What's New in Decommissioning of Nuclear Facilities

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Recent and Upcoming meetings and activities
Interim Guidance Development
Lessons Learned

Recent and Upcoming Meetings and Activities

The NRC consolidated its decommissioning guidance in a three volume NUREG-1757 series, which was originally issued in 2003. NUREG-1757, Volume 2 was recently issued for public comment . Comments were addressed and the document finalized on July 19, 2022 (Revision 2). Other decommissioning guidance document revisions that were recently issued include: NUREG-1507, Rev. 1, “Minimum Detectable Concentrations with Typical Radiation Survey for Instruments for Various Contaminants and Field Conditions”, and NUREG-1700, Rev. 2, “Standard Review Plan for Evaluating Nuclear Power Reactor License Termination Plans”. MARSSIM Rev. 2, draft for public comment, (NUREG-1575, Rev. 2) was also issued for public comment. The public comment period was reopened on December 28, 2021, for 45 days and the public comment period ended on February 11, 2022 (see 86 FR 73757). The Environmental Protection Agency’s Science Advisory Board (SAB) peer reviewed draft MARSSIM, Rev. 2. The SAB’s comments can be found in their final report. The MARSSIM working group is currently addressing public and SAB comments on the draft report.

NUREG-1700

NUREG-1757

NUREG-1507

MARSSIM

Some comments received on NUREG-1757, Volume 2, Rev. 2 were more difficult to address (comments on subsurface surveys and discrete radioactive particles) and are expected to result in significant changes to the guidance document. Therefore, the NRC plans to take additional time to address those comments and provide opportunities for interested stakeholders to weigh in on the need for revised guidance prior to incorporation of the guidance in the next revision to NUREG-1757, Volume 2. The interim guidance development section below provides additional information on the potential need for additional guidance in the areas of subsurface surveys and discrete radioactive particles, as well as historical and more recent information pertinent to the guidance that is being considered in making a decision on draft interim guidance. The following table lists upcoming meetings and activities to keep interested stakeholders informed of NRC progress on guidance development as well as provide information on opportunities for public participation in the guidance development process.

