ML25218A298
| ML25218A298 | |
| Person / Time | |
|---|---|
| Site: | Triso-X |
| Issue date: | 08/06/2025 |
| From: | Triso-X |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML25218A296 | List: |
| References | |
| TX0-REG-LTR-0081 | |
| Download: ML25218A298 (1) | |
Text
TX0-REG-LTR-0081 Enclosure - Set 19 Environmental Safety RAI Responses Page 1 of 4 RAI-1 Transuranic and Fission Product Contaminants in Effluents Regulatory Basis:
Title 10 of the Code of Federal Regulations (10 CFR) Section 20.1302(a) states The licensee shall make or cause to be made, as appropriate, surveys of radiation levels in unrestricted and controlled areas and radioactive materials in effluents released to unrestricted and controlled areas to demonstrate compliance with the dose limits for individual members of the public in § 20.1301. The dose limits in § 20.1301 apply to the total effective dose equivalent from the licensed operation.
Description of Issue:
The applicant stated that feed material may contain transuranic and fission product contamination.
Although the survey program is described in LA chapter 4, there is limited information on the monitoring of transuranic and fission product activities in effluents. Additional information is needed to evaluate the proposed emissions controls with respect to transuranic and fission product contamination.
Information Needed:
Incorporate in the LA or by cross reference a sufficient description of the methods, such as action levels related to receipt of contaminated feed material, to determine when it is appropriate to survey for transuranic or fission product contamination in effluents.
TRISO-X Response to RAI-1:
License Chapter 1, Section 1.2.4, Type, Quantity, and Form of Licensed Material, includes transuranic and fission product limits that are applied to the contaminants in enriched uranium feedstock. TRISO-X performed effluent activity concentration calculations which demonstrate if feedstock with contaminants up to these specified limits is received and processed, then any offsite receptor would receive significantly less than 10 mrem per year, which meets 10 CFR 20 requirements. Supplier sampling documentation is independently reviewed to ensure source material contaminant values are less than specified limits. Source material with contaminants greater than the limits specified in License Chapter 1, Section 1.2.4 will not be accepted by TRISO-X. Therefore, surveys for specific transuranic or fission product contamination in effluents are not necessary to demonstrate compliance with 10 CFR 20.
RAI-2 Frequency and Type of Ambient Air Sampling and Analysis Regulatory Basis:
As stated in 10 CFR 20.1302(b), a licensee shall show compliance with the annual dose limit in § 20.1301 by (1) demonstrating by measurement or calculation that the total effective dose equivalent to the individual likely to receive the highest dose from the licensed operation does not exceed the annual dose limit; or (2) demonstrating that the annual average concentrations of radioactive material at the boundary of the unrestricted area do not exceed values specified in table 2 of appendix B to part 20.
The guidance in Section 9.4.3.2.2 (A5) of NUREG-1520, Rev. 2, Standard Review Plan for Fuel Cycle Facilities License Applications, states that sampling and analysis frequencies must be appropriate. Section 9.4.3.2.2 (A6) of NUREG-1520, Rev. 2 states that radionuclide specific analyses are required. Section 9.4.3.2.2 (A4) states that monitoring for all routine and nonroutine events should be performed quarterly.
TX0-REG-LTR-0081 Enclosure - Set 19 Environmental Safety RAI Responses Page 2 of 4 Description of Issue:
The applicant currently proposes collecting weekly effluent samples from the stacks and analyzing the samples for isotopic uranium. This commitment satisfies the identified regulatory requirements for stack releases. Ground level ambient air sampling is the method proposed by the applicant for monitoring potential environmental doses associated with nonroutine events that result in ground level releases. Furthermore, the applicant has committed to perform ambient air measurements as a method for early detection of nonroutine ground level releases. The methods for analyzing uranium in ambient air should be able to distinguish potential releases from the licensed facility from natural background or nearby sources. The simple and reliable method for distinguishing the licensees uranium releases from background or nearby sources is the isotopic ratio of U-234/U-238 in high assay low enriched uranium feedstock.
The applicants commitment to early detection could be satisfied by more frequent sampling, such as sampling ambient air weekly and measuring gross alpha and gross beta weekly. Monthly sampling for gross radioactivity appears to be inconsistent with a commitment for early detection.
Section 9.5 of the revised LA states that ambient air samplers verify the absence of routine ground level gaseous effluent releases and provide a method for early detection of nonroutine ground level gaseous effluent releases. Table 9-1 shows that stack discharges are sampled weekly, but ground level ambient air is sampled monthly and that isotopic uranium analyses are not required for ambient air samples. The methods for analyzing uranium in ambient air does not identify a method to distinguish potential releases from the licensed facility from natural background or nearby sources. Measurements, such as quarterly specific isotopic analyses of composite ambient air samples, should be performed on ambient air samples consistent with guidance in NUREG-1520, Rev. 2 to identify the source of uranium measured in ambient air.
Information Needed:
Update the LA to clearly explain how TRISO-X effluent monitoring will ensure early detection of potential nonroutine releases from ground level events and identify releases that are specific to the TRISO-X facility.
