ML25143A218

Enclosure 1 - RAI Responses for the TRISO-X Environmental Report Supplement

ML25143A218
Person / Time
Site:	Triso-X
Issue date:	05/23/2025
From:	Triso-X
To:	Office of Nuclear Material Safety and Safeguards
Shared Package
ML25143A216	List: ML25143A217 ML25143A218 ML25143A219
References
TX0-REG-LTR-0072
Download: ML25143A218 (1)

Text

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 1 of 10 RAI ER Supplement - 1 Provide updated ER text or explanation for the following inconsistencies in the ER Supplement submitted in two parts on January 31st and March 31, 2025.

1) Air Sampling-The last paragraph of Page 6-8 states that six air samplers will be located based on the directions of potential receptors. However, table 6.1.2-1 on page 6-14 shows only one air sampler

2) Workers - Revised text in sections 2 and 4 provide inconsistent counts for workers required for construction and operation. Inconsistencies include the following:

For the construction phase:

Sections 2.1.2.1.2 and 4.2.2.4 state construction will require 188 workers (268 peak daily workers)

Section 4.10.2.1 states construction will require a peak construction workforce of up to 332 employees For the operational phase:

Sections 2.1.2.1.3 and 4.10.2.2 state operation will require a total peak workforce of 1,569 workers Section 4.2.2.5 states the maximum daily operational workforce at full capacity is estimated at 881 employees

3) Stack Effluents - Revised table 4.6-1 refers to figure 4.6-1 to show the locations of new facility component emissions sources. The narrative and table 4.6-1refer to three stacks vice the two stacks in the original submittal. However, there does not appear to be a figure 4.6-1 in the revised ER.

In addition, the following inconsistencies were noted.

a. Figure 4.7.2-1 shows no stacks on the site (and shows the Graphite Matrix Power (GMP) building south of the TX-2 building.

b. Figure 4.9.2-1 shows two stacks, no TX-1 building, GMP north of TX-2

c. Figure 4.9.2-2 (2/5) shows TX-2 stacks, GMP north of TX-2, no TX-1

d. Figure 4.9.2-2 (3/5) shows no TX-1

e. Figure 4.9.2-2 (5/5) shows two stacks, GMP north of TX-2

4) Meteorology - It is unclear if a meteorological tower is present, and the height of the tower is not provided. Please provide clarification on the presence and details of the tower if applicable.

In the March 31, 2025, ER supplement update, Revised figure 2.1-1 shows a tower as present SE of TX-2. Revised figure 4.9.2-1 shows the tower SE of TX-2. Revised section 6.2.1.1 states the tower is SE of figure TX-2, as shown in figure 2.1-1. However, sections 4.5.2.2.1, 4.9.2, 4.9.2.2.1, and 4.9.2.2.1.1 all have references to the tower and the tower height removed from the text.

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 2 of 10 TRISO-X Response to RAI ER Supplement - 1

1) License Table 9-1 (December 2024) states there are 6 ambient air samplers. License Figure 9-1 provides typical sampler locations for the six air samplers along the security fence. These air samplers are located near the environmental dosimeters (See Figure 6.1.2-1 of the Environmental Report). See clarification updates to Environmental Report Table 6.1.2-1 below after item 4).

2) The worker counts differ because they measure distinct attributes: one reflects the average or peak number of workers onsite per day, while the other represents the total number of workers employed during that period. Sections 2.1.1.2 and 4.2.2.4 state construction will require a daily average of 188 workers, and a daily peak of 268 workers.

This daily count of onsite workers is used to assess factors such as traffic impacts.

Section 4.10.2.1 considers the total number of construction workers employed during the peak construction period (up to 332 employees), which is used to determine demographic and population impacts. Similarly, Section 4.2.2.5 states the maximum daily operational workforce at full capacity is estimated at 881 employees, which is the maximum number onsite per day. Sections 2.1.2.1.3 and 4.10.2.2 reference the total number of operational workers employed (1,569 workers), which exceeds the daily onsite workforce due to multiple shifts and work schedules, time off, absences, etc.