Meeting/Activity	Date/Timeframe	Meeting Notice/Notes
Issuance of: Interim Staff Guidance on Subsurface Investigations DUWP-ISG-02	October 2023	The guidance is focused on surveys of open surfaces in the subsurface (open excavations, building substructures, and materials planned for reuse), as well as support for use of RESRAD for submerged substructures, risk-significant parameters, and estimation of dose from existing groundwater contamination. The Federal Register Notice 88 FR 72112 announcing availability of the ISG for comment was issued on 10/19/2023. The public comment period ends on 12/18/2023.
Issuance of: Recommendations for VSP Enhancements for Continuously Collected Survey Data, PNNL-32664, Rev. 1	July 2023	This report identifies options for additional tools that could be added to Visual Sample Plan (VSP) to facilitate data importation and management, visualization, and analysis using continuous (without surveyor vigilance) methods for surface (2D) radiological surveys.
Issuance of: Overview of a Methodology for Calculating the A Priori Scan Minimum Detectable Concentration for Post-Processed Radiological Surveys, PNNL-34211, Rev. 1	June 2023	This report expands upon NUREG-1507 to provide a priori scan MDC calculations assuming surveys will be completed without vigilance based on audio click data, providing an incremental advance in the a priori scan MDC methodology by moving from a with-vigilance to a without-vigilance surveying paradigm.
Issuance of: Dose Coefficients (DC) for Discrete Radioactive Particles (DRPs) and Ulcerations Threshold Recommendations techical reports.	May 2023	Two Renaissance Code Development (RCD) reports on dosimetry for discrete radioactive particles in decommissioning were issued.
Federal Register Notice on Modern Approaches for Radiological Measurement, Data Collection, and Data Analysis of Surface and Subsurface Residual Radioactivity To Support NRC License Termination	May 4, 2023 (30-day comment period; comments due June 5, 2023)	The U.S. Nuclear Regulatory Commission (NRC) is requesting comments on the current state-of-art in approaches to radiological survey and data analysis to support decommissioning and license termination, and any associated guidance gaps. Comments on the use of modern survey instrumentation with continuous data logging; and novel instrumentation, data collection and analysis methods for subsurface investigations are being collected. The link to the Federal Register Notice is found here: 88 FR 28618
Decommissioning Lessons Learned Public Meeting	May 2, 2023	The US NRC hosted a decommissioning lessons learned meeting in conjunction with NEI and other industry representatives. The meeting materials can be found at the bottom of the public meeting notice. The meeting summary can be found here: ML23160A134.
RIC Hybrid 2023 (Reactor Decommissioning Session)	March 15, 2023	Session W9, Reactor Decommissioning: Decommissioning in a Dynamic Environment. The W9 hybrid session focused on providing an overview of the decommissioning status of facilities, including discussions of identified challenges discovered during decommissioning in the areas of radiological, industrial, and fire protection safety. The session also shared lessons learned from the implementation of new approaches, corrective action plan management, and recent license termination processes and guidance. In addition, the technical staff shared research and development activities to support decommissioning reviews and engagement with internal and external stakeholders. Session W9 was held on Wednesday, March 15 at 1:30 pm. Watch the video of Reactor Decommissioning: Decommissioning in a Dynamic Environment.
Public Meeting on NEI 22-01	November 16, 2022	A hybrid public meeting on NEI 22-01 License Termination Process is being held on November 16, 2022. See meeting summary at ML22347A104.
Public Meeting on Discrete Radioactive Particles (DRP) Video Recording of Meeting	November 3, 2022	A hybrid workshop was held November 3, 2022, to discuss survey and dose modeling considerations for DRPs in decommissioning. See presentations, meeting summary and transcript at ML22301A159.
Issuance of Final PNNL Scoping Report on VSP Tools to Aid in Subsurface Investigations: Subsurface Radiological Survey Design and Geospatial Analysis Tool Recommendations	November 2022	The final report was published in November 2022.
Public Meeting on NUREG-1757, Volume 2, Rev. 2 Video Recording of Meeting	October 11, 2022	NRC staff held a public meeting to provide information on issuance of the final NUREG-1757, Volume 2, Rev. 2 which was published in the Federal Register on July 22, 2022. See presentations, meeting summary, and transcript at ML22291A443.
Issuance of Final SC&A Subsurface Technical Letter Report	September 2022	The final report was published in September 2022.
Final NUREG-1757, Volume 2, Rev. 2	July 19, 2022	The public comment period ended in April 2021. Over 200 comments in 9 comment letters were received on the draft document. Comments were addressed in Comment Response Document. The final report was issued on July 19, 2022. The Federal Register notice announcing the public availability of the document was published on July 22, 2022
Drones for Decommissioning: Proof of Concept	July 2022	The Pacific Northwest National Laboratory (PNNL) evaluated the use of an unoccupied aerial vehicle (UAV) to conduct radiological surveys that could be used in decommissioning to reduce time, cost, and potential safety risks to humans compared to current survey methods. The objective of this project was to evaluate the performance and limitations of a UAV to support a decommissioning radiological survey and compare it to a radiological survey conducted by a human.
Public comment period for proposed rule “Regulatory Improvements for Production and Utilization Facilities Transitioning to Decommissioning”	March 3, 2022 – August 30, 2022	See NRC’s dedicated web page with a link to the proposed rule and related documents.
RIC Virtual 2022 (Reactor Decommissioning Session)	March 8-10, 2022	Session W14, Reactor Decommissioning: Planning for Tomorrow. The W14 virtual session focused on initiatives and enhancements within the reactor decommissioning program. Presenters highlighted the overall program status, key accomplishments in the decommissioning program, resource initiatives to enhance the program, and implementation of “Be RiskSMART” initiatives. Session W14 was held on Wednesday, March 9 at 1:00 pm. Watch the video of Reactor Decommissioning: Planning for Tomorrow. A digital exhibit on Subsurface Soil Surveys and Characterization—Research Update is also available on the RIC web site.

