ML21104A058

Comment (6) of Bruce Montgomery on Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria

ML21104A058
Person / Time
Site:	Nuclear Energy Institute
Issue date:	04/08/2021
From:	Montgomery B Nuclear Energy Institute
To:	Office of Administration
References
86FR6683 00006, NRC-2020-0192
Download: ML21104A058 (16)

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4/14/2021 blob:https://www.fdms.gov/468950c4-85e8-41b5-9c27-5161575b3cfa SUNSI Review Complete Template = ADM-013 As of: 4/14/21 7:09 AM E-RIDS=ADM-03 Received: April 08, 2021 PUBLIC SUBMISSION ADD: Cynthia Barr, Mary Neely Status: Pending_Post COMMENT (6)

Tracking No. kn9-1myc-zk28 PUBLICATION DATE: Comments Due: April 08, 2021 1/22/2021 Submission Type: Web CITATION 86 FR 6683 Docket: NRC-2020-0192 Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria Comment On: NRC-2020-0192-0001 Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria Document: NRC-2020-0192-DRAFT-0009 Comment on FR Doc # 2020-26876 Submitter Information Email: atb@nei.org Organization: Nuclear Energy Institute General Comment See attached file(s)

Attachments 04-08-21_NRC_NEI Comment Letter_NUREG-1757 blob:https://www.fdms.gov/468950c4-85e8-41b5-9c27-5161575b3cfa 1/1

BRUCE S. MONTGOMERY Director, Decommissioning and Used Fuel 1201 F Street, NW, Suite 1100 Washington, DC 20004 NUCLEAR ENERGY INSTITUTE P: 202.739.8128 bsm@nei.org nei.org April 8, 2021 Office of Administration Mail Stop: TWFN-7-A60M U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTN: Program Management, Announcements and Editing Staff Project Number: 689

Subject:

NEI Comments on Draft NUREG-1757, Volume 2, Revision 2, Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria, Docket ID NRC-2020-0192.

Subm itted via regulations.gov

Dear Program Management,

Announcements and Editing Staff:

The Nuclear Energy Institute (NEI) 1, on behalf of our members, appreciates the opportunity to provide comments on Draft NUREG-1757, Volume 2, Revision 2, Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria. This draft revision includes significant changes to address advancements and lessons learned in the area of radiological site remediation. The guidance provided in this NUREG will provide an important source of information for the development and implementation of license termination plans, final status surveys, and associated reporting. Because this NUREG is written to be applicable to a broad range of facility types and licensees, it is necessarily a large compilation of acceptable processes, methods, standards and criteria. As a positive attribute, the ample use of appendices in this revision helps direct users to technical information that is selectively applicable to the unique situations encountered at a specific site.

In recent years, the license termination process has become increasingly lengthy and burdensome to both license termination applicants and NRC reviewers. To reverse this trend, NEI intends to develop a technical 1

The Nuclear Energy Institute (NEI) is responsible for establishing unified policy on behalf of its members relating to matters affecting the nuclear energy industry, including the regulatory aspects of generic operational and technical issues. NEIs members include entities licensed to operate commercial nuclear power plants in the United States, nuclear plant designers, major architect and engineering firms, fuel cycle facilities, nuclear materials licensees, and other organizations involved in the nuclear energy industry.

NUCLEAR. CLEAN AIR ENERGY

Program Management, Announcements and Editing Staff April 8, 2021 Page 2 report for use by typical commercial nuclear power plant licensees to guide them through the license termination process, and this revision to NUREG-1757, Volume 2 will be a key source document for that report. In light of that forthcoming effort, NEI has reviewed the NUREG-1757, Volume 2 and offers the attached comments which we believe need to be addressed to improve the efficiency of regulatory activities associated with license termination. For example:

• While Tables 1.1 and 1.2 provide a good overview of applicability, the usefulness of the NUREG could be further improved by including a crosswalk to NUREG-1700, Revision 2, Standard Review Plan for Evaluating Nuclear Power Reactor License Termination Plans so that licensees could readily identify how the many elements addressed in NUREG-1757, Vol. 2, Rev. 2 should be used in developing a license termination plan.

