ML22357A067
| ML22357A067 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 12/30/2022 |
| From: | Division of Operating Reactor Licensing |
| To: | Omaha Public Power District |
| Shared Package | |
| ML22357A065 | List: |
| References | |
| EPID L-2021-LIT-0000 | |
| Download: ML22357A067 (10) | |
Text
Fort Calhoun License Termination Plan Review Request for Additional Information
Technical Evaluation
TE-1 Characterization and Application of Fill/Backfill Material
Comment: Clarification is needed to describe the characteristics of the proposed clean backfill material and that backfill material will only be applied follow ing the remediation and Final Status Surveys (FSSs) of individual survey units.
Basis: Adequate surveys are needed if the fill materials may contain residual radioactivity, or may be covering residual radioactivity, and must be considered for the survey unit to be compliant with 10 CFR 20.1402 and 10 CFR 20.1501. In multiple p laces, the LTP states that clean backfill will be used to fill excavations, voids and ba sements (e.g., Sections 3.3 and 3.5.1.3 of the LTP) to grade level. However, Sections 5.4.1.5 a nd 6.19 discuss attributing a dose from the proposed backfill materials. Therefore, clarification is needed on what is meant by clean fill materials. Similarly, the LTP describes in multipl e places that backfill and grading will be performed after FSSs.
Request: Define the characteristics of clean backfill material and de scribe how backfill material will be verified/characterized as clean prior to use. Details related to the selection process for any additional backfill material, beyond what is av ailable from the excavation of the rail spur expansion project, should also be provided. In additi on, please verify, and provide a description of the process, by which the final status survey an d application of backfill (e.g., when fill/backfill materials are not added until the final status su rvey is complete) are performed at individual survey units as part of license termination and FSSs.
TE-2 Operational Contamination Control Program and Remedial Act ion Support Surveys
Comment: Additional information is needed regarding how Remedial Actio n Support Surveys (RASSs) support the operational contamination control program.
Basis: To ensure compliance with 10 CFR 20, Subpart F, Surveys and M onitoring, additional information is needed on how RASSs support the operational cont amination control program.
Sections 4.2 and 4.3 of the LTP describe the remediation action s and their expected impact on the sites Radiation Protection Program (which includes the con tamination control program).
However, the information provided is not sufficient for the NRC to conclude that RASSs will be used to support the contamination control program and are adequ ate for mitigating any unexpected releases of material to the environment. For example, the LTP does not specify any criteria that would trigger the contamination control program i f contamination were unintentionally created or spread by decommissioning or waste p rocessing activities. Of particular interest to the NRC is how the contamination control program addresses the potential creation and spread of discrete radioactive particles (DRPs) or discrete radioactive objects.
Additionally, the proposed methodologies for RASSs are not desc ribed in sufficient detail to
1 ensure that DRPs would be identified, remediated, and documente d if their presence is suspected.
Request: Add additional information to the LTP with regards to how the contamination control program is supported by RASSs. Describe the survey frequencies (e.g., after each work shift in areas where operations are conducted) and methods that will be used for operational surveys for waste generation/processing activities. Information on the methods should include appropriate detectors and methods suitable for identifying the potential presence of contamination including DRPs or r adioactive objects that may be generated during decommissioning. A summary of the remedial actions that will be taken in the event DRPs or objects are present outside of a controlled operational area sh ould also be included.
TE-3 Basement Survey Unit Size Limits
Comment: Section 5.2.2 of the LTP indicates that basement survey units have no size limit regardless of classification.
Basis: To do adequate surveys of structures with residual radioactivi ty in compliance with 10 CFR 20.1501, Multi-Agency Radiation Survey and Site Investigati on Manual (MARSSIM) guidance (NUREG-1575, Revision 1) i ndicates that Class 1 structural survey units have a size limit of 100 m2 and Class 2 structural survey units have a size limit of 1,000 m2. Also, lower structure classification survey units include the floor and low er 2 meters of the structural walls which are most likely to have been impacted by facility operati ons.
Request: Provide justification for indicating that there are no survey unit size limits in basement survey units or revise Section 5.2.2 to be consistent with the structural survey unit size guidance in MARSSIM and NUREG-1757, Vol 2.