Interim Guidance Development

Because the NRC’s Consolidated Decommissioning Guidance is only updated every few years, interim guidance can be used between guidance revisions to communicate methods to demonstrate compliance with radiological criteria for license termination related to important topics of interest to NRC licensees. Two areas for which the NRC is currently developing or assessing the need for interim guidance include: (i) subsurface investigations and (ii) discrete radioactive particles. The NRC staff is issuing additional guidance or other information for these two topics to allow members of the public to participate in the process. Opportunities for public engagement in the guidance development process are listed in the Recent and Upcoming Meetings and Activities section. Historical and recent information related to subsurface and discrete radioactive particle surveys are listed in the sections below to provide context for the issue. Staff will consider the historic record on these topics in developing interim guidance or other type of communication which will ultimately be folded into the next revision of NUREG-1757.

Subsurface Investigations

Many complex materials and decommissioning sites undergoing decommissioning have significant levels of residual radioactivity in subsurface soils and groundwater. The Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) addresses radiological surveys for surface residual radioactivity; however, federal guidance does not currently address characterization and radiological surveys for the subsurface. Subsurface soils are more difficult to access, and traditional scanning techniques are ineffective at measuring residual radioactivity at depth. Given challenges and limitations with subsurface surveys, methods to leverage existing data and optimize subsurface survey design will be proposed. Potential tools currently available to assist with remedial and final status survey decisions will be described. Additionally, the NRC has contracted out with Pacific Northwest National Laboratory to scope out additional tools for implementation in Visual Sample Plan to assist with subsurface survey design and data analysis to support decommissioning decision-making. The following table provides historical and more recent information related to the topic that will be considered in developing the draft interim guidance.

Document No./Title	Date	Notes
NUREG/CR-7021, "A Subsurface Decision Model for Supporting Environmental Compliance"	January 2012	Preliminary technical basis for design of subsurface surveys using the Spatial Analysis Decision Assistance (SADA) code.
NUREG-1757, Volume 2, Rev. 2, "Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria: Draft Report for Comment"	December 2020	The draft for public comment was issued in December 2020. New subsurface survey and dose modeling guidance was included in Appendix G and J.
NUREG-1757, Volume 2, Rev. 2 Public Meeting Presentation Slides (ML21057A335) Public Meeting Notice (ML21057A335)	March 2021	A public meeting was held on March 15, 2021, to discuss updates to Volume 2 of NUREG-1757, as well as listen to comments on the draft document. The March 15, 2021, meeting summary and transcript can be found here: ML21102A144.
2021 Subsurface Soils Workshop Research Information Letter 2021-12 Subsurface Soil Surveys Public Workshop - DAY 1 Subsurface Soil Surveys Public Workshop - DAY 2	July 14-15, 2021	The NRC held a workshop in July 2021 that was attended by over 160 participants. Topics included use of geostatistical methods for complex reactor and material decommissioning; dose modeling and elevated area considerations for subsurface soils; and challenges associated with surveys of open excavations. Additional information can be found here: ML21208A206.
2022 Subsurface Investigations Workshop Subsurface Investigations Public Workshop - Video	May 11, 2022	The NRC held a workshop on May 11, 2022, that was attended by approximately 130 participants. Discussion topics included geospatial approaches to optimize subsurface survey design and support decommissioning decision-making; innovative technologies (e.g., electrical resistivity tomography) for subsurface characterization; and lessons learned and case studies related to subsurface projects. See detailed meeting agenda, transcript and presentations at ML22117A070.
Guidance on Surveys of Subsurface Radiological Contaminants, White Paper	September 30, 2022	Final report on characterizing and evaluating subsurface residual radioactivity (authored by NRC contractor: SC&A Inc.)
Subsurface Radiological Survey Design and Geospatial Analysis Tool Recommendations	November 2022	Issuance of final PNNL scoping report recommending VSP tools to aid in subsurface investigations.

