ML24053A258
| ML24053A258 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 03/01/2024 |
| From: | Reactor Decommissioning Branch |
| To: | |
| Shared Package | |
| ML24053A165 | List: |
| References | |
| Download: ML24053A258 (10) | |
Text
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 1
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 1
Limited Site Characterization Use with Final Site Survey (FSS) 50.82(a)(9)(ii)(A)
The license termination plan must include - (A) site characterization.
A.2, Site Characterization Subsection on Radionuclides Present at Each Location, 1st bullet See Section 4.2 Information to be submitted The LTP provided limited site characterization results for land areas, building structures, embedded piping, basement structures, and pavement covered areas and concrete slabs.
Characterize those areas with limited or no data and provide a summary of the site characterization results to provide reasonable assurance that an adequate characterization was conducted to fully understand the residual radioactivity in soil, structures, piping, etc.
This summary is needed to enable the NRC staff to understand how the licensee uses the results to determine radionuclides of concern, determine radionuclide mixtures/fractions, determine insignificant contributors, inform the remediation planning, estimate waste streams, design the final status survey, establish area classifications, calculate modified derived concentration guideline levels (DCGLs), gross activity DCGLs, request sample analyses, and determine instrument efficiencies.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 2
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 2
Gamma Scans 50.82(a)(9)(ii)(A)
The license termination plan must include - (A) site characterization.
2.2.1, Acceptance Criteria, 4th bullet point Sections 4.2 on Site Characterizatio n and 4.3 on Remedial Action Support Surveys LTP Section 2.3, Site Characterization Surveys provides a description of soil and building sampling and open land scans and references use of the ScanPlotSM Overland Scanning System ultra-all-terrain vehicle for scans of all accessible land areas of the site. The LTP contains a short description of the vehicles configuration but goes on to explain that there is no technical basis document (TBD) for the system which summarizes the detection capability of the system for Cs-137 or any other potential VY plant-derived radionuclides with a gamma signature.
Other than the ScanPlotSM system and use of off-site laboratory services for sample analysis, the section does not refer to the use of any other instruments being used to support site characterization.
In addition, the LTP does not describe quality assurance practices and instrument sensitivities used during site characterization.
An explanation of when portable survey instruments were used in site characterization and a description of the quality assurance practices and instruments sensitivities is needed to support the evaluation of the overall quality of the data collected during this part of the site characterization so NRC staff can have reasonable confidence that the licensee understands the extent of hazards present and the remediation necessary for license termination.
A discussion of the sampling methodology and sampling objectives is needed to provide reasonable confidence that sufficient sampling, analysis, and evaluation was completed to assess the radionuclides present and their variability in the survey areas to support development of radionuclide mixtures/ratios as needed for waste characterization and remedial action support surveys and final status survey planning.
Additionally, justification and documentation to support the conclusion that that gamma scans indicated no elevated areas are present, given the qualitative results from the ScanPlotSM system and the inability to calibrate the system for plant derived gamma emitting radionuclides, is needed to provide reasonable confidence that significant quantities of residual radioactivity have not gone undetected.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 3
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 3
Justification of non-impacted areas 50.82(a)(9)(ii)(A)
The license termination plan must include - (A) site characterization.
A.2, Site Characterization Subsection on Characterization Surveys, 3rd bullet.
Section 4.2 on information that needs to be submitted Neither the historical site assessment (HSA) nor Chapter 2 of the LTP provide a justification for classification of areas as non-impacted.
A basis for the classification of the areas as non-impacted is needed to provide reasonable confidence that significant quantities of residual radioactivity have are not gone undetected in the non-impacted areas and to provide sufficient information for planning an adequate FSS.
4 Remaining structures clarification 50.82(a)(9)(ii)(B)
The license termination plan must include - (B) identification of remaining dismantlement activities A.3 Identification of Remaining Site Dismantlement Activities and Remediation Plan Section on Remaining Site Dismantlement Activities 1st, 3rd5th bullets The licensee included a section on the completed and pending decommissioning activities and tasks giving an overview of items removed and a plan for dismantlement and removal of systems and components.