TE-4 Isolation and Control Measures
Comment: Additional information is needed on the isolation and control measures that have or will be established for survey units once decommissioning activ ities have been completed and a decision to perform FSSs has been made.
Basis: Additional clarifications are needed about the isolation and c ontrol program and the FSS data to ensure it will be adequate to demonstrate compliance wi th 10 CFR 20, Subparts E and F. Section 5.2.3 of the LTP describes the measures for isolatio n and control that the licensee will take prior to initiating FSS and will maintain during and after FSS. This section also describes the area surveillances that will be performed after F SS to provide assurance that these areas remain unchanged.
The NRC uses FSS data to reach reasonable assurance that a site has been adequately characterized and meets the unrestricted release criteria. It i s important for this data to reflect the final site conditions. For example, if a survey unit were t o become re-contaminated after the FSS was performed, the FSS data would no longer be applicable. It is important that the controls that have already been put in place, as well as those that will be in place, ensure that no activities will occur within a survey unit that could potent ially cause the radiological conditions to change once a decision to transition to isolation has been m ade.
2 Additional clarification is needed on:
a) how isolation and control measures will be managed for open land areas that do not have a positive access control. It is not clear from the LTP wh ether the isolation and control program for these areas will be primarily through the s urveillances or if the other isolation and control measures described in the LTP also apply to these areas. For example, it is not clear whether the measures such as instructi ng individuals to contact the LT/FSS group before performing work in the area and the tra cking of entries into the area will apply to the open land areas.
b) when the licensee intends to stop using isolation and contro l measures relative to when the license for the FCS site (minus the ISFSI) is terminated. S ection 5.2.3.2 indicates that the isolation and control measures will remain in force u ntil there is minimal risk of recontamination from decommissioning or the survey unit has bee n released from the license. However, the next paragraph states that To provide additional assurance that survey units that have successfully undergone FSS remain u nchanged until final site release. It is not clear from the LTP whether any movement of materials across survey units (e.g., regrading of the site) would be allowed to occur p rior to the release of the site or if the isolation and control measures would prevent this.
c) the method that will be used to determine the rigor needed f or the surveillance surveys.
It is unclear from the LTP how the surveillances will be docume nted and whether this information will be included in the FSS reports.
Request: Please provide additional information on the controls that are or will be in place to ensure that no activities that could potentially contaminate th e survey unit will occur once a decision to transition to isolation has been made. If investiga tion surveys (e.g., Radiological Assessments (RAs)) may be used for justification that no reperf ormance of an FSS is necessary, clarify how documentat ion of such surveys will suppl ement previously performed FSSs.
TE-5 Surrogate and Insignificant Contributor Quality Control (Q C) Checks Comment: Clarification is needed regarding which surveys the licensee w ill perform to assess the insignificant contributors and surrogate ratios.
Basis: This information is needed to assure compliance with 10 CFR 20.1402 (i.e., that the total dose to potential future site occupants is less than the dose c riteria) and 10 CFR 20.1501 (i.e.,
that the site has been adequately characterized). At minimum, t he additional site characterization surveys and QC sampling during FSSs should inc lude determinations that the surrogate ratios and insignificant contributor data in each sur vey unit are consistent with the data sets utilized to establish values in the LTP (see Table 5-16 and section 6.15 of the LTP).
Clarification is also needed for the actions that will be taken if the data in any survey unit is not consistent with the established values. Section 5.2.6.2 of the LTP describes the development of surrogate radionuclide ratios (Table 5-16) while other sections (e.g., Sections 5.2.5 and 6.15) describe the mixture ratios, dose contribution, and selection o f the insignificant contributors from the initial suite of site radionuclides. In Section 5.2.5 of th e LTP, the licensee commits to analyzing 10 percent of the continuing characterization samples for all media samples collected
3 in a survey unit for the initial suite of radionuclides and pro vides a method to assure that the appropriate surrogate and insignificant contributors are consid ered. Section 5.2.6.2 also commits to directly measuring C-14 in all soil samples. However, the LTP provides insufficient details on whether FSS QC samples or other survey types (e.g., RA, RASS), or other media, will also address the surrogate/inferred radionuclides or the insign ificant contributors and whether the established values are appropriate for the survey unit.