Discrete Radioactive Particles

Lack of control of DRPs has been an issue at some decommissioning sites seeking unrestricted release. DRPs may be present as a result of operations and can be released as part of decommissioning activities. Additionally, certain decommissioning activities (e.g., reactor vessel segmentation) could generate DRPs and lead to release of DRPs without proper controls in place. Guidance is available for isolation and ventilation procedures adequate for operations with the potential for DRP, or hot particle, generation. Licensees should be cognizant of potential activities that could generate DRPs and have a program in place to control DRP to avoid issues with assessing the presence and risk significance of DRPs at the time of license termination.

The NRC staff are in the process of evaluating existing guidance, and other information sources, which will be considered in making a decision on the need for and content of draft interim guidance. A public workshop was held on November 3, 2022, to discuss this topic (see links to workshop materials in the first table above) and included two presentations and a paper from NRC’s contractors on (i) calculation of scan minimum detectable activities or MDAs (Oak Ridge Institute for Science and Education or ORISE), and (ii) dose conversion factors for DRPs (Renaissance Code Development [RCD]). ORISE’s scan MDA report was published in October 2022 and is linked in the table below. The focus of the RCD work is on a recommended ulceration dose threshold for internal DRPs exposure, and development of dose coefficients or dose conversion factors primarily for stationary DRPs for the skin surface, upper respiratory tract, and gastrointestinal tract as well as for effective dose equivalent received from insoluble particles that are stationary on skin or ingested. The RCD report is expected to be published in May 2023.

NRC also plans to develop a generic communication to address issues associated with control of DRPs/hot particles during decommissioning activities (e.g., ventilation, containment, tenting, filtering, and other controls to prevent the release of DRPs into the environment), as well as proper documentation/reporting and survey following risk-significant decommissioning activities that have the potential to release radioactivity to the environment. The intent of the generic communication is to inform licensees about how particles can be generated and become an issue, including experiences from recent power reactor decommissioning projects. Additionally, the communication will reinforce the importance of good housekeeping techniques to reduce DRPs and keep them localized during waste packaging, bioshield segmentation, reactor vessel segmentation, and other risk-significant decommissioning activities which will mitigate future DRP issues at decommissioning sites. The generic communication is planned to be issued in late-2023. The need for guidance on survey and internal dosimetry associated with DRPs in decommissioning is also being considered.

A historical listing of references is provided below. Some references provide a compendium of information and represent various viewpoints and positions. While NRC is not endorsing any particular reference or viewpoint listed below, a comprehensive review of the literature is being performed to help reach a decision on the best path forward with respect to guidance development. The NRC staff are also considering licensee provided information on discrete radioactive particles, as the information is submitted.

