ML19037A490

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Enclosure - Summary Report for the Environmental Audit of Part 3 of the NuScale Design Certification Application
ML19037A490
Person / Time
Issue date: 03/15/2019
From: Mallecia Sutton
NRC/NRO/DLSE
To: Jennivine Rankin
NRC/NRO/DLSE
Sutton M
Shared Package
ML19037A487 List:
References
Download: ML19037A490 (35)
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Text

SUMMARY

NUSCALE ENVIRONMENTAL AUDIT REPORT OCTOBER 16, 2018 TO NOVEMBER 30, 2018

1.0 BACKGROUND

AND PURPOSE By letter dated December 31, 2016, NuScale Power, LLC (NuScale), submitted its Design Certification Application (DCA) to the U.S. Nuclear Regulatory Commission (NRC) for review (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17013A229). On March 15, 2017, the NRC accepted the DCA for docketing and initiated its technical review.

The NRC staff conducted an audit from August 14, 2017, to February 28, 2018, of the documentation supporting the DCA Part 3, containing Applicants Environmental Report -

Standard Design Certification, herein denoted as the Environmental Report (ER). The NRC staff audited the methodology, models, assumptions, and calculation packages in support of the ER. The audit plan used to support these interactions can be found under ADAMS Accession No. ML17179A287 and the audit summary is under ADAMS Accession No. ML18143B667.

The NRC staff identified a need for a second environmental audit of NuScales design and severe accident mitigation design alternatives (SAMDA). In doing so, the NRC staff audited the supporting information presented in Revision 1 of the ER, including non-docketed supporting documents. The NRC staff also determined an audit would be needed in identifying and resolving specific information needs to support the NRC staffs independent evaluation and confirmatory analysis for the regulatory findings required under Title 10 of the Code of Federal Regulations (10 CFR) Part 51 (see Appendix B for the list of information needs).

This environmental audit was coordinated with the Design Control Document (DCD) Chapter 19, Probabilistic Risk Assessment, safety review. As such, some of the documents that were reviewed as part of this audit may have been reviewed as part of the DCD Tier 2, Chapter 19 safety audit. This was beneficial because these shared documents contain information from the Level 1 and Level 2 Probabilistic Risk Assessment (PRA) being applied as part of the environmental analysis used to support the SAMDA determination.

2.0 AUDIT REGULATORY BASES A regulatory audit is a planned, license or regulation-related activity, that includes the examination and evaluation of primarily non-docketed information. A regulatory audit is conducted with the intent to gain an understanding, verify information, and/or identify information that will require docketing to support the basis of the licensing or regulatory decision. The NRC staff conducted an environmental audit of select non-docketed and proprietary documents involving PRA analysis, offsite consequence analyses, SAMDA evaluation, and supporting information to assist in the review of the environmental impacts related to the NuScale DCA to support the NRCs obligations under the National Environmental Policy Act of 1969 (NEPA), as amended.

Specifically, this regulatory audit is based on the following:

  • 10 CFR 52.47, Contents of Applications; Technical Information, subpart (b)(2);

1 Enclosure

  • Regulatory Guide 4.2, Revision 3, Preparation of Environmental Reports for Nuclear Power Stations; Section 5.11.2, Severe Accidents; and Section 5.11.3, Severe Accident Mitigation Alternatives; and
  • NUREG-1555, Environmental Standard Review Plan, Section 7.2, Severe Accidents, and Section 7.3, Severe Accident Mitigation Alternatives.

3.0 AUDIT OBJECTIVES The NRC staffs objective in conducting this environmental audit was to gather information on the applicants bases for the SAMDA evaluation, including the methodology and analyses based on publicly available information and supporting non-docketed offsite consequences calculations, computer code input/output files, and related analyses that support the information contained in the ER, with the following goals:

  • Obtain sufficient information with appropriate documentation from the applicant to support the environmental review;
  • Examine and evaluate non-docketed information such as sources of information, methodology, assumptions, calculations, analysis worksheets, and computer code input/output files; and
  • Gain a clear understanding of NuScales risk assessment and cost-benefit analysis of SAMDAs contained in Part 3 of the application in the document entitled Applicants Environmental Report - Standard Design Certification, Revision 1, namely the NuScale ER (ADAMS Accession No. ML18086A070).

4.0 SCOPE OF THE AUDIT AND AUDIT ACTIVITIES The audit was conducted in accordance with the audit plan dated October 12, 2018 (ADAMS Accession No. ML18284A259), and performed from October 16, 2018, through November 30, 2018, by reviewing appropriate documents available in the NuScales electronic reading room (eRR). In addition, the NRC staff held two teleconference meetings with the NuScale staff on November 13, 2018, and November 15, 2018, to discuss the audited information for each information need. The NRC staff conducted the audit in accordance with the Office of New Reactors (NRO) Office Instruction NRO-REG-108, Regulatory Audits (Reference 1).

Members of the audit team, listed below, were selected based on their detailed knowledge of radiological consequence assessment, PRAs and severe accident consequence assessment; their experience supporting previous design certification reviews; their knowledge of the regulatory framework regarding design certification; and their knowledge regarding implementation of the review framework for small modular reactors. Audit team members included:

  • Alfred (Trey) Hathaway, Reactor Systems Engineer, (RES/DSA/AAB);
  • Ian Jung, Sr. Reliability and Risk Analyst (NRO/DSRA/SPRA);

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  • Marie Pohida, Sr. Reliability and Risk Analyst (NRO/DSRA/SPRA); and

The documents listed below were reviewed by the NRC staff via eRR or at NuScales Rockville Office during the audit:

1. ECN_0000_00004871_00_Average Fuel and Moderator Temperature Update.pdf, Average Fuel and Moderator Temperature Update
2. EC_0000_00001589_0_NuScale_Best_Estimate_Fuel_Isotopic_Inventory_Calculation.p df, Best Estimate Fuel Isotopic Inventory Calculation
3. ECN_0000_00004881_00_Average Fuel and Moderator Temperature Update.pdf, Average Fuel and Moderator Temperature Update
4. EC_0000_00001592_0_NuScale_Bounding_Fuel_Isotopic_Inventory_Calculation.pdf, Bounding Isotopic Inventory Calculation
5. ECN-P060-6853.pdf, Air as Fill Gas during Module Drop
6. ECN-P060-6207.pdf, Remove SAMDA Assessment from Dropped Module Consequence Analysis
7. ECN-P060-6411.pdf, Aerosol Contribution to Dropped Module Dose Consequence
8. ER_P060-7085_R1.pdf, Dropped Module Consequence Analysis
9. EE-P000-5623 R0.pdf, Impact of MACCS Core Inventory Error on Off-Site Consequence Results
10. ECN-P050-6126 R0.pdf, Clarifications to the LPSD PRA Notebook
11. ECN_P050_00004855_00_Low Power and Shutdown Probabilistic Risk Assessment.pdf, Low Power and Shutdown Probabilistic Risk Assessment Notebook External Reference Corrections
12. ECN-P030-00005213_00_Correction of Reactor Safety Valve Modeling in the Low Power and Shutdown PRA.pdf, Correction of Reactor Safety Valve Modeling in the Low Power and Shutdown PRA
13. ECN_P050_00005505_00_Corrections to Low Power Shutdown PRA Notebook.pdf, Corrections to Low Power Shutdown PRA Notebook
14. ER-P050-7030 Rev 1 LPSD PRA.pdf, Low Power and Shutdown Probabilistic Risk Assessment Notebook
15. ECN-P030-6303 R0.pdf, Correct Errors and Include Discussion on Simulation Methodology and Sensitivity Analyses 3
16. ER_P030_00004113_00_MELCOR_Accident_Consequence_Code_System_MACCS_B ase_Model R0.pdf, MELCOR Accident Consequence Code System MACCS Base Model
17. ER-P030-3751_R2.pdf, Severe Accident Mitigation Design Alternatives Value of Maximum Risk Calculation
18. ER-P030-4525 R1 - CVCS LOCA Inside Containment Off-Site Consequences.pdf, SAMDA Release Category 1: CVCS LOCA Inside Containment Off-Site Consequences
19. ER-P030-4524 R1 - Isolated CVCS LOCA Outside Containment Off-Site Consequences.pdf, SAMDA Release Category 2: Isolated CVCS LOCA Outside Containment Off-Site Consequences
20. ER-P030-4526 R1 - Unisolated CVCS Injection Line Break Outside Off-Site Consequences, SAMDA Release Category 3: Unisolated CVCS Injection Line Break Outside Containment Off-Site Consequences
21. ER-P030-4527 R1 - ECCS Spurious Actuation Off-Site Consequences.pdf, SAMDA Release Category 4 ECCS Spurious Actuation Off-Site Consequences
22. Folder RC 5 Off-Site Consequences
23. ER-P030-4528 R2 - Unisolated Steam Generator Tube Failure Off-Site Consequences.pdf, SAMDA Release Category 5: Unisolated Steam Generator Tube Failure Off-Site Consequences
24. ER-P030-4529 R1 - General Transient with Stuck Open RSV Off-Site Consequences.pdf, SAMDA Release Category 6: General Transient with Stuck Open RSV Off-Site Consequences
25. ER-P030-4530 R1 - General Transient with No RSVs Off-Site Consequences.pdf, SAMDA Release Category 7: General Transient with No RSVs Off-Site Consequences
26. ER-P030-5965 R0 - Dropped Module Off-Site Consequences.pdf, SAMDA Release Category 8: Dropped Module Off-Site Consequences
27. ER-P050-3815 Rev 1 - PRA for RBC- with ECN.pdf, Probabilistic Risk Assessment for Reactor Building Crane with ECN-P050-4846 Rev 0, Probabilistic Risk Assessment for Reactor Building Crane figure and table correction
28. TR-0515-13952-NP-A Risk Significance Determination Rev0 Approved.pdf, Risk Significance Determination dated October 2016
29. ER-P030-3753_R2.pdf, Severe Accident Mitigation Design Alternatives Identification and Screening
30. ER_P040_00004281_00_Seismic_Core_Damage_Frequency_Evaluation_for_Peach_B ottom_and_Surry_Sites.pdf, Seismic Core Damage Frequency Evaluation for Peach Bottom and Surry Sites 4
31. ER_P040_7026_00_Seismic_Margin_Assessment_Notebook with ECN.pdf, Seismic Margin Assessment Notebook, with ECN-P040-6688, Clarifications to Seismic Margin Assessment Notebook
32. Audit Item ER-F Response.pdf
33. Audit Item ER-K.pdf
34. Audit Item ER-P.pdf
35. Audit Item ER-Q.pdf
36. Audit Item ER-R.pdf
37. Audit Item ER-S.pdf
38. Cost Estimate Summary_ER-A Item 1c.pdf
39. Item ER-I Discussion 111318.pdf
40. Response to Sutton 103018 email_R1.pdf
41. NuScales WinMACCS Input and Output files provided at the NuScale Rockville Office
42. NuScales Maximum Benefit Calculation Excel spreadsheets provided at the NuScale Rockville Office
43. NuScales core inventory calculations Excel spreadsheets provided at the NuScale Rockville Office During the audit, the NRC staff went to NuScales Rockville Office to review several non-docketed items, such as MELCOR Accident Consequence Code System (MACCS) project folders, MACCS input files, related MACCS output files, maximum benefit calculation Excel spreadsheets, and NuScale core inventory spreadsheets.

An audit exit meeting was held on December 12, 2018, by telephone to discuss feedback from the audit and to outline the next environmental review steps. The NRC staff did not acquire any NuScale documents during the audit.

5.0

SUMMARY

OF OBSERVATIONS Based on the environmental audit of the applicants documentation, the following were observed:

1. The NRC staff reviewed and was able to understand more fully the assumptions and methodology used in the proprietary NuScale calculation packages in the eRR, for the assessment of severe accidents for the reactor building crane (RBC) failure probability, seismic hazard analysis, offsite consequences via the application of the MACCS code package for the various hazard and accident release categories, and the maximum benefit analysis for the sensitivity cases applied by NuScale.

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2. The NRC staff reviewed twenty-one information needs were presented and discussed during the audit meetings (see Appendix B). All information items were addressed and closed as a result of audit discussions. For seven items, NuScale understood the information needs and will work to revise the ER with the necessary text to address the NRC staffs concern. The NRC staff will conduct a confirmatory review of the changes in the revised ER once submitted by NuScale.
3. The NRC staff reviewed the MACCS computer code package data and output files along with various Excel spreadsheets with respect to the core inventory and maximum benefit analysis. This allowed the NRC staff to reach a clearer understanding of how NuScale applied the MACCS code package for the SAMDA assessment, especially for the dropped module release source term values, and in regards to the information sources for various tables in Appendix B of the ER.

Based on the information provided in the eRR, the NuScale Rockville Office, and the two teleconference calls, the NRC staff was able to satisfactorily close out the information needs with seven confirmatory actions for the NRC staff to verify that the following items are appropriately addressed in future ER revisions by NuScale:

1. Providing editorial changes noted in Information Needs ER-D;
2. Reevaluation of the RBC and low-power shutdown PRAs in regards to Information Needs ER-F and ER-I;
3. Reevaluation of the crane failure SAMDAs in regards to Information Needs ER-F;
4. Updating ER Section 5.2, ER Section B.3, and supporting documentation in regards to the application of population doses from the early and long-term phases in regards to Information Needs ER-K;
5. Providing clarifying edits for Equation 5-27, ER Section 6.3, Table A-1 in regards to Information Needs ER-M;
6. Providing clarifying edits in ER Section B.1.7 in regards to Information Needs ER-Q; and
7. Providing clarifying edits in ER Section B.4 with respect to the seismic hazard curves applied by NuScale in regards to Information Needs ER-U.