• Within the guidance, there appears to be a disconnect between the minimum information NRC expects to receive in a license termination plan and final status survey reports, and the types and amount of information NRC instructs its reviewers to examine. Taken on face value, it appears that with Revision 2, NRC is seeking considerably more data from licensees than has been deemed necessary by NRC in the past. This increase in the types and volume of information requested does not appear to be warranted on the basis of public safety goals, and may result in further protracted reviews, higher costs, and delays in achieving license termination.

• Some important technical areas that have been the source of uncertainty in regulatory expectations and that have been the cause of multiple requests for additional information and extended reviews in the recent past have not been addressed in this revision (e.g., hot particles, excavation surveys/assessments, and use of in-situ gama-spectrometry to address excavations). Instead of deferring these issues to the future, the NRC should work with stakeholders to develop practical, risk-informed solutions to these issues before finalizing this revision.

• This revision contains a significant quantity of information that is pulled from other, existing technical reports. To simplify NUREG-1757, and to minimize the risk that NUREG-1757 will become dated as these other documents evolve, it is strongly recommended that NUREG-1757 simply reference these other documents.

During the March 15, 2021 public meeting, the NRC staff stated that it intends to conduct a workshop on the topic of this revised NUREG this summer. NEI supports the use of a workshop as a means to ensure that the public has a more complete understanding of the many changes to this voluminous document, to facilitate a discussion on how NRC will resolve comments received to date, and to allow additional comments to be provided to the NRC.

We appreciate the NRCs effort in developing this draft guidance and encourage your consideration of all stakeholder comments prior to finalizing this draft NUREG. We trust that you will find these comments useful and informative as you finalize the draft and we look forward to future engagement on this important matter.

Program Management, Announcements and Editing Staff April 8, 2021 Page 3 Please contact me at bsm@nei.org or (202) 739-8128 with any questions or comments about the content of this letter or the attached comments.

Sincerely, Bruce Montgomery Attachment c: Patricia Holahan, NMSS Bruce Watson, NMSS Cynthia Barr, NMSS

Attachment:

NEI Detailed Comments on NUREG-1757, Vol. 2, Rev. 2, Consolidated Decommissioning Guidance

1. Section Comment Proposed Resolution

1. General Comment While Tables 1.1 and 1.2 provide a good overview of Add a crosswalk between NUREG-applicability, the usefulness of the NUREG could be further 1700 and NUREG-1757 to clarify improved by including a crosswalk to NUREG-1700, expectations for the content of Revision 2, Standard Review Plan for Evaluating Nuclear License Termination Plans (LTP).

Power Reactor License Termination Plans so that licensees could readily identify how the many elements addressed in NUREG-1757, Vol. 2, Rev. 2 should be used in developing a license termination plan.

2. General Comment This revision to the guidance contains a significant Eliminate or reduce information quantity of information that is pulled from other, existing duplicated from other technical technical reports. To simplify NUREG-1757, and to reports.

minimize the risk that NUREG-1757 will become dated as these other documents evolve, it is strongly recommended that NUREG-1757 simply reference these other documents. This will also help reduce the amount of technical detail in the report and may even eliminate the need for some appendices.

3. General Comment There appears to be a disconnect between the minimum Ensure that the license termination information NRC expects to receive in a license process is risk-informed, and that termination plan (LTP), a final status survey (FSS) plan information required to be submitted and related reports, and the types and amount of by licensees is clearly aligned to the information NRC instructs its reviewers to examine. Taken information NRC expects its staff to on face value, it appears that with Revision 2, NRC is use during the reviews of LTPs, FSSs, seeking considerably more data from licensees than has and related reports.

been deemed necessary by NRC in the past. This increase in the types and volume of information requested does not appear to be warranted on the basis of public safety goals, and may result in further protracted reviews, higher costs, and delays in achieving license termination.

