ML25240B607

Long Mott Generating Station Site Audit Plan

ML25240B607
Person / Time
Site:	05000614
Issue date:	08/28/2025
From:	Ohara J NRC/NMSS/DREFS/EPMB3
To:	Long Mott Energy
References
EPID L-2025-CPE-0000
Download: ML25240B607 (1)

Text

LONG MOTT ENERGY, LLC - LONG MOTT GENERATING STATION ENVIRONMENTAL REPORT AUDIT PLAN (CAC NO. 001912, 05000614; EPID NO. L-2025-CPE-0000)

APPLICANT INFORMATION Applicant:

Long Mott Energy, LLC Applicant Address:

530 Gaither Road, Suite 700 Rockville, MD 20850.

Plant Name(s) and Unit(s):

Long Mott Generating Station Project No(s).:

001912, 05000614

Background:

By letter dated March 31, 2025 (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML25090A057), Long Mott Energy, LLC. (LME), submitted an Environmental Report (ER) (ML25090A063) in support of a construction permit (CP) application. The staff is preparing an environmental assessment (EA) to evaluate the environmental impacts from the proposed action. On May 12, 2025, the U.S. Nuclear Regulatory Commission (NRC) staff sent LME a letter accepting the Long Mott Generating Station (LMGS) CP application for detailed review (ML25115A247). A notice of the acceptance for docketing was published in the Federal Register on May 2, 2025 (90 FR 18874).

In its initial review of data and information within the corresponding context of the ER, the staff has identified information needs (Attachment 1) for an environmental audit that would promote a better understanding of the detailed analysis and bases underlying the construction permit application. This environmental audit will provide the NRC staff with an opportunity to discuss these items with the applicant subject matter experts (SMEs), staff and contractors. During the audit, NRC staff would like to discuss a wide range of environmental matters related to land use, ground and surface water, terrestrial and aquatic ecology, human health, postulated accidents, radiological and non-radiological waste, cultural resources, alternatives, air quality and noise.

The audit will allow the NRC staff to better understand the site, environmental interfaces of the project, and modeling results, in order to draw appropriate environmental findings.

Purpose:

The NRC staff is conducting an environmental audit of the LME ER to seek clarification, improve understanding, and to verify information provided in the ER and supporting documentation.

Regulatory Audit Basis:

2 Requirements for ERs supporting CPs are specified in 10 CFR 51.50, Environmental Reports -

construction permit, early site permit or combined license stage.

Regulatory Audit Scope Audit team members will review documents and other requested information outlined in the information needs list (Attachment 1). This list covers environmental review areas outlined in the Background section of this audit plan. Attachment 2 lists areas for which pre-arranged audit discussions will be worked out between the NRC and LME project managers to take place the first week of the audit (see discussion below for audit logistics.)

Environmental Review Team Table 1 includes a list of the NRCs environmental review team assigned to the LME Site CP review and their role or review area coverage. Additional NRC staff will participate in some audit discussions based on coordination with related reviews (see Attachment 2).

Table 1. Review Areas with assigned team members Team Member Role / Review Area Dan Barnhurst Environmental Review Supervisor Joe OHara Environmental Project Manager; Site and Technical Overview; Proposed Action Robert Hoffman Environmental Project Manager; Purpose and Need Dave Goodman Project Manager - Pacific Northwest National Laboratory Hayley McClendon Project Manager - Pacific Northwest National Laboratory Don Palmrose Radiological Human Health; Postulated Accidents, Waste, HP Sarah Lopas Historic and Cultural Resources, National Historic Preservation Act Section 106 Gerry Stirewalt Ground Water and Geology Lloyd Desotell Surface Water Bradley Werling Air Quality, Climate Resilience, and Meteorology Jeff Rikhoff Socioeconomics; Cost-Benefit Discussion; Need for Power Peyton Doub Ecological Resources, Land Use and Visual Resources Rao Tammara Fuel Cycle, Non-Radiological Human Health, Radiological Waste Management, Noise, Transportation of Radioactive Material Shannon Healy Endangered Species Act Section 7 Consultation Laura Willingham Climate Resilience Tim Drzewiecki Postulated Accidents - Safety & Licensing Information and Other Material Necessary for the Regulatory Audit The NRC staff requests that all the documents and other requested information identified in be provided by LME on the online reference portal.

3 Logistics Entrance Meeting September 8, 2025 Exit Meeting January 2, 2026 (Tentative)

Audit meetings will take place at X-energys office in a virtual format, using Microsoft Teams, or via other, similar platform. The NRC and LME audit managers will schedule meetings as needed upon LMEs review of this audit plan. The audit duration is anticipated to be approximately six weeks with activities occurring regularly throughout the first three days and intermittently thereafter. Attachment 2 describes sessions to be pre-arranged for the first three days. Follow up sessions will be scheduled, if needed, until audit closure.

Special Requests The NRC staff requests that LME ensure that their technical staff are available to answer questions during the audit.

Deliverables At the completion of the audit, an exit meeting will be held at which time a summary of audit activities and discussions will be presented along with the status of staff information needs identified as part of the audit. In addition, the audit team will issue an audit summary within 90 days after the exit meeting. The audit summary will be declared and entered as an official agency record in ADAMS and be made available for public viewing through the publicly available records component of ADAMS.

