ML23271A138
| ML23271A138 | |
| Person / Time | |
|---|---|
| Site: | 99902071 |
| Issue date: | 09/28/2023 |
| From: | Hernandez J NRC/NRR/DANU/UAL2 |
| To: | Michael Wentzel Office of Nuclear Reactor Regulation |
| References | |
| Download: ML23271A138 (1) | |
Text
September 28, 2023 MEMORANDUM TO:
Michael Wentzel, Chief Advanced Reactor Licensing Branch 2 Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation FROM:
Jorge Hernandez, Project Manager
/RA/
Advanced Reactor Licensing Branch 2 Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF THE AUGUST 24, 2023, PUBLIC MEETING WITH X-ENERGY, LLC TO DISCUSS GRAPHITE QUALIFICATION FOR THE XE-100 HIGH TEMPERATURE GAS REACTOR On August 24, 2023, (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML23234A167) the U.S. Nuclear Regulatory Commission (NRC) staff held a pre-application partially closed meeting with the X Energy, LLC (X-energy) staff to discuss X-energys approach for designing and qualifying the graphite components of the Xe-100 high temperature gas reactor, in support of a construction permit application for a power reactor at the Dow Chemical Company (Dow) Seadrift site in Seadrift, TX. The slides used by X-energy during the open portion of the meeting can be found in ADAMS (ML23222A270). The proprietary slides used during the closed portion of the meeting have also been added to ADAMS (ML23222A271).
CONTACT: Jorge Hernandez, NRR/DANU 301-287-9096 Project No.: 99902071
Enclosure:
List of Meeting Attendees Distribution List (GovDelivery):
X-energy Xe-100
Enclosure
Background
By letter dated October 31, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22304A197), X Energy, LLC (X-energy) submitted a licensing topical report (LTR) Xe-100 Licensing Topical Report: Graphite Qualification Methodology, for NRC staff review. The LTR describes the method for qualification of graphite core structures used by X-energy for the Xe-100 reactor.
On December 14, 2022, the U.S. Nuclear Regulatory Commission (NRC) staff held a partially closed public meeting with X--energy to request clarification on certain aspects of the LTR.
During the meeting, the staff made various observations and identified technical deficiencies, which are documented in the meeting summary (ML23040A141). During the meeting, X-energy stated that it was very likely that they would withdraw the LTR. On December 20, 2022, Xenergy told the NRC staff that they planned to withdraw the report.
By letter dated January 3, 2023 (ML23003A803), X-energy requested to withdraw the LTR. By letter dated February 1, 2023 (ML23023A248), the staff (1) acknowledged the request to withdraw the LTR, (2) confirmed the cease of the review, and (3) documented the issues identified by the NRC staff as enclosures to the letter. The staff indicated that X-energy should address these issues if they intended to re-submit the LTR.
The X-energy team proposed conducting a series of public meetings, some of which will be partially closed, to discuss specific aspects of graphite qualification for the Xe-100 design.
By letter dated July 31, 2023 (ML23212B211), X-energy transmitted a regulatory engagement plan focused on material qualification of graphite and other graphite-related matters, along with the proposed schedule for the meetings.
Meeting Summary This meeting was the first of the seven meetings included in X-energys regulatory engagement plan for graphite components.
The X-energys staff presentation discussed the following topics:
A summary of the graphite qualification planned pre-application activities, which included two proposed technical reports in connection with the planned CP application to authorize deployment of the X-energy design at the Dow Seadrift site. The first technical report, Graphite Material Qualification and Modeling Technical Report, will include the graphite system design description and principal design criteria; this technical report will be referenced in Chapter 6 of the Preliminary Safety Analysis Report (PSAR). The second technical report, Graphite Structural Analysis Technical Report, identifies the plans for addressing degradation mechanisms specified in ASME Section III Division V and describes the scope of the planned test activities; this technical report will be referenced in the PSAR methodologies discussed in Chapter 3. The X-energy team expressed interest in understanding what information should be included in these technical reports to enable the staff to make the necessary safety findings in support of the CP application.
A crosswalk of the various aspects of the safety analysis for graphite components mapped to the documents that will establish the design basis.
The principal design criteria (PDC) that will be applicable to graphite components. The
Enclosure X-energy team noted the need to revise their PDC LTR (transmitted via letter dated July 13, 2022 (ML22195A260)), that is currently under NRC staffs review, to reflect a proposed revision to PDC 70, Reactor vessel and reactor system structural design basis. X-energy plans to submit the revised PDC LTR in the near future.
Quality assurance topics that they intend to address in the PSAR.
A breakdown of the graphite qualification-related content that X-energy is planning to include in the CP and the operating license applications.
The NRC staff made the following questions and observations:
The use and capabilities of the Irradiated Graphite Analysis Software (IGNIS) are not well understood. X-Energy plans to have a future presentation on the IGNIS software.
