosanta Chowdhury NRC, OWFN-8G9A NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-0418-59757 : NuScale Response to NRC Request for Additional Information eRAI No. 8932 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-0418-59757 :

NuScale Response to NRC Request for Additional Information eRAI No. 8932 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

Response to Request for Additional Information Docket No.52-048 eRAI No.: 8932 Date of RAI Issue: 07/30/2017 NRC Question No.: 03.07.02-4 10 CFR 50 Appendix S requires that the safety functions of structures, systems, and components (SSCs) must be assured during and after the vibratory ground motion associated with the Safe Shutdown Earthquake (SSE) through design, testing, or qualification methods.

On Page 3.7-22 of the FSAR, in the second paragraph, to discuss the adequacy of 7P Extended Subtraction Method (ESM) model, the applicant provided 7P versus 9P ISRS comparisons for the Capitola time histories in Figures 3.7.2-8 to10. However, the FSAR does not provide a comparison of transfer functions for the 7P and 9P models. The review of transfer functions is essential to ensure that the numerical implementation of the SSI analysis methods is acceptable and consistent with the guidance in DSRS Section 3.7.2. In the same paragraph, the applicant also states, This level of agreement justifies using a 7P versus a 9P model and, because the results are similar, demonstrates the acceptability of using the extended subtraction method as an alternative to the direct method. The staff believes that 7P vs 9P ESM comparison captures only an incremental enhancement between the two models. The adequacy of an ESM model should be established against the direct method (DM). Therefore, in addition to a comparison of the 7P and 9P ESM models, the applicant is requested to provide a comparison of the transfer functions for the 7P ESM and the DM models at selected nodes of the critical sections and other important locations in the RXB and CRB, or, provide technical justification for why a 7P vs 9P comparison is sufficient and acceptable. Guidance in DSRS Section 3.7.2 allows the use of reduced-size models in comparing the solutions of the subtraction or modified subtraction method (SM/MSM) with those of the DM to gain insight into the adequacy of SM/MSM.

NuScale Response:

Control Building Comparisons between the direct method (DM) and extended subtraction method (ESM) have been performed for the control building (CRB) and the reactor building (RXB). In-structure response spectra (ISRS) and spectral acceleration transfer functions have been generated from both methods and compared. Please see the ISRS and transfer functions plots provided with this response.

NuScale Nonproprietary

The ISRS calculated by the CRB 7P model are very close to those calculated by the DM model.

There are some increases found in several ISRS. A direct comparison with the DCA ISRS cannot be provided due to differences in the structural damping values used in the CRB ISRS generation model (4% structural damping) and the CRB design model (7% structural damping).

However, the ISRS generated at 7% structural damping for 7P and DM produced results that are within 15% of each other. Most corresponding values from each model are the same.

The transfer function shapes calculated by the CRB 7P model are, with the exception of a few peak values, nearly identical to those calculated by DM. No spurious peaks are found in the transfer functions.

Reactor Building To use the direct method for the SASSI SSI analysis of the full RXB model, the number of required interaction nodes (28,830) exceeds the SASSI2010 program limit of 20,000. Therefore, a half model was used to obtain the results by the DM.

The ISRS calculated by the RXB 7P model are also within 15% of those calculated by the DM model. Similar to the CRB, the transfer function shapes are nearly identical between 7P and DM, except at a few peak values. At some limited locations in the model, large differences are observed at specific frequencies, which do not affect the results.

No spurious peaks are introduced in most of the RXB transfer functions. Spurious spikes are seen in some transfer functions for both 7P and DM, namely, Figures 81, 84, 91, 108, 111, and 118 of this response, but these do not affect the RXB ISRS. Oftentimes, adding a frequency point or shifting the frequency close to a spike location eliminates the spurious spike.

NuScale Nonproprietary

Table 1: Control Building Locations for ISRS Comparison X Coord Y Coord Z Coord Location Node (East) (North) (Vert) Description No. No.

(in) (in) (in)

Northwest Corner at Top of Basemat 1 32345 4500 700 405 (El 50'-0")

Slab between Grid Lines CB-D and 2 34380 4693 -491.5 570 CB-E at El. 63'-3" Slab between Grid Lines CB-A and 3 38298 4809.67 284 1020 CB-B (Technical Support Center) at El. 100'-0" 4 39105 4500 700 1260 Northwest Corner at El. 120'-0" Northwest Corner of Roof at El.

5 39715 4500 700 1518 140'-0" Figure 1: CRB - EW (X) ISRS, Node 32345, NW Corner at El 50'-0", Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 2: CRB - NS (Y) ISRS, Node 32345, NW Corner at El 50'-0", Average of ISRS due to 5 CSDRS Inputs Figure 3: CRB - Vertical (Z) ISRS, Node 32345, NW Corner at El 50'-0",

Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 4: CRB - EW (X) ISRS, Node 34380, Slab between Grid Lines CB-D and CB-E at El. 63', Average of ISRS due to 5 CSDRS Inputs Figure 5: CRB - NS (Y) ISRS, Node 34380, Slab between Grid Lines CB-D and CB-E at El. 63', Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 6: CRB - Vertical (Z) ISRS, Node 34380, Slab between Grid Lines CB-D and CB-E at El. 63', Average of ISRS due to 5 CSDRS Inputs Figure 7: CRB - EW (X) ISRS, Node 38298, Slab between Grid Lines CB-A and CB-B (Technical Support Center) at El. 100'-0", Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 8: CRB - NS (Y) ISRS, Node 38298, Slab between Grid Lines CB-A and CB-B (Technical Support Center) at El. 100'-0", Average of ISRS due to 5 CSDRS Inputs Figure 9: CRB - Vertical (Z) ISRS, Node 38298, Slab between Grid Lines CB-A and CB-B (Technical Support Center) at El. 100'-0", Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 10: CRB - EW (X) ISRS, Node 39105, NW Corner at El. 120'-0", Average of ISRS due to 5 CSDRS Inputs Figure 11: CRB - NS (Y) ISRS, Node 39105, NW Corner at El. 120'-0", Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 12: CRB - Vertical (Z) ISRS, Node 39105, NW Corner at El. 120'-0",

Average of ISRS due to 5 CSDRS Inputs Figure 13: CRB - EW (X) ISRS, Node 39715, NW Corner of Roof at El. 140'-0",

Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 14: CRB - NS (Y) ISRS, Node 39715, NW Corner of Roof at El. 140'-0",

Average of ISRS due to 5 CSDRS Inputs Figure 15: CRB - Vertical (Z) ISRS, Node 39715, NW Corner of Roof at El. 140' 0", Average of ISRS due to 5 CSDRS Inputs NuScale Nonproprietary

Figure 16: Cracked CRB Transfer Function Amplitudes, X-TF at Node 32345, Northwest Corner at El 50'-0" for Soil Type 7 NuScale Nonproprietary

Figure 17: Cracked CRB Transfer Function Amplitudes, Y-TF at Node 32345, Northwest Corner at El 50'-0" for Soil Type 7 NuScale Nonproprietary

Figure 18: Cracked CRB Transfer Function Amplitudes, Z-TF at Node 32345, Northwest Corner at El 50'-0" for Soil Type 7 NuScale Nonproprietary

Figure 19: Cracked CRB Transfer Function Amplitudes, X-TF at Node 34380, Slab between Grid Lines CB-D and CB-E at El. 63' for Soil Type 7 NuScale Nonproprietary

Figure 20: Cracked CRB Transfer Function Amplitudes, Y-TF at Node 34380, Slab between Grid Lines CB-D and CB-E at El. 63 for Soil Type 7.

NuScale Nonproprietary

Figure 21: Cracked CRB Transfer Function Amplitudes, Z-TF at Node 34380, Slab between Grid Lines CB-D and CB-E at El. 63 for Soil Type 7 NuScale Nonproprietary

Figure 22: Cracked CRB Transfer Function Amplitudes, X-TF at Node 38298, Slab between Grid Lines CB-A and CB-B (Technical Support Center) at El. 100'-0" for Soil Type 7 NuScale Nonproprietary

Figure 23: Cracked CRB Transfer Function Amplitudes, Y-TF at Node 38298, Slab between Grid Lines CB-A and CB-B (Technical Support Center) at El. 100'-0" for Soil Type 7 NuScale Nonproprietary

Figure 24: Cracked CRB Transfer Function Amplitudes, Z-TF at Node 38298, Slab between Grid Lines CB-A and CB-B (Technical Support Center) at El. 100'-0" for Soil Type 7 NuScale Nonproprietary

Figure 25: Cracked CRB Transfer Function Amplitudes, X-TF at Node 39105, Northwest Corner at El. 120'-0" for Soil Type 7 NuScale Nonproprietary

Figure 26: Cracked CRB Transfer Function Amplitudes, Y-TF at Node 39105, Northwest Corner at El. 120'-0" for Soil Type 7 NuScale Nonproprietary

Figure 27: Cracked CRB Transfer Function Amplitudes, Z-TF at Node 39105, Northwest Corner at El. 120'-0" for Soil Type 7 NuScale Nonproprietary

Figure 28: Cracked CRB Transfer Function Amplitudes, X-TF at Node 39715, Northwest Corner of Roof at El. 140'-0" for Soil Type 7 NuScale Nonproprietary

Figure 29: Cracked CRB Transfer Function Amplitudes, Y-TF at Node 39715, Northwest Corner of Roof at El. 140'-0" for Soil Type 7 NuScale Nonproprietary

Figure 30: Cracked CRB Transfer Function Amplitudes, Z-TF at Node 39715, Northwest Corner of Roof at El. 140'-0" for Soil Type 7 NuScale Nonproprietary

Table 2: Reactor Building Selected Locations for ISRS and Transfer Function Comparison Node X (East) Y (North) Z (Vert)

Description No. (in) (in) (in)

Top of Basemat within Grid Lines A, B, 4, 4831 2093.25 621 120 5

5642 4092 873 120 Northeast Corner on Top of Basemat Top of Basemat within Grid Lines B, C, 2, 5846 925 279 132 3

6145 2609.5 305.5 132 RXM 3 Floor Node under Module East Dry Dock Wall at El. 50 11329 1191 453 420 Northeast Corner North Wall between Grid Lines 2 and 3 at 13978 723 873 570 El. 61-12 North Wall between Grid Lines 4 and 5 at 14328 2314.5 873 570 El. 61-12 673.73 16257 16271 1918.5 2019.5 305.5 406.5 673.73 RXM 1 Lug Support Locations 16287 2120.5 305.5 673.73 673.73 16621 16635 3408.5 3509.5 305.5 406.5 673.73 RXM 6 Lug Support Locations 16651 3610.5 305.5 673.73 North Pool Wall between Grid Lines RX-3 17372 1447 453 720 and RX4 at El. 75-0 Mid-Span of North Slab between Grid 23517 2314.5 621 1020 Lines RX-4 and RX-5 at El 100-0 North Pool Wall at Grid Line RX-5 at El 26084 2757 453 1320 125-0 26345 3672 453 1320 Northeast Corner of Bio Shield Crane Rail Slab at Grid Line RX-4 at El.

