Text

Project Long Mott Docs - Request for Information Needs for Long Mott Generating Station
	ML25174A248
Person / Time
Site:	05000614
Issue date:	06/23/2025
From:	; NRC
To:	; NRC/NMSS/DREFS
References
	Download: ML25174A248 (39)
	v • d • e

From:

Joe OHara Sent:

Monday, June 23, 2025 12:08 PM To:

Milton Gorden; ProjectLongMott-EnvPUBLICem Resource Cc:

Robert Hoffman; ext_Dave_Goodman; Hayley McClendon; Daniel Barnhurst

Subject:

Request for Information Needs for Long Mott Generating Station Attachments:

Long Mott Generating Station Environmental Information Needs.docx; Long Mott Generating Station Environmental Information Needs.pdf

Dear Mr. Gorden,

By letter dated May 12, 2025 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML25115A247, to Mark Feltner, the Nuclear Regulatory Commission (NRC) accepted a construction permit application for docketing submitted by the Long Mott Energy, LLC. Long Mott Energy, LLC submitted an Environmental Report (ER) (ML25090A063) as part of its construction permit (CP) application in accordance with 10 CFR Part 51, Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions regulations at 10 CFR Part 51, which implement Section 102(2) of the National Environmental Policy Act (NEPA) of 1969, include requirements for applicants to provide information as may be useful in aiding the NRC staff in complying with NEPA. The staff used NUREG-1555 Standard Review Plans for Environmental Reviews for Nuclear Power Plants, and Regulation Guide 4.2, Preparation of Environmental Reports for Nuclear Power Stations, in compiling the Information Needs.

Attached please find an Information Needs document generated by the technical review staff. The Information Needs are in alphabetical order according to resource area and are numbered. Topics which have no requested Information Needs are either N/A ed or have a statement of No issues identified.

You can place your responses in an electronic reading room of your choosing. Staff will schedule meetings to clarifying any questions you may have regarding the Information Needs. Please use the same numbering sequence in your responses so we can accurately track completion. The Information Needs are subject to change and addition.

Accessing ADAMS:

The Agencywide Documents Access and Management Systems (ADAMS) Public Electronic Reading Room is accessible at http://www.nrc.gov/reading-rm/adams.html on the NRC Website. Persons who do not have access to ADAMS, or who encounter problems in accessing the documents located in ADAMS, should contact the NRCs Public Document Room reference staff by phone at 1-800-397-4737 or via email at pdr@nrc.gov.

If you have any questions whatsoever, please contact me.

R/

Joe OHara Environmental Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Materials Safety and Safeguards Division of Rulemaking, Environmental, and Financial Support

Hearing Identifier:

XeDOW_ProjectLongMott_EnvPublic Email Number:

7 Mail Envelope Properties (DM8PR09MB6487B49BD1030AEDB24EF026EE79A)

Subject:

Request for Information Needs for Long Mott Generating Station Sent Date:

6/23/2025 12:08:03 PM Received Date:

6/23/2025 12:08:08 PM From:

Joe OHara Created By:

Joe.OHara@nrc.gov Recipients:

"Robert Hoffman" <Robert.Hoffman@nrc.gov>

Tracking Status: None "ext_Dave_Goodman" <>

Tracking Status: None "Hayley McClendon" <Hayley.McClendon@pnnl.gov>

Tracking Status: None "Daniel Barnhurst" <Daniel.Barnhurst@nrc.gov>

Tracking Status: None "Milton Gorden" <mgorden@x-energy.com>

Tracking Status: None "ProjectLongMott-EnvPUBLICem Resource" <ProjectLongMott-EnvPUBLICem.Resource@nrc.gov>

Tracking Status: None Post Office:

DM8PR09MB6487.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 2409 6/23/2025 12:08:08 PM Long Mott Generating Station Environmental Information Needs.docx 125250 Long Mott Generating Station Environmental Information Needs.pdf 289214 Options Priority:

Normal Return Notification:

No Reply Requested:

No Sensitivity:

Normal Expiration Date:

Long Mott Information Needs Info Need #

Information Need ER Section SME Accidents ACC-1 The calculated bounding dose values for postulated accidents is supplied for the time period of 0-720 hours. Please provide an 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 Jon Napier/Don Palmrose ACC-2 Please provide access to the MACCS calculations (input and output files in the ERR), any additional relevant calculational files or explanations, and an SME to discuss the calculations.

5.13 Jon Napier/Don Palmrose ACC-3 Step 1 of the 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 OL stage.

5.13 Jon Napier/Don Palmrose ACC-4 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 5.13 Jon Napier/Don Palmrose

2 Info Need #

Information Need ER Section SME calculational files or explanations (in the ERR) and an SME to discuss the calculations.

