ML26076A021
| ML26076A021 | |
| Person / Time | |
|---|---|
| Site: | 99902117 |
| Issue date: | 08/21/2023 |
| From: | Facemire J Office of Nuclear Reactor Regulation |
| To: | Staiger M X-Energy |
| References | |
| Download: ML26076A021 (0) | |
Text
From:
Jon Facemire To:
Maggie Staiger; Adrian Muniz; Jorge Hernandez Munoz Cc:
James Roll; Samuel Baylis; Travis Chapman
Subject:
[External_Sender] RE: Feedback on Graphite Engagement #1 Slides Date:
Monday, August 21, 2023 5:14:53 PM Response to those 3 bullets below. I tried address each bullet from the December 14, 2022 Staff discussion points on graphite. This first meeting was not intended to be a deep technical dive, but a roadmap for how we plan to address the NRC comments and a proposal of what will be address in the Technical Reports/PSAR, vs what we propose can wait to address in a later submittal. If it helps, we are happy to support audits following those more technical meetings.
the staff would like to understand better how the submission of the two technical reports supports the PSAR.
At a high level the Graphite Material Qualification and Modeling Technical Report will support chapter 6 of the PSAR and the Graphite Structural Analysis Technical Report will support Chapter
- 3. For those who may not have been in our CPA content meeting, our PSAR aligns with the NEI 21-07 guidance informed by DG-1404 and ARCAP. We chose to follow the ARCAP guidance in DANU-ISG-2022-02 to include Site Information in Chapter 2 and moved the NEI 21-07 Chapter 2 content to chapter 3.
the staff perceived the level of detail to be at a very high level and expects the discussion to be more elaborated than it appears.
This discussion lays out the roadmap, it was not intended to go into significant technical detail. We have 6 engagements over the coming months to do that.
the staff is uncertain of when your team is planning to address the feedback given in prior meetings.
We tried to lay that out in the slides and will try to provide more detail in the meeting. At a high level, the feedback will be formally addressed in the two technical reports submitted alongside the PSAR. We understand that the staff is eager to see our work which is why we are having the technical engagements over the next 6 months and we are happy to support audits (virtual or in person) following each of those technical presentations to go over the contents of those presentations in more detail. Slide 6 of the presentation is where we lay out the roadmap for when we are going to address NRC feedback. We would appreciate input on anything we are missing.
Going through the bullets provided by the NRC on December 14, 2022:
Graphite Oxidation will be discussed in our Graphite Structural Analysis Technical Report and the Evaluation of other loading conditions proposed for the week of January 15, 2024 Graphites role in supporting the PDC will be addressed in PSAR Chapter 6 with more detail in the supporting Technical Reports. I do give a preview of this in the slides. For PDC 16 specifically, our PDC LTR calls out the fuel and our helium pressure boundary (HPB) as our credited barriers for radionuclide retention. The NEI 18-04 process has not identified radionuclide retention as a safety-significant PSF for graphite. The graphite supports radionuclide retention through other PDC like PDC 10 and by supporting the fuel and HPB integrity through heat removal, maintaining core geometry (for controlling heat removal, controlling reactivity, etc.) and supporting inherent reactivity. These are laid out in the slides.
The bounding Xe-100 conditions will be provided in the Graphite Structural Analysis Technical Report and the testing needs will be described in Section 3.1.5 of the PSAR
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informed by our IGNIS material property reference (discussed in the TR and extrapolation meeting week of Sept 18), IGNIS Software Qualification plan (discussed in the TR and the Sept 25 meeting), the design loading condition evaluations (discussed in TR and the Nov 13 meeting) and the evaluation of other loading conditions (discussed in the TR and the Jan 15 meeting).
Wigner energy will be covered in the Graphite Structural Analysis Technical Report and discussed in the evaluation of other loading conditions (the Jan 15 meeting).
Graphite drawings and anticipated temperatures and fluence were provided in the WP provided in the electronic reading room, but more mature analysis supporting the bounding conditions will be specified in the preliminary graphite design spec supporting the Graphite Structural Analysis Technical Report. We will discuss these in the Nov 13 meeting on Design Loading Conditions and the Jan 15 Meeting on other loading conditions.
Creep will be covered in the Graphite Structural Analysis Technical Report and discussed in the meetings on extrapolation methodology, IGNIS, Design Loading Conditions and Evaluation of Other Conditions. The development of the creep model will be discussed in the meetings on extrapolation methodology and IGNIS To address the testing comments, Xe-100 test plans will be compiled to support PSAR chapter 3.1.5 and will be discussed in applicable engagements (extrapolation, IGNIS which includes Qualification Plan, design loading conditions and other loading conditions).
The above is our current plan based on NRC feedback received to date. We intend to adjust as needed based on the feedback we receive over the coming months, so none of the above should be seen as commitments.
Jon
From: Maggie Staiger <mstaiger@x-energy.com>
Sent: Thursday, August 17, 2023 7:26 PM To: Jon Facemire <jfacemire@x-energy.com>
Subject:
FW: Feedback on Graphite Engagement #1 Slides
Feedback on comments and discussion points from the NRC
From: Jorge Hernandez Munoz (He/Him) <Jorge.Hernandez@nrc.gov>
Sent: Thursday, August 17, 2023 6:21 PM To: Maggie Staiger <mstaiger@x-energy.com>
Cc: Adrian Muniz <Adrian.Muniz@nrc.gov>
Subject:
Feedback on Graphite Engagement #1 Slides
Hi Maggie,
I just wanted to convey some initial reactions to the slide deck for the graphite engagement #1 meeting. The staff understands that (per your current engagement plan) this first meeting is to be a high-level overview of the approach. However, we would like your team to be aware that there are certain aspects that generated interest and will likely prompt some questions that will lead into a greater level of detail. For example:
the staff would like to understand better how the submission of the two technical reports supports the PSAR.
the staff perceived the level of detail to be at a very high level and expects the discussion to be more elaborated than it appears.
the staff is uncertain of when your team is planning to address the feedback given in prior meetings.
In general, the consensus after reviewing the slides is that while we understand this aligns with your engagement plan, the staff is very eager to engage in discussions that are beyond the level of detail presented, and the team should be prepared to tackle those types of questions.
Should you have any questions/concerns dont hesitate to contact us.
- Regards,
Jorge Hernández Munoz, P.E.
Project Manager NRR/DANU/UAL2 (o) 301.287.9096 l (c) jorge.hernandez@nrc.gov