27649 1872 453 1548 145-6 Northwest Corner on Top of North 29098 0 873 1824 Exterior Wall 30350 2019.5 0 1980 Center of Roof NuScale Nonproprietary

Figure 31: RXB - East-West (X) ISRS, Node 4831, Top of Basemat within Grid Lines A, B, 4, 5, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 32: RXB - North-South (Y) ISRS, Node 4831, Top of Basemat within Grid Lines A, B, 4, 5, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 33: RXB - Vertical (Z) ISRS, Node 4831, Top of Basemat within Grid Lines A, B, 4, 5, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 34: Cracked RXB East-West (X) ISRS at Node 5642, Northeast Corner on Top of Basemat due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 35: Cracked RXB North-South (Y) ISRS at Node 5642, Northeast Corner on Top of Basemat due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 36: Cracked RXB Vertical (Z) ISRS at Node 5642, Northeast Corner on Top of Basemat due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 37: RXB - East-West (X) ISRS, Node 5846, Top of Basemat within Grid Lines B, C, 2, 3, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 38: RXB - North-South (Y) ISRS, Node 5846, Top of Basemat within Grid Lines B, C, 2, 3, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 39: RXB - Vertical (Z) ISRS, Node 5846, Top of Basemat within Grid Lines B, C, 2, 3, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 40: Cracked RXB East-West (X) ISRS at Node 6145, RXM 3 Floor Node under Module due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 41: Cracked RXB North-South (Y) ISRS at Node 6145, RXM 3 Floor Node under Module due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 42: Cracked RXB Vertical (Z) ISRS at Node 6145, RXM 3 Floor Node under Module due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 43: Cracked RXB East-West (X) ISRS at Node 11329, East Dry Dock Wall at El. 50-0, Northeast Corner due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 44: Cracked RXB North-South (Y) ISRS at Node 11329, East Dry Dock Wall at El. 50-0, Northeast Corner due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 45: Cracked RXB Vertical (Z) ISRS at Node 11329, East Dry Dock Wall at El. 50-0, Northeast Corner due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 46: RXB - East-West (X) ISRS, Node 13978, North Wall between Grid Lines 2 and 3 at El. 61-12, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 47: RXB - North-South (Y) ISRS, Node 13978, North Wall between Grid Lines 2 and 3 at El. 61-12, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 48: RXB - Vertical (Z) ISRS, Node 13978, North Wall between Grid Lines 2 and 3 at El. 61-12, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 49: RXB - East-West (X) ISRS, Node 14328, North Wall between Grid Lines 4 and 5 at El. 61-12, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 50: RXB - North-South (Y) ISRS, Node 14328, North Wall between Grid Lines 4 and 5 at El. 61-12, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 51: RXB - Vertical (Z) ISRS, Node 14328, North Wall between Grid Lines 4 and 5 at El. 61-12, due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 52: Cracked RXB North-South (Y) ISRS, Node 16257, RXM 1 at West Lug Support Location due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 53: Cracked RXB East-West (X) ISRS, Node 16271, RXM 1 at North Lug Support Location due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 54: Cracked RXB North-South (Y) ISRS, Node 16287, RXM 1 at East Lug Support Location due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 55: Cracked RXB North-South (Y) ISRS, Node 16621, RXM 6 at West Lug Support Location due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 56: Cracked RXB East-West (X) ISRS, Node 16635, RXM 6 at North Lug Support Location due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 57: Cracked RXB North-South (Y) ISRS, Node 16651, RXM 6 at East Lug Support Location due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 58: Cracked RXB East-West (X) ISRS at Node 17372, North Pool Wall between Grid Lines RX-3 and RX4 at El. 75-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 59: Cracked RXB North-South (Y) ISRS at Node 17372, North Pool Wall between Grid Lines RX-3 and RX4 at El. 75-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 60: Cracked RXB Vertical (Z) ISRS at Node 17372, North Pool Wall between Grid Lines RX-3 and RX4 at El. 75-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 61: Cracked RXB East-West (X) ISRS at Node 23517, Mid Span of North Slab between Grid Lines RX-4 and RX-5 at El 100-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 62: Cracked RXB North-South (Y) ISRS at Node 23517, Mid-Span of North Slab between Grid Lines RX-4 and RX-5 at El 100-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 63: Cracked RXB Vertical (Z) ISRS at Node 23517, Mid-Span of North Slab between Grid Lines RX-4 and RX-5 at El 100-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 64: Cracked RXB East-West (X) ISRS at Node 26084, North Pool Wall at Grid Line RX-5 at El 125-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 65: Cracked RXB North-South (Y) ISRS at Node 26084, North Pool Wall at Grid Line RX-5 at El 125-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 66: Cracked RXB Vertical (Z) ISRS at Node 26084, North Pool Wall at Grid Line RX-5 at El 125-0 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 67: Cracked RXB East-West (X) ISRS at Node 26345, Northeast Corner of Bioshield due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 68: Cracked RXB North-South (Y) ISRS at Node 26345, Northeast Corner of Bioshield due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 69: Cracked RXB Vertical (Z) ISRS at Node 26345, Northeast Corner of Bioshield due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 70: Cracked RXB East-West (X) ISRS at Node 27649, Crane Rail Slab at Grid Line RX-4 at El. 145-6 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 71: Cracked RXB North-South (Y) ISRS at Node 27649, Crane Rail Slab at Grid Line RX-4 at El. 145-6 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 72: Cracked RXB Vertical (Z) ISRS at Node 27649, Crane Rail Slab at Grid Line RX-4 at El. 145-6 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 73: Cracked RXB East-West (X) ISRS at Node 29098, Northwest Corner of Exterior Wall at Roof Level due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 74: Cracked RXB North-South (Y) ISRS at Node 29098, Northwest Corner of Exterior Wall at Roof Level due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 75: Cracked RXB Vertical (Z) ISRS at Node 29098, Northwest Corner of Exterior Wall at Roof Level due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 76: Cracked RXB East-West (X) ISRS at Node 30350, Roof Slab between Grid Lines RX-4 and RX-5 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 77: Cracked RXB North-South (Y) ISRS at Node 30350, Roof Slab between Grid Lines RX-4 and RX-5 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 78: Cracked RXB Vertical (Z) ISRS at Node 30350, Roof Slab between Grid Lines RX-4 and RX-5 due to Five CSDRS Inputs for Soil Type 7 NuScale Nonproprietary