Air Quality AQ-1 Please provide regional NAAQS measurements, or links to publications with these measurements (ESRP-2.7) 2.7 Brad Fritz AQ-2 Please provide monthly dewpoint and monthly average temperatures (ESRP-2.7) 2.7 Brad Fritz AQ-3 Please provide a summary of monthly stability class (ESRP-2.7) 2.7 Brad Fritz 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 Brad Fritz 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 Dave Goodman/Swasti Saxena 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 the 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 9.2.2 Dave Goodman/Swasti Saxena

3 Info Need #

Information Need ER Section SME 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).

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 Dave Goodman/Swasti Saxena 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 Dave Goodman/Swasti Saxena 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 Dave Goodman/Swasti Saxena 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 Peyton Doub/Caitlin Wessel 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 Peyton Doub/Caitlin Wessel 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 Peyton Doub/Caitlin Wessel 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 2.4.2, 3.3, 3.4.2.6, 4.2.1, 5.10.2.1, Peyton Doub/Caitlin Wessel

4 Info Need #

Information Need ER Section SME pump station and water intake structure on the GBRA Calhoun Canal to provide water via Basin #5, digital, zoomable maps showing location of each structure, and copies of the current TPDES permit and SWPPP.

(ESRP 2.4.2) 5.10.2.2, Figure 3.1-3 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 Peyton Doub/Caitlin Wessel 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 Peyton Doub/Caitlin Wessel 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 Peyton Doub/Caitlin Wessel AE-8 Please provide additional information, at least at a conceptual level, about mitigation needed to offset impacts to the West Coloma Creek (per USACE). (ESRP 4.3.2) 4.3.2 Peyton Doub/Caitlin Wessel

5 Info Need #

Information Need ER Section SME 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 Peyton Doub/Caitlin Wessel AE-10 Please provide copies of any responses and other related communications from USFWS, NOAA National Marine Fisheries Service (NMFS), and 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 Peyton Doub/Caitlin Wessel/Shannon Healy 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 Peyton Doub/Caitlin Wessel AE-12 What material(s) are/ will the condenser tubes be made of? (ESRP 4.3.2) n/a Peyton Doub/Caitlin Wessel 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 Peyton Doub/Caitlin Wessel 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))

Peyton Doub/Caitlin Wessel/Shannon Healy 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 Peyton Doub/Caitlin Wessel

6 Info Need #

Information Need ER Section SME 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 Peyton Doub/Caitlin Wessel/Shannon Healy 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 Peyton Doub/Caitlin Wessel/Shannon Healy 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 Shannon Healy 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 Shannon Healy

7 Info Need #

Information Need ER Section SME

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

Benefit-Cost BC-1 N/A 10.6 Jeff Rikhoff Climate Change 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.

Brian Glowacki Cumulative Impacts CI-1 N/A Chapter 7 Jeff Rikhoff Decommissioning No issues related to decommissioning were identified.

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

Jon Napier Historic and Cultural Resources HCR-1 Provide ArcGIS shapefiles of the archaeological APE, the architectural APE, and for the polygons in Figure 3.1-3.

Lindsey Renaud Cleve Davis HCR-2 Provide a discussion on pre-construction activities covered under DOEs NEPA process and the construction activities expected to be covered under NRCs NEPA analysis, including estimated areas of disturbance and depth of excavation.

Lindsey Renaud Cleve Davis

8 Info Need #

Information Need ER Section SME 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 used for assessing architectural significance and any specific techniques applied during the surveys.

2.5.3.1 2.5.3.2 Lindsey Renaud Cleve Davis 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 Enclosure 6 of the ER).

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

Part VI Supplemental Information Lindsey Renaud Cleve Davis

9 Info Need #

Information Need ER Section SME

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 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 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.

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 Lindsey Renaud Cleve Davis

10 Info Need #

Information Need ER Section SME 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 Lindsey Renaud Cleve Davis HCR-7 Provide any other company policies, procedures, and/or best management practices that address the protection of cultural resources.

Lindsey Renaud Cleve Davis Human Health - Radiological HHR-1 Please provide the version number of NRCDose used to complete the GASPAR II modelling and population dose assessment for effluent releases.

If NRCDose3 was used, were the generic representative biota used for the analysis. If not, what biota were modelled?

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 Jon Napier Human Health - Non-Radiological

11 Info Need #

Information Need ER Section SME 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 Kim Leigh/Hayley McClendon 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 Swasti Saxena/Rebecka Iveson/Phil Meyer/Gerry Stirewalt 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. NEI 07-07).

6.6.3.2 Swasti Saxena/Rebecka Iveson/Phil Meyer/Gerry Stirewalt GW-3 ESRP 4.2.1 requires identification of hydrologic alterations expected to result from the project related 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 4.2.1.1.1 Swasti Saxena/Rebecka Iveson/Phil Meyer/Gerry Stirewalt

12 Info Need #

Information Need ER Section SME details about the design of the basins, including depth, lining material, and anticipated inflow and outflow rates.