Because the insignificant contributors and inferred radionuclid es are not directly measured, it is necessary to verify that assumptions made based on initial char acterization data hold true throughout the site during and after decommissioning and that t he dose considerations for these components of potential dose are appropriately addressed.
In addition, the technical evaluation performed in RSCS TSD 21- 043, Rev 1, should be updated after all relevant site characterization data and final status survey QC data are available and included with the data set in the TSD and the impact to all FSS s determined.
Request: Update the LTP sections dealing with future site characterizat ion (e.g., Sections 1.5.2, 2.2.2, 2.2.6, 5.2.5), QC during FSSs (e.g., Sections 5.2.6.2, 5.6.3, 5.7.1.), as well as other sections pertaining to other survey types, as appropriate, to e xplicitly include data evaluations to validate that the insignificant contributors and surrogate rati os are correct and what actions the licensee will take if the data indicate inconsistency with the previously established values.
Clarify for which surveys and for which media verification of t he surrogate ratios and insignificant contributors will occur. Please confirm that the evaluation performed in RSCS TSD 21-043 will be updated after all applicable future characteriza tion and FSS QC data is included in the data set and that the impact of the newly updated radion uclide mixture fractions, insignificant contributors, and surrogate ratios will be assess ed for all FSSs.
TE-6 Data Quality Objectives for Groundwater Monitoring
Comment: More information is needed on the Data Quality Objectives (DQO s) for groundwater monitoring during decommissioning.
Basis: The LTP does not provide information on the DQOs for the groun dwater monitoring and whether they are sufficient to provide reasonable assurance tha t the final conditions of the site are consistent with the dose criteria in 10 CFR 20.1402 and tha t the site has been adequately characterized per 10 CFR 20.1501. Section 2.4 of the LTP descri bes surface and groundwater characterization that has previously been performed and Section 5.4.1.10 describes the survey methodology that will be used for groundwater. Section 5.4.1.10 states that the assessments of residual radioactivity in groundwater at the site will be via g roundwater monitoring wells installed at FCS and that the ongoing monitoring includes the Radiologica l Environmental Monitoring Program (REMP), Radiological Groundwater Protection Program, an d National Pollutant Discharge Elimination System monitoring. In some cases, the inf ormation needed to demonstrate compliance with the decommissioning regulations is different than the information needed during operations, and the groundwater program may need to be adjusted accordingly.
Groundwater monitoring during and following decommissioning act ivities should include residual radioactivity identified in the groundwater during decommission ing, if any, and investigations of subsurface residual radioactivity identified prior to or during decommissioning that could be associated with groundwater contamination. These investigations generally consider the
4 conceptual site model, and transport time and spatial length sc ales for relevant radionuclides.
The NRC provides guidance on Surface Water and Groundwater Char acterization as part of decommissioning in NUREG-1757, Vol 2, Rev 2.
Sections 5.2.6.6 and 6.18 of the LTP describe the methodology t hat the licensee will use to determine the dose from groundwater contamination, if any, that exists at the time of license termination. However, neither of these sections describes how t he radionuclides of concern (ROCs) for groundwater will be determined and whether they are expected to differ from the ROCs identified for other media. Additionally, it is not clear if the concentrations of all the ROCs will be evaluated as part of the groundwater monitoring program. As part of developing DQOs for groundwater monitoring, the licensee should describe how th ey will determine the ROCs for the groundwater pathway. The DQOs should be sufficient to deter mine the concentration of the ROCs in the groundwater and their associated dose.
Additionally, the DQOs for the groundwater monitoring are expec ted to be sufficient to allow comparison to the U.S. Environmental Protection Agency (EPA) Ma ximum Contaminant Levels, and monitoring should be sufficient to statistically demonstrat e that residual radioactivity concentrations in water are stable or decreasing (e.g., use of the Mann-Kendall test). For reference, see the Memorandum of Understanding (MOU) between EP A and NRC for Consultation and Finality on Decommissioning and Decontaminatio n of Contaminated Sites (Agencywide Documents Access and Management System [ADAMS] Acce ssion No.
