ML18254A340

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LLC, Design Certification Application (DCA) Follow-Up Audit Summary for Limited-Scope Review of Supporting Information for Chapter 17 and 19 RAI Responses (52-048)
ML18254A340
Person / Time
Site: NuScale
Issue date: 09/13/2018
From: Rani Franovich
NRC/NRO/DLSE/LB1
To: Samson Lee
NRC/NRO/DLSE/LB1
Franovich R / 415-7334
References
Download: ML18254A340 (7)
v • d • e


Text

September 13, 2018 MEMORANDUM TO: Samuel S. Lee, Chief Licensing Branch 1 Division of Licensing, Siting and Environmental Analysis Office of New Reactors FROM: Rani Franovich, Project Manager /RA/

Licensing Branch 1 Division of Licensing, Siting and Environmental Analysis Office of New Reactors

SUBJECT:

U.S. NUCLEAR REGULATORY COMMISSION AUDIT OF THE PROBABILISTIC RISK ASSESSMENT AND SEVERE ACCIDENT EVALUATION OF THE NUSCALE POWER, LLC DESIGN As part of its safety review of the design certification application from NuScale Power, LLC (NuScale), the U.S. Nuclear Regulatory Commission (NRC) staff performed an audit of information supporting Chapters 19 and 17.4 of the final safety analysis report (FSAR) submitted with the application. In particular, the purpose of the audit was for the NRC staff to examine and evaluate documents that support responses to the staffs requests for additional information (RAIs) in Table 1. This examination and evaluation was intended to inform the NRC staffs review of the responses to the RAIs.

The audit commenced on March 6, 2018, and was originally scheduled to end on April 3, 2018.

Subsequently, the audit was extended to April 24, 2018, to provide additional time to complete the audit. The audit was conducted via the NuScale electronic reading room (ERR), in NuScales Rockville office, and through periodic telephone conversations between appropriate NRC and NuScale staff. An exit meeting was conducted on April 24, 2018, where the overall results of the audit were reported, and the ERR stayed open through May 18, 2018.

The audit was conducted per the audit plan issued March 5, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18053A216).

CONTACT: Rani Franovich, NRO/DLSE (301) 415-7334

S. Lee 2 Members of the audit team included the following NRC staff:

  • Mark Caruso (Office of New Reactors (NRO), Audit Lead)
  • Shawn Campbell (Office of Nuclear Regulatory Research (RES), Severe Accident Phenomenology)
  • Brad Harvey (NRO, Meteorology)
  • Greg Makar (NRO, Materials/Structural)
  • Patrick Purtscher (RES, Materials/Structural)
  • BP Jain (NRO, Seismic/Structural)

Audit Activities In accordance with the audit plan, the NRC staff examined documents supporting the RAI responses in Table 1. The complete list of documents examined by the NRC during the audit is provided in Table 2. During the course of the audit staff reviewed documents and asked questions for purposes of clarifying the information being reviewed.

The staff interacted with the following NuScale staff during audit discussions:

  • James Curry (Project Manager For Audit)
  • William Galyean (Probabilistic Risk Analysis)
  • Sarah Bristol (Probabilistic Risk Analysis)
  • Etienne Mullin (Probabilistic Risk Analysis)
  • Scott Weber (Probabilistic Risk Analysis)

S. Lee 3

  • Luke Mcsweeney (Probabilistic Risk Analysis)
  • Grant Buster (Probabilistic Risk Analysis)

Audit Results For four of the RAIs, the document review and the dialogue between the staff and the applicant obviated the need for a formal supplemental RAI. For six of the RAIs, the applicant provided supplemental RAI responses to address the staffs outstanding information needs. For two of the RAIs, the staff is considering alternative approaches to resolve the issue. The audit results for each of the twelve RAIs included in the audit are provided in the last column of Table 1.

These results were discussed with the applicant during the audit exit meeting on April 24, 2018.

ML18254A340 *via email NRC-001 OFFICE NRO/DLSE/LB1: PM NRO/DLSE/LB1: LA NAME RFranovich MMoore*

DATE 9/13/2018 9/13/2018 S. Lee 5 Table 1: Summary of Audit Topics and Results NRC NuScale RAI FSAR Audit topic Results RAI Response Number Section Number 8882 RAIO-0817-55372 19.2 Scrubbing of fission product NuScale issued supplemental RAI response RAIO-(ML17222A683) aerosols by the reactor pool for a 0618 (ML18165A438) to resolve outstanding issues.

module drop accident.

8903 RAIO-0917-55876 19.2 Bi-directional flow through No outstanding issues.

(ML17251B163) reactor recirculation valves arresting core damage.

