ML17317B555
| ML17317B555 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 11/13/2017 |
| From: | Rad Z NuScale |
| To: | Document Control Desk, Office of New Reactors |
| References | |
| RAIO-1117-57171 | |
| Download: ML17317B555 (11) | |
Text
RAIO-1117-57171 November 13, 2017 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.
222 (eRAI No. 9116) on the NuScale Design Certification Application
REFERENCE:
U.S. Nuclear Regulatory Commission, "Request for Additional Information No.
222 (eRAI No. 9116)," dated September 12, 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 Questions from NRC eRAI No. 9116:
09.02.07-4
09.02.07-5 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 Carrie Fosaaen at 541-452-7126 or at cfosaaen@nuscalepower.com.
Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A Anthony Markley, NRC, OWFN-8G9A : NuScale Response to NRC Request for Additional Information eRAI No. 9116 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com
NuScale Response to NRC Request for Additional Information eRAI No. 9116 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.: 9116 Date of RAI Issue: 09/12/2017 NRC Question No.: 09.02.07-4 10 CFR 52.47(c)(2) requires that a standard design certification of a nuclear power reactor
design that uses simplified, inherent, passive, or other innovative means to accomplish its
safety functions must provide an essentially complete nuclear power reactor design except for
site-specific elements such as the service water intake structure and the ultimate heat sink, and
must meet the requirements of 10 CFR 50.43(e).
FSAR Tier 2, Section 1.2 states that the scope of the certified design and site-specific design is
shown in Figure 1.2-2. FSAR Tier 2, Section 9.2.7 provides information regarding the design of
the site cooling water system (SCWS). The staff could not verify whether the entire SCWS,
including the structure, is within the scope of the design certification because it is not shown on
Figure 1.2-2, nor described in FSAR Tier 2, Section 1.2.1. In addition, FSAR Tier 2, Section
9.2.7.2.1 makes conclusions regarding missile generation from the cooling tower fan based on
location and site arrangement of the cooling tower.
The applicant is requested to provide in the FSAR a description of which portions of the SCWS
are part of the design certification and which are considered site-specific or conceptual design
information, and appropriately identify the site cooling water tower and pump structure in Figure
1.2-2.
NuScale Response:
The entire Site Cooling Water System (SCWS) is conceptual design information (CDI). The NuScale design requires a system to cool nonsafety-related equipment (described in Tier 2, Section 9.2.7); however, the COL applicant is responsible for final design. The SCWS is an asset-protection system. The NuScale SCWS does not provide essential cooling to safety-related SSCs and is not considered safety-related or important to safety as assumed by SRP 9.2.1.
FSAR Section 1.2.1 has been revised to list the SCWS as CDI. FSAR Figure 1.2-2 has been revised to show the proposed location of the SCWS pumps and cooling tower. In addition, NuScale Nonproprietary
FSAR Table 3.2-1 has been revised to show that the location for the SCWS components is various instead of yard. The location of the SCWS letdown line radiation monitor is still the yard.
Impact on DCA:
FSAR Section 1.2.1, Table 3.2-1, and Figure 1.2-2 have been revised as described in the response above and as shown in the markup provided in this response.
NuScale Nonproprietary
Response to Request for Additional Information Docket No.52-048 eRAI No.: 9116 Date of RAI Issue: 09/12/2017 NRC Question No.: 09.02.07-5 GDC 2 requires that structures, systems, and components (SSCs) important to safety be
designed to withstand the effects of postulated natural phenomena, such as earthquakes and
tornadoes without loss of the capability to perform their safety functions.
FSAR Tier 2, Section 9.2.7.1 states consistent with GDC 2, the site cooling water system (SCWS) complies with the requirements of Regulatory Guide 1.29, Position C.2, which
indicates that those portions of SSCs of which continued function is not required but of which
failure could reduce the functioning of safety-related SSCs (identified in Position C.1, items 1.a
through 1.q) to an unacceptable safety level or could result in incapacitating injury to occupants
of the control room should be designed and constructed so that the safe-shutdown earthquake
(SSE) would not cause such failure. Thus, FSAR Tier 2, Section 9.2.7.1 indicates that portions
of the SCWS could be assigned as seismic category II.