References The audit will follow the guidance in the Office of Nuclear Reactor Regulations (NRR) Office Instruction LIC-111, Revision 1, Regulatory Audits, (ML19226A274).

Contacts Please contact Joe OHara at (301) 415-6854 or by email at Joe.OHara @nrc.gov about any issues related to the conduct of the audit.

Date: August 28, 2025 Theodore Smith, Branch Chief Environmental Technical Review Branch 2 Division of Rulemaking, Environmental and Financial Support Office of Nuclear Materials Safety and Safeguards

ML25240B607 OFFICE NMSS/REFS/EPMB3/PM NMSS/REFS/EPMB3/BC NAME JOHara TSmith DATE 8/27/2025 8/28/2025

LME CP Application Environmental Audit Information Needs List Info Need #

Information Need ER Section Plan for Audit Accidents ACC-1 The calculated bounding dose values for postulated accidents is supplied for the time period of 0-720 hours. Please provide a Subject Matter Expert (SME) to discuss the dose value for the worst 2-hour period requested in guidance (see RG 4.2 Revision 3 Section 5.11.1, Design-Basis Accidents) with respect to the 0-720 hour dose values associated with this calculation and access to related calculational files.

This information need and any related access to calculational files should be coordinated with the NRC Safety Staff.

5.13 Discuss at audit -

provide an SME Confirm that because Exclusion Area Boundary (EAB) = Low Population Zone (LPZ) and that no doses exceed 25 Rem requirement that the 0-2 hour dose is not required as per 10 CFR 50.34(a)(ii)(D)(1) because the total dose does not exceed the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> requirement.

ACC-2 Please provide access to the MELCOR Accident Consequence Code System (MACCS) calculations (input and output files in the Electronic Reading Room (ERR)),

any additional relevant calculational files or explanations, and an SME to discuss the calculations.

5.13 RESOLVED ACC-3 Step 1 of the Severe Accident Mitigation Alternative (SAMA) analysis has been described as being complete. Please provide an SME to discuss the analysis from step 1 and why the maximum benefit value (step 2) from items identified in step 1 of the analysis was not performed, and what will be addressed at the Operating License (OL) stage.

5.13 Discuss at audit -

provide an SME Need additional justification regarding Step 1 of the SAMA analysis.

2 ACC-4 Sector Population, Land Fraction, and Economic Estimation Program (SecPop) version 4.3.0 is based on the 2010 census data and 2007 county data. Please confirm that the population land use data used as an input to the accident analysis has been adjusted for potential changes in use over the time period analyzed (e.g., adjustment based on 2020 census data and years beyond along with recent county data). The staff observed population data in Section 2.5.1 and Section 5.13.2.2, however it is unclear if the population projections discussed in both sections are the same. Please provide any additional relevant calculational files or explanations (in the ERR) and an SME to discuss the calculations.

5.13 Discuss at audit -

provide an SME Potential Request for Confirmatory Information (RCI) of Long Mott Energy (LME) response in order to clarify text in ER.

3 ACC-5 The last row in ER Table 5.13.101, Design Basis Accidents, is for seismic DBA sequences with N/A as initiating event along with the remarks statement As discussed in Preliminary Safety Analysis Report (PSAR) Section 2.5, a seismic event is not a credible initiating event for the LMGS site. However, PSAR Section 3.6.12 is entitled Seismic Design Basis Accident (DBA) and results of the seismic DBA analysis is an overall dose at the EAB of less than 15 rem (TEDE), satisfying the 25-rem limit (see the end of PSAR Section 3.6.12.4, Dose Consequence, at the top of PSAR page 3.5-72). Please provide an SME(s) to discuss the apparent difference between ER Table 5.13.1-1 and PSAR Section 3.6.12.

5.13 Discuss at audit -

provide an SME The last row in ER Table 5.13.101, Design Basis Accidents, is for seismic DBA sequences with N/A as initiating event along with the remarks statement As discussed in PSAR Section 2.5, a seismic event is not a credible initiating event for the Long Mott Generating Station (LMGS) site.

However, PSAR Section 3.6.12 is entitled Seismic DBA and results of the seismic DBA analysis is an overall dose at the EAB of less than 15 rem (TEDE), satisfying the 25-rem limit (see the end of PSAR Section 3.6.12.4, Dose Consequence, at the top of PSAR page 3.5-72). Please provide an SME(s) to discuss the apparent difference between ER Table 5.13.1-1 and PSAR Section 3.6.12.

Air Quality AQ-1 Please provide regional National Ambient Air Quality Standards (NAAQS) measurements, or links to publications with these measurements (ESRP-2.7) 2.7 RESOLVED AQ-2 Please provide monthly dewpoint and monthly average temperatures (ESRP-2.7) 2.7 RESOLVED

4 AQ-3 Please provide a summary of monthly stability class (ESRP-2.7) 2.7 RESOLVED AQ-4 Please provide information on emissions during pre-construction and construction. While emission factors by vehicle type were provided, no data on total use of these was provided. Some mechanism to determine the total emissions during construction and pre-construction should be added.

(10 CFR 51.45(c) and ESRPs 4.4.1, 5.3.2.1, and 5.3.3.1) 7.2.7 Discuss at audit.