Figure 79: Cracked RXB Transfer Functions in X-Direction at Node 4831, Top of Basemat within Grid Lines A, B, 4, 5, for Soil Type 7 NuScale Nonproprietary

Figure 80: Cracked RXB Transfer Functions in Y-Direction at Node 4831, Top of Basemat within Grid Lines A, B, 4, 5, for Soil Type 7 NuScale Nonproprietary

Figure 81: Cracked RXB Transfer Functions in Z-Direction at Node 4831, Top of Basemat within Grid Lines A, B, 4, 5, for Soil Type 7 NuScale Nonproprietary

Figure 82: Cracked RXB Transfer Functions in X-Direction at Node 5642, Northeast Corner on Top of Basemat, for Soil Type 7 NuScale Nonproprietary

Figure 83: Cracked RXB Transfer Functions in Y-Direction at Node 5642, Northeast Corner on Top of Basemat, for Soil Type 7 NuScale Nonproprietary

Figure 84: Cracked RXB Transfer Functions in Z-Direction at Node 5642, Northeast Corner on Top of Basemat, for Soil Type 7 NuScale Nonproprietary

Figure 85: Cracked RXB Transfer Functions in X-Direction at Node 5846, Top of Basemat within Grid Lines B, C, 2, 3, for Soil Type 7 NuScale Nonproprietary

Figure 86: Cracked RXB Transfer Functions in Y-Direction at Node 5846, Top of Basemat within Grid Lines B, C, 2, 3, for Soil Type 7 NuScale Nonproprietary

Figure 87: Cracked RXB Transfer Functions in Z-Direction at Node 5846, Top of Basemat within Grid Lines B, C, 2, 3, for Soil Type 7 NuScale Nonproprietary

Figure 88: Cracked RXB Transfer Functions in X-Direction at Node 6145, RXM 3 Floor Node under Module, for Soil Type 7 NuScale Nonproprietary

Figure 89: Cracked RXB Transfer Functions in Y-Direction at Node 6145, RXM 3 Floor Node under Module, for Soil Type 7 NuScale Nonproprietary

Figure 90: Cracked RXB Transfer Functions in Z-Direction at Node 6145, RXM 3 Floor Node under Module, for Soil Type 7 NuScale Nonproprietary

Figure 91: Cracked RXB Transfer Functions in X-Direction at Node 11329, East Dry Dock Wall at El. 50 Northeast Corner, for Soil Type 7 NuScale Nonproprietary

Figure 92: Cracked RXB Transfer Functions in Y-Direction at Node 11329, East Dry Dock Wall at El. 50 Northeast Corner, for Soil Type 7 NuScale Nonproprietary

Figure 93: Cracked RXB Transfer Functions in Z-Direction at Node 11329, East Dry Dock Wall at El. 50-0 Northeast Corner, for Soil Type 7 NuScale Nonproprietary

Figure 94: Cracked RXB Transfer Functions in X-Direction at Node 13978, North Wall between Grid Lines 2 and 3 at El. 61-12, for Soil Type 7 NuScale Nonproprietary

Figure 95: Cracked RXB Transfer Functions in Y-Direction at Node 13978, North Wall between Grid Lines 2 and 3 at El. 61-12, for Soil Type 7 NuScale Nonproprietary

Figure 96: Cracked RXB Transfer Functions in Z-Direction at Node 13978, North Wall between Grid Lines 2 and 3 at El. 61-12, for Soil Type 7 NuScale Nonproprietary

Figure 97: Cracked RXB Transfer Functions in X-Direction at Node 14328, North Wall between Grid Lines 4 and 5 at El. 61-12, for Soil Type 7 NuScale Nonproprietary