ML073090532) and the paper written on implementing the MOU (ADA MS Accession No. ML051380168).
Request: Update the LTP to include DQOs for groundwater monitoring simi lar to the DQOs established for FSS sampling. The DQOs should address the initi al suite of radionuclides established in the LTP (Table 5-2) and should provide sufficien t information to provide reasonable assurance that the groundwater conditions remaining at the site at the time of license termination are consistent with the NRC regulations.
TE-7 Surveys of Excavations
Comment: Surveys (including FSSs and RASSs) of excavations should inclu de the sidewalls as well as the footprint of the excavation (see NUREG-1757, Vol 2, Section G.3.2.1).
Basis: The FSS should incorporate all exposed surfaces in an excavati on to be compliant with 10 CFR 20.1501. In Section 5.4.1.4 of the LTP (as well as other sections), the licensee states that an FSS) designed as an open land survey will be performed of excavations. Clarify that this means both the excavation footprint as well as any sidewalls of the excavation will be subject to the FSS and RASS, as appropriate.
Request: Clarify in Section 5.4.1.4 (and others as appropriate) that ex posed sidewalls of excavations will be incorporated into any RASS or FSS.
5 TE-8 Discrete Radioactive Particle Definition and Surveys Comment: Justify the definition of DRPs of concern and actions to be t aken in event of DRP release.
Basis: A dose basis and activity level for DRPs of concern that are anticipated to remain on site at the conclusion of decommissioning are needed for the NRC sta ff to assess the potential dose impact of any DRPs to future site occupants and compliance with decommissioning regulations in 10 CFR 20.1402. In addition, justification that the survey m ethodology is sufficient to detect DRPs that have an activity level of concern and the additional information on survey techniques is needed to ensure surveys would be compliant with 10 CFR 20.1 501.
Section 5.4.1.11 of the LTP provides a description of survey co nsiderations for areas that are suspected to have DRP contamination. In this section, DRPs are defined as specks of radioactive material identified usually as either activated cor rosion product such as cobalt-60, or an irradiated fuel fragment exhibiting greater than 10,000 corr ected counts per minute (100,000 dpm). Due to issues such as what instruments are being utilized, how instruments are set up, detector/source geometry, shielding materials that may be prese nt, etc. basing a definition on instrument response is inadequate.
Section 5.4.1.11 of the LTP provides information on the survey methods that the license will use in suspected DRP areas. However, this survey information does n ot include a justification that the methodology is sufficient to detect DRPs that have an activ ity level of concern. Also, the description of the survey methodology does not specify if alarm s are going to be used to identify DRPs during scanning and, if so, what the instrument set points will be.
Also, the LTP does not appear to address radioactive objects wh ich are larger in volume than the typical DRP but of a lesser volume than would typically be considered for materials and equipment. Information is needed on whether the same approach will be used for these discrete radioactive objects as will be used for DRPs. The LTP does not clarify if the DRPs or radioactive objects will be considered and evaluated even if co mposed of materials not directly related to plant operations and not specifically excluded from 10 CFR 20.1402 (e.g., TENORM).
Finally, Section 5.4.1.11 states that a condition report will b e generated for each DRP encountered. However, the LTP does not appear to commit to perf orming contamination control surveys to identify and disposition DRPs in a timely manner to avoid potential secondary transport and if DRP remediation efforts will be complete prior to any additional soil disturbing activities in the affected area.
Request:
a) Please propose a dose basis and activity level for DRPs of c oncern if such are anticipated to be part of the residual radiation present at the conclusion of decommissioning.
b) Describe the method for surveying for DRPs that demonstrate that it will be sufficient to identify DRPs of concern.
c) If using alarms to identify DRPs during scanning, justify th e proposed alarm set point for the surveys and what instruments the set points will apply to.