FSAR Tier 2, Section 9.2.7.3 states the SCWS is located sufficiently far from any Seismic
Category I or II structures, or safety-related components; in addition, FSAR Tier 2, Table 3.2-1
states the SCWS is located in the yard. These statements contradict the system design which,
in part, provides supply and return cooling water to reactor component cooling water system,
reactor pool cooling system, spent fuel pool cooling system. Also, FSAR Tier 2, Figure 9.2.7-1
illustrates the SCWS as providing cooling water to the Reactor Building.
In addition, FSAR Tier 2, Section 9.2.7.1 states the portions of the SCWS whose structural
failure could adversely affect the function of Seismic Category I structure, systems, and
components (SSC) are Seismic Category II. However, FSAR Tier 2, Table 3.2-1 indicates the
entire SCWS is seismic Category III. Because the SCWS diagram provided in Figure 9.2.7-1 is
not detailed enough to determine SCWS pipe routing and seismic classification, it is not clear to
the staff which portions of the SCWS are seismic Category II.
The applicant is requested to:
- a. Revise the information in FSAR Tier 2, Section 9.2.7.3, and FSAR Tier 2, Table 3.2-1 to ensure they accurately reflect the design of the SCWS and its location(s).
- b. Clearly identify in the FSAR how the SCWS is routed in the Reactor Building, and NuScale Nonproprietary
which portions of the SCWS are classified as seismic Category II.
NuScale Response:
Response to part a):
FSAR Figure 1.2-2 has been revised to show the proposed location of the site cooling water system (SCWS) pumps and cooling tower. In addition, FSAR Table 3.2-1 has been revised to show that the location for the SCWS components is various instead of yard. The location of the SCWS letdown line radiation monitor is still the yard.
Response to part b):
In the response to RAI No. 8866, Question 09.02.02-1, transmitted by letter RAIO-0817-55425 on August 14, 2017 (ADAMS Accession No. ML17226A370), NuScale provided an update to FSAR Tier 2 Table 3.2-1, "Classification of Structures, Systems and Components." The update to Table 3.2-1 provided Note 5 which applies to the Seismic Classification of SSCs, including the SCWS. Note 5 states, "Where SSC (or portions thereof) as determined in the as-built plant which are identified as Seismic Category III in this table could, as the result of a seismic event, adversely affect Seismic Category I SSC or result in incapacitating injury to occupants of the control room, they are categorized as Seismic Category II consistent with Section 3.2.1.2 and analyzed as described in Section 3.7.3.8."
The sentence in FSAR Tier 2, Section 9.2.7.1, Design Bases, which reads, The portions of the SCWS whose structural failure could adversely affect the function of Seismic Category I structure, systems, and components (SSC) are Seismic Category II is meant to be consistent with FSAR Tier 2, Table 3.2-1, Note 5. This note addresses the NRC RAI question, since SCWS components that could affect Seismic Category I SSCs, including the portion routed in the Reactor Building, will be designed to Seismic Category II standards.
Impact on DCA:
FSAR Section 1.2.1, Table 3.2-1, and Figure 1.2-2 have 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 General Plant Description The following structures are included in the NuScale certified design (Figure 1.2-1 and Figure 1.2-2):
- 1) Reactor Building (RXB): located above and below grade, houses the following facilities (among others that are not specifically discussed in this section):
- ultimate heat sink (reactor pool, refuel pool, and spent fuel pool)
- fuel handling areas
- remote shutdown station
- primary systems Additional details of the RXB are provided in Section 1.2.2.1.
