ML24273A002
| ML24273A002 | |
| Person / Time | |
|---|---|
| Site: | 99902056 |
| Issue date: | 09/18/2024 |
| From: | Allen Fetter NRC/NRR/DNRL/NLIB |
| To: | |
| References | |
| 20241141 | |
| Download: ML24273A002 (3) | |
Text
U.S. Nuclear Regulatory Commission Public Meeting Summary
Title:
Meeting between the U.S. Nuclear Regulatory Commission (NRC) and Tennessee Valley Authority (TVA) regarding TVAs Letter Requesting Regulatory Interpretation of the Applicability of 10 CFR 50.10(a)(1) to the Permanent Backfill Underneath the Power Block Foundations for the Clinch River Nuclear Site (Docket No. 99902056)
Meeting Identifier: 20241141 Date of Meeting: September 18, 2024 Location: Teams Meeting/Teleconference Type of Meeting: Observation Meeting Purpose of the Meeting: The purpose of this meeting was to have technical discussions between the Nuclear Regulatory Commission (NRC) and Tennessee Valley Authority (TVA) staff on TVAs letter Requesting Regulatory Interpretation of the Applicability of Title 10 of the Code of Federal Regulations (10 CFR) 50.10(a)(1) to the Permanent Backfill Underneath the Power Block Foundations for the Clinch River Nuclear (CRN) Site (under Agencywide Document Access and Management System (ADAMS) Accession No. ML24241A269). Prior to the meeting, the staff made discussion topics available in ML24261A136. Specifically, the staff requested clarification on the discrepancies between the text of the letter which refers to permanent backfill (an NRC regulated construction activity) and the enclosure figures, which illustrate site grading (considered preconstruction and not regulated by the NRC). The staff also sought understanding of the implications for the geologic mapping of excavations for safety-related engineered structures foundations as stipulated in ESP-006 (ML19352D868) Permit Condition 3.
CONTACT: Allen Fetter, NRR/DNRL (301) 415-8556
2 LISTING OF ATTENDEES MEETING BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION (NRC) AND TENNESSEE VALLEY AUTHORITY (TVA) REGARDING TVAS LETTER REQUESTING REGULATORY INTERPRETATION OF THE APPLICABILITY OF 10 CFR 50.10(A)(1) TO THE PERMANENT BACKFILL UNDERNEATH THE POWER BLOCK FOUNDATIONS FOR THE CLINCH RIVER NUCLEAR SITE (Docket No. 99902056)
September 18, 2024 Participant Affiliation Michelle Hayes U.S. Nuclear Regulatory Commission (NRC)
Ian Tseng NRC Allen Fetter NRC Greg Cranston NRC Luissette Candelario-Quintana NRC Zuhan X NRC Jenise Thompson NRC Billy Gleaves NRC Megan Wright NRC Julie Ezell NRC Ray Schiele Tennessee Valley Authority (TVA)
Michele Moorrees TVA Ray Alexander TVA Andrew Dewhurst TVA Cagri Cinkilic (RIZZO)
TVA Jan Mazza Public Summary of Meeting NRC staff started the observation meeting with opening remarks, discussion of logistics and process and introductions of the lead participants. The TVA subject matter expert, Michele Moorrees, stated that she had read the discussion topics enclosure prior to the meeting and clarified that the term permanent backfill was used as a conservative term and that no excavation, thus backfilling, would be involved in order to bring the site up to grade, rather, fill would be used as part of the site preparation grading process. According to TVA, the only backfilling activity planned to be conducted would be the backfilling of the annular space between the excavation walls and the embedded BWRX-300 reactor, if a construction permit is granted.
NRC staff Zuhan Xi noted that the stability of the power block structures surface mounted foundations and the potential interactions during seismic loading between the reactor building seismic Category 1 structures and surrounding power block structures (which would be underlain by reinforced concrete caissons and fill) would need to be addressed by TVA in a
3 future construction permit application for the CRN Site. Zuhan referenced Appendix A, GE-Hitachi Nuclear Energy (GEH) Response to NRC Question 02.05.04-06 on Topical Report (TR) NEDO-33914-A, Revision 2, BWRX-300 Advanced Civil Construction and Design Approach, (ML22168A010) as precedent for this. TVA staff, Ray Alexander, noted that this request for additional information response was written in consideration of the power block structure behavior on soils, and did not consider the potential presence of reinforced concrete caissons as power block foundation supports. TVA noted that GEH might submit a revised TR to account for reinforced concrete caissons as power block foundation supports.
NRC staff Jenise Thompson asked TVA about implications for the geologic mapping of excavations for safety-related engineered structures foundations, prior to the placement of reinforced concrete caissons, as stipulated in ESP-006 (ML19352D868) Permit Condition 3.
She stated that having geologic mapping information from the base of each caisson would be important for confirming the geologic profile under plant structures, consistent with the permit condition. TVA noted that this was a topic for further consideration and potential future engagement with the NRC.
NRC staff Luissette Candelario-Quintana noted that TVA will need to address the backfilling of the annular space between the excavation walls and the embedded BWRX-300 reactor consistent with the combined license (COL) action items in ESP-006 on excavation and backfill (Section 2.5, Excavation and Backfill - COL Action Items). TVA noted that this was a topic for further consideration and potential future engagement with the NRC.
References:
- 1) TVA letter to NRC (August 27, 2024), with a request for regulatory interpretation of the applicability of 10 CFR 50.10(a)(1) to the permanent backfill underneath the power block foundations (ML24241A269). 2) NRC generated Topics for Discussion (ML24261A136) attached to 3) meeting notice 20241141 (ML24249A202)
Action Items/Next Steps: TVA clarified that its reference to the terminology engineered backfill was intended to be conservative and that fill used for raising parts of the site by up to ten (10) feet would be for site grading and engineered backfill would not be required. Based on the clarifying information shared by TVA during the meeting, NRC staff subsequently decided to provide a written response to TVAs letter (ML24241A269) and NRC staff will also support future engagement with TVA on the permit condition and COL Action Item brought up during the meeting.