6.0 REFERENCES

1. NRO Office Instruction, NRO-REG-108, Regulatory Audits, Revision 0, April 2009.

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APPENDIX A: ENVIRONMENTAL AUDIT AGENDA OCTOBER 16, 2018 THROUGH NOVEMBER 30, 2018 DISCUSSION OF NUCLEAR REGULATORY COMMISSION STAFFS INFORMATION NEEDS Location: Teleconference between NRC Headquarters and NuScales Corvallis Headquarters Date: Tuesday, November 13, 2018 11:00 a.m. Audit Meeting Opens Discussion of Information Needs Items ER-A, ER-B, ER-C, ER-D, ER-E, ER-F, ER-H, ER-I, ER-M, ER-N, and ER-U 1:00 p.m. Audit Meeting Ends Date: Thursday, November 15, 2018 1:30 p.m. Audit Meeting Opens Discussion of Information Needs Items ER-F, ER-G, ER-I, ER-J, ER-K, ER-L, ER-O, ER-P, ER-Q, ER-R, ER-S, ER-T, and ER-U 4:00 p.m. Audit Meeting Ends REVIEW OF ELECTRONIC READING ROOM AND NUSCALES ROCKVILLE OFFICE FILES Dates: October 16, 2018 to November 30, 2018

  • Audit of documents and calculation files provided via the NuScale electronic reading room
  • Review of MACCS input and output material, core inventory spreadsheets, and maximum benefit spreadsheets at the NuScale Rockville Office 7

APPENDIX B: SECOND ENVIRONMENTAL AUDIT INFORMATION NEEDS No. Information Needs ER-A Provide access to the Nuclear Regulatory Commission (NRC) staff on the NuScale Power, LLC (NuScale) electronic reading room (eRR) for the NuScale documents as they relate to the following topic areas in support of Revision 1 of the Environmental Report (ER):

Reactor building crane (RBC) failures and improving reliability of same Evaluation of the costs of enhancements associated with improving the RBC MACCS source term documentation for Release Category 8 Calculation file(s) for the information provided in Tables B-5 and B-6 Calculation file(s) for the information provided in Table B-26 Offsite consequence calculation file(s) for each release category regarding the Peach Bottom site similar to the information provided in Table B-27 for the Surry site Surry and Peach Bottom seismic information and determination of related seismic code damage frequencies Other documents that relate to the changes applied in ER Revision 1 Potential documents to provide, but not limited to, for access in the eRR include:

ER-P030-3751_R1_SAMDA Value Max Risk Calc.pdf ER-P050-3815_R1_PRA for Reactor Building Crane.pdf ER-P060-7085_R1_Dropped Module Conseq_Analysis.pdf ER_P030_3753_01_SAMDA_Identification_and Screening.pdf ER_P030_4113_R0_MELCOR_Accident_Consequence_Code_System_MACCS_Base_Model.pdf ER_P040_4281_R0_Seismic_Core_Damage_Freq_Eval_for_Peach_Bottom_Surry_Sites.pdf ER_P040_7026_R0_Seismic_Margin_Assessment_Notebook.pdf TR-0515-13952-NP-A Risk Significant Determination Approved Version.pdf While these documents may have been reviewed in the first audit, the NRC staff needs to assess the source documents that were the basis for the changes in Revision 1 of the ER.

[Related to ER-01 from the first environmental audit]

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No. Information Needs Audit Notes:

At the start of the audit, all of the requested documents were provided in the eRR. Additional files were provided in the eRR as the audit progressed based on the NRC staff feedback and requests. The files not specifically called out above and the additional files for the SAMDA audit were:

ER-P030-4525 R1 - CVCS LOCA Inside Containment Off-Site Consequences.pdf, SAMDA Release Category 1: CVCS LOCA Inside Containment Off-Site Consequences ER-P030-4524 R1 - Isolated CVCS LOCA Outside Containment Off-Site Consequences.pdf, SAMDA Release Category 2:

Isolated CVCS LOCA Outside Containment Off-Site Consequences ER-P030-4526 R1 - Unisolated CVCS Injection Line Break Outside Off-Site Consequences, SAMDA Release Category 3:

Unisolated CVCS Injection Line Break Outside Containment Off-Site Consequences ER-P030-4527 R1 - ECCS Spurious Actuation Off-Site Consequences.pdf, SAMDA Release Category 4 ECCS Spurious Actuation Off-Site Consequences ER-P030-4528 R2 - Unisolated Steam Generator Tube Failure Off-Site Consequences.pdf, SAMDA Release Category 5:

Unisolated Steam Generator Tube Failure Off-Site Consequences ER-P030-4529 R1 - General Transient with Stuck Open RSV Off-Site Consequences.pdf, SAMDA Release Category 6: General Transient with Stuck Open RSV Off-Site Consequences ER-P030-5965 R0 - Dropped Module Off-Site Consequences.pdf, SAMDA Release Category 8: Dropped Module Off-Site Consequences ECN_0000_00004871_00_Average Fuel and Moderator Temperature Update EC_0000_00001589_0_NuScale_Best_Estimate_Fuel_Isotopic_Inventory_Calculation ECN_0000_00004881_00_Average Fuel and Moderator Temperature Update EC_0000_00001592_0_NuScale_Bounding_Fuel_Isotopic_Inventory_Calculation ECN-P050-6126 R0.pdf, Clarifications to the LPSD PRA Notebook, ECN-P050-6126, Revision 1 ECN_P050_00004855_00_Low Power and Shutdown Probabilistic Risk Assessment.pdf ECN_P050_00005213_00_Correction of Reactor Safety Valve Modeling in the Low Power and Shutdown PRA.pdf, Correction of Reactor Safety Valve Modeling in the Low Power and Shutdown PRA, ECN-P050-5213, Revision 1 ECN_P050_00005505_00_Corrections to Low Power Shutdown PRA Notebook.pdf, Corrections to Low Power Shutdown PRA Notebook, ECN-P050-5505, Revision 1 EC-P050-7030 Rev1 LPSD PRA.pdf, Low Power Shutdown Probabilistic Risk Assessment Notebook, ER-P050-7030, Revision 1 Audit Item ER-F Response.pdf Audit Item ER-K.pdf Audit Item ER-Q.pdf Audit Item ER-R.pdf 2

No. Information Needs Audit Item ER-S.pdf Cost Estimate Summary_ER-A Item 1c.pdf Item ER-I Discussion 111318.pdf Response to Sutton 103018 email_R1.pdf Action Items: None CLOSED 3

No. Information Needs ER-B Provide access to the NuScale WinMACCS input and output files in native format for the Surry site base case and all sensitivity cases.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection III, Review Procedures, item (3) has the staff determine if the method (computer code) used to evaluate the environmental consequences is appropriate and that it evaluates consequences to a distance of 80 km (50 mi). Additionally, items (4) through (10) has the staff determine if various inputs applied in the consequence assessment methodology are appropriate.

[Related to ER-02 from the first environmental audit]

Audit Notes:

Access to the WinMACCS input and output files was provided by NuScale via their Rockville Office. Based on review of the files provided in the NuScale Rockville Office and in the eRR as to the information in output files, the NRC staff developed a good understanding as to the analysis performed by NuScale with MACCS for the off-site consequence analysis.

From the access to this material, other Information Needs were supported and this material assisted in clarifying questions to ask NuScale about their MACCS modeling techniques during the teleconference on November 15, 2018.