Alternatives ALT-1 Dow's corporate decarbonization goals are cited as one of the project needs for the installation of Xe-100 reactor. It would be beneficial to comprehend the significance of these objectives in relation to the anticipated reduction in CO2 emissions (ESRP 9.2).

9.2 RESOLVED ALT-2 As outlined in ER Section 9.2.2, it appears that several energy alternatives may not fully align with the project's dual goals of 1) demonstrating the Xe-100 reactor and 2) supplying the power needs of Seadrift Operations (SDO) while also reducing the carbon footprint from the current natural gas cogeneration plant, leading to their preliminary exclusion. Nonetheless, Section 9.3.1 suggests that the new power plant's main aim is to supply electricity and steam directly to SDO, which may be achievable through various energy alternatives.

Could you clarify whether the primary focus is on the demonstration of the Xe-100 reactor, the generation of electricity and steam, or both? (ESRP 9.2.2).

9.2.2 RESOLVED

5 ALT-3 The proposed action is to authorize the construction of four Xe-100 modules; if the objective is demonstration rather than generation, why is construction and operation of four modules necessary? (ESRP 9.2.2) 9.2.2 RESOLVED ALT-4 Please provide the Site Feasibility Study and Alternative Site Study, particularly to support the requirement that the reactors be located within 1.5 miles of SDO.

(ESRP 9.3) 9.3.1 RESOLVED ALT-5 Please clarify the comparative acreages of Sites A, B, C, and D. If Site A is the Proposed Site, then according to Sec 4.3.1 it is 1537 acres, of which appr. 721 acres would be disturbed. Site B is reported as 235 acres, Site C as 166 acres, and Site D as 193 acres.

Yet in Figure 9.3-1, Site A does not appear to be several times bigger than Sites B, C, or D.

9.3.2 Figure 9.3-1 and the comparative acreages of Sites A, B, C, and D appear to be inconsistent. What is the best way to resolve this inconsistency?

Potential Request for Additional Information (RAI)?

Aquatic Ecology AE-1 Please provide any report(s) and data from the macroinvertebrate and fish surveys conducted in 2023 and 2024 that supported development of Tables 2.4-9 and 2.4-10. (ESRP 2.4.2) 2.4.2.2 Potential RAI to make referenced information available.

AE-2 Please provide shapefiles OR digital, zoomable map depicting benthic macroinvertebrate sampling locations in West Coloma Creek.

(ESRP 2.4.2) 2.4.2.2 What is the water body of the sample taken next to FM2235?

AE-3 Please provide information on which organisms listed in Table 2.4-9 are key indicator organisms that are particularly vulnerable to impacts from plant construction or operation.

(ESRP 2.4.2)

Table 2.4-9 RESOLVED

6 AE-4 Please provide additional information (e.g. flow rates, grates and spacing, trash racks and spacing, temperature data, etc.) on the existing intake and discharge structures for the Seadrift Plant, the new pump station and water intake structure on the Guadalupe-Blanco River Authority (GBRA) Calhoun Canal to provide water via Basin #5, digital, zoomable maps showing location of each structure, and copies of the current Texas Pollutant Discharge Elimination System (TPDES) permit and Stormwater Pollution Prevention Plan (SWPPP). (ESRP 2.4.2) 2.4.2, 3.3, 3.4.2.6, 4.2.1, 5.10.2.1, 5.10.2.2, Figure 3.1-3 If the TPDES permit is publicly available, please identify the location. Otherwise, we may need an RAI to put it on the docket.

AE-5 Please provide a digital, zoomable map OR shapefile layers for the information displayed in Figure 4.3-

1. (ESRP 4.3.2)

Figure 4.3-1 RESOLVED

7 AE-6 Please provide a proposed construction schedule, including expected timing and duration of specific construction activities.

Potential activities that should be included are but are not limited to:

placement of intake and discharge structures, channel modifications for navigation or flow control, placement and removal of cofferdams, construction of bulkheads, piers, jetties, basins, and storm sewers, direct dredging, including the area that may be affected by resulting siltation and turbidity, percent (or the width and depth) of the waterbody cross section that might be obstructed by construction activity at any time, time and duration of such obstruction, potential changes to water quality caused by exposure of substrate to contaminants during construction (e.g., dredging for intake channels, cofferdam construction). (ESRP 4.3.2)

Table 1.3-1 (just says construction start Oct 2028),

4.3.2.2 RESOLVED AE-7 Please provide information on the existing intake structure for the Seadrift Plant on GBRA Calhoun Canal. Including information on location, depth, size, intake flow velocity, any racks or grate systems, impingement and entrainment rates, etc. (ESRP 4.3.2 and 5.3.1.2, 40 CFR 125.84(b)(2))

Figure 3.1-3, Section 3.3, Section 3.4.2.6, 4.3.2.2 RESOLVED AE-8 Please provide additional information, at least at a conceptual level, about mitigation needed to offset impacts to the West Coloma Creek (per U.S. Army Corps of Engineers (USACE). (ESRP 4.3.2) 4.3.2 RESOLVED

8 AE-9 Does the Section 10 permit currently held by the applicant for maintenance dredging apply to dredging done as part of the LMGS? If yes, please provide a copy of the permit. (ESRP 4.3.2)

Table 1.4-1 Is a Section 10 permit expected to be required? Verify that no work is being done within the Victoria Barge Canal or any other Section 10 water.