3) In the March 28, 2025, submittal of the Environmental Report, Figure 4.6-1 was updated to indicate the locations of HVAC stacks. The stack labels are TX-1 HVAC-EX, TX-2 HVAC-1, and TX-2 HVAC-2. The updated figure is located immediately after page 4-146.

a. The focus of Figure 4.7.2-1 is noise source locations. The stacks were not identified as noise generating equipment; and therefore, they are not included in this figure. The figure was updated in the March 28, 2025, submittal, and the location of the GMP building was adjusted to the southwest area of the site.

b. Figure 4.9.2-1 was updated in the March 28, 2025, submittal, and six stacks are shown - one thermal oxidizer stack and one HVAC stack on the west side of TX-1, and two thermal oxidizer stacks and two HVAC stacks on the east side of TX-2.

The location of the GMP building was adjusted to the southwest area of the site, and TX-1 is shown immediately west of TX-2. The thermal oxidizers were considered in the March 28, 2025, updates to Table 4.6-3 and Figure 4.9.2-1, but were inadvertently not included in Table 4.6-1, Section 4.6.4.2.3, or Section 4.9.2.2.1. See Environmental Report changes below after item 4).

c. Figure 4.9.2-2 was updated in the March 28, 2025, submittal, and the total number of sheets is now four. Sheet 1 of 4 shows an aerial view from the southwest, with TX-1 on the left with one HVAC stack, and TX-2 on the right with two HVAC stacks.

d. Figure 4.9.2-2 (Sheet 2 of 4) shows an aerial view from the east, with the GMP building on the left, TX-1 in the middle, and TX-2 on the right.

e. Figure 4.9.2-2 (Sheet 3 of 4) shows an elevation view from the east at parking lot level where TX-1 is in the left background and TX-2 is on the right.

f.

Figure 4.9.2-2 (Sheet 4 of 4) shows an elevation view from the south at parking lot level where TX-1 is not visible on the left and the tops of the two HVAC stacks for TX-2 are on the far right.

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 3 of 10

4) Figure 2.1-1 (Rev 2) and Figure 4.9.2-1 (Rev 1) show the correct location of the meteorological tower, east of the TX-2 Process Building. Based on current designs, the tower is approximately 33 feet (10 m) in height, which is notably reduced from the Rev 0 submittal (200 feet [61 m] or less). At approximately 200 feet (61 m), the meteorological tower warranted special consideration in the analyses in Sections 4.5.2.2.1 (avian collision risk) and 4.9.2 (visual impacts). However, at its current height of approximately 33 feet (10 m), the tower has a lower profile than the Process Buildings and thus is no longer a significant factor in avian collision risk or visual impacts and was therefore removed from these sections.

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 4 of 10 Environmental Report Changes Changes to Table 4.6-1 are shown in redline.

Table 4.6-1 (Sheet 1 of 2)

Physical Characteristics of Atmospheric Emissions Sources at the TRISO-X Fuel Fabrication Facility Source Label (Figure 4.6-1)

Location (UTM, zone 16)

Grade Elevation (ft., AMSL)

Release Height (ft., AGL)

Exit Diameter (in.)

Exit Velocity (fps)

Exit Temperature (F)

Eastings (m)

Northings (m)

TX-2 HVAC exhaust (Production line #1)

TX-2 HVAC-1 737,320.635 3,983,040.318 810.5 100 80 50 75 TX-2 HVAC exhaust (Production line #2)

TX-2 HVAC-2 737,359.337 3,982,993.192 810.5 100 68 50 75 TX-1 HVAC exhaust TX-1 HVAC-EX 737,015.667 3,982,760.691 810.5 100 68 50 100 TX-2 TO 1 exhaust Figure 4.9.2-1(8) 737,328.329 3,983,045.846 810.5 100 TX-2 TO 2 exhaust Figure 4.9.2-1(8) 737,365.672 3,983,000.368 810.5 100 TX-1 TO exhaust Figure 4.9.2-1(8) 737,001.455 3,982,765.985 810.5 100 GMP building vent(1)

GMP 737,445.110 3,982,615.671 810.5 TX-1 Diesel generator #1(2,3,4,5)

TX-1 DG-1 736,979.566 3,982,794.565 810.5 15 12 38.3 803 TX-1 Diesel generator #2 TX-1 DG-2 736,984.788 3,982,788.203 810.5 15 12 38.3 803 TX-2 Diesel generator #1 EGENTX-2 DG-1 737,207.403 3,983,043.205 810.5 15 12 160.9 884.2 TX-2 Diesel generator #2 EGENTX-2 DG-2 737,216.828 3,983,050.944 810.5 15 12 160.9 884.2 TX-2 MDCT - West(1,2)