- 2) Control Building (CRB): located above and below grade, adjacent to the RXB, provides space for the following facilities:
- main control room (MCR): located below grade, houses the equipment, controls, and indications for operation of the NPMs
- technical support center-located above the MCR, outside the radiological controlled area, provides space to support emergency operations and personnel Additional details of the CRB are provided in Section 1.2.2.2.
- 3) Radioactive Waste Building (RWB): located above and below grade, provides space for heating ventilating and air conditioning (HVAC) equipment; and radioactive waste treatment and storage equipment. Additional details of the RWB are provided in Section 1.2.2.3.
The following structures are discussed as CDI (Figure 1.2-1 and Figure 1.2-2):
- 1) Turbine Generator Buildings (TGBs): house the turbine generators and associated equipment. Additional details of the TGBs are provided in Section 1.2.2.5.1.
- 2) Annex Building (ANB): controls access into the radiologically controlled area (RCA) and provides space for health physics facilities, servicing potentially radioactive and non-radioactive tooling, fixtures, and instrumentation, security services, and various personnel services. Additional details of the ANB are provided in Section 1.2.2.5.2.
- 3) Security Buildings (SCBs): provide for controlled access into the SOCA and the PA of the plant. Additional details of the SCBs are provided in Section 1.2.2.5.3.
- 4) Central Utility Building (CUB): houses various equipment for the chilled water system and other ancillary equipment for balance of plant systems. Additional details of the CUB are provided in Section 1.2.2.5.4.
- 5) ((Diesel Generator Buildings (DGBs): house the backup diesel generators and associated equipment.)) Additional details of the DGBs are provided in Section 1.2.2.5.5.
RAI 09.02.07-4. RAI 09.02.07-5 Tier 2 1.2-2 Draft Revision 1
NuScale Final Safety Analysis Report General Plant Description
- 6) ((Site Cooling Water System (SCWS): provides cooling water to plant auxiliary systems.))
Additional details of the SCWS are provided in Section 1.2.1.6.
1.2.1.1 Facility Description Process Overview The reactor core is located in a core support assembly, which is seated in the lower RPV assembly. A central hot leg riser is connected to the top of the core support assembly.
The reactor core transfers heat into the reactor coolant and the heated reactor coolant flows upward through the core and lower and upper riser assemblies. The heated coolant exits the upper riser assembly and is redirected downwards into the SG region between the vessel wall and the upper riser assembly. As the reactor coolant transfers heat to the SGs, it cools and becomes denser, which drives the natural circulation flow.
The coolant returns to the bottom of the vessel through the downcomer and back into the reactor core, where the cycle begins again (Figure 1.2-7).
On the secondary side, preheated feedwater is pumped into the tube side of the SGs where it boils. As the steam flows upward in the tubes, it is continually heated to produce superheated steam before exiting the top of the SGs.
The superheated steam is directed to a dedicated steam turbine. A generator, driven by the turbine, creates electric power that is delivered to the utility grid through a step-up transformer. A turbine bypass line provides up to 100% of the rated main steam flow directly from the associated steam generators to the main condenser in a controlled manner to remove heat from the reactor following a load reduction or loss of electrical load.
Steam that exits or bypasses the turbine is directed to the condenser. A shared circulating water loop removes heat and condenses the steam for up to 6 condensers.
The condensate is pumped through condensate polishing equipment to the inlet of the variable speed feedwater pumps. A small amount of steam is extracted from turbine stages to preheat the feedwater and increase plant efficiency. Feedwater regulating valves control feed flow into the SGs.
((Heat from the circulating water loop from up to 6 condensers is rejected to atmosphere by a set of evaporative mechanical-draft cooling towers. Two sets of cooling towers are provided for 12 NPMs.))