6 d) Describe the procedures, if any, that will apply to surveys for radioactive objects which are larger in volume than the typical DRP but of a lesser volum e than would typically be considered for materials and equipment (e.g., activated concr ete pebble/rock).
e) Describe how DRPs or radioactive objects will be considered and evaluated including if they are composed of materials not directly related to plant op erations and not specifically excluded from 10 CFR 20.1402 (e.g., TENORM).
f) If a release of DRPs does occur, describe the contamination control surveys to be used to identify and disposition DRPs, and how they will be done to avoid potential secondary transport. Also describe how DRP remediation efforts will be do ne in relation to any soil disturbing activities in the affected area. Describe how the a ctivities will be documented.
Clarification RAIs
CL-1 Criteria for Determining when Changes to the LTP Require N RC Approval
Comment: The LTP change criteria listed in the proposed license amendme nt do not include all the criteria listed in NUREG-1700, Revision. 2.
Basis: To evaluate that the LTP demonstrates meeting the requirements of 10 CFR Part 20, Subpart E, Radiological Criteria for License Termination, NRC uses NUREG-1700, Standard Review Plan for Evaluating Nuclear Power Reactor License Termin ation Plans. NUREG-1700 recognizes that the licensee may make changes to the LTP follow ing its approval by the NRC.
However, NUREG-1700 identifies that there are areas of the LTP that cannot be changed without prior NRC approval because it would represent a change to the approved license termination methodology. To control this change process, NUREG-1700 contains a list of LTP areas that cannot be changed without prior NRC approval and sta tes that the LTP should include a provision that addresses how changes are made to the LTP after approval.
The license amendment request (LAR) proposes to add license con dition (LC) 3.D to the FCS license. The LC would approve the LTP and identify areas of the LTP that cannot be changed without NRC approval. The LAR states that the proposed LC is in accordance with NUREG-1700, Revision 1, Appendix 2, which is a list of NRC identified areas of the LTP that would require prior NRC approval to be changed. The proposed LC essen tially captures the list in NUREG-1700, Revision 1, Appendix 2. However, NUREG-1700 has bee n updated (Revision 2) and contains a list, in Appendix B, that is more comprehensive than that in Revision 1. The list from Revision 2 contains two additional areas of evaluation tha t, if changed in the LTP, would need approval by NRC. These areas are: 1) a change to the appro ach used to demonstrate compliance with dose criteria, and 2) a change to the dose asse ssment parameter values or pathway dose conversion factors that would lead to a lower calc ulated dose than what was approved in the LTP.
Request: For proposed LC 3.D, please clarify that the proposed list of LTP areas that cannot be changed without NRC approval does not include the two additiona l areas described in NUREG-1700, Revision 2, Appendix B or, revise the proposed LC to refl ect those two additional areas. If those two additional evaluation areas are not to be included in proposed condition 3.D, please describe how any changes to those two areas would be controlled in the LTP.
7 CL-2 Clarification of Figures Showing Random Sample and Scan Lo cations Comment: The information shown on the figures need to be clarified.
Basis: The Survey Unit Random Sample and Scan Locations figures refer enced in Sections 2.3.2.1.1-2.3.2.1.3, are inconsistent in the information convey ed. Survey Unit 8100 Figure 2-26 has a legend that includes locations for walkover grids, Figure 2-28 (SU 8200) has no legend, and Figure 2-30 (SU 8300) and others show a legend with only sa mple locations. The dot within a circle indicates a soil sample location per the legend in the lower right corner of Figure 2-30 but does not state if the circle represents the scan area like the legend for Figure 2-26. The title of Figure 2-26 indicates that it includes "Scan Locations." Fig ure 2-30 is believed to convey the same information but has a legend in the lower left showing the circled dot as a sample location rather than as a random sample location. Consistent survey data presentation in figures is required under 10 CFR 20.1501(a)(2) and is needed by NRC staff to better understand the information in the figures.
Request: The licensee should provide updated figures with consistent leg ends and data consistent with the legend and titles for those figures that in dicates the meaning of each mark on the figure and that corresponds to the text describing the f igure.
CL-3 Scan Alarms
Comment: Provide a description for the Scan Alarms indicated in Table 2-83.