Confirm no dredging is expected with this action.

AE-10 Please provide copies of any responses and other related communications from U.S. Fish &

Wildlife Service (USFWS), National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service (NMFS),

and Texas Parks and Wildlife Service (TPWD) concerning aquatic species that have been received since writing the ER. (ESRP 2.4.2 and 4.3.2) 2.4.2.3, Appendix 1A RESOLVED AE-11 Please provide additional information on the proposed locations of pile driving activities and any anticipated impacts to aquatic resources. (ESRP 4.3.2) 4.4.1.4 Will any of the pile driving occur in onsite waterbodies and if yes which ones (ex. bridge construction, utility crossing)?

AE-12 What material(s) are/ will the condenser tubes be made of?

(ESRP 4.3.2) n/a RESOLVED AE-13 Please provide the through-screen design intake velocity. (ESRP 5.3.1.2, 40 CFR 125.84(b)(2))

Table 3.3-1, 5.10.2.1 RESOLVED

9 AE-14 Please provide information on the original source of water (natural waterbody) that will supply the LMGS, beyond GBRA Calhoun Canal, to where the Canal gets its water from. Please include a figure(s) depicting the flow path, any relevant diversion structures, and the alternate intake location mentioned in ER Section 5.2.1.1.1 that draws from canal water downstream (east). Please clarify the scenario in which the alternate intake will be utilized and the expected frequency of utilization.

(ESRP 5.3.1.2, 40 CFR 125.84(b)(2))

Potential RCI:

Freshwater from the Guadalupe River is diverted near Tivoli east into the GBRA Diversion Canal and flows into Goff Bayou. Just above Goff Bayou Salt Barrier two 96 pipelines convey water underneath the Victoria Barge Canal to the GBRA/Dow pump station (owned by GBRA and operated by Dow SDO at GBRA direction). The pump station is equipped with seven submersible pumps of varying capacity and conveys water into the Calhoun Canal network. The canal runs south along HWY 185 and then turns towards Port Lavaca and runs along the southside of the SDO facility where it is pulled from the canal into the operating basins, currently via the GBRA Relift 1 Pump Station. A new LMGS intake will be constructed along this same segment of the canal nearby and downstream of the existing (ER pg. 3.4-5) to serve Basin #5 for LMGS. It is assumed that the new intake structure would be similar to the existing pump station.

10 AE-15 Please provide, if available, data about impingement and entrainment of aquatic species at the other intake structures on the GBRA Calhoun Canal and at the pump station for GBRA. (ESRP 5.3.1.2) 5.10.2.1 RESOLVED AE-16 Please provide a description detailing the existing discharge structure (ex. Where it reenters the waterway, info. about current flow rate and temperature, anticipated change in discharge flow rate and variations with season once LMGS goes online, and impacts to biota downstream; ESRP 5.3.2.2) 1.2.4, 2.4.2.1 Potential RCI:

Nonradiological effluent from LMGS would be 3rd party wastewater to the existing TPDES permitting the SDO combined outfall at the Victoria Barge canal and would be treated to meet their existing acceptance criteria thereby causing no additional impact at the discharge location.

AE-17 Please provide a copy of TDOT, 2016-Essential Fish Habitat Assessment, Neches River Bridge Study, CSJ:7220-01-001, Texas Department of Transportation.

2.4.2, 2.11 RESOLVED AE-18 ER Section 4.3.2 mentions avoidance of building activities during ecologically sensitive times (i.e., spawning), please provide the dates during which building activities will be avoided and any supporting information for the avoided dates.

4.3.2 Confirm that there are no set dates during which LME will avoid conducting building activities.

11 AE-19 The implementing regulations for Section 7(a)(2) of the ESA define action area as all areas affected directly or indirectly by the Federal action and not merely the immediate area involved in the action (50 CFR 402.02). The action area effectively bounds the analysis of federally listed species and critical habitats because only species and habitats that occur within the action area may be affected by the Federal action. Please provide a description of the ESA action area, including all potential direct and indirect impacts of construction and operation. In the description, address:

1. transportation activities, including the mode of transportation, route of transportation, material to be transported, the frequency and timing of the transportation, and any associated impacts;

2. the extent of impacts associated with diverting water from the Guadalupe River, including the downstream limit where flow and salinity impacts may be experienced;

3. the extent of impacts associated with the withdrawal of water from the GBRA Calhoun Canal; and

4. any other potential direct or indirect impacts associated with this action.

Clarify whether any construction materials will be transported to the site via barge and likely RCI whether or not barging will be utilized.

Benefit-Cost No issues related to benefit-cost identified 10.6 RESOLVED Climate Change

12 CC-1 Has X-Energy conducted thermal discharge studies that account for potential increases in water temperature in the Guadalupe River due to climate change? If so, please provide a copy.

RESOLVED Cumulative Impacts No issues related to cumulative impacts identified Chapter 7 RESOLVED Decommissioning No issues related to decommissioning were identified.

RESOLVED Fuel Cycle No issues related to the uranium cycle were identified.