MDCT-W 737,066.995 3,982,953.422 810.5 18.2 120 23 96 TX-2 MDCT - Middle MDCT-M 737,078.424 3,982,962.806 810.5 18.2 120 23 96 TX-2 MDCT - East MDCT-E 737,089.854 3,982,972.190 810.5 18.2 120 23 96

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 5 of 10 Table 4.6-1 (Sheet 2 of 2)

Physical Characteristics of Atmospheric Emissions Sources at the TRISO-X Fuel Fabrication Facility

1) Emissions parameters to be determined in detailed engineering

2) Nominal stack heights and diameters for each generator are subject to change based on results from air dispersion modeling.

3) Exit velocity for each generator is based on a flow rate of 7582.8 cfm and a nominal 12 in.-diameter stack.

4) Operation for each generator is up to 100 hr. per year for maintenance, testing and non-emergency use, including no more than 50 hr. per year for non-emergency situations.

5) Enclosure housing dimensions for each generator: length: 384, width: 101, height: 148.

6) Cooling tower cell dimensions: height: 18-2 1/2; length: 14-1 3/4; width: 11-10. Fan diameter: 10 ft.

7) The water flow rate for the cooling towers in the PHR System is 1,600 gpm per cell. The water flow rate for the cooling tower in the HVAC is 2,100 gpm per cell.

8) On Figure 4.9.2-1 the thermal oxidizer stacks and HVAC stacks are labeled Vent Stacks.

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 6 of 10 Changes to Section 4.6.4.2.3 are shown in redline.

4.6.4.2.3 Air Pollutant Emissions Air emissions from the TRISO-X FFF (TX-1 and TX-2 facilities) include nitrogen oxides (NOx),

carbon monoxide (CO), sulfur oxides (SOx), hydrocarbons in the form of volatile organic compounds (VOCs), hazardous air pollutants (HAPs), particulate matter (PM) having an aerodynamic diameter less than 2.5 microns (PM2.5), and particulate matter having an aerodynamic diameter less than 10 microns (PM10).

Potential annual emissions from the TX-1 and TX-2 facilities are provided in Table 4.6-3. The emissions are based on an annual production rate of 5 MTU from the TX-1 facility and 20 MTU from the TX-2 facility. The potential annual emissions of each criteria pollutant is below the applicable 250 tons per year (TPY) major source threshold for Prevention of Significant Deterioration (PSD) under New Source Review regulations. The potential annual emissions of each criteria pollutant is below the applicable 100 TPY major source threshold under Title V regulations. Regarding the potential emissions of HAPs, emissions from the facility are below the Title V major source threshold of 25 TPY of any combination of HAPs or less than 10 TPY of any single HAP. Therefore, the TRISO-X FFF is a minor air pollutant source. Carbon monoxide and several HAPs listed in Table 4.6-3 are reduced or eliminated by a thermal oxidizer to CO2 and H2O at 98 percent efficiency and discharged to the environment through the Thermal Oxidizer (TO) stacks. The TO stacks are listed on Table 4.6-1 (1 TO stack for TX-1 and 2 TO stacks for TX-2).

Changes to Section 4.9.2.2.1 are shown in redline.

4.9.2.2.1 Visual Impact Features The layout of the TRISO-X FFF is shown on Figure 4.9.2-1. Exterior renderings of the facility are shown on Figure 4.9.2-2 (Sheets 1 through 4). As shown on these figures, the largest and most dominant structures associated with the TRISO-X FFF are the process buildings, to which administration buildings are also attached. The tallest point on these buildings is the top of the process buildings second floor parapet, which is approximately 64 ft. (19.5 m) above the exterior grade. The GMP building and security/EOC building have much smaller footprints and extend to approximately 26.5 ft. (8.1 m) and 20.5 ft. (6.2 m) above exterior grade, respectively. Ground-level support facilities, such as external mechanical and electrical equipment, are located to the north and west of the process buildings. The only ground-based equipment of notable height are the six vent stacks (3 HVAC stacks and 3 TO stacks) which measure approximately 100 ft. (30.5 m) above exterior grade, four of which are located at the northeast end of the TX-2 process building and two of which are located at the southwest end of the TX-1 process building (see Figure 4.9.2-1).