4. General Comment Some important technical areas that have been the source NRC should work with stakeholders of uncertainty in regulatory expectations and that have to develop practical, risk-informed

been the cause of multiple requests for additional solutions to these issues before information and extended reviews have not been finalizing this revision.

addressed in this revision (e.g., hot particles, excavation surveys/assessments, and use of in-situ gamma spectrometry to address excavations). Instead of deferring these issues to the future, the NRC should work with stakeholders to develop practical, risk-informed solutions to these issues before finalizing this revision.

5. General Comment In a few cases, the organization of the report with regard While some changes in the report will to the portrayal of the flow of work, licensee submittals to help alleviate this issue, it is NRC and subsequent NRC approvals, does not reflect the recommended that this topic be a sequence of activities that will actually occur during focus of future industry guidance on decommissioning. the license termination process.

6. 2.2, page 6, line 3 In the insert Cautions on Making Assumptions or Consider providing additional detail Committing to a Methodology, the NRC does not provide (examples and/or criteria) to guide any criteria or examples for what types of assumptions or the user in the advisability of methodologies would need advance discussions with NRC advance discussions with NRC on the to allow the use of the flexible approaches discussed in use of flexible approaches.

this section.

7. 3.3, page 3-5, line 2 Text states: Ratios should be conservatively selected so Incorporate alternative approaches that they do not underestimate the potential dose that have been approved by NRC contributions of the insignificant radionuclides (e.g., use of staff.

minimum detectable concentrations (MDCs) for undetected radionuclides, and use of the 95th percentile ratios of insignificant to significant radionuclides).

Other approaches that have been approved by NRC staff for establishing these ratios have included:

1. The use of actual reported concentrations (even when less than MDCs) using MARLAP principles, and

2. Using the 75th percentile of radionuclide fractions to represent conservative ratios vs. the 95th percentile.

8. 4.1.2, page 4-4, line The parenthetical qualifier with subsequent PSR is not Remove qualifier or provide more 33 needed since side-by-side surveys may be used for other explanation why this may exclusively FSS activities or, the PSR may be delayed for practical apply.

reasons.

9. 4.1.3, page 4-5, This section provides two methods to submit information Provide additional detail to lines 11 through 26 on the final radiation surveys. The two methods are very discriminate Method 1 from Method similar with little discrimination between them. 2, or combine into one method.

10. 4.2.1, page 4-6, The statement: Therefore, the licensee shall perform a Change shall to should...

lines 37-38 scoping survey is too restrictive.

11. 4.5, page 4-15, This opening paragraph offers an opportunity to provide Add as second sentence of lines, 23-24 additional clarity on FSS report (FSSR) content. paragraph: As a minimum the FSSR should contain the information outlined in 4.5.1.1.3.

12. 4.5.1.2, page 4-17, Second paragraph last sentence: the NRC reviewer may Replace may need to with should lines 21-22 need to obtain previous NRC--generated reports on the FSS

13. 4.5.1.2.3, pages 4- This section appears to effectively negate the objective Consider incorporating other means 18 through 4-20 stated in 4.5.1.2.2 to establish a risk-informed approach to to more effectively establish the need selecting the number of survey units for detailed review. for detailed reviews of survey units.

The section lists almost two dozen factors and examples, that, if any one of which could be attributed to a survey unit, could lead NRC to consider the need for a detailed review. This would appear to have the effect of defaulting the reviewer to performing detailed reviews in many cases when not warranted by the risk significance of the survey unit.

14. 4.5.1.2.3, Page 4-19 Reference is made to DCGLW. Should be DCGL W .

lines 27 - 29

15. 4.5.1.2.3, Page 4- Reference is made to using MARSSIM statistical tests Please provide a source of guidance.

20, line 6 when hot particles are present. This document provides no guidance on evaluating data when hot particles are present.

16. 4.5.1.2.4, page 4-20 A few of the questions under Detailed Review Topics Delete these questions and consider have questionable value in the decision-making process incorporating specific guidance into and appear to be arbitrary: Appendix D.

