ML19296D805

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LLC Response to NRC Request for Additional Information No. 526 (Erai No. 9719) on the NuScale Design Certification Application
ML19296D805
Person / Time
Site: NuScale
Issue date: 10/23/2019
From: Rad Z
NuScale
To:
Document Control Desk, Office of New Reactors
References
RAIO-1019-67696
Download: ML19296D805 (11)
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Text

RAIO-1019-67696 October 23, 2019 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.

526 (eRAI No. 9719) on the NuScale Design Certification Application

REFERENCE:

U.S. Nuclear Regulatory Commission, "Request for Additional Information No.

526 (eRAI No. 9719)," dated October 03, 2019 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. 9719:

06.03-8 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 Nadja Joergensen at 541-452-7338 or at njoergensen@nuscalepower.com.

Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8H12 Omid Tabatabai, NRC, OWFN-8H12 Samuel Lee, NRC, OWFN-8H12 Cayetano Santos, OWFN-8H12 Michael Dudek, NRC, OWFN-8H12 : NuScale Response to NRC Request for Additional Information eRAI No. 9719 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-1019-67696 :

NuScale Response to NRC Request for Additional Information eRAI No. 9719 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.: 9719 Date of RAI Issue: 10/03/2019 NRC Question No.: 06.03-8 Title 10 of the Code of Federal Regulations (10 CFR) Section 52.47, "Contents of applications; technical information," requires that an application for a design certification must include performance requirements and design information sufficiently detailed to permit its acceptance by the U.S. Nuclear Regulatory Commission (NRC). Specifically, §52.47(a)(2)(iii), states, in part, that the NRC will take into consideration the following reactor design characteristics that include, "the extent to which the reactor incorporates unique, unusual or enhanced safety features having a significant bearing on the probability or consequences of accidental release of radioactive materials."

10 CFR 50, Appendix A, GDC 37 requires, in part, the emergency core cooling system to be designed to permit appropriate functional testing to assure "the operability of the system as a whole and, under conditions as close to design as practical, the performance of the full operational sequence that brings the system into operation, including operation of applicable portions of the protection system."

The staff is seeking an as-built performance test of the ECCS to demonstrate the system meets fundamental design requirements of the safety analysis. The integrated functionality of a full scale NuScale ECCS system has not been tested and demonstrated. Although the staff has confidence that NuScale analytical codes have been adequately validated within the existing state of practice, performance of the full scale, as-built ECCS system can be impacted by the geometry and functional arrangement of key components, variations in as-built parameters, and uncertainties associated with complex thermal hydraulic phenomena, especially when considering the integrated system. Functional testing of the full scale ECCS would provide assurance that the as-built system response conforms to analytical predictions.

NuScale Nonproprietary

To date the staff held approximately eleven public meetings where the adequacy of the proposed ECCS performance test (Test #47) was at least one of the topics discussed. The most recent meeting was held on September 11, 2019. Currently, NuScale DCA Part 2, Tier 2, Table 14.2-47, Revision 3 identifies the acceptance criteria for ECCS Test #47 as:

i. RPV riser level remains above the top of the core ii. CNV pressure remains below design pressure identified in Table 6.2-1 CNV temperature remains below design temperature identified in Table iii.

6.2-1 The proposed acceptance criteria above are not sufficient to demonstrate the as-built performance capability of the ECCS to satisfy design requirements because the stored energy during test conditions is significantly less than the full power stored energy corresponding to the proposed test acceptance criteria (accident acceptance criteria). Therefore, the applicant is requested to modify an existing ECCS test or develop a new test to demonstrate acceptable performance of the as-built ECCS, based on predicted system response under expected test conditions, to ensure the system as a whole meets fundamental design requirements of the safety analysis.

Given the fundamental purpose of this type of test - to confirm the performance of a first-of-a-kind safety system and verify the conservatism in the safety analyses in calculating the performance of a novel design feature - and expected standardization of the NuScale power module design and construction, the requested test is an appropriate candidate for a first-of-a-kind test to be performed for at least the first module only.

NuScale Response:

Subsequent to the September 11, 2019 public meeting, the NRC and NuScale had several public meetings discussing potential changes to Table 14.2-47: Emergency Core Cooling System Test #47. The NRC Staff explained that they were seeking a test which demonstrates the ability of the containment vessel to transfer heat to the ultimate heat sink. As this is a function of the containment system, and not the emergency core cooling system (ECCS),

acceptance criteria demonstrating heat transfer were not included in the original ECCS System Level Test #47-1.