Figure 98: Cracked RXB Transfer Functions in Y-Direction at Node 14328, North Wall between Grid Lines 4 and 5 at El. 61-12, for Soil Type 7 NuScale Nonproprietary

Figure 99: Cracked RXB Transfer Functions in Z-Direction at Node 14328, North Wall between Grid Lines 4 and 5 at El. 61-12, for Soil Type 7 NuScale Nonproprietary

Figure 100: Cracked RXB Transfer Functions in Y-Direction at Node 16257, RXM 1 at West Lug Support Location, for Soil Type 7 NuScale Nonproprietary

Figure 101: Cracked RXB Transfer Functions in X-Direction at Node 16271, RXM 1 at North Lug Support Location, for Soil Type 7 NuScale Nonproprietary

Figure 102: Cracked RXB Transfer Functions in Y-Direction at Node 16287, RXM 1 at East Lug Support Location, for Soil Type 7 NuScale Nonproprietary

Figure 103: Cracked RXB Transfer Functions in Y-Direction at Node 16621, RXM 6 at West Lug Support Location, for Soil Type 7 NuScale Nonproprietary

Figure 104: Cracked RXB Transfer Functions in X-Direction at Node 16635, RXM 6 at North Lug Support Location, for Soil Type 7 NuScale Nonproprietary

Figure 105: Cracked RXB Transfer Functions in Y-Direction at Node 16651, RXM 6 at East Lug Support Location, for Soil Type 7 NuScale Nonproprietary

Figure 106: Cracked RXB Transfer Functions in X-Direction at Node 17372, North Pool Wall between Grid Lines RX-3 and RX4 at El. 75-0, for Soil Type 7 NuScale Nonproprietary

Figure 107: Cracked RXB Transfer Functions in Y-Direction at Node 17372, North Pool Wall between Grid Lines RX-3 and RX4 at El. 75-0, for Soil Type 7 NuScale Nonproprietary

Figure 108: Cracked RXB Transfer Functions in Z-Direction at Node 17372, North Pool Wall between Grid Lines RX-3 and RX4 at El. 75-0, for Soil Type 7 NuScale Nonproprietary

Figure 109: Cracked RXB Transfer Functions in X-Direction at Node 23517, Mid Span of North Slab between Grid Lines RX-4 and RX-5 at El 100-0, for Soil Type 7 NuScale Nonproprietary

Figure 110: Cracked RXB Transfer Functions in Y-Direction at Node 23517, Mid Span of North Slab between Grid Lines RX-4 and RX-5 at El 100-0, for Soil Type 7 NuScale Nonproprietary

Figure 111: Cracked RXB Transfer Functions in Z-Direction at Node 23517, Mid Span of North Slab between Grid Lines RX-4 and RX-5 at El 100-0, for Soil Type 7 NuScale Nonproprietary

Figure 112: Cracked RXB Transfer Functions in X-Direction at Node 26084, North Pool Wall at Grid Line RX-5 at El 125-0, for Soil Type 7 NuScale Nonproprietary

Figure 113: Cracked RXB Transfer Functions in Y-Direction at Node 26084, North Pool Wall at Grid Line RX-5 at El 125-0, for Soil Type 7.

NuScale Nonproprietary

Figure 114: Cracked RXB Transfer Functions in Z-Direction at Node 26084, North Pool Wall at Grid Line RX-5 at El 125-0, for Soil Type 7 NuScale Nonproprietary

Figure 115: Cracked RXB Transfer Functions in X-Direction at Node 26345, Northeast Corner of Bio Shield, for Soil Type 7 NuScale Nonproprietary

Figure 116: Cracked RXB Transfer Functions in Y-Direction at Node 26345, Northeast Corner of Bio Shield, for Soil Type 7 NuScale Nonproprietary

Figure 117: Cracked RXB Transfer Functions in Z-Direction at Node 26345, Northeast Corner of Bio Shield, for Soil Type 7 NuScale Nonproprietary

Figure 118: Cracked RXB Transfer Functions in X-Direction at Node 27649, Crane Rail Slab at Grid Line RX-4 at El. 145-6, for Soil Type 7 NuScale Nonproprietary

Figure 119: Cracked RXB Transfer Functions in Y-Direction at Node 27649, Crane Rail Slab at Grid Line RX-4 at El. 145-6, for Soil Type 7 NuScale Nonproprietary

Figure 120: Cracked RXB Transfer Functions in Z-Direction at Node 27649, Crane Rail Slab at Grid Line RX-4 at El. 145-6, for Soil Type 7 NuScale Nonproprietary

Figure 121: Cracked RXB Transfer Functions in X-Direction at Node 29098, Northwest Corner of Exterior Wall at Roof Level, for Soil Type 7 Impact on DCA:

FSAR Tier 2, Section 3.7.2.1 has been revised as described in the response above and as shown in the markup provided in this response.

NuScale Nonproprietary

NuScale Final Safety Analysis Report Seismic Design SASSI2010 are created from the SAP2000 models. The structural analyses are performed using SAP2000 as described in Section 3.8.4.

3.7.2.1.1.2 ANSYS A finite element structural analysis model of the RXB was developed using ANSYS to determine the hydrodynamic pressures on the reactor pool walls and foundation from a Fluid-Structure Interaction analysis. This was necessary since neither the SAP2000 nor SASSI2010 computer programs have an explicit fluid element formulation to accurately calculate the hydrodynamic effects due to all three directional components of earthquake input motions. The ANSYS model of the RXB is based on the SAP2000 model. The use of ANSYS to develop correction factors is described in Section 3.7.2.1.2.4. The addition of the water mass that is modeled with fluid finite elements is meshed accordingly to match the existing meshing of the RXB and NPM finite elements.

