ML18333A361
| ML18333A361 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 04/11/2019 |
| From: | Rani Franovich NRC/NRO/DLSE/LB1 |
| To: | Samson Lee NRC/NRO/DLSE/LB1 |
| R FRANOVICH/415-7334 | |
| References | |
| Download: ML18333A361 (7) | |
Text
April 11, 2019 MEMORANDUM TO:
Samuel S. Lee, Chief Licensing Branch 1 Division of Licensing, Siting, and Environmental Analysis Office of New Reactors FROM:
Rani L. Franovich, Senior Project Manager /RA/
Licensing Branch 1 Division of Licensing, Siting, and Environmental Analysis Office of New Reactors
SUBJECT:
SUMMARY
OF THE AUGUST 14, 2018, AND AUGUST 28, 2018, PUBLIC TELECONFERENCES WITH NUSCALE POWER, LLC.,
TO DISCUSS VARIOUS TOPICS RELATED TO NUSCALES CHAPTER 19, PROBABILISTIC RISK ASSESSMENT AND SEVERE ACCIDENT EVALUATION, AND CHAPTER 15, TRANSIENT AND ACCIDENT ANALYSES, OF THE NUSCALE DESIGN CERTIFICATION APPLICATION (DOCKET NO.52-048)
On August 14, 2018, and August 28, 2018, representatives of the U.S. Nuclear Regulatory Commission (NRC) and NuScale Power, LLC., (NuScale), held a public teleconference meeting.
The purpose of this meeting was to discuss NuScales responses to the NRC staffs Requests for Additional Information (RAI) 9241 and RAI 8899 related to Chapter 19, and RAI 9501 and RAI 9502 related to Chapter 15.
A complete copy of NuScales Design Certification Application is available on the NRC public Webpage at https://www.nrc.gov/reactors/new-reactors/design-cert/nuscale/documents.html.
, Summary of the August 14, 2018, and August 28, 2018, Teleconference between the NRC Staff and NuScale, provides a summary of the topics discussed during the teleconference.
CONTACT: Rani L. Franovich, NRO/DLSE 301-415-7334
The Meeting Agenda and List of Attendees are provided in Enclosures 2 and 3, respectively.
The meeting notices are available in the NRCs Agencywide Documents Access and Management System, under Accession Numbers ML18226A167 and ML18218A264.
Docket No.52-048
Enclosures:
- 1. Meeting Summary
- 2. Meeting Agenda
- 3. List of Attendees
- via email NRC-001 OFFICE NRO/DLSE/LB1: PM NRO/DLSE/LB1: LA NRO/DSRA/SPRA: BC NAME RFranovich CSmith*
MHayes*
DATE 2/12/2019 12/11/2018 2/13/2019 OFFICE NRO/DSRA/SRSB: BC NAME RKaras DATE 4/11/2019 U.S. NUCLEAR REGULATORY COMMISSION
SUMMARY
OF AUGUST 14, 2018, AND AUGUST 28, 2018 PUBLIC TELECONFERENCE WITH NUSCALE POWER, LLC.
Chapter 19, Probabilistic Risk Assessment And Severe Accident Evaluation NuScale Power, LLCs (NuScale) response to the following requests for additional information (RAIs):
RAI 9501 (Chapter 15, Technical Specifications)
In its response to RAI 9501, NuScale indicated that Limiting Condition for Operation (LCO) 3.4.1 protects the reactor coolant system (RCS) pressure ranges and average RCS temperature shown in Table 15.0-6, Module Initial Conditions Ranges for Design Basis Event Evaluation, for all design basis events (loss-of-coolant accident [LOCA],
non-LOCA, containment vessel [CNV] pressure). If LCO 3.4.1 addressed all design basis events, the staff requested NuScale to update the Technical Specification (TS)
Bases for LCO 3.4.1 and include the containment pressure analyses in TS 5.6.3.
NuScale did not provide markups to the TS Bases or TS 5.6.3. The staff asked the applicant why the requested changes were not made and when this perhaps would be added to the containment pressure analysis methodology under TS 5.6.3 (related to a different RAI response)? NuScale explained it did not provide revised TS bases for LCO 3.4.1. and referred the staff to Final Safety Analysis Report (FSAR) Section 6.2.2, Containment Heat Removal, FSAR Table 6.2-1, Containment Design and Operating Parameters, and FSAR Section 3.3, Wind and Tornado Loadings. NuScales position is that LCO 3.4.1 deals with critical heat flux (CHF) and not containment pressure and that the FSAR is adequate to control the initial conditions used in the containment response analysis.