To satisfy the NRC Staff's request for a test demonstrating the containment vessel (CNV) response during ECCS operation, a new test was created to replace Test #47-1. This test is a NuScale Nonproprietary

one-time in-situ system performance test of the ECCS and CNV. The test will be performed during hot functional testing to allow ECCS actuation at elevated reactor coolant system (RCS) pressure and temperature conditions without engaging the inadvertent actuation block (IAB) design feature of the ECCS valves. The two acceptance criteria for this test include maintaining the core covered with water and that the CNV pressure response is as predicted during ECCS operation.

Table 14.2-47: Emergency Core Cooling System Test #47 was revised to replace System Level Test #47-1 with the ECCS and CNV response test described above. In support of this change, Section 14.2.2.3, Testing of First-of-a-Kind Design Features, and Table 14.2-110: ITP Testing of New Design Features were revised to incorporate information regarding the new test.

Additionally, Table 14.2-63: Module Protection System Test #63 was revised to standardize language associated with the IAB RCS pressure threshold.

Impact on DCA:

Tier 2 Section 14.2 "Initial Test Plan Program" 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 Initial Plant Test Program RAI 05.04.07-7S1, RAI 14.02-1 The test results for the CVAP program testing of the first NPM are to inform the required CVAP testing on subsequent NPMs as described in Section 6.0 of TR-0716-50439. All other ITP testing of FOAK design features is performed for each NPM, except as described below.

RAI 06.03-8 Table 14.2-47: Emergency Core Cooling Test #47 includes a one-time in-situ system performance test of the emergency core cooling system (ECCS). The test demonstrates valve and containment response to manual emergency safety feature actuation of the ECCS at hot functional test pressure and temperature.

RAI 05.04.07-7S1 Section 5.4.3.4 contains a description of the decay heat removal system (DHRS) one-time in-situ RCS heat removal test. The test will be performed per test abstract Table 14.2-48: Decay Heat Removal System Test # 48.

RAI 14.02-1 Table 14.2-110 provides a summary of the ITP testing (i.e., preoperational and startup testing) for new design features. Each test will be performed for all NPMs.

RAI 14.02-1 Section 1.5.1 contains a description of testing programs which have been completed or are currently in progress for NuScale design features for which applicable data or operational experience did not previously exist. The section describes tests specific to fuel design, steam generator (SG) and control rod assemblies.

14.2.3.4 Generic Component Testing Component testing is generally executed after a systems transfer from the construction organization to the startup organization. Generic component testing executes standardized tests for a family of related component types, independent of the components system assignment. Each generic component test procedure will be completed and approved before the component is required as a prerequisite to a preoperational test performance. The completion of generic component testing will be listed as a prerequisite in each preoperational test procedure as applicable.

Examples of components that may require generic component testing are as follows:

  • Mechanical Components pumps motors chillers compressors
  • Valves Tier 2 14.2-11 Draft Revision 4

NuScale Final Safety Analysis Report Initial Plant Test Program RAI 06.03-8, RAI 14.03-S1 Table 14.2-47: Emergency Core Cooling System Test # 47 Preoperational test is required to be performed for each NuScale Power Module.

System Level Test #47-1 is only required to be performed once for NPM #1. This test supports first-of-a-kind (FOAK) testing as described in Section 14.2.3.3.

The emergency core cooling system (ECCS) is described in Section 6.3, and the functions verified by this test are:

System Function System Function Categorization Function Verified by Test #

1. The ECCS supports the reactor safety-related Test #47-1 coolant system (RCS) by opening the Module Protection System Test #63-6 ECCS reactor vent valves and reactor recirculation valves when their respective trip valve is actuated by the module protection system (MPS).
2. The ECCS supports the RCS by safety-related Test #47-1 providing recirculated coolant from Module Protection System Test #63-6 the containment to the reactor pressure vessel (RPV) for the removal of core heat.