8977 RAIO-1017-56550 19.2 Large release definitions for at- NuScale issued supplemental RAI responses RAIO-(ML17284A652) power and shutdown (module 0318-59269 (ML18085A516) and RAIO-0518-60189 drop) accidents. (ML18145A136) to resolve outstanding issues.

9043 RAIO-1017-56516 19.2 Corium retention in the reactor Due to phenomenological uncertainties, the staff (ML17283A413) pressure vessel (RPV) lower continues to evaluate NuScales conclusion that plenum and the containment core debris retention is assured.

lower plenum by external cooling by water in the containment and in the reactor pool.

8889 RAIO-0118-58186 19.1 The probability of severe No outstanding issues.

(ML18016A240) accident induced steam generator tube failure.

91121 RAIO-1017-56897 19.2 The potential for high pressure Due to phenomenological uncertainties, the staff is (ML17303A578) melt ejection of corium from the continues to evaluate this topic for resolution.

RPV to the containment to cause direct containment heating.

93672 Not applicable 19.2 The NRC staffs independent No outstanding issues.

MELCOR confirmatory analysis.

S. Lee 6 NRC NuScale RAI FSAR Audit topic Results RAI Response Number Section Number 8899 RAIO-0118-58237 19.1.5 Fragility calculations for reactor NuScale issued a supplemental RAI response to (ML18018B375) bay wall, reactor building (RBX) resolve outstanding issues.

exterior wall, and RXB roof.

Bases for screening structures, systems, and components with fragilities below the plant-level high confidence of low probability of failure.

8840 RAIO-0717-55003 19.1.4 Containment isolation for loss of NuScale issued supplemental RAI responses RAIO-(ML17262B215) coolant accidents inside 0518-59975 (ML18135A269) and RAIO-0718-60731 containment. (ML18183A554) to resolve outstanding issues.

8926 RAIO-0917-56321 19.1.6 Dropped module consequence NuScale issued supplemental RAI response RAIO-(ML17272B031) analysis. 0518-60115 (ML18141A882) to resolve outstanding issues.

91281 RAIO-0218-58534 19.1 Module drop accident. NuScale issued supplemental RAI response RAIO-(ML18036B203) 0618-60457 (ML18165A431) to resolve outstanding issues.

8879 RAIO-0817-55698 17.4 Expert panel decision-making No outstanding issues.

(ML17241A139) process.

Footnotes to Table 1:

1The applicants responses to RAIs 9128 and 9112 were added to the audit subsequent to issuing the audit plan.

2The issues identified in draft RAI 9112 were resolved as a result of the audit, so the RAI was not issued as final.

S. Lee 7 Table 2: Documents in the Applicants Electronic Reading Room CFD SSC Classification Report - Rev2.pdf CFDS (B191) Data Sheet - Expert Panel Approved 10-27-16 Revised 12-8-16.pdf COR Energy Balance.pdf CVC (B010) 2019 Data Sheet - EP Approved 9-7-17 Revised 2-8-18.pdf CVCS SSC Classification Report Rev4.pdf Documents Supporting PRA Audit 2_042518.pdf ECN-P000-6271_R0_Evaluation of Additional MACCS Sensitivity Cases.pdf ER-P010-5689_R0.pdf ER-P020-3536_R0 with ECN.pdf ER-P020-4450_R0 with ECN.pdf ER-P060-5441_Rev_0.pdf ER-P060-5441_Rev_1.pdf ER-P060-7035 Rev 0.pdf ER-P060-7048 Rev 0.pdf ER-P060-7082_Rev_1_NRELAP5 Base Model.pdf ER-P060-7085 Revision 1, Dropped Module Consequence Analysis ECN P060-6053 Air as Fill Gas during Module Drop, Revision 0 ER_P030_5150_R0.pdf ER_P040_5858_R0.pdf List of Design Data Requested - Modified 3-27-2018.pdf NuScale IVR Discussion Slides.pdf PRA Audit 2_Question 0309-1.pdf PRA Audit 2_Question 0315-1.pdf PRA Audit 2_Question 0424-1 re. RAI 8977.pdf RAI_8840_Cl_Fail_Audit_Slides 2018-04-19.pdf RBC (F011) 2109 datasheet - Expert Panel Approved 9-21-2017.pdf RBC SSC Classification Report Rev 2- Signed.pdf Slides - SMA_042418.pdf TI-SGTF discussion slides Ver 3.pdf PRA_Audit_UHS_Modeling_8840.pdf PRA_Audit_HPME_Discussion.pdf RAI 8926 Air as Fill Gas Slides.pdf ECN-P060-6411, Aerosol Contribution to Dropped Module Dose Consequence

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