Basis: Table 2-83, Turbine Building Scan Results, indicates that at four locations there were Scan Alarms. Clarification is needed to demonstrate complianc e with 10 CFR 20.1501(a)(2) on the adequacy of surveys for residual radioactivity.
Request: Please provide a description on what the Scan Alarms are.
CL-4 Inconsistent Low-Level Waste Volumes Comment: The low-level radioactive waste volumes given in two places in the LTP are different from each other and both are different than the volume given in the Site-Specific Decommissioning Cost Estimate (DCE).
Basis: The requirement in 10 CFR 50.82(a)(9)(ii)(F), for an updated si te-specific estimate of remaining decommissioning costs in the LTP, requires an estimat e of low-level radioactive waste volumes from decommissioning so that waste disposal costs can be estimated as part of the site-specific DCE.
Page 3-21 of the LTP states the total volume of radioactive w aste for disposal has been estimated at 3,222,861 cubic feet. The sum of the volumes of w aste in Class A, Class B/C and Greater than Class C in Table 3-4 is 3,334,679 cubic feet. Tabl e 6-5 of the DCE, that was provided in the June 15, 2022, LTP RAI response, contains a bre akdown of Class A, B/C and Greater than Class C waste. The total volume of those wastes is 2,499,928 cubic feet.
Request: Clarify the difference between these estimates of the total qu antity of radioactive waste and/or provide a consistent projected volume for each cla ss of radioactive waste.
8 CL-5 Methods Anticipated to be Used to Determine Ambient Background
Comment: Clarify the methods anticipated to be used to determine ambien t background as discussed in section 5.2.4 of the LTP.
Basis: Section 5.2.4, Reference Areas and Materials, does not speci fically state what methods would be used to determine ambient background when perf orming surveys. This information is necessary to demonstrate compliance with 10 CFR 20.1501(a)(2) on the adequacy of surveys for residual radioactivity.
Request: The licensee should describe the process for obtaining ambient background levels during surveys. A specific consideration for staff would be a d iscussion on how ambient background might change in a survey unit and how a revised ambi ent background would be determined.
CL-6 Verification of As Low As is Reasonably Achievable (ALARA) Parameters
Comment: The ALARA evaluation are using parameters inconsistent with th e values present in the references/citations.
Basis: In Section 4.4.1.2 of the LTP, the licensee references a trans portation fatal accident rate that appears inconsistent with the value in the cited document. The licensee should verify it is using the correct values in the reference document, or more rec ent document if available, to perform its evaluations.
Request: Revise the ALARA evaluations, as appropriate, to be consistent with the cited values/parameters after verifying the values being cited.
CL-7 In Situ Object Counting System (ISOCS) Use Comment: Clarification is needed on how the licensee will address ISOCS field of view (FOV) uncertainties as discussed in sections 5.3 through 5.5 of the L TP. Verify that the RASS performed prior to ISOCS measurements will ensure a relatively homogenous radiation fluence is present in the ISOCS FOV (i.e., no DRPs or hot spots will be present).
Basis: Section 5.3, Final Status Survey Design, Section 5.4, Final Status Survey Implementation, and Section 5.5, Final Status Survey Data Ass essment of the LTP address the use of ISOCS measurements for RASS and FSS. NUREG-1700, Section 5, Final Radiation Survey Plan, calls for a demonstration that the in-situ sample measurements with field instruments, and the associated survey methods, have adequate s ensitivity as part of the FSS design. Accordingly, the LTP should address survey areas where inconsistent geometry is present (e.g., corners, junctions of walls, etc.) relative to I SOCS measurements and what determines when an ISOCS measurement location is unsuitable. This is needed to ensure an adequate survey is conducted consis tent with the requirements o f 10 CFR 20.1501.
Request: Update the appropriate discussions in the LTP regarding use of ISOCS and how prior to the use of ISOCS it is ensured that no DRPs or elevated area s are present in the ISOCS
9 FOV. Describe how if an elevated area is present, the ISOCS may still be used to investigate the area relative to its FOV of the elevated area. Also discuss the possibility of utilizing combinations of in situ and conventional measurements as part o f the overall FSS design and how ISOCS measurements will be c onservatively performed when uncertain geometries are being measured.
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