The ECCS functions verified by other tests are:

System Function System Function Categorization Function Verified by Test #

1. The ECCS supports the RCS by safety-related Module Protection System Test #63-6 providing low temperature overpressure protection (LTOP) for maintaining the reactor coolant pressure boundary.
2. The ECCS supports the containment safety-related Containment System Test #43-1 system (CNTS) by providing a portion of the containment boundary for maintaining containment integrity.
3. The ECCS supports MPS by providing nonsafety related Safety Display and Indication System post accident monitoring instrument Test #66-2 information signals.

Prerequisites Verify an instrument calibration has been completed, with approved records and within all calibration due dates, for all instruments required to perform this test.

Component Level Tests None System Level Test #47-1 Test #47-1 is performed at hot functional testing to allow ECCS actuation at elevated RCS pressure and temperature conditions, without engaging the inadvertent actuation block (IAB).

Test 47-1 is performed at hot functional testing concurrently with Turbine Generator System Test #33-1 (reference Table 14.2-33) and MPS Test #63-6 to allow testing of ECCS actuation at normal operating pressure and elevated temperatures. Test #33-1 heats the RCS from ambient conditions to the highest temperature achievable by module heatup system (MHS) heating. These hot functional testing conditions provide the highest differential pressure and temperature conditions that can be achieved prior to fuel load.

The RCS is heated to the highest temperature achievable by module heatup system (MHS) heating. These hot functional testing conditions provide the highest temperature conditions that can be achieved prior to fuel load. The RCS level is within the expected range of module operation, near the low end of the normal operating range for hot zero power conditions.

Tier 2 14.2-112 Draft Revision 4

NuScale Final Safety Analysis Report Initial Plant Test Program Table 14.2-47: Emergency Core Cooling System Test # 47 (Continued)

Test Objective Test Method Acceptance Criteria

i. Verify the RPV liquid level remains i. Ensure RCS pressure is as close to, but i. RPV riser level remains above the above the top of the core during and below, the IAB RCS pressure top of the core.

following ECCS actuation. threshold as practical. ii. CNV pressure remains within upper ii. Verify the heat removal capacity of ii. Ensure RCS temperature is at the and lower bounds calculated using the ECCS, operating with the maximum temperature achievable safety analysis methods, while containment vessel (CNV), is by heating the RCS using MHS accounting for test initial conditions consistent with the design basis. heating. and instrumentation uncertainty.

i.Verify collapsed liquid level remains iii. Ensure RCS level is as low in the i.RPV riser level remains above the top of above the top of the core during ECCS normal operating band as is the core.

actuation. practically achievable for the ii. CNV pressure remains below design ii. Containment vessel (CNV) pressure established plant conditions.

pressure identified in Table 6.2-1.

remains below the design pressure iv. Manually initiate ECCS from the main limit during ECCS actuation. iii. CNV temperature remains below control room.

design temperature identified in iii. Containment temperature remains v. Allow RPV riser level and CNV level to Table 6.2-1.

below the design temperature limit become relatively stable.

during ECCS actuation. Ensure the RCS is at normal operating pressure and at maximum temperature achievable by warming the RCS using MHS heating.

i. Manually initiate ECCS from the main control room (MCR).

ii. Allow RPV riser level and CNV level to become relatively stable.

Tier 2 14.2-113 Draft Revision 4

NuScale Final Safety Analysis Report Initial Plant Test Program RAI 06.03-8 Table 14.2-63: Module Protection System Test #63 Preoperational test is required to be performed for each NuScale Power Module (NPM).

The module protection system (MPS) is described in Sections 7.0, 7.1, and 7.2 and the functions verified by this test and power ascension testing are:

System Function System Function Categorization Function Verified by Test #

1. The MPS supports the containment safety-related Test #63-6 system (CNTS) by removing electrical power to the trip solenoids of the following containment isolation valves (CIVs) on a CNTS isolation actuation signal:
  • Pressurizer (PZR) spray CIVs
  • Containment evacuation system CIVs
  • Reactor component cooling water system CIVs RVVs
  • Containment flooding and drain system (CFDS) CIVs
2. The MPS supports the CNTS by safety-related Test #63-6 removing electrical power to the trip solenoids of the following valves on a decay heat removal system (DHRS) actuation signal.
  • MSIBVs
3. The MPS supports the emergency safety-related Test #63-6 core cooling system (ECCS) by removing electrical power to the trip solenoids of the following valves on an ECCS actuation signal.
  • Reactor vent valves (RVVs)
  • Reactor recirculation valves (RRVs)

Tier 2 14.2-147 Draft Revision 4

NuScale Final Safety Analysis Report Initial Plant Test Program Table 14.2-63: Module Protection System Test #63 (Continued)

Prerequisite Verify an instrument calibration has been completed, with approved records and within all calibration due dates, for all instruments required to perform this test.