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 7 of 10 Changes to Table 6.1.2-1 are shown in redline.

Table 6.1.2-1 Summary of Radioactive Environmental Monitoring Program Station ID Location(a)

Monitor Type(b)

Sample Frequency Target CAS-1 WSW fence line Continuous Air Sampler Quarterly Gaseous Effluent Particulate TLD-1 N fence line TLD Quarterly Dose from gaseous effluents/ direct radiation CAS-1 Continuous Air Sampler Monthly Gaseous Effluent Particulate TLD-2 ENE fence line TLD Quarterly Dose from gaseous effluents/ direct radiation CAS-2 Continuous Air Sampler Monthly Gaseous Effluent Particulate TLD-3 SE fence line TLD Quarterly Dose from gaseous effluents/ direct radiation CAS-3 Continuous Air Sampler Monthly Gaseous Effluent Particulate TLD-4 SSW fence line TLD Quarterly Dose from gaseous effluents/ direct radiation CAS-4 Continuous Air Sampler Monthly Gaseous Effluent Particulate TLD-5 W fence line TLD Quarterly Dose from gaseous effluents/ direct radiation CAS-5 Continuous Air Sampler Monthly Gaseous Effluent Particulate TLD-6 NW fence line TLD Quarterly Dose from gaseous effluents/ direct radiation CAS-6 Continuous Air Sampler Monthly Gaseous Effluent Particulate a)

The air samplers are located near the environmental dosimeters a)b) TLD - Thermoluminescent dosimeters

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 8 of 10 RAI ER Supplement - 2 Provide updates to the traffic estimates based on current forecasted estimates or updated traffic study data.

The traffic study described in section 3.2.2 is based on the previous estimates for construction and operations traffic volumes. Provide explanation that this study is still valid, and the accuracy of the conclusions are still relevant. If the external study has not or will not be updated, then the ER should be updated or bounded using new forecasted traffic volumes.

TRISO-X Response to RAI ER Supplement - 2 The traffic volumes for the construction and operation of TX-1 and TX-2 were updated as discussed in Section 4.2.2.4 and Table 4.2.2-1 (Construction) and Section 4.2.2.5 and Table 4.2.2-2 (Operation). The updates include the timing of construction and operation of TX-1 and TX-2 as discussed in Sections 4.2.2.4 and 4.2.2.5. The updated Traffic Study dated June 24, 2024, is included in Enclosure 2.

Environmental Report Changes None.

RAI ER Supplement - 3 Provide details of the feedstock shipping containers.

Revised section 4.2.3.3 introduces LR-230s packages as shipping containers for feedstock, but these are not mentioned or described anywhere else in the ER. Verify that this inclusion is accurate. In addition, the radioactive shipment data should be updated to show the return of the (nearly) empty LR-230 packages to the supplier as radioactive material shipments.

TRISO-X Response to RAI ER Supplement - 3 Uranyl nitrate feedstock will be transported in LR-230 shipping packages, and uranium oxide feedstock will be transported in VP-55 shipping packages. The text of Section 4.2.3.3 will be revised to discuss that there are 11 shipments of LR-230 packages to the TRISO-X facility from the supplier and then 11 shipments to return the empty LR-230 packages to the supplier. The empty packages will have a trace amount of radioactive contamination inside (due to the small remaining heel quantity), therefore these return packages will contribute a negligible amount to the incident free dose to the public and workers.

Environmental Report Changes Changes to Section 4.2.3.3, first paragraph, are shown in redline.

LEU and HALEU oxide is transported in Versa-Pac 55 (VP-55) packages. The VP-55 packages meet the requirements of 10 CFR 71 (CFR, 2021a), 49 CFR 100-180 (CFR, 2021b), and are approved by the NRC (Docket Number 71-9342). The VP-55 packages can contain uranium oxide with a mass limit of 605 g of U-235 (NRC, 2020). Forty Fifty-one shipments of LEU oxide, HALEU oxide, and UN occur annually with each truck containing 48 VP-55 packages or 9 LR-230s packages. The 51 shipments consist of 29 shipments of VP-55 packages and 22 shipments of LR-230 packages. LR-230 packages are used to ship UN. LR-230 packages are shipped back to the supplier (11 shipments to TRISO-X and 11 shipments back to the supplier)

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 9 of 10 and contain a trace amount of radioactive contamination inside (due to the small remaining heel quantity) in the return shipment. Containers meet the surface dose rate limits of 10 CFR 71.47(a) and 49 CFR 173.441(a) and the group of containers meet the 1 m (3.3 ft) dose rate limits of 49 CFR 173.441(d).