• Does the licensees analysis rely on a large number For example, criteria based on having of results expressed at MDA (minimum detectable a lot of MDC values should not be a activity) or MDC values? trigger for a more detailed review.

• Is there a discernible trend in results within and Rather, this may simply be an among survey units (e.g., when comparing survey indicator of an area with very low methods, locations, or media matrices)? residual radioactivity.

• Are there any assumptions about the variability (variance) of the population?

17. 4.5.1.2.4, page 4-21 This criterion asks the reviewer to look for data outliers Include an acceptable approach for Line 4 and determine whether their disposition was appropriate, identifying and justifying the but provides no guidance on how to make that removing outliers or delete the determination. criterion (consider incorporating into Appendix D).

18. 4.5.1.2.4, page 4/21 Identifies the use analytical tools as a criterion for Incorporate guidance for which line 7 performing a detailed review. analytical tools are acceptable (or unacceptable) for use without requiring a detailed review.

19. Section 5, General Survey or modeling considerations for hot particles (or Add descriptions or references to Comment discrete radioactive particles) are not addressed in this modeling and survey techniques for section despite being issues faced by decommissioning hot particles that have been licensees. These are issues that are expected to continue successfully implemented by to challenge licensees in the future. licensees.

20. 5.2, page 5-6, lines The intake-to-dose conversion factors from Allow the use of the most recent 36-40 Federal Guidance Report No. 11, Limiting Values of dose conversion factors Radionuclide Intake and Air Concentration developed/published by EPA, NRCP, and Dose Conversion Factors for Inhalation, Submersion, or ICRP for effective dose or total and Ingestion, issued September effective dose equivalent.

1988 (EPA 520/1-88-020) (EPA, 1988b), which are based primarily on adults, should be used when calculating internal exposures.

21. 5.3, page 5-8 (lines Appendix Q is referenced and is not applicable in most Remove sentences referencing 29, 36) cases. (See comment #56 below) Appendix Q.

22. 5.5.1, page 5-16, Regarding Residual Radioactivity Spatial Variability the Add clarification on what is lines 7-19 document directs NRC staff to review the licensees homogeneous or heterogeneous.

information on conditions before and those projected after the decommissioning alternative is complete. Based on this information, the NRC should determine whether it is appropriate to assume homogeneity (1) for the whole facility [or for surface soils, areas] or (2) for subsections of the facility when evaluating building surfaces.

This is subjective in that the document does not define how the degree of homogeneity is to be determined.

Similar comment on page 5-19, lines 1-7

23. 6.3.3, page 6-3, line The fourth bullet is written in a manner that is Revise to: that residual 11 unnecessarily restrictive. radioactivity distinguishable from background remaining at the site at termination is less than 10% of the dose criteria.

24. Appendix A, General Much of the information in this Appendix appears to have Consider whether Appendix A is Comment been simply extracted from MARSSIM. needed given its redundancy with MARSSIM.

25. Appendix B, General This Appendix provides abbreviated guidance for the Consider providing guidance to Comment application of the MARSSIM alternative approach or the achieve successful NUREG-1757 alternative approach, however states these remediation/demolition of clean simple approaches can only be used for facilities/open land areas (i.e., non-Decommissioning Groups 1-3. It would be helpful if power impacted or Class 3) prior to reactor licensees could utilize a simplified approach for approval of the LTP so that work is activities in relatively clean areas of the sites to achieve not considered at risk. Use of demolition of such structures prior to approval of the LTP, screening values, a standard including guidance for the ability for use of such material statistical sampling approach, as fill material on the site. This is often required for acceptable approaches for use of logistical purposes to provide unobstructed areas for safe clean material as fill for onsite work conditions. And use of clean material as fill on site excavations, etc. are examples of reduces or eliminates the risk associated with handling guidance that would greatly enhance and shipping of materials offsite. safety at large D&D projects.

26. Appendix C, General Most of the material in this Appendix is academic and has Consider whether this Appendix is Comment limited usefulness. needed.