Document No./Title	Date	Notes
ICRP Publication 23, Report of the Task Group on Reference Man	1975	Comprehensive work on reference male and female, including data on mass of various organs, chemical composition of the body, and various tissue and physiological data. The report is supplemented and amended by ICRP Publication 89.
NUREG/CR-0130, Vol. 1, Technology, Safety and Costs of Decommissioning a Reference Pressurized Water Reactor Power Station	June 1978	Among other decommissioning topics, provides data on concentrations of activation products associated with concrete biological shield at pressurized water reactors.
ICRP Publication 30, Limits for Intakes of Radionuclides by Workers	1979	Recommends Annual Limits for Intakes of radionuclides by workers and much of the biokinetic information forms the basis of newer dosimetry available in ICRP 60, and dose coefficients in ICRP Publications 68, 69, 71, and 72.
NUREG/CR-3474, Long-lived Activation Products in Reactor Materials	August 1984	Provides results of sampling stainless steel, vessel steel, and concrete to develop a database of activatable major, minor, and trace elements to determine possible nuclear reactions that could lead to long lived activation products. Estimated concentrations of activation products in reactor internals, core shrouds, core barrels, thermal pads, and vessel cladding are provided.
Information Notice No. 86-23, Excessive Skin Dose Due to Contamination with Hot Particles	April 1986	Discusses skin contamination incidents from hot particles at reactor sites and follow-up protective measures.
Information Notice 87-39, Control of Hot Particle Contamination at Nuclear Power Plants	August 1987	Discusses hot particle events, fuel degradation, and lack of controls during fuel reconstitution and associated lessons learned.
Collection and Characterization of Aerosols from Metal Cutting Techniques Typically Used in Decommissioning Nuclear Facilities, Am. Ind. Hyg. Assoc. J. 48:11, 922-932	November 1987	Provides information on aerosol production rate, shape, and size for various metal cutting tools.
Information Notice 90-33, Sources of Unexpected Occupational Radiation Exposures at Spent Fuel Storage Pools	May 1990	Discusses potential sources of radiation exposure from spent fuel storage pools.
Enforcement Policy Regarding Occupational Doses from ‘Hot Particles’, Policy Statement (55 FR 31113)	July 1990	Enforcement policy for skin dose from discrete radioactive particles.
Information Notice 90-48, Enforcement Policy for Hot Particle Exposures	August 1990	Discusses enforcement discretion for skin exposure from hot particles.
Enforcement Policy for Hot Particle Exposure – Answers to Three Questions	November 1990	Clarifies statements made in IN 90-48.
Discrete radioactive particles at nuclear power plants; Prevention, mitigation and control, Radiation Protection Measurements, Vol. 8, No. 5, p. 65-79	1991	Provides radiological safety professionals at nuclear power plants with information on the prevention, mitigation, and control of discrete radioactive particles.
Characterization of Aerosols from Dismantling Work of Experimental Nuclear Power Reactor Decommissioning, J. Aerosol Sci., Vol. 22, Suppl. 1, p. S747-S750	September 1991	Looks at aerosol generation for stainless steel pipe segmentation with mechanical vs. thermal cutting tools and mitigative measures.
Annals of the ICRP, Publication 66. Human Respiratory Tract Model for Radiological Protection	1994	The report describes a revision to the model used in ICRP Publication 30 to calculate radiation doses to the respiratory tract of workers from intake of airborne radionuclides.
Biokinetics of Nuclear Fuel Compounds and Biological Effects of Nonuniform Radiation, Environmental Health Perspectives, Vol. 103, No. 10	October 1995	Data on hot particles, including sources, dosimetry, and human exposure are discussed. The biokinetics of insoluble nuclear fuel compounds in the gastrointestinal tract and respiratory tract are reviewed, and short- and long-term biological effects of nonuniform alpha- and beta-irradiation on the gastrointestinal tract, lungs, and skin are discussed.
NUREG/CR-5884, Vol. 1, Revised Analysis of Decommissioning for the Reference Pressurized Water Reactor Power Station	November 1995	Provides information regarding decommissioning of pressurized water reactors including ventilation controls.
EPRI Report No. NP-5969, Problem Assessment of Discrete Radioactive Particles	August 1998	A survey was conducted to gather existing information and to determine the incidence of DRPs in operating nuclear power plants, methods of detection, locations, isotopic analyses, and other relevant data.
EPRI Report No. 104125, Industry Experience with Discrete Radioactive Particles	August 1994	Presents operating nuclear power plant survey results with regard to prevalence and nature/type of DRPs identified.