The Reactor Building, Radwaste Building, and Turbine Building will be reduced.
Miscellaneous above-grade and below-grade structures will be removed; however, a specific list of these structures, or detail on associated decommissioning and dismantlement (D & D) activities, is not provided.
Clarify which above and below-grade structures will remain, and any safety and execution issues that were encountered when dismantling or remediating contaminated, structures, systems, and equipment.
Additionally, elaborate on the mechanisms used to control the spread of contamination via air and surface water during and after dismantlement and remediation activities.
This information is needed by the NRC staff to provide reasonable assurance that the licensee accounted for the risk significance of the D & D of structures. This will assist in developing and coordinating inspection and confirmatory survey activities.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 4
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 5
As Low as Reasonably Achievable (ALARA) Analysis 50.82(a)(9)(ii)(B)
The license termination plan must include - (c)
Plans for site remediation.
10 CFR 20.1402 i.e., that residual radioactivity has been reduced to levels that are ALARA.
A.5 Compliance with Radiological Criteria for License Termination (Dose Modeling)
Subsection on ALARA Analysis 2nd, 3rd bullets.
See Chapter 6 and Appendix N LTP Section 4.4 makes a commitment to include an ALARA evaluation in the FSS Report for each survey area or that a generic ALARA evaluation will be created for the site.
Section 4.5 contains a description of the proposed methodology for performing an ALARA analysis and Table 4.1 contains parameter values to be used in the ALARA analysis. However, the LTP itself does not contain survey area or generic ALARA evaluations.
Clarification on if the licensee intends use survey area specific ALARA evaluations or Generic ALARA evaluations.
For ALARA evaluations, provide a quantitative cost-benefit analysis with a description of how costs were estimated for the generic ALARA scenario(s) with justification for the selection of parameters used in the calculation, and a description of what remediation activities are considered as a part of this analysis.
This information is needed to provide reasonable assurance that the licensee will perform remediation sufficient to fully demonstrate compliance with 10 CFR 20.1402.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 5
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 6
MDC and FSS instrument sensitivity 10CFR 20.1402 10CFR 20.1501 A.4 Final Radiation Survey Plan Subsection on Remediation survey 2nd bullet.
Subsection on Final Status survey design, 5th bullet.
A.2 Site Characterization Subsection on Characterization Surveys, 1st bullet.
See Appendix A, Section A.5, Appendix E Table 5-8 of LTP identifies instrument currently proposed for use in the FSS along with Table 5-9 which provides a list of parameters relevant to the evaluation of the instruments sensitivity and the nominal and static Minimum Detectable Concentrations (MDCs) for a limited number of the instruments identified for FSS. Various sections of the LTP commit to having instrumentation that is capable of detecting residual radioactivity at 10-50% of the DCGL.
MDCs for instrumentation referenced in the LTP should be in units comparable to the DCGLs to demonstrate that the instruments have adequate sensitivity to detect residual radioactivity at 10-50% of the DCGL including an explanation of the process used to develop radionuclide fractions, weighted instrument efficiency and the process for accounting for Hard-to-Detect (HTD) radionuclides as it relates to the MDCs.
This information is needed to provide reasonable assurance that the licensee will utilize survey instrumentation capable of detecting residual activity below the DCGL, or ideally at 10-50% of the DCGLs as recommended in NUREG-1575 (MARSSIM) and discussed in the LTP.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 6
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 7
FSS Background reference area determination 50.82(a)(9)(ii)(A)
The license termination plan must include (D) Detailed plans for the final radiation survey Section A.4 Final Radiation Survey Plan Subsection on Final Status Survey Design: 3rd bullet.