RESOLVED Historic and Cultural Resources HCR-1 Provide Geographic Information System (ArcGIS) shapefiles of the archaeological APE, the architectural APE, and for the polygons in Figure 3.1-3.

RESOLVED HCR-2 Provide a discussion on pre-construction activities covered under Department of Energy (DOE)

National Environmental Policy Act (NEPA) process and the construction activities expected to be covered under NRCs NEPA analysis, including estimated areas of disturbance and depth of excavation.

Discuss at audit.

13 HCR-3 Section 2.5.3.1 and 2.5.3.2 mention archaeological and architectural surveys conducted but do not include any information on the purpose of the surveys, who conducted the surveys, who sponsored the surveys, or how they are connected to NRCs licensing action (issuance of a construction permit). Section 2.5.3.2.1 identified consultation that occurred through the Department of Energy for ground-disturbing site characterization and environmental monitoring activities at the LMGS site, but it is unclear how it is connected to NRCs licensing action. To support NRCs NHPA Section 106 review and avoid duplication of efforts, provide the following:

1. Provide copies of (a) the scope of work (SOW) for the July 2023 survey, and (b) correspondence from May and June 2023 regarding WSPs submission of the SOW to the Texas Historical Commission (THC) and THCs concurrence on the SOW.

2. If not described in the SOW or THCs concurrence on the SOW, provide summary descriptions of the methodologies used for both archaeological and architectural surveys. This should include a) explanation of the justification for differing APEs between archaeological and architectural surveys, b) specifics about the shovel test intervals and placement strategies, and c) criteria 2.5.3.1 2.5.3.2 Potential RCI for the inclusion of the information in the SOW referenced in the info need response.

14 used for assessing architectural significance and any specific techniques applied during the surveys.

15 HCR-4 Confirm that the Phase I archaeological survey results are documented in two separate reports: (1) August 1, 2023 Hunter and Cantrell, Xe-100 Dow Seadrift Site Phase I Intensive Archaeological Survey, Calhoun County, Texas Negative Finding Short Report, and (2) February 19, 2024 Hunter and Cantrell, Phase I Intensive Archaeological Survey for the Proposed Project Long Mott, Calhoun County, Texas - Negative Finding Report (provided in of the ER).

1. Please provide a copy of the August 1, 2023, Hunter and Cantrell report.

2. For both reports, describe the undertaking and activities associated with the undertaking that were considered when determining there would be no effect on historic properties. Please clarify why the reports do not address the proposed construction of a small modular reactor and nor include details on pre-construction and construction activities.

3. For both reports, please provide copies of correspondence that submitted the reports to the Texas Historic Commission (THC) for their concurrence.

(This could include correspondence from DOE to THC in August 2023, or from WSP to THC in January or February of 2024.)

4. Pages 74 and 76 in Appendix A of the ER are Part VI Supplemental Information

1. Potential RAI -

Request for the August 2023 report to be submitted on the docket to show full shovel-test pot coverage of the APE

2. RESOLVED

3. Unclear whether additional documentation is in the ER or whether additional information is on the Texas State Historic Preservation Officer (TX SHPO) portal

4. Discuss at audit.

5. Potential RCI of this response

16 letters from THC concurring on the reports. Is there any other correspondence related to THCs concurrence on the reports?

If so, please provide copies.

It is unclear what undertaking THC was considering in its concurrence letter dated February 16, 2024.

5. In the August 1, 2023, Hunter and Cantrell report, the Management Summary states that from July 10-19, 2023, WSP conducted a Phase I intensive archaeological survey of 1,277 acres in support of the ER for the Xe-100 Dow Seadrift Site in Calhoun County, Texas. That report covered a 617.4-acre portion of the 1,277-acre survey.

The February 19, 2024, report covers a 930.6-acre portion portion of the Long Mott project that has not been previously submitted for consultation. This totals 1,548 acres, which is total survey acreage cited in the ER. Please explain the discrepancy between the 1,277-acreage cited in the August 1, 2023, report and 1,548-acreage cited in the ER.

17 HCR-5 Based on the information provided in the ER, there is no clear indication that Traditional Cultural Places (TCPs) were considered or that efforts were made to identify them as part of the cultural resources review. Provide documentation and/or summary that demonstrates the level of effort to identify potential TCPs.

2.5.3 Potential RCI of LME info need response.

HCR-6 Section 4.1.3.4 of the ER mentions the development of an Inadvertent Discovery Plan with a description to provide three provisions for human burials or human remains. However, it is limited to human remains only and only supports consultation with THC and not the Tribes. Provide the Inadvertent Discovery Plan, or provide additional details about how inadvertent discoveries of cultural resources will be managed, such as: 1) immediate steps to halt work and secure the area; 2) contact details for archaeological personnel who will be involved in the evaluation of any discoveries; 3) protocols for notifying local enforcement, the coroners office, federal agencies, Tribes, and the Texas Historical Commission; and

4) projected timeline outlining how investigations and evaluations will occur after a discovery to minimize project delays and ensure effective preservation.

4.1.3.4 Potential RCI regarding Inadvertent Discovery Plan.

HCR-7 Provide any other company policies, procedures, and/or best management practices that address the protection of cultural resources.

RESOLVED Human Health -

Radiological

18 HHR-1 Please provide the version number of NRCDose used to complete the GASPAR II modelling and population dose assessment for effluent releases.