27. C.2, page C-2, line Not all terms in Equation C-1 are defined. Define all terms.

34

28. C.2, page C-9 Although there are values presented for the critical value Define u 1 , I 1 and u 2 .

terms u 1 , I 1 and u 2 presented in Table C.1 on page C-9, those terms are not defined in the Appendix.

29. Appendix D, D.4 Based on experience, the NRC has stated via RAIs that the Include specific language in Appendix criteria for QA acceptance for FSS data was too loosely D that points to MARLAP Appendix C defined, and the procedure used to perform QC QC acceptance criteria for assessments was inadequate for comparing samples with comparisons of (1) on-site analytical levels of residual radioactivity near MDC. In addition, results to off-site analytical results, MARLAP was not a heavy influence on project QAPPs; (2) on-site split or duplicate samples instead, methods from previous decommissioning projects to standard samples, and (3) and experiences were employed. Project managers and replicate static measurements to licensees should have a primary guidance in MARLAP standard static measurements.

when it comes to laboratory QA.

30. Appendix F, General This Appendix refers to groundwater or surface water Consider replacing contamination Comment contamination throughout. with residual radioactivity.

31. Section F.1, page The statement: In these cases, unmodified screening Reword this section.

F.1, lines 15-18 derived concentration guideline levels (DCGLs) for soil are inappropriate to use, because the screening levels assume surface water and groundwater are usually based on initially uncontaminated.

This assumption is only applicable for RESRAD-ONSITE.

RESRAD-OFFSITE allows for an initial groundwater source term as well as other potential modeling approaches.

32. F.3, general This section provides an extensive discussion of need to Incorporate acceptable compliance develop a Conceptual Site Model (CSM) but no mention on metrics such as duration of how to show compliance through monitoring well sample monitoring period and trend of results. monitoring well concentrations.

33. F.3, page F-3, lines consideration of scale affects is provided in Appendix Appendix Q does not contain the 29-30 Q. term scale affects. Remove sentence.

34. F.4, page F-4, lines

• storage tanks, waste tanks, and/or piping (above or Reword to known to have or 6-7 below ground) that held or transported radioactively suspected of having leaked contaminated fluids and are known to have leaked

35. F.4, page F-4, lines

• surface water or atmospheric discharge of radioactive Clarify to state that radioactivity from 19-21 effluents including authorized releases and spills (e.g., these types of releases that are releases in compliance with 10 CFR Part 20, Appendix located outside the site boundary B effluent concentrations or spills) need not be characterized or need to meet site release limits as they have been accounted for as part of reported site releases.

36. F.4, page F-4, lines

• an accident or spill on site, where liquid radioactive Add ...with a potential pathway to 24-25 material was released to the interior of a building. the environment at the end.

37. F.5, general This section, in addition to analyzing groundwater samples Clarify that the NRC does not require for radioactivity, states that the following parameters be these additional analyzes.

analyzed for: sulfate, chloride, carbonate, alkalinity, nitrate, total dissolved solids, total organic carbon, Eh, pH, calcium, sodium, potassium, iron, and dissolved oxygen.

These additional analyses seem excessive for most sites and may only be necessary for site with very complex hydrogeology and/or elevated levels of soil/groundwater contamination.

38. F.5, general This section is silent regarding the need for NRC approval Should add that monitoring well prior to making changes to the monitoring well network. network can be changed without NRC pre-approval.

39. F.5, general Similar to the comment on Section F.3 above, this section Should add that compliance with site provides no guidance on how to demonstrate compliance release limits for groundwater can be with groundwater site release limits through monitoring shown with monitoring well results well sample results. that do not show an increasing trend for an 18-month period after all remediation is complete and which includes two high groundwater level seasons.

40. F.7, page F10, lines The remedial action objective of attaining permitted This is a confusing sentence and 18-20 standards, such as groundwater protection standards, or should be clarified.