NCRP Report No. 130, Biological Effects and Exposure Limits for “Hot Particles”	1999	This report considers “hot particles” on and off the skin, in the eye and ear, and those that might be inhaled or ingested. Also provides information on characteristics of DRPs.
SECY-98-117, Shelwell Services, Inc., Risk Assessment	May 1998	Provides risk assessment approach that considers the likelihood and consequences of exposure to discrete radioactive particles.
DOE/EM-0392, Liquid Nitrogen Cooled Diamond-Wire Concrete Cutting	December 1998	Provides aerosol data for diamond-wire cutting.
DOE/EM-0527, Diamond Wire Cutting of the Tokamak Fusion Test Reactor Vacuum Vessel	April 2000	Provides aerosol data for diamond-wire cutting.
HCET-2000-D052-001-04, Size Distribution and Rate of Production of Airborne Particulate Matter Generated During Metal Cutting	January 2001	The study presents data regarding the metal cutting rate, particle size distribution, and generation rate for different cutting tools and metals.
Regulatory Analysis of Revisions to 10 CFR 20: Unified Skin Dose Limit	October 2001	Regulatory analysis to support skin dose rulemaking related to discrete radioactive particles.
Information Notice 2002-03, Highly Radioactive Particle Control Problems During Spent Fuel Pool Cleanout	January 2002	Discusses issues associated with evaluation and control of radioactive particles generated during removal of material from spent fuel pools prior to shipping the material for offsite disposal.
Regulatory Issue Summary 2002-10, Revision of the Skin Dose Limit in 10 CFR Part 20	July 2002	Provides information on the change in regulatory dose limit for the skin in 10 CFR Part 20, effective June 4, 2002.
Exhibit CY-5-Panel 1 - Panel Attachment 4: Health Physics Department, Technical Support Document, HP Number BCY-HP-0125, Rev. 0: Dose Estimate for an Ingested Particle	December 2002	Provides a dose estimate for an ingested particle in Haddam Neck hearing.
Doses and Risks from the Ingestion of Dounreay Fuel Fragments, Radiation Protection Dosimetry, Vol. 105, Nos 1-4, 49-54,	February 2003	MCNP calculation of dose to the lower large intestine of Dounreay fuel fragment particles found in a marine environment
Haddam Neck - Exhibit 4 (CY Exhibit 5-PANEL 1) - Panel Attachment 4 - Health Physics Department Technical Support Document - Dose Estimates for Ingested Particle	March 2003	Ingestion dose calculation from hot particles at Connecticut Yankee
Haddam Neck - Exhibit 17 (CY Exhibit 5-GEC): Letter to Mr. Gad from G. Chabot regarding dose from hot particle in Extrathoracic Region ET2 of Respiratory Tract	March 2003	Dose calculations for 10 um hot particle to extrathoracic region of the respiratory tract
EPRI Report No. 1002823, Implementing the EPRI Effective Dose Equivalent (EDE) Methodology for Discrete Radioactive Particles on the Skin	October 2004	Discusses effective dose equivalent (EDE) method to calculate hot particle exposures.
RPD-EA-9-2005, Public Health Implications of Fragments of Irradiated Fuel: Module 3: The Likelihood of Encountering a Fuel Fragment on Sandside Beach	June 2005	Provides information on the number of fuel fragments found on Sandside Beach and activities and likelihood of individuals coming into contact with such fragments.
Hot Particle Dosimetry and Radiobiology – Past and Present, J. Radiol. Prot. Vol. 27, No. 3A, p. A97-109	August 2005	Hot particle dosimetry, considerations, and changes over time.
Spatially-Dependent Measurements of Surface and Near-Surface Radioactive Material Using In situ Gamma Ray Spectrometry (ISGRS) for Final Status Surveys, Prepared for US NRC in support of RFTA-06-010	November 2006	Evaluates the ability of in-situ gamma ray spectrometry for detection of discrete radioactive particles
Techniques Employed for Detection of Hot Particle in the Marine Environment, J. Radiol. Prot., Vol. 27, No. 3A, A39-A44	August 2007	Survey methods for hot particles in a marine environment near the Maine Yankee nuclear plant.
Letter from S. Redeker (Sacramento Municipal Utility District) to J. Hickman (NRC), dated April 2, 2007, Re: Response to NRC Request for Additional Information	April 2007	Among other topics, the presence, programs to control, detectability, and assessment of dose from discrete radioactive particles is discussed.
DTRA-TR-09-16, Radiation Doses to Skin from Dermal Contamination	October 2010	Presents a methodology to estimate doses to skin from dermal contamination due to a uniform deposition of airborne radioactive material in specific regions of the body.
ICRP Publication 130, Occupational Intakes of Radionuclides: Part 1	2015	Replaces ICRP Publications 30 and 68 to provide revised dose coefficients for occupational intakes of radionuclides by inhalation and ingestion using the Human Alimentary Tract Model (ICRP Publication 100) and a revision of the Human Respiratory Tract Model (ICRP Publication 66) that accounts for more recent data. Information is provided on absorption into blood following inhalation and ingestion of different chemical forms of elements and associated radioisotopes.
