ML24215A013

LLC, Response to Sdaa Audit Question Number A-3.4.2-4

ML24215A013
Person / Time
Site:	05200050
Issue date:	08/02/2024
From:	NuScale
To:	Office of Nuclear Reactor Regulation
Shared Package
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References
LO-169995
Download: ML24215A013 (1)

Text

Response to SDAA Audit Question Question Number: A-3.4.2-4 Receipt Date: 07/03/2023 Question:

COL Item 3.4-5 states that an applicant that references the NuScale Power Plant US460 standard design will confirm that nearby structures exposed to external flooding will not collapse and adversely affect the Reactor Building or Seismic Category I portion of the Control Building.

The RXB includes both Seismic Category I and II structures.

a.

Clarify whether the Reactor Building in COL Item 3.4-5 shall be changed into Seismic Category I portion of the RXB.

b.

Clarify whether the wording or in COL Item 3.4-5 shall be changed into and.

Response

Item A:

SDAA COL Item 3.4-5 is revised for clarification of the Seismic Category I portion of the RXB.

Item B:

COL Item 3.4-5 is revised for clarification to reflect the inclusion of Seismic Category I portions of both the Reactor Building and the Control Building. The language is incorporated into SDAA Section 3.4 as shown below :

An applicant that references the NuScale Power Plant US460 standard design will confirm that nearby structures exposed to external flooding will not collapse and adversely affect the Seismic Category I portions of the Reactor Building or Seismic Category I portion of the Control Building.

NuScale Nonproprietary NuScale Nonproprietary

NuScale Final Safety Analysis Report Interfaces with Standard Design NuScale US460 SDAA 1.8-3 Draft Revision 2 COL Item 3.4-2:

An applicant that references the NuScale Power Plant US460 standard design will develop the on-site program addressing the key points of flood mitigation. The key points to this program include the procedures for mitigating internal flooding events; the equipment list of structures, systems, and components subject to flood protection in each plant area; and providing assurance that the program reliably mitigates flooding to the identified structures, systems, and components.

3.4 COL Item 3.4-3:

An applicant that references the NuScale Power Plant US460 standard design will develop an inspection and maintenance program to ensure that each water-tight door, penetration seal, or other degradable measure remains capable of performing its intended function.

3.4 Audit Question A-3.4.2-10 COL Item 3.4-4:

An applicant that references the NuScale Power Plant US460 standard design will determine the extent of waterproofing and damp proofing needed for the underground portion of the Reactor Building, including the duct bank connection to the Reactor Building based on site-specific conditions. Additionally, the applicant will provide the specified design life for waterstops, waterproofing, damp proofing, and watertight seals.

If the design life is less than the operating life of the plant, the applicant will describe how continued protection will be ensured.

3.4 Audit Question A-3.4.2-4 COL Item 3.4-5:

An applicant that references the NuScale Power Plant US460 standard design will confirm that nearby structures exposed to external flooding will not collapse and adversely affect the Seismic Category I portions of the Reactor Building or Seismic Category I portion of the Control Building.

3.4 COL Item 3.5-1:

An applicant that references the NuScale Power Plant US460 standard design will demonstrate the site-specific turbine missile parameters are bounded by the standard design analysis, or provide a missile analysis using the site-specific turbine generator parameters to demonstrate that barriers adequately protect essential structures, systems, and components from turbine missiles. Parameters to verify are: limiting turbine missile spectrum (rotor and blade material properties); turbine rotor design, geometry and number of blades; final design of the Reactor Building exterior wall; and location of the turbines with respect to the Reactor Building and Control Building.

3.5 COL Item 3.5-2:

An applicant that references the NuScale Power Plant US460 standard design will confirm the design-basis automobile missile parameters for the reference plant of velocity and maximum altitude of impact will not be exceeded as a result of extreme wind conditions that may occur in the vicinity of the site.

3.5 Table 1.8-1: Combined License Information Items (Continued)

Item No.

Description of COL Information Item Section

NuScale Final Safety Analysis Report Water Level (Flood) Design NuScale US460 SDAA 3.4-5 Draft Revision 2 waterproofing, damp proofing, and watertight seals. If the design life is less than the operating life of the plant, the applicant will describe how continued protection will be ensured.

The design establishes a design-basis flood level (including wave action) of one foot below the plant grade elevation. Therefore, there are no dynamic flood loads on the RXB and CRB. The lateral hydrostatic pressures on the structures due to the design flood level, ground water, and soil pressure are factored into the structural design as static and dynamic loads discussed in Section 3.8.4.

3.4.2.2 Probable Maximum Precipitation The design uses bounding parameters for rain and snow. These site parameters are presented in Table 2.0-1.

The RXB and CRB roofs are designed to prevent buildup of standing water.

The RXB and CRB roofs, including the bounding rain and snow loads, are evaluated as part of the structural analysis described in Section 3.8.4.

3.4.2.3 Interaction of Non-Seismic Category I Structures with Seismic Category I Structures Section 3.7.2 describes how nearby structures are assessed, or analyzed if necessary, to ensure that there is no credible potential for interactions that could adversely affect the Seismic Category I portions of the RXB and Seismic Category I portions of the CRB.

Analysis shows the CRB is capable of withstanding effects of the probable maximum precipitation.

Audit Question A-3.4.2-4 COL Item 3.4-5:

An applicant that references the NuScale Power Plant US460 standard design will confirm that nearby structures exposed to external flooding will not collapse and adversely affect the Seismic Category I portions of the Reactor Building or Seismic Category I portion of the Control Building.