Action Items: None CLOSED 4

No. Information Needs ER-C Provide knowledgeable experts to discuss NuScales Final Safety Analysis Report (FSAR) Section 19.2.6, Consideration of Potential Design Improvements Under 10 CFR 50.34(f). For example, the discussion would include Combined License (COL)

Items 19.2-2 (FSAR Chapter 19, page 19.2-36) and COL Items 19.2-3 (FSAR Chapter 19, page 19.2-39) and their significance to SAMDA 85 and the 35 SAMDAs associated with Training/procedural changes are not required for design certification. The staff needs to understand NuScales rationale for including the COL items as part of the DCA Chapter 19 review while not discussing them with respect to related SAMDAs in the ER.

NuScale FSAR Chapter 19 (ADAMS Accession No. ML18086A192) discusses SAMDAs in Section 19.2.6. As part of this discussion, two COL items are provided regarding COL applicants using a site-specific probabilistic risk analysis (PRA) and assessing other components of SAMAs that could be assessed at the COL stage (e.g., procedural enhancements, surveillance action enhancements, training, other design elements not previously considered, etc.). However, there is not a discussion in the ER for each of the two COL items.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, states under Review Interfaces, to coordinate with the responsible [Design Certification Document (DCD) Tier 2, Chapter 19] reviewer for the design certification to ensure consistency with the severe-accident analyses given by the applicant in the ER.

Audit Meeting Discussion Notes of November 13, 2018:

NuScale explained that COL applicants can have different contractors for the safety analysis report (Part 2 of a COL application) and for the environmental report (Part 3 of a COL application). The environmental contractor may not be aware of these COL items and the PRA will be updated at the COL stage. Thus, the two COL items are flags for future COL applicants.

Action Items: None CLOSED 5

No. Information Needs ER-D Provide knowledgeable experts for clarification on the following information given in the ER:

Page 5: the system level event always fails to operate.

Page 41: The meaning of X in ECCS RVV trip valve X Pages B-46 and B-47: The rationale for the statement Therefore, the base case is acceptable, Page B-47: The basis for the statement This seismic CDF analysis used a preliminary NuScale PRA model, however in the context of the results of this report the use of the preliminary PRA model compared to the final PRA model to establish seismic CDF produces a more conservative result and should not significantly affect the identification of SAMDAs. For example, the basis for saying the preliminary PRA model produces a more conservative result along with what result is being referred to.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection III, Review Procedures, item (2) has the staff determine if the information given in the ER on which the applicants analysis is based is appropriate (release sequences, core damage frequencies, and source terms).

Audit Meeting Discussion Notes of November 13, 2018:

NuScale understands the NRC staffs comments given in the first and second bullets above. For the third bullet, the NuScale staff explained that the analysis demonstrated that there would not be a noticeable change from the base case. For the fourth bullet, the NuScale staff understands the NRC staffs comment and that the text is conveying that component fragility is not as important in the final PRA model Action Items:

NuScale will revise the ER text as follows:

Page 5 - Correct the text to .the system always fails to operate Page 41 - Change X to A, as in ECCS RVV trip valve A Pages B-46, B Consider providing additional rationale for why the base case is acceptable when discussing MACCS sensitivity results in Section B.3 of the Environmental Report Page B Consider additional explanation of the seismic core damage frequency (CDF) analysis as in .the preliminary PRA model produces a more conservative result and revising the related ER text for further clarification.

CLOSED, CONFIRMATORY 6

No. Information Needs ER-E Provide knowledgeable experts to discuss how key insights from the Level 1 PRA and Level 2 PRA evaluations provided in FSAR Tables 19.1-23 and 19.1-32 were applied in the NuScale SAMDA assessment. Section 4.0 is the only place in the ER where FSAR Tables 19.1-23 and 19.1-32 are mentioned and there is no indication on how the information informed the SAMDA assessment.

Environmental Standard Review Plan, NUREG-1555, Section 7.3 under Subsection III, Review Procedures, item (2)(b) has the staff verify that the applicants list of potential SAMAs includes a reasonable range of applicable SAMAs derived from consideration of previous analyses and based on insights from the Level 1 and Level 2 portions of the applicants PRA or IPE/IPEEE.

Audit Meeting Discussion Notes on November 13, 2018:

Table 19.1-23 is used as a basis for not including SAMDAs for external events since they are largely the same as those found risk significant for internal events.

Table 19.1-32 is used for screening of SAMDAs related to the phenomena/components described in the table.

Action Items: None CLOSED 7

No. Information Needs ER-F Provide knowledgeable experts to discuss the process for creating the NuScale specific SAMDAs for the RBC failure along with the expected cost to be greater than $450,000.

Due to the nature of the failures as discussed in Section 4.1.11, Reactor Building Crane Failures, the staff needs to understand the development process, assumptions, and assessments conducted by NuScale in identifying the specific Reactor Building Crane SAMDAs for consideration as potentially cost-beneficial. Specifically, the staff needs to understand what was considered to improve reliability for SAMDA 200 and redundancy for SAMDA 201 along with the process for determining the appropriate cost to implement each SAMDA. Additionally, the staff needs to understand how information from the safety analysis was or was not factored into the SAMDA assessment.

For example, during the NuScale DCA safety review, the staff discussed that Table 17.4-1, Design Reliability Assurance Program Structure, System, and Component Functions, Categorization, and Categorization, does not include instrumentation for the Reactor Building Crane (see meeting summary provided in ADAMS Accession No. ML18204A124). The staff also requested additional information regarding module drop event failures in eRAI 9128. NuScale provided responses in two submittals in regards to this eRAI: the original response dated February 5, 2018, under ADAMS Accession No. ML18036B203 and a supplemental response dated June 14, 2018, under ADAMS Accession No. ML18165A431.

Environmental Standard Review Plan, NUREG-1555, Section 7.3 under Subsection II, Acceptance Criteria, has the following acceptance criteria: Completeness and reasonableness, also with respect to the following: (1) the identification of SAMAs applicable to the plant or design under consideration, (2) the estimation of core damage frequency (CDF) reduction and averted person-rem for each SAMA, (3) the estimation of cost for each SAMA, (4) the ranking of value-impact screening criteria to identify SAMAs for further consideration, and (5) the final disposition of promising SAMAs. Additionally, under Subsection III, Review Procedures, items (4) and (5) has the staff assessing whether the applicants cost estimates for the SAMDAs and the benefit-cost comparison are reasonable.

Audit Meeting Discussion Notes on November 13, 2018:

The NRC staff discussed the information in the above notes with NuScale. As for the RBC failure probability, it was explained that the connection between the RBC PRA, low-power shutdown (LPSD) PRA, and the probability values applied in the ER needs to be linked together. The LPSD PRA document, ER-P050-7030, lists the 8.75E-08 value. So, there is that connection from the ER to the LPSD PRA.

As for the cost of the RBC SAMDAs, the NRC staff needs greater clarification as to how NuScale can justify the $450,000 value just based on being a multiple from the cost to modify the module lifting adapter. This is especially true since the top cutsets from the RBC PRA involve operator errors of commission and failure of RBC instrumentation resulting in module drop.

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No. Information Needs This discussion needs to continue in the November 15, 2018, teleconference.