Hydrology - Surface Water SW-1 10 CFR 51.45(c) and (d). Please provide a knowledgeable person(s) to describe floodplains at and near the LMGS site and any federal, state, or local approvals, permits, and/or authorizations needed for the proposed project.

1.4, 2.3.1.1.2, 4.1.1.1, and 4.2.1.1.1 Rajiv Prasad 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 Rajiv Prasad SW-3 10 CFR 51.45(c). Please provide a knowledgeable person(s) to describe LMGS water treatment systems including treatment chemicals, points of addition, chemical quantities, treatment frequency, and water treatment operating modes.

3.3, 3.6 Rajiv Prasad 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.

3.3 Rajiv Prasad SW-5 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss peak LMGS water demand and its effect on GBRA Calhoun Canal flow and diversions from the Guadalupe River.

3.3 Rajiv Prasad SW-6 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss the existing SDO wastewater discharge system including the outfall location, layout/drawings of the outfall structure, any needed structural modifications or constituent composition modifications related to LMGS, and physical effects including thermal and/or constituent plumes of the additional LMGS discharge.

3.6, 5.3.2, 5.5.1.2 Rajiv Prasad

13 Info Need #

Information Need ER Section SME SW-7 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss naturally occurring materials/chemicals in the LMGS effluent stream and in the ambient waters.

3.6, 5.5.1.2 Rajiv Prasad SW-8 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss LMGS plant water use during operations in relation to other surface water uses in/from the GBRA Calhoun Canal.

5.2.1 Rajiv Prasad SW-9 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss total and reliable water rights in the Guadalupe River, water rights of GBRA Calhoun Canal water users downstream of LMGS intake, and their relation to SDO and LNGS maximum water demand. To facilitate this discussion, please provide a clearly labeled schematic or a map showing the Guadalupe River, GBRA Calhoun Canal diversion location, USGS gauges locations, existing SDO intake location, proposed LMGS intake location, diversion locations for other users downstream of the proposed LMGS intake, and waterways/streams/canals/bays/estuaries near the site that may have hydrologic connections to the Guadalupe River and the GBRA Calhoun Canal.

5.2.1 and 2.3.1 Rajiv Prasad SW-10 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss alternative intake systems for LMGS. This discussion is to include costs (capital, maintenance, operating, and site adaptation costs) associated with the alternative intake systems.

9.4 Rajiv Prasad SW-11 10 CFR 51.45(c). Please provide a knowledgeable person(s) to discuss alternative discharge systems for LMGS. This discussion is to include costs (capital, maintenance, operating, and site adaptation costs) associated with the alternative discharge systems.

9.4 Rajiv Prasad 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 Rajiv Prasad

14 Info Need #

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

4.2.1 Rajiv Prasad 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 Peyton Doub LU-2 Provide 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 Peyton Doub Need for Power NFP-1 N/A Chapter 8 Jeff Rikhoff 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 Dave Goodman Socioeconomics SOC-1 N/A 4.4 and 5.8 Jeff Rikhoff 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 Peyton Doub/Dana Vesty 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, 4.3.1.1.2 Peyton Doub/Dana

15 Info Need #

Information Need ER Section SME vegetation conversion; and 3) copies of the jurisdictional determination package submitted to the USACE including relevant data sheets.

Vesty/Shannon Healy 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 Peyton Doub/Dana Vesty 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 Peyton Doub/Dana Vesty 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 Peyton Doub/Dana Vesty/Shannon Healy 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 Peyton Doub/Dana Vesty/Shannon Healy 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 Peyton Doub/Dana Vesty/Shannon Healy 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 Peyton Doub/Dana Vesty 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 Shannon Healy

16 Info Need #

Information Need ER Section SME 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)

Shannon Healy 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 Shannon Healy 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 Shannon Healy 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 (https://ipac.ecosphere.fws.gov/) and provide a copy of the answers.

Shannon Healy 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 Shannon Healy 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 5.6.1, 5.10.1.1 Shannon Healy

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Information Need ER Section SME

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

Transportation TR-1 Please provide the input and output files used for the transportation routing and risk analysis. Please include TRAGIS (or WebTRAGIS) and RADTRAN input and output files and provide an SME to discuss the analysis.

Jon Napier 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 Peyton Doub 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 Kim Leigh/Hayley McClendon 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 Kim Leigh/Hayley McClendon 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 Kim Leigh/Hayley McClendon

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Information Need ER Section SME Waste - Radiological 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 3.4.2 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.

Jon Napier/Don Palmrose