See Ch 4,
Background
- Survey, Appendix A, Section A.3 LTP Section 5.3.4, Background Reference Area, mentions that reference area measurements, if needed, will be collected using the methods and procedures required for Class 3 final survey units and provides a generalized discussion of the characteristics of a suitable background reference area.
Identify the specific background reference areas and materials used in support of statistical tests and give a justification for their selection. Describe in greater detail the radiological survey and sampling methodology used for these areas. Discuss the criteria for applying the indistinguishable from background approach and the site-specific justification for its application.
This is needed for staff to ensure that a suitable background is being utilized when demonstrating compliance using FSS.
8 Insignificant contributors 10 CFR 20.1402 NUREG 1757 Vol 2. Rev. 2 Section 3.3 The LTP does not discuss a mechanism for accounting for insignificant contributors in the dose contributions for comparison with the 0.25 mSv/year (25 mrem/year) dose criterion or how these will be verified throughout the decommissioning process.
Describe the approach used to account for the dose contribution from insignificant contributors when evaluating compliance with the dose criterion.
This information is needed by the NRC staff to provide reasonable assurance that the licensee is properly surveying for, and accounting for, dose contributions from all plant related radionuclides to demonstrate compliance with the radiological criteria for unrestricted use in 10 CFR 20.1402.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 7
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 9
HSA/Site Characterization 50.82(a)(9)(ii)(A)
The license termination plan must include-(A)
Site Characterization A.2 Site Characterization Subsection on Radiological Contamination Structures, Systems, and Equipment, 3rd, 4th, and 5th bullets.
Section 4.1.1 Historical Site Assessment, HSA contains information on incidents and subsequent clean up of potentially contaminated media and provides a commitment to perform further characterization and remediation of potentially impacted areas. However, there is limited discussion on the data gaps identified during the HSA and how they will be accounted for in subsequent scoping and characterization surveys.
Discuss the potential contaminants, potentially contaminated media, data gaps, and supporting documents by area/structure.
This information is needed by the NRC staff to provide reasonable confidence that the licensee has identified all areas containing potentially significant quantities of residual radioactivity. The HSA is a key component in the development and planning of subsequent scoping/characterization surveys, which inform remediation plans and the FSS.
10 Survey of Backfill material and assessment of dose contributions 10 CFR 20.1402, 10 CFR 20.1501 Section G.3.2, Survey of Excavations and Use of Backfill Soil for Excavated Land Areas The LTP does not discuss the survey of backfill materials.
Describe the survey and sampling process and subsequent data analysis of backfill material to ensure dose contributions from any residual radioactivity present in backfill material are accounted.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 8
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 11 Validation of theoretical determination of ROCs 10 CFR 20.1402 2.5.1, Acceptance Criteria, 1st bullet Section 3.3, Insignificant Radionuclides and Exposure Pathways Table 6-1 represents a list of radionuclides potentially present at VY based on applying the selection process described in Enclosure 3 to the combined list of potential radionuclides from regulatory guidance contained in NUREG/CR-3474 and NUREG/CR-4289 and historical 10 CFR Part 61 analyses or site characterization samples.
The executive summary of the Enclosure 3 discusses NOT discounting radionuclides contributing less than 0.1 percent to the total activity which have other methods of production in addition to activation of reactor components and/or have been observed in 10 CFR 61 waste stream analyses or site characterization samples.
Section 4.3 of Enclosure 3 mentions identifying Cm-243, Am-241, and Pu-241 as part of the historical analysis of the 10 CFR 61 waste stream and including these radionuclides in the list of radionuclides potentially present at VY. A discussion regarding specific details e.g. (methodology and scope) of the historical analysis of the 10 CFR 61 waste stream or the site characterization that was evaluated is not provided.
Discuss the site characterization and waste analyses used to validate the theoretical determination of the radionuclides of concern.
Include information on the type of analyses conducted on characterization samples.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 9
Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 12 Dose from existing ground water contamination 10 CFR 20.1402 Section A.5.