DCGLs should be demonstrated before monitoring and the license are terminated to ensure that the required standards are actually achieved in the long-term (Pope et al., 2004).

41. F.8, page F-12, lines This section states that: For offsite effluent discharges, It should be clarified that the NRC 4-9 offsite decommissioning activities are not required by NRC does not require characterization of regulations. State and local entities may require different off-site areas due to contamination treatment of offsite areas that are contaminated by from the migration in groundwater or normal effluent discharges. For NRC, however, surface water as the radioactivity characterization may be needed to assess environmental from these releases has been impacts as part of the environmental assessment or accounted for as part of reported site impact statement. Similarly, groundwater seepage of releases. Additionally, any onsite residual contamination to offsite surface waters assessment of future impact to off-must be incorporated into environment assessments or site areas due to these migrations impact statements. can be performed using characterization data from on-site This statement is not clear as to where the groundwater monitoring wells or on-characterization data for this assessment is to be collected site surface water bodies.

from.

42. F.7, page F-10, line The licensee should establish surface water and Remove quality.

30 groundwater quality and water levels There is no definition of groundwater quality. In fact, the paragraph is focused on groundwater elevation measurements vs. quality.

43. F.7, pages F-10 and The guidance in this section regarding frequencies and Consider removing prescriptive F-11 methods appears to be overly prescriptive. wording.

44. F.10, page F-13, RESRAD-ONSITE does not consider existing groundwater Recommend deletion of the words:

lines 34-35 contamination and only addresses the potential, future does not consider existing transport of residual radioactivity and contamination of groundwater contamination and only ground and surface water and associated doses.

Similar to comment 30 above, although not often used, the RESRAD-OFFSITE code does allow for input of existing

groundwater activity concentrations after entering the time since material placement, to derive the distribution coefficients.

45. Appendix F, Section This section provides a high degree of detail in the Provide a very high-level description F.10 descriptions of and comparisons between various codes of the analytical codes and including RESRAD-ONSITE, RESRAD-OFFSITE, MODFLOW capabilities/limitations with a caveat and several others. This level of detail may go beyond that using these tools generally what is needed for the user of this guidance. requires very specific education or training to achieve proficiency in application.

46. G.3.1, page G-6, The approach laid out in NUREG/CR-7026 (Application of Add an acceptable sampling density lines 24-27 Model Abstraction Techniques to Simulate Transport in or a method to determine an Soils) presents one potentially acceptable method that acceptable sampling density.

may be used in conjunction with radiological survey data to demonstrate compliance.

This section does not define an acceptable sampling density.

47. G.3.2.1, page G-9 This section discusses the need for an FSS of an open Add the required sample density or excavation prior to backfilling but does not provide the method to determine the needed requirements for that FSS. The section discusses sampling density for excavations. Add a of the excavation but does not provide a required sample discussion of the use of in-situ density or method to determine the needed density. gamma spectrometry as a method of Additionally, the section does not mention the use of In- assessing the excavations and any situ gamma spectrometry as a method of assessing the requirements for such assessments.

excavations which has been approved in the past for some power plant sites.

48. G.3.2.2, page G-13, This section states, for backfill derived from offsite sources Consider alternative methods for lines 2-10 that to support this assumption of no added residual sampling and analysis to radioactivity would be to use a two-sample statistical test demonstrate indistinguishable from such as a Scenario B type analysis to show background for backfill materials.

indistinguishability from background, as described in Chapter 13 of NUREG-1505.

For large-scale backfill operations where large volumes of material is brought to the site, it would be impractical to conduct a survey to achieve this criterion.

49. I.6.4.4, page I-88, If dose and compliance risk are sensitive to the selection For selecting values for dose lines 2-7 of K d , it may be necessary to conduct experiments using modeling input parameters that are site materials to provide support for K d values used in shown to be sensitive in affecting dose modeling. For those isotopes where the K d does not dose from a particular radionuclide, have a significant impact on the dose assessment based continue to allow the use of the value on a sensitivity analysis (i.e., the dose results are not a from the worst-case quartile of the sensitive to K d ), limited justification will be needed to parameter distribution as the input support selection of the parameter value. parameter to a deterministic RESRAD run to determine DCGLs.