Please provide any additional relevant calculational files or explanations (in the ERR) and an SME to discuss the results of the analysis discussed in Section 5.4.4 and results provided in Table 5.4-

26.

This information need should be coordinated with the NRC Safety Staff.

5.4.1.2 RESOLVED Human Health -

Non-Radiological HHN-1 Per Regulatory Guide 4.2, Revision 3, Section 4.4.1, please provide a statement on blasting activities, what those noise levels would attenuate to at the nearest resident, and any mitigation that would be put in place due to blasting activities.

4.4.1 Potential RCI regarding confirmation there will be no blasting.

Hydrology -

Groundwater GW-1 ESRP 2.3.1 and 2.3.2 require maps of sufficient detail to show the relationship of the site to major hydrological systems that could affect or be affected by plant construction or operation. In conformance, the following figures are requested in higher resolution to ensure the readability of labels and descriptions - Figure 2.3.2-19, Figure 2.3.2-27, Figure 2.3.2-29, Figure 2.3.2-32, Figure 2.3.2-33, Figure 2.3.2-34, Figure 2.3.2-35.

2.3 RESOLVED

19 GW-2 Section 6.6.3.2 of the ER describes operational monitoring of groundwater quality. The ER states, Following the first annual monitoring interval, the list of parameters is reviewed and revised to focus on specific indicators for the long-term monitoring program.

ESRP 6.3 requires an operational monitoring program be established to identify the impacts of operation of the plant and to detect any unexpected impacts arising from plant operation. Describe in detail how the long-term monitoring program will be assessed and executed, including detail on anticipated indicator species and adherence to industry standards for groundwater protection (i.e. Nuclear Energy Institute (NEI) 07-07).

6.6.3.2 RESOLVED GW-3 ESRP 4.2.1 requires identification of hydrologic alterations expected to result from the project related to construction activities. ESRP 5.2.1 requires a description of operational activities expected to result in hydrologic alterations within the site and vicinity. A temporary sediment basin and permanent stormwater basin are described in section 4.2.1.1.1 of the ER. These basins may also hold construction dewatering water and may interact with groundwater. Provide additional details about the design of the basins, including depth, lining material, and anticipated inflow and outflow rates.

4.2.1.1.1 RESOLVED Hydrology -

Surface Water

20 SW-1 10 CFR 51.45(c) and (d). Please describe any floodplains at or near the LMGS site located in areas for construction operations or locations of new permanent structures. If applicable, please specify if any approvals (local, state, federal) are needed to work in or develop floodplain areas and describe the timeline of operations.

1.4, 2.3.1.1.2, 4.1.1.1, and 4.2.1.1.1 RESOLVED SW-2 10 CFR 51.45(c). Please provide higher-resolution ER Figures 3.4-1 and 3.4-2 for the staffs review.

3.4 RESOLVED SW-3 REMOVE N/A RESOLVED SW-4 10 CFR 51.45(c). Please provide a knowledgeable person(s) to describe LMGS cooling systems water use and consumptive water use associated with process steam and electricity generation.

Specifically, the different sources of consumptive water use for LMGS and their relative magnitudes and whether the frequency of steam generation expected to influence seasonal water demands from the Guadalupe River via the GBRA diversion.

3.3 Discuss at audit -

provide a knowledgeable person SW-5 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss peak water demand under future operation of LMGS and how the magnitude relates to diversion rights on the Guadalupe River and the conveyance capacity of the GBRA Calhoun Canal.

3.3 Discuss at audit -

provide a knowledgeable person

21 SW-6 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss the existing SDO wastewater discharge system. Are there any anticipated changes to SDO facility effluent (temperature, volume, solute/constituent loading) due to the shift from the current power plant to the LMGS? If so, are the changes substantial enough to require changes to the existing SDO TPDES permit? If there is an increase to the volume of discharge, are any structural modifications to the existing outfall required to accommodate the increased outfall discharge?

3.6, 5.3.2, 5.5.1.2 Discuss at audit -

provide a knowledgeable person SW-7 10 CFR 51.45(c). Are there any naturally occurring materials in the ambient surface waters that influence TPDES permit limits or monitoring requirements related to LMGS - SDO operation?

3.6, 5.5.1.2 Potential RCI of LME response.

SW-8 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss LMGS plant water use in relation to other surface water uses in the GBRA Calhoun Canal.

5.2.1 Discuss at audit -

provide a knowledgeable person SW-9 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss downstream water rights in the Guadalupe River and GBRA Calhoun Canal and their relation to SDO and LMGS maximum water demand. Would anticipated water use for LMGS influence downstream water supply for users in either the Calhoun Canal or the Guadalupe River? I.e., is the change in water use from the current generating station to the LMGS substantive enough to affect water supply to downstream users?

5.2.1 and 2.3.1 Discuss at audit -

provide a knowledgeable person SW-10 REMOVE N/A RESOLVED

22 SW-11 REMOVE N/A RESOLVED SW-12 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss alternative water treatment systems.

This discussion is to include costs (capital, maintenance, operating, and site adaptation costs) associated with the alternative water treatment systems.

9.4 Discuss at audit -

provide a knowledgeable person SW-13 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss the development and the associated timeline of the Spill Prevention, Control and Countermeasure (SPCC) Plan.