1.2.1.1.1 Principal Design Criteria The design provides a simple, safe reactor and provides the following:
- reliable, passive safety systems that are simple in design and operation, and are not reliant on electrical power to fulfill their safety functions
- safety features that assure a core damage frequency significantly lower than the current light water reactor fleet
- the absence of RPV or containment penetrations below the top of the reactor core Tier 2 1.2-3 Draft Revision 1
Tier 2 NuScale Final Safety Analysis Report RAI 09.02.07-4, RAI 09.02.07-4S1, RAI 09.02.07-5, RAI 09.02.07-5S1 Figure 1.2-2: NuScale Functional Boundaries Owner Controlled Area NUSCALE POWER PLANT Security Owner Controlled Area (SOCA) Fence Cooling Tower Protected Area (PA) Boundary Double Fence BDG ANB TGB Admin/Training Structures within the CERTIFIED DESIGN NUSCALE POWER MODULES (NPMS)
AAP SEC SEC 1.2-23 RWB RXB CRB CUB SWYD Warehouse SCWS Pumps TGB SCWS Tower BDG Protected Area (PA) Boundary Double Fence Cooling Tower Security Owner Controlled Area (SOCA) Fence General Plant Description Certified Design Structures or Components NuScale Power Modules Structures not described in the FSAR Draft Revision 1 Conceptual Design Structures containing Certified Design SSCs Owner Controlled Area boundary Conceptual Design SSCs NuScale Power Plant boundary (SOCA Fence)
NuScale Final Safety Analysis Report Classification of Structures, Systems, and Components RAI 03.02.01-2, RAI 03.02.01-3, RAI 03.02.02-2, RAI 03.02.02-6, RAI 06.02.04-2, RAI 09.02.02-1, RAI 09.02.04-1, RAI 09.02.05-1, RAI 09.02.06-1, RAI 09.02.07-4, RAI 09.02.07-5, RAI 09.02.09-2, RAI 11.02-1, RAI 19-14 Table 3.2-1: Classification of Structures, Systems, and Components SSC (Note 1) Location SSC Classification RTNSS Category QA Program Augmented Design Requirements Quality Group / Safety Seismic Classification (Ref.
(A1, A2, B1, B2) (A,B,C,D,E) Applicability (Note 3) Classification RG 1.189 or RG 1.29 or RG (Note 2) (Ref RG 1.26 or RG 1.143) 1.143)
(Note 4) (Note 5)
CNTS, Containment System All components (except as listed below) RXB A1 N/A Q None A I
- RXM Lifting Lugs RXB B1 None AQ-S
- ANSI/ANS 57.1-1992 N/A I
- Top Auxiliary Mechanical Access Structure
- ASME NOG-1
- Top Auxiliary Mechanical Access Structure Diagonal Lifting Braces
- NUREG-0554 CFDS Piping in containment RXB B2 None AQ-S None B II Piping from (CES, CFDS, CVCS, FWS, MSS, and RCCWS) CIVs to disconnect flange (outside containment) RXB B2 None AQ-S None D I Hydraulic Skid for valve reset RXB B2 None None None D III CIV Close and Open Position Sensors: RXB B2 None AQ-S IEEE 497-2002 with CORR 1 N/A I
- CES, Inboard and Outboard
- CFDS, Inboard and Outboard
- CVCS, Inboard and Outboard PZR Spray Line
- RCCWS, Inboard and Outboard Return and Supply
- SGS, Steam Supply CIV/MSIVs and CIV/MSIV Bypasses Containment Pressure Transducer (Wide Range) RXB B2 None AQ-S IEEE 497-2002 with CORR 1 N/A II
- Containment Air Temperature (RTDs) RXB B2 None AQ-S None N/A II
- FW Temperature Transducers SGS, Steam Generator System
- SG tubes RXB A1 N/A Q None A I
- Feedwater plenums
- Steam plenums
- SG tube supports
- SG tube supports RXB A1 N/A Q None N/A I
- Steam piping inside containment RXB A2 N/A Q None B I
- Feedwater piping inside containment
- Feedwater supply nozzles
- Main steam supply nozzles
- Thermal relief valves Flow restrictors RXB A2 N/A Q None N/A I RXC, Reactor Core System Fuel assembly (RXF) RXB A1 N/A Q None N/A I Fuel Assembly Guide Tube RXB A2 N/A Q None N/A I Incore Instrument Tube RXB B2 None AQ-S None N/A I CRDS, Control Rod Drive System
