ML18351A110
| ML18351A110 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 01/11/2019 |
| From: | Getachew Tesfaye NRC/NRO/DLSE/LB1 |
| To: | Samson Lee NRC/NRO/DLSE/LB1 |
| Tesfaye G X/nro/8013 | |
| References | |
| Download: ML18351A110 (6) | |
Text
January 11, 2019 MEMORANDUM TO:
Samuel S. Lee, Chief Licensing Branch 1 Division of Licensing, Siting, and Environmental Analysis Office of New Reactors FROM:
Getachew Tesfaye, Senior Project Manager /RA/
Licensing Branch 1 Division of Licensing, Siting, and Environmental Analysis Office of New Reactors
SUBJECT:
SUMMARY
OF THE DECEMBER 12, 2018, CATEGORY 1 PUBLIC TELECONFERENCE TO DISCUSS ACCIDENT SOURCE TERM METHODOLOGY ASSOCIATED WITH THE NUSCALE POWER, LLC., DESIGN CERTIFICATION APPLICATION The U.S. Nuclear Regulatory Commission (NRC) held a Category 1 public teleconference meeting on December 12, 2018, to discuss the NuScale Power, LLC., (NuScale) accident source term methodology associated with its design certification application. This teleconference was a follow-up to the June 7, 2018, June 27, 2018, August 9, 2018, and August 29, 2018, meetings on the same subject. The meeting attendees included personnel from NuScale. There were no members of the general public in attendance.
The public meeting notice dated December 12, 2018, can be found in the NRCs Agencywide Documents Access and Management Systems under Accession Number ML18346A179. This meeting notice was also posted on the NRC public Website.
Enclosed is the Meeting Agenda (Enclosure 1), List of Attendees (Enclosure 2), and the Meeting Overview (Enclosure 3).
Docket No.52-048
Enclosures:
As stated cc w/encl.: DC NuScale Power, LLC Listserv CONTACT: Getachew Tesfaye, NRO/DLSE 301-415-8013
- via email NRO-002 OFFICE DLSE/LB1:PM DLSE/LB1:LA DLSE/RPAC DLSE/LB1:PM NAME GTesfaye(c)
CSmith MHart GTesfaye (s)
DATE 12/16/2018 01/07/2019 12/17/2018 01/11/2019
U.S. NUCLEAR REGULATORY COMMISSION CATEGORY 1 PUBLIC MEETING TO DISCUSS ACCIDENT SOURCE TERM METHODOLOGY ASSOCIATED WITH THE NUSCALE POWER, LLC DESIGN CERTIFICATION APPLICATION MEETING AGENDA December 12, 2018 Time Topic 1:00 p.m. - 1:15 p.m.
Introductions and Identification of topics 1:15 p.m. - 2:20 p.m.
Discussion of Accident Source Term Methodology 2:20 p.m. - 2:30 p.m.
Public Comments/Questions 2:30 p.m.
Adjorn
U.S. NUCLEAR REGULATORY COMMISSION CATEGORY 1 PUBLIC MEETING TO DISCUSS ACCIDENT SOURCE TERM METHODOLOGY ASSOCIATED WITH THE NUSCALE POWER, LLC DESIGN CERTIFICATION APPLICATION LIST OF ATTENDEES December 12, 2018 Name Organization Getachew Tesfaye U.S. Nuclear Regulatory Commission (NRC)
Zachary Gran NRC Ronald LaVera NRC Michelle Hart NRC Hanh Phan NRC Michael Dudek NRC Robert Taylor NRC Michelle Hayes NRC Olivia Mikula NRC Thomas Steinfeldt NRC Jeremy Bowen NRC Brian Smith NRC Sheila Ray NRC Olivier Lareynie NRC Jorge Cintron-Rivera NRC Jason Schaperow NRC Edward Stutzcage NRC Ian Jung NRC Kevin Coyne NRC John Monninger NRC Samuel Lee NRC Tom Bergman NuScale Power, LLC. (NuScale)
Gary Becker NuScale Peter Subaiya NuScale Robert Gamble NuScale Mark Shaver NuScale Scott Weber NuScale Paul Guinn NuScale Sarah Bristol NuScale Greg Myers NuScale Patrick Conley NuScale Bill Galyean NuScale
U.S. NUCLEAR REGULATORY COMMISSION OVERVIEW OF THE DECEMBER 12, 2018, PUBLIC MEETING TO DISCUSS ACCIDENT SOURCE TERM METHODOLOGY ASSOCIATED WITH THE NUSCALE POWER, LLC DESIGN CERTIFICATION APPLICATION MEETING OVERVIEW The purpose of this meeting was for the U.S. Nuclear Regulatory Commission (NRC) staff to continue the dialogue on NuScale Power, LLCs (NuScale) planned changes to the methodology for accident source term (AST) that was previously discussed in public meetings on June 7, 2018 (Agencywide Documents Management and Access System (ADAMS)
Accession Number ML18173A260), June 27, 2018 (ML18206A933), August 9, 2009 (ML18240A210), and August 29, 2018 (ML18249A261).