4.2.1 Discuss at audit -

provide a knowledgeable person Land Use LU-1 Clarify technical basis used to identify prime farmland on the site.

What about Unique Farmland or Farmland of Statewide or Local Importance? Provide NRCS 2022 reference.

2.2.1 RESOLVED LU-2 Provide National Resources Conservation Service (NRCS) Form AD-1006 completed for the site.

Explain key assumptions used in completing the form. Provide copies of key correspondence with the NRCS, if any.

4.1.1 Potential RAI of NRCS correspondence unless publicly available.

LU-3 Please provide any information from the Coastal Zone Management (CZM) Certification Package that submitted March 2025 that was not included in the letter to Texas GLO requesting consistency certification with the TX Coastal Management Program goals and policies and any response that have been received by the Texas GLO.

4.1.1.1 RESOLVED Need for Power

23 No issues related to need for power were identified.

Chapter 8 RESOLVED Site and Technical Overview STO-1 In the Approvals and Authorizations listed in Table 1.4-1, please provide the anticipated dates for approvals (column 6) as known.

Table 1.4-1 RESOLVED Socioeconomics No issues related to socioeconomics were identified.

4.4 and 5.8 RESOLVED Terrestrial Ecology Resources TE-1 Per Regulatory Guide 4.2, Revision 3, Section 2.1.1, please provide GIS data underlying Figures 4.2-1 and 4.3-1.

4.2 and 4.3 Would also like permanent and temporary impact shapefiles.

TE-2 Per Regulatory Guide 4.2, Revision 3, Section 4.3.1, provide 1) confirmation of the jurisdictional status of wetlands from USACE once received; 2) a breakout of wetland impacts by impact type, e.g., fill, vegetation conversion; and

3) copies of the jurisdictional determination package submitted to the USACE including relevant data sheets.

4.3.1.1.2

1. RESOLVED

2. Potential RCI to cite info need response

3. RESOLVED TE-3 Per Regulatory Guide 4.2, Revision 3, Section 4.3.1, provide 1) the height of building equipment that will be 50 feet or more; and 2) the height of the proposed MET tower.

4.3.1.1.3 Potential RCI to cite info need responses.

TE-4 Per Regulatory Guide 4.2, Revision 3, Section 4.3.1, provide information on conceptual approach to meeting wetland mitigation requirements.

4.3.1.1.2 Does LME have mitigation standards or a preferred mitigation strategy?

24 TE-5 Per Regulatory Guide 4.2, Revision 3, Section 4.3.1 and 5.3.1, provide more information on planned vegetation maintenance under onsite transmission line and switchyard. Please include the Best Management Practices for transmission line maintenance around aquatic and wetland habitats mentioned in Section 5.6.2 of the ER.

5.6 Potential RCI to cite info need responses.

TE-6 Per Regulatory Guide 4.2, Revision 3, Section 5.3.1, provide information on measures to prevent avian injury from transmission lines and meteorological tower guy wires.

4.3.1.3 Potential RCI to cite info need responses.

TE-7 Per Regulatory Guide 4.2, Revision 3, Section 2.3.1 and 5.3.1, provide additional information on potential habitat on the site for the monarch butterfly and the construction and operation impacts.

4.3.1, 5.3.3.2, 5.6.1, 5.3.3.2, 5.10.1, and 7.2.3.1 Potential RCI to cite info need responses.

TE-8 Per Regulatory Guide 4.2, Revision 3, Section 9.3.5, confirm that the same studies for the site would be used for the alternatives or if another study was performed.

9.3 RESOLVED TE-9 Please provide copies of any responses and other related communications from USFWS, NMFS, and TPWD concerning terrestrial species that have been received since writing the ER.

(ESRP 2.4.1 and 4.3.1) 2.4.1.5 RESOLVED TE-10 Please provide details regarding any tree clearing activities on site.

Include the number or acreage of trees (alive or dead) that will be removed and specify where on site the clearing will occur. (ESRP 4.1.1)

Potential RCI/RAI to cite info need responses.

RCI may be sufficient, but the figure may be helpful to RAI to use in consultation.

25 TE-11 Please provide additional information on the proposed locations of pile driving activities and any anticipated impacts to terrestrial resources. (ESRP 4.3.1) 4.4.1.4 RESOLVED TE-12 Please provide any report(s) and data from the terrestrial surveys conducted in 2023 that supported development of Tables 2.4-3, 2.4-4, 2.4-5, 2.4-6 and 2.4-7. (ESRP 2.4.1) 2.4.1 Potential RCI to cite info need responses.

TE-13 Per section 7(a)(2) of the Endangered Species Act, the NRC is required to examine all potential direct and indirect impacts of the Federal action on federally listed species. To fulfill this requirement, please complete the USFWS Northern Long-Eared Bat and Tricolored Bat Range-Wide Determination Key (DKey)

(https://ipac.ecosphere.fws.gov/)

and provide a copy of the answers.

Potential RAI for DKey results.

Are there any culverts onsite including 1. those greater than 2x23 (may be used by bats) or 2.

ag field culverts (may be used by burrowing owls) and any potential impacts?

TE-14 Please provide additional information regarding the potential non-radiological waste treatment options including whether any associated ground disturbance is anticipated and, if so, describe the potentially impacted habitats.