TRISO-X Response to RAI-2:
License Chapter 9, Section 9.5 states that ambient air samplers provide a method for early detection of nonroutine ground level gaseous effluent releases. As stated in the response to RAI 2-1 ER-POH-1 (ADAMS Accession No. ML23354A288 dated December 20, 2023), ambient air samplers are used to document the absence of ground level emissions under normal operating conditions and to measure the off-site impact in the event of a ground level air emission.
Sampling monthly for gross alpha/beta is appropriate to document the absence of ground level emissions under normal operating conditions and provides the opportunity to detect a negative trend well before potentially exceeding 10 CFR 20 annual limits. If the gross alpha/beta analysis determines that action levels were exceeded, then isotopic Uranium analysis will also be performed to determine the reason for elevated activity (whether from an on-site release or from natural background or nearby off-site sources). License Section 9.5, paragraph 3, is clarified below.
The guidance in NUREG-1520 Rev. 2, Section 9.4.3.2.2, Item A.4 for quarterly sampling to confirm radioactivity in effluent is not significant is applicable to effluent discharge points.
Therefore, this guidance is applied to the thermal oxidizer effluent discharge points as shown in the License Changes for Table 9-1. Ambient air monitors are sampled monthly and analyzed for gross alpha/beta activity. If action levels are exceeded, then isotopic Uranium analysis will be
TX0-REG-LTR-0081 Enclosure - Set 19 Environmental Safety RAI Responses Page 3 of 4 performed to determine the reason for elevated activity. For consistency, the same approach is applied to groundwater, soil, vegetation, and stormwater sampling as shown in the License Changes for Table 9-1.
The number of locations for air effluent discharge points has been updated in the License Changes for Table 9-1 to be consistent with the Environmental Report and the response to RAI ER Supplement - 1, Item 3)b., dated May 23, 2025. License Chapter 9, Figure 9-1 shows three air effluent discharge locations marked by a yellow star. Each of these yellow stars represents one process ventilation discharge point and one thermal oxidizer discharge point.
License Changes:
9.5 Environmental Monitoring TRISO-X conducts a routine environmental surveillance program. Compliance with 10 CFR 20.1301 is achieved using the option provided in 10 CFR 1302(b)(2)(i) to demonstrate that the annual average concentrations of radioactive material released in gaseous effluents at the boundary of the unrestricted area (the point of stack discharge) do not exceed the values specified in Table 2 of Appendix B to Part 20. Demonstration is accomplished by calculation and validated by measurement. This ensures that environmental concentrations at the site boundary and offsite are well below regulatory limits.
Surface environmental media and groundwater samples are collected from strategic locations in the surrounding environs and analyzed for pertinent constituents of concern. Baseline levels of radionuclides in media surrounding the facility are established through sampling and analysis prior to operations using SNM. Feed material is characterized for enrichment and other potential contaminants prior to use. Future sample results are evaluated against action levels and the facility source term to identify any confounding natural sources of radioactivity or sources from operations external to the facility. Action levels and associated responses are specified for each environmental medium and radionuclide as defined in approved procedures.
The program provides early detection and response to a negative trend in environmental data, and support data in the event of a release of radioactive material. Continuous stack monitoring provides a method for early detection of a negative trend in gaseous effluent releases from normal operations. Ambient air samplers verify the absence of routine ground level gaseous effluent releases and provide a method for early detection means for measuring the off-site impact in the event of a ground level gaseous effluent releases from an off-normal event. Information from these monitoring activities is used to support assessments of normal operations or following off-normal events. Environmental dosimeters are co-located with the ambient air samplers to confirm the absence of ambient external dose rates above background in unrestricted areas and to assist with the assessment of potential accidents.
A summary of typical sampling activities is included in Table 9-1. Typical sampling locations are provided in Figure 9-1. The locations for sampling of soil and vegetation will be concentrated along the predominant wind directions. The locations for ambient air sampling are selected based on predominant wind directions and the direction of potential receptors. Four groundwater observation wells are installed on the site. Groundwater elevation measurements and modeling indicate that groundwater generally flows in a southwest direction toward East Fork Poplar Creek.
There are no known household, public, or industrial users of groundwater downgradient of the site.
TX0-REG-LTR-0081 Enclosure - Set 19 Environmental Safety RAI Responses Page 4 of 4 Table 9-1: Environmental Monitoring Parameters Type of Sample Analyses Number of Locations Typical Sampling Frequency Air Effluent Discharge Points - Process Ventilation Gross Alpha/Beta Isotopic Uranium 23 Continuous (collection weekly)
Air Effluent Discharge Points - Thermal Oxidizer Gross Alpha/Beta Isotopic Uranium 3
Quarterly Ambient Air Gross Alpha/Beta1 6
Continuous (collection monthly)
Groundwater Gross Alpha/Beta1 Isotopic Uranium 4
Quarterly Soil Gross Alpha/Beta1 Isotopic Uranium 4
Semi-annually Vegetation Gross Alpha/Beta1 Isotopic Uranium 4
Semi-annually Stormwater Gross Alpha/Beta1 Isotopic Uranium 3
Quarterly Environmental Dosimetry Determined by NVLAP accredited vendor 6
Quarterly 1Isotopic Uranium analysis is performed when gross alpha/beta action levels are exceeded.