Committee on Radiation Protection and Public Health

Transcription

1 Unclassified NEA/CRPPH/R(2015)3 Organisation de Coopération et de Développement Économiques Organisation for Economic Co-operation and Development 01-Sep-2016 English - Or. English Nuclear Energy Agency NEA/CRPPH/R(2015)3 Unclassified Committee on Radiation Protection and Public Health Proceedings of the Joint Topical Session on Underground Safety in Nuclear Waste Repositories 15 April 2015 Paris, France SPECIAL NEA PRESENTATION AGREED WITH DOCUMENTS DESK For more information about this document, please contact Dr Edward Lazo (edward.lazo@oecd.org) English - Or. English JT Complete document available on OLIS in its original format This document and any map included herein are without prejudice to the status of or sovereignty over any territory, to the delimitation of international frontiers and boundaries and to the name of any territory, city or area.

2 RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

3 FOREWORD The Radioactive Waste Management Committee (RWMC) and the Committee on Radiation Protection and Public Health (CRPPH) of the Nuclear Energy Agency (NEA) have conducted joint meetings in the past to discuss areas of mutual interest to the members of their committees. The previous joint topical session, in 2012 was titled, Radiological Protection Aspects of Long- Lived Radioactive Waste Management. The joint session was held to discuss radiological protection aspects of long-lived radioactive waste management in order to move toward a common view of the concepts and processes that have and will be developed for policy, regulation and practice. That session also discussed the new, at the time, International Commission on Radiological Protection (ICRP) draft recommendations on geologic disposal. At the conclusion of the joint session, the two committees felt satisfied that the radiation protection framework could be adapted to radioactive waste management in the long-term and that a good dialog process between both NEA committees could be established in order that the approach for justification and optimization could be clarified. Participants also identified emerging issues that operators of disposal or repository facilities should consider in the implementation phase when optimizing radiation protection principles. The joint session further concluded that it would be good to communicate to the public that there is internationally a good understanding of the radiation protection principles as applicable to radioactive waste disposal. The two committees also agreed that they could pass on this message jointly after proper coordination (NEA/RWM/M(2012)2). Building upon the success and relationships established from the 2012 joint topical session in 2014, the RWMC and CRPPH bureaus, committees and secretariats, agreed to conduct a halfday joint topical session, Underground Safety in Nuclear Waste Repositories, on 15 April This document provides a summary of the presentations and discussions of the joint topical session and notes some opportunities identified by the two committees to consider for future collaboration and cooperation. ACKNOWLEDGMENTS The Radioactive Waste Management Committee (RWMC) and Committee on Radiation Protection and Public Health (CRPPH), of the Nuclear Energy Agency (NEA) would like to thank the organizers, presenters and committee members for an excellent joint topical session of mutual interest. The committees would also like to thank the joint session Rapporteur, Mr C. Rick Jones, for summarizing the session and for the preparation of this document RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 3

4 TABLE OF CONTENTS Public and policy overview...5 List of abbreviations and acronyms...6 Executive summary Introduction...9 Background...9 Objectives...9 Workshop format Setting the stage An implementer s and regulator s perspective...13 Implementer s perspective...13 Regulator s perspective Lessons learned...17 Events at the WIPP repository...17 Decommissioning of the Asse Mine Joint session outcome...21 Considerations for and features of a radiation protection program for an underground nuclear waste repository...21 Fulfillment of joint session objectives...21 References...23 Topical session agenda...25 List of participants for CRPPH-73 and RWMC RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

5 PUBLIC AND POLICY OVERVIEW The Radioactive Waste Management Committee (RWMC) and the Committee on Radiation Protection and Public Health (CRPPH) of the Nuclear Energy Agency (NEA) have focused on addressing topics of interest to both committees in order to combine their expertise to answer difficult questions about complex technical topics. Worker and environmental protection in underground disposal facilities for radioactive material, or underground nuclear waste repositories, is just such a topic. While there are relatively few underground nuclear waste repositories in operation today, this number is increasing. Effectively managing worker safety and environmental protection raises challenging questions of how to balance mining safety with radiation protection this joint topical session was intended to identify these challenges, and to identify how the RWMC and the CRPPH could work together to find answers. Currently underground nuclear waste repositories are generally being designed to operate for approximately 100 years before they are anticipated to be completely filled and then closed. During this time, workers must be protected from radiation from the radioactive material, which can include radioactive dust, radioactive gases such as radon, and direct radiation from the radioactive material packages. In an underground facility, protection of workers also particularly focuses on fire hazards, and on industrial accidents. Mining and radiation safety can thus be difficult to balance. For example, mine fires call for extensive ventilation to protect workers in inherently confined spaces deep underground. Yet such ventilation can spread radioactive dust and gases, and can cause environmental releases. The two NEA committees agreed to work together to study national policies, legislation and regulation of underground nuclear waste repositories. Their aim is to find and share the best approaches to worker safety and environmental protection, covering the multi-generational operational time frames for the operation of these disposal facilities RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 5