5.10.2.2 RESOLVED

26 TE-15 Section 5.6.1 of the ER states that herbicide use around wetlands will be prohibited and Section 5.10.1.1 states that mowing and heavy equipment operation will be avoided within wetlands and streams.

Please provide clarifying information including:

1. details regarding whether/how wetlands will be marked in the field to prevent mowing or herbicide use;

2. whether a riparian buffer will be maintained around the streams on site or if mowing will occur up to the bank of streams on site; and

3. whether herbicides will be used onsite during the operating period for purposes other than transmission line maintenance and targeted invasive plant management.

5.6.1, 5.10.1.1 Potential RCI to cite info need responses.

Transportation

27 TR-1 Please provide the input and output files used for the transportation routing and risk analysis. Please include Transportation Routing Analysis Geographic Information System (TRAGIS) (or WebTRAGIS) and Radioactive Material Transport (RADTRAN) input and output files and provide an SME to discuss the analysis.

Need additional information regarding lack of accident analysis.

Population Scaling Factor of 1.074 is for 10 years, why not 1.11?

(1.074^1.5 for 15 years instead of 10)

Discuss population conversion using csv.

How does that factor into the 1.074?

Used WebTRAGIS. Did they directly import kml?

If so, what link tab information was replaced in the import?

Visual Resources VIS-1 Provide copies of one or more available ground photographs depicting the area within the site where the plant would be constructed. An ideal photograph would show in the foreground the area where the plant would be constructed and the existing Seadrift industrial complex in the background.

4.4.3.1 RESOLVED Waste - Non-Radiological WNR-1 Per Regulatory Guide 4.2, Revision 3, Section 3.4.3, please provide an estimate of the quantities of solid nonhazardous waste generated during construction.

4.4.5 Need additional project-specific information regarding project construction.

28 WNR-2 Per Regulatory Guide 4.2, Revision 3, Section 3.4.3, please provide a statement that outlines a proposed schedule or timeline as to when the SDO TPDES Permit No.

WQ0000447000 would be modified to include the sanitary waste and other liquid process wastes from the Long Mott facility, if appropriate.

3.6

1) Section 4.4.5.2 of the ER, Impacts to Water, mentions use of a nonradioactive liquid drainage system that will be collected and conveyed to existing Dow process sewers.

What is the nonradioactive liquid drainage collection system for (e.g.,

stormwater or something else)?

What are they collecting during construction?

2) Section 4.4.5.2 also mentions use of a dedicated piping system and storage tank for sanitary wastes. Please explain what this is.

WNR-3 Per Regulatory Guide 4.2, Revision 3, Section 3.4.3, please provide a statement that clarifies whether Long Mott facility waste will be disposed of at SDOs North Landfill Expansion Cell.

3.6, 2.3.2.1.3.2 RESOLVED Waste -

Radiological

29 WM-1 Regulatory Guide 4.2 Revision 3, Section 6.1.6 states the following should be described in the environmental report:

The annual total number of curies from low level reactor solid wastes and if it is within the bounds of the estimated total of curies of solid waste identified in Section 3.5.2 Radioactive Waste Management. (Table 3.5-2 and Table 3.5-3 provide solid waste volumes, but not activity)

Being cognizant of the analysis in NUREG-2157 Generic Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel. Final Report, describe the plans for offsite storage of spent fuel.

o NUREG-2157 Section 1.8.6 states that advanced reactors (e.g., high-temperature and gas-cooled reactors) are not addressed because they are not within the scope of the review.

Please provide an SME to discuss the characteristics of expected radiological waste to be generated on an annual basis and to discuss the applicability of NUREG-2157 to the proposed reactor design.

Regarding WM-1b, Section 5.7.1.1 (Pg 5.7-

8) says that DOE/EIS-0559 indicates storage impacts would be SMALL, however EIS-0559 is for production of HALEU, not use of HALEU or specifically TRISO. Additionally, NUREG-2157 does not address HTGRs as stated in Section 1.8.6.

This discussion does not seem to address the issue because it is not specific to HALEU TRISO.

LME Site CP Application Environmental Audit Sessions for September 8th Time (Eastern)

Audit Sessions Anticipated NRC staff to attend 10-11am Introductory Meeting (Audit Kickoff)

All audit participants 11am-12pm Historic and Cultural Resources Sarah Lopas 1pm-3pm Surface Water/Groundwater Lloyd Desotell/Gerry Stirewalt LME Site CP Application Environmental Audit Sessions for September 9th Time (Eastern)

Audit Sessions Anticipated NRC staff to attend 10am-12pm Postulated Accidents/Rad Health/HP/Rad Waste/Transportation Donald Palmrose/Tim Drzewiecki/Rao Tammara 1pm-3pm Aquatic Ecology/Terrestrial Ecology Peyton Doub LME Site CP Application Environmental Audit Sessions for September 10th Time (Eastern)

Audit Sessions Anticipated NRC staff to attend 10am-12pm Alternatives, Land Use, Air Quality Peyton Doub, Bradley Werling, 1pm-3pm Non-Rad Waste, Non-rad Human Health/Noise; Other Topics or Follow-Up as Necessary Rao Tammara/Don Palmrose