Audit Meeting Discussion Notes on November 15, 2018:

NuScale stated that the needed level of detail was with the hoist, as the dominate risk, and did not analyze any deeper. NuScale notes that the RBC PRA is still being worked and under a state of flux. The NRC staff view is based on the discussion and details provided by eRR documents which would help inform the cost estimate on what can be done to improve RBC reliability and redundancy rather than just a simplification of a multiple value of some other part of the crane system. The NRC staff mentioned finding a webpage by KoneCrane that discusses making upgrades to large bridge cranes.

The NRC staff also discussed that there are additional files provided by NuScale to the eRR for LPSD and RBC PRA. Initial NRC staff indications based on a very preliminary review of the files is that the linkage is there between the three documents (RBC PRA, LPSD PRA, and ER). However, the NRC staff will continue to review these files in more detail.

Additionally, the NRC staff asked NuScale about having access to the five cost estimates referenced in Assumption 2.1.1 of the NuScale document ending in -3753. NuScale responded that these five documents have internal NuScale design decision discussions that are not related to design alternative costing analysis. The NRC staff asked if only relevant pages could be provided, for example as a hardcopy in the NuScale Rockville Office.

Action Items:

As described in a file provided in the eRR after the teleconferences, NuScale will re-evaluate SAMDA 200, which seeks to improve crane reliability, to focus on automation of module movement to reduce operator errors of commission. NuScale agrees that this design alternative is likely to cost less than $450,000 referenced in the ER, and that an estimate of $100,000 is conservative.

NuScale plans to remove SAMDA 201 since adding components is not an effective path to improving crane reliability since the RBC is designed as American Society of Mechanical Engineers (ASME) NOG-1, Type 1, single failure proof crane. NuScale intends to revise the ER and supporting documentation. NuScale also provided in the eRR a summary file regarding the cost estimates given in the five documents mentioned in the above meeting discussion notes (see Information Need ER-M)

CLOSED, CONFIRMATORY 9

No. Information Needs ER-G Provide knowledgeable experts to discuss references for:

Reactor building crane description and related failures discussed in Section 4.1.11 (e.g., no citation to FSAR Section 9.1.5)

Sensitivity results presented in Table 5-5 Core inventories applied for the Base Case and Sensitivity Case No. 5 as provided in Tables B-5 and B-6 (e.g., no citation to FSAR Table 11.1-1 or other source material)

Tables B-7 up to and including Table B-26 The changes to Section B.2 in Appendix B of ER Revision 1 which included new tables or changes to the prior tables in ER Revision 0. Many of these tables do not reference the sources for the provided information.

The seismic CDFs for the Surry and Peach Bottom sites provided in Table B-30 The above identified items do not have citations to the source documents to permit a reviewer to independently evaluate the appropriateness of using the information for assessing the specific environmental impacts.

The degree of detail provided by the applicant in their Environmental Report should satisfy Regulatory Guide 4.2, Revision 2, Preparation of Environmental Reports for Nuclear Power Stations, Section A.7.c, Presentation of Information, (see Regulatory Guide 4.2, Revision 2, page x under ADAMS Accession No. ML003739519).

[Related to ER-07 from the first environmental audit]

The eRR files provide information on the above as follows:

Reactor Building Crane ER-P050-3815 R1 has information Sensitivity results presented in Table 5-5 Each of the RC off-site files in the eRR have a discussion of sensitivity cases but not a summary table. Also, there is a discussion in the Maximum Benefit calculation report (ER-P030-3751) with absolute dose and economic cost data. The individual maximum benefit sensitivity calculations for each APE, AOC, AOE, and AOSC categories were provided at a later date in the audit.

10

Core Inventories See Information Needs ER-A: should be EC-0000-1589 for base case and EC-0000-1592 for high burnup. However, unable to make direct comparison of what is in ER Table B-5 and Table B-6 to the information in both engineering calculation documents.

References for source information provided in Appendix B Release Category Plume RC 1 Off-site Consequences - ER Table B-8: ER-P030-4525 R1 Table A-1 RC 2 Off-site Consequences - ER Table B-10: ER-P030-4524 R1, Table A-1 RC 3 Off-site Consequences - ER Table B-11: ER-P030-4526 R1, Table 4-1; ER Table B-13: ER-P030-4526 R 1, Table A-1 RC 4 Off-site Consequences - ER Table B-15: ER-P030-4527 R1, Table A-1 (Case S.7, all radionuclides in containment are available for release - airborne and deposited - hourly release info from Table A-2)

RC 5 Off-site Consequences - ER Table B-17: ER-P030-4528 R2 Table 4-1; ER Table B-18: ER-P030-4528 R2 Table A-1 RC 6 Off-site Consequences - ER Table B-20: ER-P030-4529 R1 Table A-1 RC 7 Off-site Consequences - ER Table B-22: Should be in ER-P030-4530 R1 Table A-1 RC 8 Off-site Consequences - ER Table B-23: ER-P030-5965 R0 Table 3-1 (TOC has Table 4-1); ER Table B-24: ER-P030-5965 R0 Table A-1 ER Table B-25 information for RC 1 through RC 7 matches information provided in ER-P030-3751, Revision 1. RC 8 CDF is based on EC-P050-7030 Revision 1, the LPSD PRA, for the per module risk of 8.75E-06, namely 8.75E-8 x 12 = 1.05E-06 value in Table B-25.

ER Table B-26 provides a summary from the RCs release tables. However, the Iodine value for RC 8 appears to be incorrect.

Reference for ER Table B-30 See discussion in regard to Information Needs ER-U.

Audit Meeting Discussion Notes on November 15, 2018:

NuScale staff discussed this with the NRC staff in that Excel spreadsheets would be made available in the NuScale Rockville Office with the various cost analysis details to support the NRC staffs review. These files were provided after the teleconference and were reviewed by the NRC staff.

NuScale staff also explained that the core inventory values in the ER tables would be different that for the DCD Tier 2 information since this safety information is based on a 2-year period of core life where the max nuclide value during that 2-year period was applied in the safety analysis. However, the core inventory provided in the ER is taken at the end of the burnup cycle.

11

No. Information Needs Action Items: None CLOSED 12

No. Information Needs ER-H Provide knowledge experts to discuss the rationale for the values presented in Tables 5-1 and 5-2 changing in ER Revision 1 when compared to ER Revision 0.

Tables 5-1 and 5-2 values in ER Revision 1 for Release Categories 1 through 7 generally had a decrease in their per event values while Release Category 8 had a slight increase for off-site dose and off-site economic impact. While the change in values does not affect the overall results previous presented in ER Revision 0 (off-site consequences only account for less than 0.1 percent of the maximum benefit), the staff needs to understand the basis for the changes as being appropriate for the off-site assessment.

For example, code version differences could result in slight changes in results. In the case of NuScales DCA, ER Revision 0 applied MACCS Version 3.10.0 and MELCOR Version 1.8.6 while ER Revision 1 applied MACCS Version 3.10.1.2 and MELCOR Version 2.2.9541. However, there were only two radionuclide inventory changes in the best estimate core inventory, which was input for the base case assessment (Note: ER Rev. 1 also provides in Table B-6 as new information a high burnup core inventory that is applied in Sensitivity Case 5).