6 LIST OF ABBREVIATIONS AND ACRONYMS ALARA BfS CAM CMR CRPPH DOE EGOS HLW HMGU IAEA ICRP IGSC ILW LANL LLW M&O NEA NUMO RP RWMC SFR SKB SNF TRU UG WIPP As-low-as-reasonably-achievable Bundes Schweizerischer Frauenvereine Continuous air monitor Central monitoring room Committee on Radiation Protection and Public Health Department of Energy Expert Group on Operational Safety High-level waste Helmoholtz Zentrum München International Atomic Energy Agency International Commission on Radiological Protection Integration Group for the Safety Case Intermediate-level waste Los Alamos National Laboratory Low-level waste Management and operations Nuclear Energy Agency Nuclear Waste Management Organization of Japan Radiological protection Radioactive Waste Management Committee Short-lived radioactive waste Svensk Kämbränslehantering AB Spent nuclear fuel Permanent disposal of transuranic Underground Waste Isolation Pilot Plant RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

7 EXECUTIVE SUMMARY Building upon the success and experience from the conduct of the 2012 joint topical session the Nuclear Energy Agency (NEA), Radioactive Waste Management Committee (RWMC) and the Committee on Radiation Protection and Public Health (CRPPH) conducted another joint topical session, 15 April 2015, on the topic of Underground Safety in Nuclear Waste Repositories. The objectives of this joint topical session were to present the key policy, regulatory and operational aspects of underground mining safety in radiological environments, to identify areas where optimization of protection is challenging because of radiation protection and miningsafety considerations, and to identify areas where further joint RWMC and CRPPH work could help to resolve conflicts and difficulties in the field. Presentations at the joint session provided committee members with an overview and operational examples of the types of installations and issues that may arise during each phase of an underground nuclear waste repository, from siting to construction, operation, closure and post-closure. The half-day joint session identified a number of considerations for, and features of, an appropriate safety program, including radiation protection, relevant to an underground nuclear waste repository. A spectrum of issues were identified that the committees determined must be considered during each of the various phases of a repository (e.g. site selection, construction, operation, closure, and beyond). In addition, consideration of the various regulations that apply to underground nuclear waste repositories during each phase of operation (e.g. operational radiation protection, long-term radiation protection, conventional safety, protection of the environment and society needs) must also be fully integrated in the planning phases of such projects. Flexibility, optimization, balance and integration were noted to be key factors in applying identified relevant and competing regulations in the development of suitable operating procedures and programs, including a well-integrated radiation protection program. The importance of establishing programs that are consistent when addressing the variety of waste streams (e.g. low-level waste to spent nuclear fuel) was also noted. The need to address the unique and relevant safety aspects of surface facilities, access to the underground and the operation at the underground disposal locations was also recognized as a significant feature of an effective and efficient safety program. Developing and implementing an appropriate program of emergency preparedness and response, and to mitigate the impact on the environment during each phase of operation, were also identified as critical to continued operations at an underground nuclear waste repository. It was also noted that in the development of procedures and programs, as well as during operations, it is important to establish appropriate training and lifetime learning (e.g. knowledge management) to take advantage of and implement lessons learned. A holistic, systems approach to address safety is also critical in the operation, management and oversight of a nuclear waste repository. The presentations and discussions identified a number of findings in support of the three objectives of the joint session. Objective one was to present key policy, regulatory and operational aspects of underground mining safety in radiological environments. In support of this objective, the session identified the need for clear national policy and legislation to address the various phases of a nuclear waste repository. A flexible and optimized regulatory framework with sound, comprehensive 2015 RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 7