In the past, NRC has approved the use of literature values from the worst-case quartile of the parameter distribution for input parameters that are shown to have a significant impact on dose. The requirement to conduct experiments using actual site materials to determine site-specific K d values replaces an already conservative methodology and is an unreasonable burden on licensees.

50. Table I-12, page I- Same previous comment Same as previous comment 89

51. J.1.1, page J-2, If the soil at a site is assumed to be capable of growing Consider removing or modifying this lines 1&2 crops without significant soil engineering, then plant condition.

ingestion should be considered.

The decision of whether to include plant ingestion involves many other considerations and not solely on the capability of the soil itself.

52. Figure J.8, page J- In the approval of past LTPs, NRC has agreed that this is Delete this scenario.

11 not a realistic exposure scenario. Even though this section states that the license can argue that this scenario is unreasonable, its presence in the NUREG makes the

licensee perform unnecessary and burdensome justifications.

53. J.3.1, pages J-12 & This section describes the need to assess the radioactivity Add guidance on the level of survey J-13 content in basement surfaces and volumetrically in needed to assess the contamination basement concrete (if applicable). No guidance is given as on/in building basement concrete.

to the level of survey needed to perform this assessment.

54. Appendix O, Section provides some specific direction and examples for More simplified and straightforward General Comment implementation - however is quite complex and would composite sampling model(s) that require a statistician or other high-level SME for could be applied for different interpretation and compliance (guidance points to scenarios would reduce time required academic publications). Guidance also includes words of for development, review, and caution to the user that appear to point to subjectivity in approval of such models and ensure interpretation which could result in disagreement among consistency in implementation of NRC implementers and regulators. For example: The guidance.

composite sampling is used as a method to increase the probability of elevated area or hot spot detection and to Otherwise - such an approach would reduce analytical cost. However, this situation w ould likely be cost prohibitive to most require considerable evaluations perform ed on a sites/licensees.

case-by-case basis . As such, this guidance provides only a general scenario and the associated variables. If composite sampling is proposed to alleviate sampling requirements associated with HTD radionuclides, the licensee should contact the NRC early in the process to discuss the acceptability of the proposal.

55. O.3.1.1, page O-5, The following statement appears to contradict itself: Please provide clarification.

lines 15-22 Composite sampling may be used during characterization or to provide additional FSS survey unit coverage for Class 2 and 3 areas to ensure proper classification of the unit.

Because Class 2 and Class 3 survey units should not have residual contaminant concentrations in excess of the DCGLW when properly classified, under most FSS conditions, there is limited, if any, benefit to composite sampling in properly classified Class 2 or 3 FSS units. Use

of composite sampling in these classifications would necessitate application of an MIL that is a fraction of the reclassification investigation level.

56. O.3.1.1, page O-5, Composite sampling may be used for HTD radionuclides Provide examples of how composite lines 23-31 for which an actual MDCSCAN cannot be established (e.g., sampling could be practically applied.

pure beta or alpha emitter in soil) and there are no surrogate radionuclide relationships available. The composite sampling is used as a method to increase the probability of elevated area or hot spot detection and to reduce analytical cost. How ever, this situation w ould require considerable evaluations perform ed on a case-by-case basis. (em phasis added) As such, this guidance provides only a general scenario and the associated variables.

57. Appendix Q This Appendix is a new addition compared to Rev 1. The Delete Appendix.

information contained here is generally not applicable to D&D sites. Rather, it appears applicable to waste disposal sites for long-term assessments. The Appendix should either be removed or defined when the principles that are discussed apply to D&Ds. The information contained in the Appendix is mostly general considerations on how model uncertainties should be handled for complex modeling, beyond the considerations of RESRAD probabilistic analysis. Also, this Appendix makes mentions of performing analysis for thousands of years whereas 10CFR20 Subpart E is limited to 1000 years.