Subsection on Unrestricted release criteria using site-specific information, 4th bullet
- ISG Subsurface* 4.1 (note: the ISG will be incorporated into next version of NUREG-1757)
LTP section 2.2.1 mentions the detection of tritium in groundwater and section 5.4.4.7 of the LTP states that the groundwater contamination will be below U.S.
Environmental Protection Agencys (EPAs)
Maximum Concentration Limits (MCLs) at site release. Also, staff notes that contamination may arise due to perturbations during demolition activities.
However, there are no pathway dose conversion factors with which to combine with groundwater concentrations to calculate a dose due to existing groundwater contamination.
Provide a description of the approach used for calculating dose from existing groundwater contamination and how that dose is factored into the total dose estimate to meet the dose criteria in 10 CFR 20.1402.
13 Information supporting the basis for modeling parameters 10 CFR 20.1402 Section A.5 Subsection unrestricted release criteria using site-specific information, 5th bullet The basis for several modeling parameters referred to documents not included in the LTP submittal.
Provide the following documents cited in the Tables G-1 & I-1 in LTP Chapter 6 as the basis for modeling parameter inputs:
H&A 129657-040 GZA GeoEnvironmental Inc. (GZA),
2011, Hydrogeologic Investigation of Tritium in Groundwater, Vermont Yankee Nuclear Power Station, May 2011.
H&A Memorandum, dated 2/9/2021 (regarding subsurface sampling)
This information is needed so that staff can determine if the DCGLs were developed using information representative of the site, and/or if the input values can be considered conservative.
Vermont Yankee License Termination Plan Acceptance Review Information Insufficiencies 10 Item No.
Regulation(s)
NUREG-1700 Rev. 2 NUREG-1757 Vol. 2 Rev. 2 Information Provided Information Needed 14 Demonstration of compliance from multiple sources 10 CFR 20.1402 Section 2.7 The LTP does not discuss an approach for accounting for dose contributions from multiple sources (e.g., surface soil, subsurface soil, buried piping, buried structures, backfill material, existing groundwater contamination).
Describe the approach to meeting the radiological criteria for unrestricted use (10 CFR 20.1402) for an individual who could potentially be exposed to multiple contaminated media.
Without that information the staff cannot assess compliance with 10 CFR 20.1402.
15 Dose from embedded piping and subsurface soil 10 CFR 20.1402 Section A.4.
Subsection on Final Radiation Survey Plan, 1st bullet.
LTP Section 5.3.6.3.2 discusses plans to submit a technical basis document for DCGLs for embedded piping prior to implementation, however it is not clear how this would affect surface soil DCGLs in LTP Table 6-2.
Additionally, section 5.4.3.2 indicates that potential complications of introducing subsurface soil DCGLs will be considered in the Data Quality Objectives (DQO) process, however it is not clear staff whether this involves adjustments to the surface soil DCGLs in LTP Table 6-2.
Describe how potential future DCGLs mentioned in LTP Section 5.3.6.3.2 and LTP section 5.4.3.2 would affect the surface soil DCGLs provided in LTP Table 6-2.
Without this information the staff is unable to assess compliance with 10 CFR 20.1402.
16 Dose from non-gamma emitting radionuclides 10 CFR 20.1402 Section A.4.
Subsection directly under Final Radiation Survey Plan bullet 4 LTP Section 5.6.2.1 and Equation 5-12 appear to apply the unity rule only to gamma-emitting radionuclides. The section does not address how the DCGLs account for the dose contribution from non-gamma emitting radionuclides.
Describe how the unity rule will be used to include the dose from non-gamma emitting radionuclides in the development of DCGLs for soils, building surfaces, and any other DCGL values the licensee chooses to submit.
Without this information the NRC staff will be unable to assess whether the DCGL values can be used to demonstrate compliance with the dose criterion in 10 CFR 20.1402.