3.7.2.1.1.3 SASSI2010 For the seismic analyses, the finite element models of the RXB and CRB developed using the SAP2000 computer program are converted to SASSI2010 models with identical input data of the geometry, material properties, element connectivities, and boundary conditions. The SASSI2010 models are used to perform soil structure interaction (SSI) analysis. In addition to individual models for the RXB and CRB, a large-scale finite element model was constructed that includes both buildings and the Seismic Category II RWB. This model is referred to as the triple building model and is used to examine structure-soil-structure interactions (SSSI). SASSI2010 can handle models in excess of 100,000 nodes with approximately 20,000 interaction nodes. SASSI2010 analyzes the finite element models using the Complex Frequency Response Analysis Method. To perform the analysis, the time history of input ground motion is transformed to the frequency domain by fast Fourier transform. The seismic responses calculated in the frequency domain are then transformed back to the time domain by inverse fast Fourier transform.

Model Dimensions In the vertical direction, the finite element model of each building extends to the bottom of the foundation. In performing the analyses, soil layers to 300 feet below grade level are included. Below 300 feet, the parameters (shear wave velocity, density and poisson's ratio) of the four generic soil profiles described in Section 3.7.1.3.1 remain constant. Therefore the variable depth method of SASSI2010 is used to add soil layers in order to simulate a semi-infinite halfspace at the bottom of the soil layer base.

In the horizontal direction, the finite element model of each building is extended out 25 feet around the entire perimeter of the building, to model the backfill soil. Beyond the 25 foot backfill soil region, SASSI2010 extends the parameters of the in-situ or free-field soil (i.e., Soil Type 7, 8, 9 or 11) as a semi-infinite elastic half space.

Tier 2 3.7-107 Draft Revision 2

NuScale Final Safety Analysis Report Seismic Design Free-field soil is included in the triple building model. This model has an overall length of 2005.5 feet, a width of 768.5 feet and a depth of 360 feet. For dynamic analysis of the triple building model using SASSI2010, the free field boundaries extends to elastic halfspace implicitly. This is accomplished by SASSI2010 itself.

For static analyses, the SAP2000 models explicitly adds the free field soil beyond the backfill soil boundaries. The triple building model is used to determine the static response of the three buildings including the effects of differential displacements. The vertical depth is deeper than the SSI model. At this depth, the vertical displacement become insignificant due to soil stiffness.

The horizontal boundaries are also extended a sufficient distance to have insignificant change in the static response of the buildings.

Cut-off Frequency For the analysis of Soil Types 7, 8 and 11 with the CSDRS the cut-off frequency was established at 52 Hz. This is higher than the wave passing frequency of the soft soil profile (Soil Type 11) but less than the passing frequency of the other two soils (see Table 3.7.1-20). The low wave passing frequency of the soft soil is not a concern. Although high frequency content is not transmitted into or through the building for Soil Type 11, it is transmitted by the Soil Type 7 and Soil Type 8 profiles and by the Soil Type 7 and Soil Type 9 profiles evaluated with the CSDRS-HF. The buildings and associated SSC are designed to remain operable following any of these earthquake/soil combinations, therefore high frequency content is addressed in the design of the site independent Seismic Category I structures by the use of soil profiles that are stiffer than Soil Type 11.

For the analysis with the rock profiles (Soil Type 7 and 9) and the CSDRS-HF, the cut-off frequency was established at 72 Hz. The CSDRS-HF at a cut-off frequency of 72 Hz is less than the peak ground acceleration frequency, which occurs at 100 Hz. Using a 72 Hz cut off frequency is acceptable because it is above the frequency where maximum acceleration occurs (25 Hz horizontal and 50 Hz vertical).

RAI 03.07.02-2S1, RAI 03.07.02-3S1 The building models have element sizes that are similar to the 6.25 feet layers that were used to determine the wave passage frequency of the soil. There are instances where development of the model required individual elements to have a dimension as large as 12 feet in the RXB and as large as 20 feet in the CRB. However, the typical element size is approximately 6 feet. Therefore the wave passage frequencies of both buildings is above the cut-off frequencies used for the analysis.

RAI 03.07.02-2S1, RAI 03.07.02-3S1 In the CRB model, the elements with large dimensions or aspect ratios are nonstructural areas or membrane elements used for the purpose of applying wind loads to the steel beams and columns of the steel frame structure above elevation 120 ft. The 20 ft elements are located on the north and south walls whereas the 12 ft elements are located on the east and west walls above elevation 120 ft. Similar surface area loads are applied to the CRB roof to evenly Tier 2 3.7-108 Draft Revision 2

NuScale Final Safety Analysis Report Seismic Design distribute applied loads. The loads are applied as surface pressure on these areas and then transferred to the structural elements through the shared nodes. These coarse elements are not present in the seismic analyses and will not, therefore, affect the seismic demand results. In the RXB model, there are 24 elements with approximate dimensions of 12 ft x 6 ft at the pool floor. These are transition solid elements beginning in the top layer of solid elements used to model the basemat. The mesh transitions into the uniform soil mesh, matching the soil interaction nodes at the base elevation of the basemat, with an average element size of approximately 6.25 ft. The single layer of coarse basemat transition elements have minimal or no effect on the seismic analysis results.