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection III, Review Procedures, item (3) has the staff determine if the method (computer code) used to evaluate the environmental consequences is appropriate and that it evaluates consequences to a distance of 80 km (50 mi). Additionally, items (4) through (10) has the staff determine if various inputs applied in the consequence assessment methodology are appropriate.

[Related to ER-14 from the first environmental audit]

Audit Meeting Discussion Notes on November 13, 2018:

NuScale staff confirmed the changes were from an updated MELCOR model based (V2.2) and a final Chapter 19 module model.

Action Items: None CLOSED 13

No. Information Needs ER-I Provide knowledgeable experts to discuss the process for determining the release frequency associated with the dropped module during transport release category.

In reference to RAI 9128, Question 19-37, the staff has identified the need to reconcile the NuScale module drop probability and previous heavy load drop probabilities developed in EPRI Report 1009691 and NUREG-1774 (see meeting summary provided in ADAMS Accession No. ML18204A124). Of note, NuScales failure probability per lift is one order of magnitude lower than estimated in EPRI Report 1009691, and two orders of magnitude lower than estimated in NUREG-1774. Additionally, it is the staffs understanding based on the FSAR Chapter 19 review that module drop events are driven by human error.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, states the following: (1)

Under Review Interfaces, coordinate with the responsible [DCD, Tier2, Chapter 19] reviewer for the design certification to ensure consistency with the severe-accident analyses given by the applicant in the ER; and (2) Under Data and Information Needs, information should be obtained on the release sequences (accident classes) for severe accidents with their associated core damage frequencies and source terms (from the ER and the design certification PRA submittal).

Audit Meeting Discussion Notes on November 13, 2018:

Discussion with NuScale centered around how information in Table D-1 in the ECN ending with 4846 was applied into Table G-1 of the LPSD PRA in the document EC-P050-7030. NuScale did not have the primary subject matter expert (SME) present for this discussion and would have them available for the meeting on November 15, 2018.

Audit Meeting Discussion Notes on November 15, 2018:

Two items of note occurred since the November 13, 2018, meeting. Additional files were provided in the eRR for the NRC staff to review and the NuScale SME was present to discuss the issue. Based on an initial review of the new files provided in the eRR, the traceability of the information from source document to end use documents appears to be there. Also, the NuScale SME was able to confirm that the seismic determination applied by NuScale was based on the seismic information coming from the NTTF 2.1 reviews (See Information Need ER-U for additional discussion of the seismic CDFs). Use of this information is not the same as described in the NuScale ER but is the same source information the NRC staff applied for confirmatory analysis of the seismic CDFs provided in ER Table B-30.

14

No. Information Needs Action Items:

NuScale confirmed if the RBC risk analysis (e.g., dropped module CDF) is revised, the LPSD PRA will also be revised.

CLOSED, CONFIRMATORY 15

No. Information Needs ER-J Provide knowledgeable experts to discuss the analytical results for the offsite consequences and for each averted cost components for the Peach Bottom sensitivity case.

Environmental Standard Review Plan, NUREG-1555, Section 7.3 under Subsection III, Review Procedures, in items (4) and (5) has the staff assessing whether the applicants cost estimates for the SAMDAs and the benefit-cost comparison are reasonable.

[Related to ER-17 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

Similar to Information Need ER-G, the various files provided in the eRR helped to support the NRC staffs review. Additionally, NuScale staff discussed this with the NRC staff regarding Excel spreadsheet files that would be made available in the NuScale Rockville Office with the specific costing details for the Peach Bottom sensitivity case. These files were provided and reviewed by the NRC staff and provided the necessary information to support the NRC staffs independent evaluation.

Action Items: None CLOSED 16

No. Information Needs ER-K Provide knowledgeable experts to discuss the WinMACCS calculations for the sensitivity cases discussed in ER Section 5.8, Maximum Benefit Sensitivity Study.

Environmental Standard Review Plan, NUREG-1555, Section 7.3 under Subsection III, Review Procedures, in items (4) and (5) has the staff assessing whether the applicants cost estimates for the SAMDAs and the benefit-cost comparison are reasonable.

Additional guidance is provided in NEI 05-01A, Section 8 for sensitivity analysis (see NuScale reference 8.1-1).

[Related to ER-17 and ER-18 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

NuScale and NRC staff discussed the application of WinMACCS where NuScale results are from the long-term phase while the NRC staff would also include the early/emergency phase results. This discussion also involved the type number parameter values a MACCS analyst needs to specify to have the proper results provided in the output file. As a result of this discussion, the breakdown of the time periods within the WinMACCS analysis was also discussed. While NuScale understands the NRC staffs comments regarding the doses from the early/emergency phase results, adding these doses would likely have no or little impact on the maximum benefit results due to the small relative contribution that off-site consequences to the maximum benefit.

Action Items:

NuScale would consider updating ER Section 5.2, ER Section B.3, and supporting documentation in regards to the application of population doses from the early and long-term phases. Due to the discussion, the NRC staff has the information it needs to make a determination as part of their independent evaluation.

CLOSED, CONFIRMATORY 17

No. Information Needs ER-L Provide knowledgeable experts to discuss the assumptions and sources of information for the WinMACCS input parameter values ascertained for the Surry and Peach Bottom sites.

The staff has developed specific Surry site and Peach Bottom site MACCS input decks based on the information and references provided in the ER Revision 1. However, there are several MACCS input parameters that the staff cannot assign a value based on ER Revision 1 information or the staff needs access to the information applied in MACCS calculations for certain sensitivity cases (e.g., high burnup core inventory).

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, and Subsection III, Review Procedures, the data and information needs along with guidance for conducting the review. This includes estimating the environmental consequences of severe accidents using an acceptable methodology such as MACCS/WinMACCS. Not all of the WinMACCS input parameter values can be determined based on the information currently provided in ER Revision 1.

[Related to ER-18 and ER-19 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

The NRC staff discussed with the NuScale staff some of the sources of information and some of the prior discussion (e.g.,

Information Need ER-K). Based on information provided in the eRR and the NuScale Rockville Office, the NRC staff was able to create our own WinMACCS input files and to obtain very similar results for both the Surry and Peach Bottom sites. The NRC staff was able to view files in the NuScale Rockville Office regarding the two core inventory tables in ER Appendix B (Tables B-5 and B-

6) that they could verify as the source documents for ER Tables B-5 and B-6.

Action Items:

Based on the above discussions with NuScale and additional information provided under this Information Needs, no additional actions by NuScale and NRC staff is necessary.

CLOSED 18

No. Information Needs ER-M Provide knowledgeable experts to discuss the evaluation of potentially cost-beneficial SAMDAs based on a comparison to the Maximum Benefit sensitivity calculations specifically involving SAMDAs 200, 201, and 202.

The maximum benefit value and the sensitivity cases were revised in ER Revision 1. The staff needs to understand the assumptions and their bases applied in the sensitivity cases, especially for Sensitivity Cases 3, Peach Bottom along with their assessment to the averted cost.