The specific objective of this meeting was for the NRC staff to gain updated knowledge on NuScales activities on the proposed approach for AST since the last meeting and for the staff to provide historical practices and regulatory requirements for accident source terms for both safety analyses and equipment qualification (EQ) evaluations.
A.
NuScale provided an update on its activities that focused on evaluating equipment needed in the event of severe accidents and how long the equipment needed to survive to perform its function. Working with its vendor, NuScale was able to determine that the limiting equipment is the electrical penetration assembly (EPA). The positive EPA test data that NuScale was able to find from its vendor is for neutron radiation from a source slightly higher than iodine spike doses. NuScale has not yet found similar test data for the expected higher gamma doses. NuScale is also considering an engineering solution to reduce dose. NuScale expects the EPA to perform its safety function following a severe accident.
NuScale stated that in the event of a severe accident, the containment will not be opened to take sample since it is the primary barrier for radiological release. NuScale will rely on external radiation monitors to perform the post-accident sampling function.
Therefore, NuScale plans to ask for exemption from the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.34(f)(2)(viii) requirements on post-accident sampling.
B.
The NRC staff stated that historically, every application has used a core melt accident radiation source for siting, EQ, and other related analyses under the regulations. The staff further stated that despite historical treatment of equipment qualification and siting analyses, there is a marked difference in the wording of 10 CFR 50.49 compared to 10 CFR 50.34 and 10 CFR 100.11, with regard to accidents considered.
The language in 10 CFR 50.49(e)(4) requires electrical equipment qualification to address a radiation environment based on the most severe design basis accident during or following which the equipment is required to remain functional. Title 10 CFR 50.49(f)(4), identifies methods for qualifying electrical equipment including [a]nalysis in combination with partial type test data that supports the analytical assumptions and conclusions.
The language in the footnote associated with 10 CFR 50.34(f)(2)(vii) and 10 CFR 100.11(a), states explicitly that the accidents analyzed for these evaluations have generally been assumed to result in substantial meltdown of the core.
C.
The NRC staff also provided information on the equipment survivability analysis normally done to demonstrate functionality of difficult to qualify equipment. The staff cited SECY 90-016, Evolutionary Light Water (LWR) Certification Issues and Their Relationship to Current Regulatory Requirements and SECY 93-084, Policy, Technical, And Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor (ALWR) Designs and the respective Commissions SRMs that approved the staffs position:
features provided only for severe-accident protection need not be subject to the 10 CFR 50.49 environmental qualification requirements; and mitigation features must be designed so there is reasonable assurance that they will operate in the severe-accident environment for which they are intended and over the time span for which they are needed.
D.
Next steps:
NuScale plans to submit a request for exemption from the 10 CFR 50.34(f)(2)(viii) requirements on post-accident sampling by the end of January 2019, with a pre-submittal meeting to be scheduled in mid-January 2019.
NuScale plans to submit a white paper describing its approach for resolution of the AST issue in the very near future. The staff would evaluate the proposed resolution and provide feedback to NuScale in a public meeting to follow.
The expected date of the submittal of the revision to the NuScale Accident Source Term Methodology topical report and related changes to the NuScale FSAR will be determined later.