8 and integrated standards, including limits and exclusion levels, was identified to be of great importance. The regulatory framework should also include an effective and efficient review and approval program, as well as specifying the approval authority. Experience has shown that issues (e.g. worker exposures, fire, ventilation, radon, industrial, environmental protection) can be managed by engineering design and management principles, and be performed using an integrated systems approach. Operational aspects such as enforcement of a relevant safety and radiation protection culture, as well as implementation of relevant training and lessons learned programs are also important. Objective two was to identify areas where optimization of protection is challenging because of radiation protection and mine-safety considerations. The management of risks and integration of operational safety during all phases and operations was identified as particularly challenging. Specific challenges identified during the session were radon exposures and the recording of the resultant worker doses, the design for and conduct of maintenance activities, ventilation and the placement of air monitors, and the proper placement of instruments for and measurement of meteorological conditions. Establishing and implementing the features of an extensive and streamlined radiation protection relevant program and safety culture also presents a challenge. An appropriate and relevant training program, with lifetime learning, was another identified challenge given the variety of operations and different operating environments (e.g. above ground, in access to the underground and underground). Oversight and its evolution from site characterization to site closure and beyond, was also identified as a challenge. Public communications during all phases of a nuclear waste repository presents additional challenges to management and safety professionals. The third objective was to suggest where the RWMC and the CRPPH should focus efforts to effectively to help resolve conflicts and difficulties. The session participants initially identified three areas where the RWMC and the CRPPH could consider joint action: 1. Review national policies, legislation and regulations governing underground nuclear waste repositories to identify and distribute best practices in support of safe and effective design, construction, operation and closure of geologic repositories. 2. Review, collect and distribute operational experience and lessons learned, particularly in the areas of: a. The management of radon and treatment of worker exposures b. Establishment, operation and management of an optimized, flexible and relevant radiation protection and safety culture c. Worker training and lifetime learning knowledge management d. Protection of the environment e. Public communications and societal issues f. The evolution of effective and efficient oversight over time 3. The two committees could also consider more active participation in international organizations (e.g. ICRP, International Atomic Energy Agency (IAEA)) activities to incorporate and distribute lessons learned and best practices concerning underground nuclear waste repositories. The joint topical session concluded with the Chairs of the RWMC and CRPPH agreeing to another joint session during their 2016 annual meetings. The topic or theme of the session was proposed to be Transfer of Responsibility RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

9 1. INTRODUCTION Background Radioactive waste is generated in a number of everyday activities, such as medical and veterinary procedures, research and industry. Most of these materials are defined as low-level waste (LLW) of low activity. Such relatively short-lived radioactive LLW are disposed of in nearsurface sites, usually at depths of around tens of meters that are licensed by the appropriate national regulatory authorities. Intermediate-level waste (ILW), high-level waste (HLW), and spent nuclear fuel (SNF) from reactors, are considered high activity, containing long-lived radioactive materials that require longer-term management (e.g. a hundred thousand years or more). Various options for the long-term management of ILW, HLW and SNF have been well researched and investigated, concluding that deep geologic repositories, at depths of between 250 meters to meters, are the most commonly accepted option (NEA 2012, WNA, 2015). Several countries are in various stages of pursuing deep geologic repositories for the storage of ILW, HLW and SNF. Argentina, Australia, Belgium, Czech Republic, Finland, Japan, Netherlands, Korea, Russia, Spain, Sweden, Switzerland, and United States have identified deep geologic repositories as their preferred option for the disposal of long-lived radioactive waste, such as HLW and SNF from reactors. In March 1999, the United States began operation at the Waste Isolation Pilot Plant (WIPP) outside of Carlsbad, New Mexico as the location for the disposal of defense-related transuranic waste. France and Sweden have identified preferred sites for the disposal of HLW and SNF from reactors. Construction on the Finish SNF underground nuclear waste repository rock characterization facility commenced in Finland's radiation protection and nuclear safety authority, STUK, in February 2015 gave its backing for the construction of the final repository and waste encapsulation plant. For more details on the progress and status of the world s first underground nuclear waste repository being built in Finland, go to: With the WIPP facility in operation and the first underground nuclear waste repository for SNF now under construction in Finland, there is an opportunity for the international community to observe the operations at these facilities and to draw the lessons learned from them. It is in this spirit of learning that the RWMC and the CRPPH thought it prudent and timely to conduct a joint topical session to identify any issues, particularly between mine safety and radiation protection safety so that the committees could jointly pursue actions to resolve any identified potential conflicts or difficulties encountered. Objectives The objectives of this joint topical session were to present the key policy, regulatory and operational aspects of underground mining safety in radiological environments, to identify areas where optimization of protection is challenging because of radiation protection and miningsafety considerations, and to identify areas where the RWMC and the CRPPH could work together to resolve conflicts and difficulties in the field. 1. To present the key policy, regulatory and operational aspects of underground mining safety in radiological environments. 2. To identify areas where optimization of protection is challenging because of radiation protection and mining-safety considerations RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 9