Modeling Approach Analysis Methods There are several modeling approaches that can be used for modeling the excavated soil in the SSI analysis: the direct method (DM), the subtraction method (SM), the modified subtraction method (MSM), and the extended subtraction method (ESM). Each method has different computational demands. A brief discussion of the different methods follows:

The direct method partitions the soil structure system between the building and the excavated soils. It requires only the free-field motions and the free-field soil impedances to compute the seismic excitations on the foundation of structure. The soils to be excavated are retained with the foundation.

Therefore, interaction between the structure and the foundation is calculated at all excavated soil nodes. In the analysis, the DM treats all translational degrees of freedoms of the excavated soil as SSI interaction nodes. This corresponds to a theoretical exact SSI model for the excavated soil dynamics.

DM analysis is computationally intensive and cannot be used with the large detailed models created for the NuScale buildings.

To reduce computational time, a simplified method, called the subtraction method was developed. The SM assumes only the nodes at interface of the excavated soil volume and surrounding free field soils as interaction nodes. In mathematical implementation, only those specified interaction nodes are described by correct equations of motion. The seismic load component and free field soil impedance are neglected for the non-interaction nodes within the excavated soil volume. Therefore the excavated soil motion can produce spurious vibration modes. This simplification results in anomalies in the transfer functions, usually seen as spurious spikes for soft free field soils at relative high frequency ranges. The SM approach for the excavated soil can be visualized as the five planes that represent the sides and bottom of the "box" that models the excavated volume.

The modified subtraction method includes the nodes at the ground surface of the excavated soil as interaction nodes. The MSM approach for the excavated soil can be visualized as the six planes that represent the sides, bottom, and top of the "box" that models the excavated volume. The inclusion of the ground Tier 2 3.7-109 Draft Revision 2

NuScale Final Safety Analysis Report Seismic Design surface nodes as interaction nodes provides significantly improved boundary conditions and improves the excavated soil response accuracy.

Within SASSI2010, a further enhancement of the MSM is available; this methodology is called the extended subtraction method. In the ESM intermediate planes may be defined within the excavated volume. The addition of intermediate planes reduces the amount of interpolation that must perform within the excavated volume and further improves the accuracy of the excavated soil response. As additional planes are added, the ESM approaches the DM in both accuracy and computational time. The NuScale buildings are evaluated with an ESM model.

Benchmarking For the analysis of the Seismic Category I RXB and CRB with the extended subtraction method, a single intermediate plane was used. This approach is designated as 7P to reflect the four sides of the excavated volume, and the top, bottom and middle horizontal planes. Benchmarking of the 7P approach was performed by comparing the results to a nine plane model. In the 9P model, additional planes are added above and below the center plane, halving the vertical distance used for interpolation of results. This benchmarking was performed to confirm that the results of the 7P and 9P model were similar and further confirms that the ESM approaches the DM in accuracy.

The comparison of 7P to 9P is accomplished by looking at the in-structure response spectra (ISRS) at three locations in the reactor building:

  • The northeast corner on top of the basemat as shown in Figure 3.7.2-5.
  • The NPM1 East bay wall at the lug support as shown in Figure 3.7.2-6.
  • The center of the roof slab as shown in Figure 3.7.2-7.

In addition, bending moments at the center of the roof are compared to investigate if the moment responses calculated by the analysis using the 7P interaction nodes are close to those from the analysis using the 9P interaction nodes. These comparisons are performed with the CSDRS and all five CSDRS compatible time histories for Soil Type 11 (soft soil) and Soil Type 7 (rock) using cracked concrete and 4 percent damping.

The 7P versus 9P ISRS comparisons for the Capitola time histories are provided in Figure 3.7.2-8, Figure 3.7.2-9, and Figure 3.7.2-10. The corresponding results for the other time histories are similar. As can be seen in these figures, there is very close correlation between the 7P and 9P models, with the larger variation occurring in the soft soil. This level of agreement justifies using a 7P versus a 9P model and, because the results are similar, demonstrates the acceptability of using the extended subtraction method as an alternative to the direct method.

While the results are similar, they are not exact. This difference is not a concern because of the methodology used in developing accelerations and forces in the structures. Each building is evaluated with several soil types and two Tier 2 3.7-110 Draft Revision 2

NuScale Final Safety Analysis Report Seismic Design stiffnesses. In addition, for the CSDRS, five separate time histories are evaluated, and the results are averaged.

Ensuring Accurate Results Both the MSM and ESM reduce the potential for the spurious results produced by the subtraction method. The use of intermediate planes in ESM method make it even less likely than the MSM to produce inaccurate results. When they occur, these errors can be seen in the transfer functions. However due to the size and complexity of these models it is not practical to review transfer functions at all the nodes in the models. Therefore errors are found by questioning unexpected results. During those investigations, transfer functions may be plotted and reviewed. However, no indication of the anomalies associated with using the subtraction method have been seen.

The design process for the site independent RXB and CRB is to consider multiple soil types, two building stiffnesses (for cracked and uncracked concrete), and multiple time histories. This large data set makes it more likely to notice an anomaly since it is unlikely to occur in all the different combinations used as input.