Environmental Standard Review Plan, NUREG-1555, Section 7.3 under Subsection III, Review Procedures, in items (4) and (5) has the staff assessing whether the applicants cost estimates for the SAMDAs and the benefit-cost comparison are reasonable.

[Related to ER-20 from the first environmental audit]

Audit Meeting Discussion Notes on November 13, 2018:

NuScale noted that the factor of 12 for an improvement cost was only applied for the case where all 12 modules are affected under the maximum benefit (see Equation 5-26). For the issue about the Peach Bottom alternative site, this is not the site that should be addressed as the location for setting the site parameters. The site parameter setting location is the Surry site. NuScale wanted to understand the sensitivity of impacts to a different site and selected Peach Bottom site due to access to SOARCA-based information. The NRC staff understands the rationale being applied by NuScale in regards to the issues under this Information Need.

NuScale also provided in their eRR a summary file regarding the basis of cost estimates for several of the design alternatives discussed in ER Section 4, also discussed under Information Need ER-F. These files were helpful to the NRC staff in understanding the cost values of non-Reactor Building Crane SAMDAs.

Action Items:

NuScale will add a footnote in Table A-1 to clarify that the cost comparison is based on 12-module costs and 12-module benefits.

An explanatory note will also be added to ER Section 6.3. In regards to the maximum benefit being calculated assuming releases from three horizontal modules, explanatory text related to Equation 5-27 will be added to the ER.

CLOSED, CONFIRMATORY 19

No. Information Needs ER-N Provide knowledgeable experts to discuss SAMDA 17 and SAMDA 85 bases in regards to a single unit site while technically a multiunit site and their assessment by a COL applicant for a site that contains multiple plants.

The maximum benefit analysis provided in Section 5.7 of ER Revision 1 is based on a site-wide seismic event involving all 12 NuScale Power Modules (NPMs). The staff needs clarification on how NuScale defines a single unit site versus multiple plants or multiunit site.

Environmental Standard Review Plan, NUREG-1555, Section 7.3 under Subsection III, Review Procedures, in items (4) and (5) has the staff assessing whether the applicants cost estimates for the SAMDAs and the benefit-cost comparison are reasonable.

[Related to ER-21 from the first environmental audit]

Audit Meeting Discussion Notes on November 13, 2018:

NuScale staff explained that the SAMDAs with this type of note in the description concerns a potential site where there would be multiple 12-NPM plants. In such a case, there is the potential for inter-plant connections between adjacent reactor buildings (note:

a reactor building contains the UHS pool with 12 NPMs.)

Action Items: None CLOSED 20

No. Information Needs ER-O Provide knowledgeable experts to discuss the implementation of the off-site economic models.

Appendix B of the ER Revision 1 states the SOARCA models used for the basis of the analysis did not intend to evaluate the off-site economic consequences. The staff needs clarification on the development of the parameters required to implement the offsite economic model (e.g., parameters defining the ingestion pathway).

Environmental Standard Review Plan, NUREG-1555, Section 7.2, under Subsection I, Areas of Review, and Subsection III, Review Procedures, describes the data and information needs along with guidance for conducting the review. This includes estimating the environmental consequences of severe accidents using an acceptable methodology such as MACCS/WinMACCS.

Not all of the WinMACCS input parameter values can be determined based on the information currently provided in ER Revision 1.

Audit Meeting Discussion Notes on November 15, 2018:

NuScale staff applied the economic information from SOARCA and general information given in the sample problem. They did conduct a sensitivity case by increasing the economic inputs by a factor of 10 and with the high end sensitivity case for decontamination cost (i.e., the CLI-16-07 case). NuScale staff applied the default COMIDA information that comes with MACCS installation package and did no other developments. The information applied by NuScale is consistent with SOARCA and with past practices.

Based on the discussions with NuScale and additional information provided in the eRR for this Information Need, no additional actions by NuScale and NRC staff are necessary.

Action Items: None CLOSED 21

No. Information Needs ER-P Provide knowledgeable experts to discuss modification and implementation of the Dose Conversions.

The dose conversion file Fgr13dcf.inp was referenced in Appendix B of the ER Revision 1 and the dose conversion factors of this file were updated to modify the chronic inhalation dose factors for nuclides identified in the SOARCA Peach Bottom Uncertainty analysis. The staff needs clarification on how NuScale implemented these modifications and if the implementation included consideration to the other parameters which may be influenced by these changes such as the Cancer Fatality Risk Coefficients.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, and Subsection III, Review Procedures, describes the data and information needs along with guidance for conducting the review. This includes estimating the environmental consequences of severe accidents using an acceptable methodology such as MACCS/WinMACCS.

Not all of the WinMACCS input parameter values can be determined based on the information currently provided in ER Revision 1.

[Related to ER-22 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

The NuScale staff explained the process applied for adjusting the DCF file and provided in the eRR the following information:

Applied the DCF file SOARCA organs FGR13DCF.2015-10-09.inp; Changes made for only the 69 nuclides listed in ER Tables B-5 and B-6; All dose coefficients for the pancreas are moved to the bladder wall organ; and Replaced chronic inhalation does coefficients with values in Table 4.2-8 of NUREG/CR-7155, the Peach Bottom SOARCA uncertainty analysis This is a new topic to the NRC staff for its application to a MACCS analysis.

Action Items:

There is no action for NuScale on this topic. However, the NRC staff notes that this is an extensive change to the MACCS model inputs where the NRC staff is uncertain of the technical justification to adjust the DCF file in this manner. Further NRC staff independent evaluation is necessary to address this topic.

CLOSED 22

No. Information Needs ER-Q Provide knowledgeable experts to discuss the implementation of the off-site economic models.

Appendix B of the ER Revision 1 states Relocation occurs in both the emergency phase and the long-term action phase, modeled as having a five-year duration. The staff needs clarification on the intended meaning of long-term action phase, i.e. is this the length of the long-term phase or the dose projection period during the long-term phase.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection III, Review Procedures, in item (10) has the staff evaluate the protective actions considered by the applicant in its consequence assessment and determine were protective actions properly considered.

[Related to ER-22 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

The NRC and the NuScale staff discussed MACCS user guidance for the different analysis time frames. This discussion included the documents provided in the eRR on the NuScale MACCS analysis. The NRC staff did confirm the values used were reasonable. The NRC staff understands what NuScale did for the analysis while noting that the text in the ER may have not fully describe this.

Action Items:

NuScale would consider clarifying edits in ER Section B.1.7 in regards to the long-term action phase of 5 years and the long-term exposure duration of 50 years regarding the various time periods considered within a MACCS calculation to clarify this part of their WinMACCS model.

CLOSED, CONFIRMATORY 23

No. Information Needs ER-R Provide knowledgeable experts to discuss the modeling assumptions related to the particle size distributions used for Release Categories 1, 2, 3, 4, 6, and 7.

Release Categories 1, 2, 4, 6, and 7 indicate the particle size distribution generated for Release Category 3 also applies to them. The staff needs clarification on how the particle size distribution for Release Category 3 was created and the rationale as to why it is a suitable surrogate when MELCOR should be able to generate the individual calculated particle size distributions for each release category.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, states as part of the data and information needs for the staff to obtain a list of release sequences (accident classes) for severe accidents with their associated core damage frequencies and source terms. The source term information must include the particle size distribution for each release category from the MELCOR analysis. The support program MelMACCS can easily extract from MELCOR the individual calculated particle size distributions for each release category for direct use in MACCS calculations.