RAI ER Supplement - 4 Provide updated details of the new transmission lines that have been revised since the original ER was submitted.

The ER should be updated to include potential impacts of the two new 10MW transmission circuits CORED is planning. Any activities including tree cutting and/or trenching at or adjacent to the fuel facility sites should be provided.

TRISO-X Response to RAI ER Supplement - 4 TRISO-X has reviewed Section 2.3 of the ER Supplement. Updated details regarding the two new 10 MW transmission circuits were included in Subsection 2.3.1 and Table 2.3-1 of the January 31, 2025, submittal.

As described in the January 31, 2025, submittal, two new 10 MW transmission circuits are being added to the existing 10 MW circuit that currently serves the industrial park. The two 10 MW circuits will follow the underground route of the current circuit, utilizing existing right-of-way from the CORED Blair Road substation to the Horizon Center Industrial Park, extending to the southwest corner of the TRISO-X property. The impacts of this action are considered in the evaluation of cumulative effects in the applicable subsections of the ER. In general, as the project will be constructed in an existing right-of-way, impacts are minor and are primarily limited to localized soil disturbance during construction. Because this project results in localized effects, the cumulative effect of the TRISO-X Fuel Fabrication Facility added to effects of the CORED project to expand electric transmission is SMALL.

Environmental Report Changes None.

RAI ER Supplement - 5 Provide updated information on the socioeconomic data for the area near the proposed facility.

Section 4.10. 2 of the ER should be updated with current data for employment statistics, labor force, housing availability, education, community services, health care services, etc. The current data is based on 2020 or prior values.

TRISO-X Response to RAI ER Supplement - 5 The socioeconomic data presented in Sections 3.10 and 4.10 is still considered representative of the conditions in the ROI and is accurate for the purpose of considering the scale of demographic and economic impacts associated with the project. 2020 USCB decennial census data was used where applicable and is still the most recent census data available. U.S. Census American Community Survey (ACS) Five-Year estimates (2015-2019) are another frequently cited source.

This dataset is updated annually, with the most recently published data being the 2019-2023

TX0-REG-LTR-0072 - RAI Responses for the TRISO-X Environmental Report Supplement Page 10 of 10 Five-Year estimates. As shown below, the 2023 total population estimates for the State of Tennessee and the five counties that comprise the ROI were compared to the 2019 total population estimates to assess the potential for any new and notable changes in demographics.

Geography 2015-2019 ACS Estimates 2019-2023 ACS Estimates Percent Change Roane County 53,075 54,403 2.50%

Anderson County 76,061 78,175 2.78%

Knox County 461,104 487,401 5.70%

Loudon County 52,340 56,996 8.90%

Morgan County 21,545 21,193

-1.63%

ROI Total 664,125 698,168 5.13%

Tennessee 6,709,356 6,986,082 4.12%

The population within the ROI increased by approximately 5 percent, which is comparable to the growth in the state. Recent changes are also in line with trends expected for the region, as shown in the 2025 projections in Table 3.10.1-2, with Knox and Loudon Counties experiencing higher growth rates than the other counties. Thus, recent ACS data indicates that there are no new and notable circumstances related to demographics that would result in a change to impact determinations. Additionally, given the overall small change in population associated with the construction and operations workforces, minor changes to baseline community services attributes, such as student enrollment and number of licensed healthcare facilities/professionals, are not expected to have changed significantly in recent years (since 2021 or 2022 when the data was sourced) such that it would result in a change to impact findings.

Furthermore, the NRC has recently relied upon data of similar or older vintage for socioeconomic analyses - for example, the 2023 Construction Permit for the Kairos Hermes Test Reactor EIS incorporated data from the 2019 Clinch River Nuclear EIS, which included U.S. Census ACS 2012-2016 Five-Year estimates and other sources dated 2016 through 2018, noting that much of the analysis conducted for the CRN site was relevant and accurate for the assessment of socioeconomic and EJ impacts for the proposed Hermes project.

Environmental Report Changes None.