10 3. To identify areas where the RWMC and the CRPPH could work together to resolve conflicts and difficulties in the field. Workshop format The half-day joint topical session, on 15 April 2015, began with an Introductory Session: Conceptual Overview which provided an overview of the types of waste installations and the types of regulatory and operational issues that may arise. Following this overview, the first session centered on Implementers and Regulators Approaches to Operational Safety, which provided views from both an implementer and regulator in order to identify challenges in operational safety of underground mines when implementing radiation protection and mine-safety regulations. A discussion session with both committee members followed this presentation. Next, a session on Practical Operational Safety Experience was conducted where presenters provided examples of their experience from operating underground nuclear waste repositories. This session was also followed by a spirited discussion session with the actively engaged members of the RWMC and CRPPH. The final session provided a summary of the joint topical session where the Rapporteur summarized the afternoons presentations and discussions and identified areas for consideration by the RWMC and the CRPPH to work together to enhance worker health and safety in the siting, construction, operation and closure of underground nuclear waste repositories. The Agenda for the topical session is provided in the Annex to this report. The presentations can be viewed at the Nuclear Energy Agency, password protected website at: RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

11 2. SETTING THE STAGE This section of the document will summarize the presentation by the Director of Science and Technology, Die Nationale Genossenschaft für die Lagerung Radioaktiver Abfälle (Nagra), Germany on Nuclear Waste Repositories, Safety and Protection of the Environment: An Overview on Issues of Potential Relevance. This overview provided participants examples of types of waste installations and regulatory and implementation issues that may arise during the siting, building and operation of waste repositories. As presented, the aim of a geologic repository is to provide passive safety at a sufficient level to confine the waste for the period where its toxicity remains a concern. The repository should provide adequate confinement during this period to ensure security of the waste against theft or inadvertent mishandling of the disposed waste. There is general agreement that the period of concern for long-lived high-level waste (HLW) and spent nuclear fuel (SNF) is from a few years up to one million years. It was further noted that several countries have made significant progress in the development and implementation of a repository for SNF and HLW. Site selection is well underway in some countries, sites have been selected in others, in-situ laboratories at the proposed sites are in operation, and construction licenses have been prepared or submitted in some countries. With the granting of the construction license and the start of construction, a new phase of worker safety and health begins. It is during this phase that the spectrum of worker safety and health regulations dealing with construction, operation and closure begin to be implemented in a phased approach relevant to the hazards that may be presented. This overview highlighted that it is critical for a comprehensive worker protection program to be both optimized and flexible, in order to integrate the regulations for the disciplines of radiation protection, industrial safety and mine safety. It is precisely this latter issue the development and implementation of an optimized and flexible worker protection program that present the biggest challenge. In most cases, there will be multiple operations at various locations going on simultaneously that need to be coordinated to integrate relevant worker protection programs. For example, there will be surface facilities for acceptance and processing of waste and activities in support of construction. There will also be access to the underground operations and related construction activities. And there will be underground operations where nuclear waste is eventually placed for disposal that may include the simultaneous construction of disposal rooms, chamber, and/or shafts for the emplacement of additional waste. Each of the three areas has their distinct purpose and has specific effects on the development of worker health safety and the environmental programs. Surface facilities are also needed to support construction and operation of the repository. Surface operations offer a challenge to optimize their role to improve waste properties and minimize waste volume because they need to optimize worker exposure to chemicals and radiation, as well as prevent releases to the environment. These operations will also have an impact on the nearby environment from noise, traffic and lighting for night operations, runoff and possible radioactive releases. Accesses to underground facilities (e.g. multiple access points for entry and egress, evacuation, ventilation) are needed to support construction, waste emplacement and safe operations. The challenge is to optimize the number of shafts, where they are placed and how 2015 RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 11