[Related to ER-22 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

The NRC and NuScale staff discussed the process NuScale applied for calculating the release for Release Categories 1, 2, 3, 4, 6, and 7 in part based on the documents provided in the eRR and at the NuScale Rockville Office. These releases are based on a 0.2 percent per day leak rate and by applying MELCOR for what is released into containment with a separate analysis for the releases from containment based on the 0.2 percent per day leak rate. Thus, the releases to the environment were not directly from a MELCOR analysis. The discussions also related to what the containment leakage should be due to the nature of the design. It was also noted that this topic is an ongoing issue for the safety review and the environmental analysis could be influenced by the final outcome of that part of the safety review. However, the NRC staff does not need any additional information from NuScale on this topic at this time to support the NRC staffs independent evaluation.

Action Items: None CLOSED 24

No. Information Needs ER-S Provide knowledgeable experts to discuss the creation of the Release Category 8 source terms and its implementation in MACCS.

Release Category 8 of the ER Revision 1 is a release of noble gases and two forms of Iodine (elemental and organic). The staff needs clarification on how this source term was implemented in the MACCS code, including any potential modifications to MACCS control files, dose conversion files, or ingestion models to create the model and technical justification for those modifications.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, and Subsection III, Review Procedures, describes the data and information needs along with guidance for conducting the review. This includes estimating the environmental consequences of severe accidents using an acceptable methodology such as MACCS/WinMACCS.

Not all of the WinMACCS input parameter values can be determined based on the information currently provided in ER Revision 1.

[Related to ER-22 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

The NRC staff has reviewed via the documents in the eRR and as provided in the NuScale Rockville Office the modeling of one chemical in two different forms concerning a non-standard application for MACCS analysis. The NRC staff discussed with the NuScale staff that the principal issue is the modeling of one radionuclide (iodine) in two different chemical forms is a unique application for MACCS analysis. NuScale staff made changes to the WinMACCS initialization files that includes an additional iodine chemical form to reflect the presences of methyl iodide (CH3I). NuScale staff made an assumption on the speciation of elemental and organic iodine based on Appendix B Assumption 1.3 of Regulatory Guide 1.183. The question before the NRC staff is would a release from a dropped module accident behave the same manner as a fuel handling accident?

NRC staff examination of the ER and files in the eRR, including a note from NuScale placed into the eRR after the teleconference, confirmed that, as the NuScale staff explained, a special MACCS chemical class and new iodine isotopes were created to model organic iodine. This would require copying the decay information for Iodine in the WinMACCS INDEXR.DAT file, which is an initialization file used in the calculation to handle decay and pasting the information in the file with a modified name. The WinMACCS model must then include the additional nuclides and inventory provided under the new isotope name. This must also be done for the DCF file so MACCS can calculate the dose due to the new class. This methodology has inherent assumptions that the NRC staff must consider. For example, this treatment of organic iodine implies it behaves as a noble gas. Therefore, the organic iodine will not deposit in the environment. Also, changes can be made to the WinMACCS INDEXR.DAT and DCF file, but the files defining the long-term ingestion dose are in a binary file and cannot be altered by the user. Therefore, as implemented by the NuScale staff, the mean organic iodine is not considered in the long-term ingestion dose calculation beyond plume passage, but not ingestion of milk or food products for example.

25

No. Information Needs These model changes are extensive and the inherent assumptions are not clear to the NRC staff. Therefore, the NRC staff needs to consider if this is a proper approach for the dropped module event in a large volume of water.

Action Items:

No action by NuScale at this time. The NRC staff reviewed the analysis and understands what was done by NuScale. However, as part of the NRCs independent evaluation, the NRC staff will further analyze this first-of-a-kind application to a MACCS analysis.

CLOSED 26

No. Information Needs ER-T Provide knowledgeable experts to discuss the modeling assumptions for Sensitivity Case 3 which utilizes the SOARCA Peach Bottom study as a basis.

Sensitivity case 3 uses the Peach Bottom site as a basis to consider the impact of the site on the results. The staff needs clarification on how this model was implemented, i.e. if the SOARCA Peach Bottom model served as the initial basis for the sensitivity; were deviations between the sites other than population distributions and economic parameters considered, such as differences in the hotspot and normal relocation times or long-term habitability criteria between the two sites.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, and Subsection III, Review Procedures, describes the data and information needs along with guidance for conducting the review. This includes estimating the environmental consequences of severe accidents using an acceptable methodology such as MACCS/WinMACCS.

Not all of the WinMACCS input parameter values can be determined based on the information currently provided in ER Revision 1.

[Related to ER-19 from the first environmental audit]

Audit Meeting Discussion Notes on November 15, 2018:

While the NRC staff was not able to do so based on the information in the ER, they were able to confirm inputs related to the more restrictive habitability criteria employed for the Peach Bottom site in Pennsylvania, relative to the Surry site in Virginia, based on documents in the eRR and the NuScale Rockville Office. This was discussed with the NuScale staff.

Action Items: None CLOSED 27

No. Information Needs ER-U Provide knowledgeable experts to discuss the seismic CDF information provided in Table B-30 for both the Surry and Peach Bottom sites.

Tables ES-1 and ES-2 of the SOARCA study in NUREG-1935 give seismic CDFs for Peach Bottom and Surry of 3x10-6/year and 2x10-5/year, respectively. The seismic CDF given in Table B-30 is a factor of 1000 lower than that in the SOARCA study.

Environmental Standard Review Plan, NUREG-1555, Section 7.2 under Subsection I, Areas of Review, and Subsection III, Review Procedures, describes the data and information needs along with guidance for conducting the review. This may include estimating the environmental consequences of severe accidents by applying core damage frequencies of externally-initiated events. Additionally, the degree of detail provided by the applicant in their Environmental Report should satisfy Regulatory Guide 4.2, Revision 2, Preparation of Environmental Reports for Nuclear Power Stations, Section A.7.c, Presentation of Information, (see Regulatory Guide 4.2, Revision 2, page x under ADAMS Accession No. ML003739519).

[Related to ER-01 and ER-15 from the first environmental audit]

Audit Meeting Discussion Notes on November 13, 2018:

This situation was discussed with NuScale staff. NuScale will follow-up with the NRC staff in the meeting on November 15, 2018, and will reach out to have the NuScale seismic SME at this meeting.

Audit Meeting Discussion Notes on November 15, 2018:

NuScales seismic SME did confirm that they also applied the same seismic hazard curves based on specific seismic re-evaluation tables after the Fukushima accident under NTTF Recommendation 2.1. This conforms to the NRC staffs independent confirmatory analysis of the NuScale ER Table B-30 and is consistent with the requirements from NTTF Recommendation 2.1.

Action Items:

NuScale will modify Appendix B, Section B.4 of the ER to reflect the seismic hazard curves that were used for the seismic CDF presented in ER Table B-30.

CLOSED, CONFIRMATORY 28

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