X-Energy's approach to modeling and the data used in their model to demonstrate the graphite will meet the design requirements is unclear. X-Energy plans to have future presentations to elaborate on their modeling approach, and presumably a description of the data used to verify/validate their model.
The staff recommended that X-energy performs a delta analysis or justification of changes between qualification methodologies proposed by X-energy and those in the ASME code edition endorsed by NRC.
Because the PSAR (in some areas) will only provide a high-level summary of the design, the NRC staff stated that the expectation would be for the applicant to prepare a more detailed basis and have it available for the staffs audit.
Although X-energy cited the level of detail about graphite qualification included in the Kairos Hermes PSAR, the NRC staff clarified that there are important differences between the Kairos and X-energy applications that need to be considered when determining the appropriate level of detail in the PSAR. For example, Kairos had a previously approved LTR for its graphite qualification methodology, which adds extensive detail on the docket to information provided in the Hermes PSAR. Additionally, the Hermes is a test reactor with a limited plant life, while the X-energy application will be for a power reactor with a much longer graphite component life. Therefore, relying on the Hermes PSAR level of detail to support the development of the X-energy CP application may not be appropriate. It is likely that additional information will be needed, especially in areas where X-energy proposes deviations from ASME code requirements.
The gap identified in the PDC LTR may impact the development of the safety evaluation.
The evaluation report is currently in progress and some of the content may need to be rewritten. Additional information is needed to determine the impact and the staffs level of effort.
The basis that X-energy used to determine the graphite qualification-related content of the CP application and the content to be included in the operating license application is not well understood. Further discussions on this subject will be needed.
During the meeting, the NRC staff did not make any specific comments regarding the adequacy of the X-energy approach for graphite qualification.
To close, X-energy listed the topics that will be addressed in the next meeting(s), consistent with their regulatory engagement plan for this topic.
ML23220A030 OFFICE NRR/DANU/UAL2:PM NRR/DANU/UAL2:BC NRR/DANU/UAL2:PM NAME JHernandez MWentzel JHernandez DATE 09/ 27 /2023 09/ 28 /2023 09/ 28 /2023
Enclosure List of Attendees Partially Closed Observation Public Meeting for the Nuclear Regulatory Commission (NRC) to Discuss X Energy, LLCs (X-energy) Approach for Graphite Qualification for the Xe-100 High Temperature Gas Reactor August 24, 2023 Open Meeting Name Organization Adrian Muniz NRC Alexander Chereskin NRC Boyce Travis NRC Dan Beacon NRC Greg Oberson NRC Ian Jung NRC Inseok Baek NRC Jorge Hernandez Munoz NRC Joseph Bass NRC Matthew Gordon NRC Meg Audrain NRC Michael Wentzel NRC Ondra Dukes NRC Ryann Bass NRC Zackary Stone NRC Chris Cruz X-energy FJ van Zanten X-energy Guan Yang X-energy James Roll X-energy Jasmine Wang X-energy Jon Facemire X-energy Kevin Kim X-energy Lisa Williams X-energy Maggie Staiger X-energy Tim Lucas X-energy Travis Chapman X-energy Zach Burns X-energy Gwennael Beirnaert X-energy (contractor)
Enclosure Name Organization Laura Dawson X-energy (contractor)
Michael Saitta X-energy (contractor)
Charlyne Smith Breakthrough Institute Neil Herman BWXT Carl Friesen Department of Energy Stephan Moen Energy Northwest Patrick Greer Global First Power Bobby Janecka Texas Commission on Environmental Quality Donald Behnke Westinghouse Ali Nojoumi Unknown Dominik Muszynski Unknown Emna Unknown Ryan Buck Unknown Sam Baylis Unknown Zenas McLucas Unknown Closed Meeting Name Organization Adrian Muniz NRC Alexander Chereskin NRC Boyce Travis NRC Dan Beacon NRC Greg Oberson NRC Ian Jung NRC Jorge Hernandez Munoz NRC Joseph Bass NRC Matthew Gordon NRC Meg Audrain NRC Michael Wentzel NRC Ondra Dukes NRC Ryann Bass NRC Zackary Stone NRC Chris Cruz X-energy FJ van Zanten X-energy Guan Yang X-energy
Enclosure Name Organization James Roll X-energy Jasmine Wang X-energy Jon Facemire X-energy Lisa Williams X-energy Maggie Staiger X-energy Tim Lucas X-energy Travis Chapman X-energy Zach Burns X-energy Gwennael Beirnaert X-energy (contractor)
Laura Dawson X-energy (contractor)
Michael Saitta X-energy (contractor)
Stephan Moen Energy Northwest (approved by X-energy)
Ali Nojoumi Unknown (approved by X-energy)
Emna Unknown (approved by X-energy)
Ryan Buck Unknown (approved by X-energy)
Sam Baylis Unknown (approved by X-energy)
Zenas McLucas Unknown (approved by X-energy)