RAI 9502 (Chapter 15, Treatment of Nonsafety-Related Systems)
In its response to RAI 9502, NuScale provided revisions to FSAR Section 15.0.0.6.6, Treatment of Nonsafety-Related Systems. The changes include the following statement: Nonsafety-related system normal operation that does not significantly alter the consequences of the event may be modeled. Typically, non-safety systems are assumed not to function if it mitigates an event. The staff asked the applicant why NuScale included a statement indicating that a non-safety systems may be used to alter the consequences of an event and requested that NuScale discuss some specific examples. NuScale clarified that it is not crediting a non-safety system to mitigate consequences of an accident.
RAI 9241 (Chapter 19, Aircraft Impact Assessment)
In its response to RAI 9241, NuScale stated that the description of plant monitoring and control was deleted from FSAR Section 19.5 to align with Title 10 of the Code of Federal Regulations (10 CFR) Section 50.150, 10 CFR 50.54(hh)(2), and associated regulatory guidance. The staff requested that NuScale explain the basis for this because
monitoring is an important aspect of ensuring the core remains cooled and spent fuel integrity is maintained. NuScale agreed to consider revising its response to RAI 9241.
RAI 8899, Question 19.1-2 (Seismic Margin Analysis)
During the August 14, 2018, teleconference the staff asked NuScale if anchorages of the components are included in the calculation of the high confidence low probability of failure (HCLPF) capacities as listed in the FSAR Table 19.1-38, Seismic Correlation Class Information. NuScale responded that the component boundaries used to determine the HCLPF capacities for the components listed in Table 19.1-38 include anchorage failures and failure modes involving weld or pipe failures. This was discussed further at the teleconference held on August 28, 2018, and NuScale agreed to provide a supplemental response clarifying the scope of the component boundaries in the FSAR.
The staff observed that some component HCLPF capacities in Table 19.1-38 are significantly greater than those HCLPF capacities for existing plants, and discussed its inability to verify these HCLPFs without as-built plant information and a seismic walkdown so that the higher HCLPF capacities can be reasonably attained. The staff expressed its intent to document this finding in its Safety Evaluation Report.
Additionally, in reviewing the HCLPF capacities, the staff identified that the Table 19.1-38 entries are identical for the chemical and volume control system (CVCS), containment evacuation system, feedwater system, main steam system Containment Isolation Valves (design specific) and the CVCS motor operated valve (MOV) Recirculation Valve (generic). The staff asked NuScale to clarify the fragility methods used for these two table entries. NuScale recognized that Table 19.1-38 appeared to be in error and agreed to evaluate the error to determine if other changes to the table would be needed. NuScale agreed to follow-up with a supplemental response and further noted that a correction will be made to the median capacity, randomness, uncertainty, and HCLPF capacities for the CVCS MOV Recirculation Valve as listed in FSAR Table 19.1-38.
During the follow-up teleconference on August 28, 2018, the staff asked NuScale what industry and/or regulatory guidance/basis exists for screening seismic cut-sets based on the random failure probability value? In its response, NuScale clarified that the 1 percent screening criterion was used to determine the plant-level HCLPF only. For the evaluation of the seismic risk insights no cutsets were screened. The staff asked NuScale if it found random failures or operator actions that are important to risk insights. NuScale responded that at the HCLPF ground motion the dominant contributors are structural failures, and that random failures and operator actions are not found to be important to risk insights. NuScale agreed to provide this clarification in a supplemental response with an associated revision to FSAR Section 19.1.5.1.2 Results from the Seismic Risk Evaluation.
U.S. NUCLEAR REGULATORY COMMISSION
SUMMARY
OF AUGUST 14, 2018, AND AUGUST 28, 2018 PUBLIC TELECONFERENCE WITH NUSCALE POWER, LLC MEETING AGENDA Tuesday, August 14, 2018 Time Topic Speaker 2:00 pm - 2:30 pm NuScale Response to eRAI 8899, Q 19.1-2 NRC/NuScale 2:30 pm - 3:00 pm NuScale Response to eRAI 9501 and 9502 NRC/NuScale 3:00 pm - 3:30 pm NuScale Response to eRAI 9241 NRC/NuScale Tuesday, August 28, 2018 Time Topic Speaker 2:00 pm - 4:00 pm NuScale Response to eRAI 8899, Q 19.1-2 NRC/NuScale
LIST OF ATTENDEES NuScale August 14, 2018 August 28, 2018 A. Brigantic S. Bristol S. Bristol J. Curry J. Curry B. Galyean J. Fields B. Haley B. Galyean P. Infanger K. Gross B. Haley P. Infanger D. Throckmortin J. Wike NRC Staff August 14, 2018 August 28, 2018 R. Franovich R. Franovich B. Jain B. Jain A. Neuhausen H. Phan H. Phan M. Pohida M. Pohida J. Schmidt Public August 14, 2018 August 28, 2018 S. Fields None