12 large they are, while also protecting workers during the conduct of drilling operations. These operations also form potential openings through the host rock or salt that could compromise its integrity and may impact groundwater or cause groundwater to enter the rock or salt. Underground disposal rooms, chambers, or shafts are needed to provide suitable passive engineered barriers in an adequate geological environment to ensure long-term safety. The challenges include the protection of workers from rock falls and heavy equipment to minimize the potential for incidents and accidents, as well as damage to the host rock or salt. By definition, excavation of disposal rooms disturbs the host rock or salt, so it is important to determine the optimal method of excavation, and what type and how much support is needed. Considerations for simultaneous waste emplacement operations and the construction of new waste rooms, chambers, or shafts must also be considered. It will be important to determine the needed distance or separation between emplacement and construction operations to avoid collapse or one operation adversely impacting the other. There will also be the issue of industrial hazards and potential worker dose from disposal canisters during emplacement operations that have to be optimized when considering how much time, distance or shielding to be used. Another consideration will be the conduct of any backfilling of the disposal/emplacement sites. Operations of this type may also present other hazards (e.g. heavy equipment incidents, dust, inhalation dose to workers) that also need to be optimized (e.g. such as shielding and ventilation) when developing a comprehensive and integrated worker and environmental protection program. During any construction (and eventual) operation of the facility, preparation and planning for response to incidents and accidents is essential. In order to prevent and mitigate such events, it will be important to have redundant and spatially separated safety systems that allow for escape, intervention and rescue. Depending on the severity of an event, this may also lead to additional puncturing of the host rock or salt that will then need to be resolved during the postaccident phase of an event. Safety after closure of the repository was also noted to be critical and much research has been done to plan for post-closure safety. The joint session identified work done by the Swedish Nuclear Fuel and Waste Management Company as an example. The document, Long-term Safety for the Final Repository for Spent Nuclear Fuel at Forsmark, Main Report of the SR-Site project, Volume III, provides credible scenarios to aid in the critical evaluation of repository safety over the life of the repository after closure (SKB, 2012). In the analyses of the selected scenarios, all conceivable routes to the loss of the safety function that defines the scenario are critically examined, in order to evaluate the likelihood of the scenario, its consequences and its potential contribution to the risk summation for the repository. From the understanding of the functioning of the repository system, the examination focuses on the factors contributing to the particular safety function, thus focusing the evaluation of each scenario on a limited set of uncertain factors. The findings of the report are that high levels of post-closure safety can be achieved. The presentation concluded that for a deep geological repository there are many competing requirements to be fulfilled and a large range of regulations to be observed including: long-term radiological safety, to include post-closure; radiological safety during operation, oversight and the post-closure phase; conventional safety during construction, operation, oversight and closure; protection of the environment such as groundwater, releases of pollutants, noise, traffic and lighting; and compatibility with societal views and needs. It will be important to optimize these competing requirements and regulations in order to establish comprehensive worker and environmental protection programs. In some cases, the optimization process may lead to competing design targets that have to be reconciled before operation. It will be essential to resolve these issues through coordination between different regulations and regulators, as well as involving stakeholders. In the resolution of these competing demands it will be important to build in flexibility early in the process in order to provide for future optimization initiatives as operations progress and new challenges are identified. It will also be critical to take advantage of experience and lessons learned available from other international projects such as these, in order to effectively develop a comprehensive and flexible worker and environmental protection program RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