ICRP Publication 134, Occupational Intakes of Radionuclides: Part 2	2016	The 2007 recommendations of the ICRP introduced changes that affect calculation of effective dose, and implied a revision of the dose coefficients for internal exposure, published previously in ICRP 30 and 68. The present publication provides data for the following elements: hydrogen (H), carbon (C), phosphorus (P),sulphur (S), calcium (Ca), iron (Fe), cobalt (Co), zinc (Zn), strontium (Sr), yttrium(Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), and technetium (Tc).
NUREG/CR-7227, US Commercial Spent Nuclear Fuel Assembly Characteristics: 1968-2013	June 2016	Documents a survey of all US spent nuclear fuel assemblies discharged from commercial reactors between the years of 1968 to 2013. Results include total activity, decay heat, photon emission, neutron flux, gamma heat, and plutonium content, as well as concentrations for 115 significant nuclides.
ICRP Publication 137, Occupational Intakes of Radionuclides: Part 3	2017	See ICRP 134. The third publication in the series provides data for the following elements: ruthenium (Ru), antimony (Sb), tellurium (Te), iodine (I), caesium (Cs), barium (Ba), iridium (Ir), lead (Pb), bismuth (Bi), polonium (Po), radon (Rn), radium (Ra), thorium (Th), and uranium (U).
NUREG-1700, Revision 2, Standard Review Plan for Evaluating Nuclear Power Reactor License Termination Plans	April 2018	NRC staff guidance on conduct of safety reviews of nuclear power reactor license termination plans.
ICRP Publication 141, Occupational Intakes of Radionuclides: Part 4	2019	See ICRP 134. The fourth publication in the series provides data for the following elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), actinium (Ac), protactinium (Pa), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), and fermium (Fm).
NUREG-1507, Revision 1, Minimum Detectable Concentrations with Typical Radiation Survey for Instruments for Various Contaminants and Field Conditions	August 2020	The document describes and quantitatively evaluates the effects of various factors on the detection sensitivity of commercially available portable field instruments being used to conduct radiological surveys in support of decommissioning.
Inspection Procedure 83750: Occupational Radiation Exposure at Permanently Shutdown Reactors	January 2021	Discusses inspection objectives to determine whether licensee performance (i) ensures adequate protection of worker health and safety from exposure to radiation or radioactive material at permanently shut-down reactors, and (ii) evaluate whether the licensee adequately identified problems and implements appropriate and timely corrective actions related to occupational radiation safety. The inspection procedure addresses reviews of shallow dose equivalent records related to incidents involving DRPs, as well as airborne and contamination controls.
Using VARSKIN for Hot Particles Ingestion Dosimetry Evaluation	2022	International Agreement Report, final report
Estimating Scan Minimum Detectable Activities of Discrete Radioactive Particles	October 31, 2022	Discusses survey of DRPs and provides information on calculation of scan MDAs for select radionuclides, depths and offset distances.
Issuance of Dose Coefficients (DC) for Discrete Radioactive Particles (DRPs) and Ulcerations Threshold Recommendations techical reports.	May 2023	Two Renaissance Code Development (RCD) reports on dosimetry for discrete radioactive particles in decommissioning were issued.
Estimating Scan Minimum Detectable Activities of Discrete Radioactive Particles (ML24004A133)	October 2022 (Draft) January 2024 (Final)	Discusses survey of DRPs and provides information on calculation of scan MDAs for select radionuclides, depths and offset distances. No substantive changes were made to the final.
Issuance of Dose Coefficients (DC) for Discrete Radioactive Particles (DRPs) (ML23136A178) and Ulcerations Threshold Recommendations (ML23136A207) technical reports.	May 2023	Renaissance Code Development (RCD) published two reports on dosimetry for discrete radioactive particles in decommissioning.

Lessons Learned

Lessons learned can be found at ML20052C815, "Lessons learned and Questions and Answers to Clarify Decommissioning and License Termination Guidance and Plans". Most of these lessons learned were folded into the current revisions to NUREG-1757, Volumes 1 and 2. Future lessons learned will be captured in this section to provide a basis for future guidance development.

Page Last Reviewed/Updated Tuesday, February 6, 2024

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