Component Level Tests None System Level Test #63-1 Test Objective Test Method Acceptance Criteria Verify the instrument signals of MPS Table 7.1-2 lists all of sensors which input Each MPS monitored signal is displayed monitored variables are displayed in the to MPS. on an MCR workstation and the MCR. This test may be performed concurrently module-specific safety display with safety display and indication system instrument panel (if designed for safety test #66 -2 for post-accident monitoring display instrument display).

Type B and Type C testing described in Section 14.2.12.

Inject a single signal as close as practical for each sensor listed in Table 7.1-2 and monitor its response on an MCR workstation and the module-specific safety display instrument panel (if designed for safety display instrument display).

If the sensor signal is designed to be disconnected when the NPM is moved then it will be necessary to test the signal from the sensor to the disconnect and then from the disconnect to the MCR display.

System Level Test #63-2 (Not Used)

System Level Test #63-3 Test Objective Test Method Acceptance Criteria Verify each ECCS RVV and RRV operates This test will verify the stroke time of Each ECCS RRV and RVV travels from fully to satisfy its engineered safety feature each RRV and RVV by actuating the closed to fully open in less than or equal (ESF)-actuated design stroke time. valves with RCS pressure below the IAB to the time specified in TS.

RCS pressure thresholdinadvertent actuation block setpoint.

i. Close all RVVs and RRVs.

ii. Verify RCS pressure is below the IAB RCS pressure thresholdinadvertent actuation block setpoint specified in Technical Specifications (TS).

iii. Actuate ECCS using the manual ECCS actuation switches in the MCR.

System Level Test #63-4 Test #63-4 is performed concurrently with Test #63-6 which operates all of the ESF actuation valves during hot functional testing.

Test #63-4 records the stroke times of DHRS actuation valves as they travel to their ESF-actuated position with the RCS pressure at normal operating pressure.

Test Objective Test Method Acceptance Criteria Verify each DHRS actuation valve Time the operation of all DHRS actuation Each DHRS actuation valve travels from operates to satisfy its ESF-actuated valves as they actuate to their ESF fully closed to fully open in less than or design stroke time. position during the manual ESF equal to the time specified in Technical actuation testing in Test #63-6. Specifications.

System Level Test #63-5 (Not Used)

Tier 2 14.2-150 Draft Revision 4

NuScale Final Safety Analysis Report Initial Plant Test Program RAI 05.04.07-7S1, RAI 06.03-8, RAI 14.02-1, RAI 14.02-5 Table 14.2-110: ITP Testing of New Design Features New System or Component Design Design Feature Tested in the Initial FSAR Section 14.2 Test Program Test Number Containment isolation valves

  • valve leak rate test #431
  • valve response to manual engineered #636 safety feature (ESF) action at hot functional test pressure and temperature
  • valve response time test at hot #637 functional test pressure and temperature
  • valve response to manual ESF action at #636 valve design hot functional test pressure and temperature
  • test of valve inadvertent actuation #63-6 block at design pressure ECCS operation
  • Containment response to ECCS #47-1 operation at hot functional test pressure and temperature.

Decay heat removal system (DHRS) valve

  • valve response to manual ESF action at #636 design hot functional test pressure and temperature
  • heat exchanger response to manual #48-1 ESF action at hot functional test pressure and temperature
  • heat exchanger response to manual #104 reactor trip at 100% power Containment flooding and drain system
  • automatic fill of containment #42 (CFDS)
  • automatic drain of containment Containment evacuation system
  • establish and maintain containment #41 vacuum
  • provides containment level input for #42 CFDS automatic fill and drain of containment RCS flow sensors
  • provides RCS flow indication during #77 hot functional testing and power #94 ascension testing Pressurizer (PZR) level sensors
  • provides input for PZR level control #38-1 Island mode operation
  • NuScale Power Modules can operate #105 and #106 independently from offsite transmission grid.

Tier 2 14.2-210 Draft Revision 4

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