For the CSDRS, the results from five time histories were averaged for each soil type to produce a single set of results for that soil type. These results are then combined and the maximums are used (i.e., the results are enveloped.). For the determination of forces, moments and shears, the results from the CSDRS-HF analysis are also included and thus bounded by the design. Averaging reduces the potential for a spurious peak to drive an overly conservative design.

Bounding the two stiffness and various soil combinations ensures that a spurious low will not result in an inadequate design.

Two other aspects of the design process also ensure the acceptability of the structures.

  • Standardized design of walls. The thicknesses and internal steel reinforcement of the primary wall are generally consistent throughout each building. Areas where forces are lower are not optimized for the local load.
  • Site-independent design. A site specific analysis is performed to confirm that the design is adequate for that specific location. A different SSE and soil column will not produce anomalies at the same locations. A spurious low would not result in a change to the standardized design.

RAI 03.07.02-4 7P vs Direct Method Comparison RAI 03.07.02-4 Tier 2 3.7-111 Draft Revision 2

NuScale Final Safety Analysis Report Seismic Design Comparisons between the DM and 7P ESM have been performed for the CRB and RXB. ISRS and transfer functions have been generated from both methods and compared.

RAI 03.07.02-4 The ISRS calculated by the CRB 7P model are very close to those calculated by the DM model. There are some increases found in several ISRS. A direct comparison with the DCA ISRS cannot be provided due to differences in the structural damping values used in the CRB ISRS generation model (4%

structural damping) and the CRB design model (7% structural damping).

RAI 03.07.02-4 However, the ISRS generated at 7% structural damping for 7P and DM produced results that are within 15% of each other. Most corresponding values from each model are the same.

RAI 03.07.02-4 The transfer function shapes calculated by the CRB 7P model are nearly identical to those calculated by DM, with the exception of a few peak values.

No spurious peaks are found in the transfer functions.

RAI 03.07.02-4 To use the direct method for the SASSI SSI analysis of the full RXB model, the number of required interaction nodes (28,830) exceeds the SASSI2010 program limit of 20,000. Therefore, a half model was used to obtain the results by the DM.

RAI 03.07.02-4 The ISRS calculated by the RXB 7P model are also within 15% of those calculated by the DM model. Similar to the CRB, the transfer function shapes are nearly identical show excellent agreement between 7P and DM, except at a few peak values. At some limited locations in the model, large differences are observed at specific frequencies which do not affect the results.

RAI 03.07.02-4 No spurious peaks are introduced in most of the RXB transfer functions.

Spurious spikes are seen in some transfer functions for both 7P and DM, but do not affect the RXB ISRS. Oftentimes, adding a frequency point or shifting the frequency close to a spike location eliminates the spurious spike.

Cracked Model Stiffness For SASSI2010 analyses, the plate stiffnesses are only controlled by two input parameters. The two parameters are the Young's modulus and the plate thickness. It is not possible to reduce the bending stiffness by 50 percent for cracked concrete while preserving the axial stiffness at 100 percent for in-plane forces by modifying Young's modulus. A compromise approach is used by reducing the thickness by a factor equal to cubic root of 0.5, or 0.7937 to reduce Tier 2 3.7-112 Draft Revision 2

NuScale Final Safety Analysis Report Seismic Design the bending stiffness in half for the cracked concrete condition. In this approach, the uncracked axial stiffness is reduced by a factor of 0.7937.

Soil Separation A study was performed to investigate the effects of a gap forming between the RXB and the backfill soil during an earthquake.

The RXB was analyzed for Soil Type 7 with cracked concrete properties and 7 percent concrete material damping. Soil Type 7 was chosen because that is the case that produced the highest ISRS and forces and moments at the majority of the locations. Cracked concrete properties were chosen to be consistent with the use of 7 percent damping for the concrete material.

To model the soil separation, the Young's modulus of the backfill elements down to a depth of 25 (the top four layers of backfill elements) was decreased by a factor of 100.

Soil separation has negligible effect on the response of the structure. The primary point of comparison is at the NPM. The study showed that the maximum reaction force at the base of the NPMs decreased by approximately 5 percent, and the maximum reaction force at the NPM lug restraints decreased by more than 15 percent. In addition to examining the forces on the NPM, the in-structure response spectra were compared at the top of the basemat and the roof of the building. The ISRS virtually overlay each other, comparable in shape, and peak of response. Therefore, based upon the results of this study, modeling the structures as fully embedded is an acceptable design approach.

3.7.2.1.2 Finite Element Models RAI 03.07.02-1 Meshing of the area elements was done automatically using SAP2000 by defining a maximum element size in each direction. The aspect ratios were also kept as low as possible (closer to square shape), and internal sharp angles were avoided.

RAI 03.07.02-1 Meshing for both the RXB and CRB models were refined further, and it is shown that further refinement does not affect the structural response. The mesh refinement was done by dividing each side of the area elements into two, breaking each element to four elements. The structural responses compared include both local and global responses of the structure. The comparison shows that effects of further mesh refinement on the structural response is negligible. In addition to the modal analysis, to compare the natural frequencies and mass participation ratios, static analysis cases due to 1g loading in the x, y or z directions were used to make different comparisons. Soil elements' height were determined based on 1/5th of the wave length.

RAI 03.07.02-1, RAI 03.07.02-1S1 Tier 2 3.7-113 Draft Revision 2

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