- Control Rod Drive Shafts RXB A1 N/A Q None N/A I
- Control Rod Drive Latch Mechanism CRDM Pressure Boundary (Latch Housing, Rod Travel Housing, Rod Travel Housing Plug) RXB A2 N/A Q None A I CRDS Cooling Water Piping and Pressure Relief Valve RXB B2 None AQ-S None B II Rod Position Indication (RPI) Coils RXB B2 None AQ-S None N/A I
- Control Rod Drive Coils RXB B2 None AQ-S None N/A II
- CRDM power cables from EDN breaker to MPS breaker
NuScale Final Safety Analysis Report Classification of Structures, Systems, and Components Table 3.2-1: Classification of Structures, Systems, and Components (Continued)
SSC (Note 1) Location SSC Classification RTNSS Category QA Program Augmented Design Requirements Quality Group / Safety Seismic Classification (Ref.
(A1, A2, B1, B2) (A,B,C,D,E) Applicability (Note 3) Classification RG 1.189 or RG 1.29 or RG (Note 2) (Ref RG 1.26 or RG 1.143) 1.143)
(Note 4) (Note 5)
All components TGB B2 None None
- NEI 97-06 D III
- EPRI PWR Secondary Water Chemistry Guidelines, Rev 7 HVDS, (Feedwater) Heater Vents and Drains System All components TGB B2 None None None D III CHWS, Chilled Water System All components Various B2 None None None N/A III ABS, Auxiliary Boiler System High Pressure and Low Pressure Aux Boiler skids TGB B2 None None No D III Radioactivity Instruments Various B2 None AQ ANSI N42.18-2004 N/A III CARS, Condenser Air Removal System All components (except as listed below) TGB B2 None None None D III
- Effluent Radiation Element TGB B2 None AQ IEEE 497-2002 with CORR 1 N/A III
- Effluent Radiation Transmitter
- Discharge Flow Transmitter TGS, Turbine Generator System All components (except as listed below) TGB B2 None None None N/A III TG Gland Seal Exhauster Radiation Monitor TGB B2 None AQ ANSI N42.18-2004 N/A III TLOSS, Turbine Lube Oil Storage System All components TGB B2 None None None N/A III CPS, Cathodic Protection System Cathodic Protection System Various B2 None None None N/A III CWS, Circulating Water System All components TGB, Yard B2 None None None D III SCWS, Site Cooling Water System All components (except as listed below) VariousYard B2 None None None D III Letdown line rad monitor Yard B2 None AQ ANSI N42.18-2004 N/A III PWS, Potable Water System All components (except as listed below) Various B2 None None None N/A III Supply and return piping from the CRE penetration (includes only the isolation devices and the piping CRB B2 None None None N/A II between the isolation devices and the outer wall of the CRE)
UWS, Utility Water System All components (except as listed below) Various B2 None None None N/A III Wastewater effluent discharge portion of UWS Various B2 None None None D III Letdown Line Rad Monitor RWB B2 None AQ ANSI N42.18-2004 N/A III DWS, Demineralized Water System All components (except as listed below) Various B2 None None None D III
- DWS potentially radioactive loop Various B2 None AQ None D III
- Grab sample isolation valves
- Grab sample ports
- DWS headers - radiation indication instruments NDS, Nitrogen Distribution System All components Yard, RWB B2 None None None N/A III SAS, Service Air System All components Various B2 None None None N/A III IAS, Instrument and Control Air System All components Various B2 None None None N/A III TBVS, Turbine Building HVAC System All components TGB B2 None None None N/A III Tier 2 3.2-21 Draft Revision 1