13 3. AN IMPLEMENTER S AND REGULATOR S PERSPECTIVE The joint session continued with presentations of the experiences of an implementer and a regulator of underground nuclear waste repositories. This section of the document summarizes their perspectives. Implementer s perspective The Chair of the Integration Group for the Safety Case (IGSC) Expert Group on Operational Safety (EGOS) of the NEA provided the implementer s perspective in, Implementer s Views on Operational Safety in Underground Disposal Installations. The presentation identified that implementers have a large body of research and professional documents to assist in the establishment of radiation protection programs appropriate to geological repositories. Since the 2012 joint topical session, the International Commission on Radiological Protection (ICRP) has published ICRP Publication 122, Radiological Protection in Geological Disposal of Long-lived Solid Radioactive Waste (ICRP, 2013). The Abstract to ICRP Publication 122 states: This report updates and consolidates previous recommendations of the International Commission on Radiological Protection (ICRP) related to solid waste disposal. The recommendations given apply specifically to geological disposal of long-lived solid radioactive waste. The report explains how the ICRP system of radiological protection described in Publication 103 can be applied in the context of the geological disposal of long-lived solid radioactive waste. Although the report is written as a standalone document, previous ICRP recommendations not dealt with in depth in the report are still valid. (ICRP, 2013) ICRP Publication 122 goes on to state that the objectives of geologic repositories are to contain and isolate the waste from the environment for as long as possible. This includes developments over different time scales, with different levels of human institutional controls. Engineered repositories located in suitable geologic formations are an internationally accepted option for radioactive waste, and that the development of a repository is a stepwise process involving various stakeholders. ICRP 122 also notes that repository operations may consider retrieving emplaced waste and make provisions for the retrievability or reversibility of waste, but that this should not have unacceptable radiological protection consequences. In 2013, the Radioactive Waste Management Committee (RWMC) noted the importance of operational safety in developing geological repositories and approved the creation of the EGOS, under the auspices of the IGSC. The Group was chartered for the period to: share technical, regulatory, or stakeholder related experience in operational safety; identify plausible hazards in a geological repository by using experience gained from the operation of mines (both uranium and non-radioactive), nuclear facilities and relevant engineering projects from outside the nuclear industry; share and improve know-how on the practical assessment of hazards; define best practices and technical solutions for risk prevention and mitigation; and enable the IGSC to foster in-depth exchanges with other international organizations/projects in the field of operational safety. For more information on EGOS, see: EGOS found that deep geological repositories will be sited, designed, constructed, operated, and closed to isolate radioactive waste from the accessible biosphere, and surface operations are as important as activities in the underground (UG). Infrastructure like shafts and/or ramps will be used to connect the UG with the surface. In addition, deep geological repositories may remain 2015 RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 13

14 operational for a long period (e.g. up to 100 years) and may be expanded as needed. They also identified that the practice of limiting dose to as-low-as-reasonably-achievable (ALARA) and the defense-in-depth strategy along with engineered barriers are often applied collectively to minimize exposure. The good work of EGOS has concluded that operational hazards, both radiological and nonradiological, are typically managed by engineering design, management practices and monitoring that includes institutional oversight. EGOS concluded that while oversight during operations confirms the repository behavior, a repository system must be designed to maintain its long-term protective capability when oversight no longer exits. EGOS also supported the radiation protection principle of justification in concluding that the optimization of protection must do more good than harm. EGOS concluded that optimization must be performed using an integrative approach considering all the characteristics of all involved components, that stakeholders must understand the safety implications of the optimized elements, and optimization results must be handled in a transparent manner. They also noted that the use of dose and risks in optimization should be limited due to the increasing uncertainties associated with the long timescale and the often low projected radiological impacts. EGOS also identified the critical need for national acknowledgment programs to recognize effective management principles and provide crucial support for the management of operational hazards in underground nuclear waste repositories. Regulator s perspective The Head of Facility Radiation Protection from the Swedish Radiation Safety Authority presented its regulatory view in RP Issues in Underground WM, A Regulator s View on Operational Radiological Protection Regulation in Underground Disposal Installations. The Swedish nuclear industry established the Swedish Nuclear Fuel and Waste Management Company (SKB) in the 1970s. The central interim storage facility for spent nuclear fuel (Clab) began operations in 1985 and the final repository for short-lived radioactive waste (SFR) began operations in Thus far, over tons of uranium spent nuclear fuel (SNF) are in interim storage at Clab, and over m 3 of LLW and intermediate-level waste (ILW) has been disposed of, or is pending disposal, at the SFR facility. Annual collective doses at Clab have ranged from slightly over 0.03 millimansieverts (mmansv) in 2008 to slightly more than mmansv in These doses are received during operations for the receipt and storage of spent fuel, ion exchange resins, and filters, as well as daily control and safeguards operations. The SFR facility uses freight containers for LLW, and concrete tanks, shafts and silo s for ILW. The waste in the silos has approximately 80% of the total radioactivity content at the site. The waste is immobilized in containers of steel or concrete and the containers are then embedded in concrete. The silos also have one-meter thick walls as an additional barrier. Rock vaults are also in use at SFR. The total radioactivity in the rock vaults is much lower, less than 20% of the total radioactivity. The barriers at SFR are the waste packages themselves, the concrete backfilling, the rock vault s concrete structure, and ultimately, the surrounding rock itself. Waste disposal operations at SFR use remotely controlled equipment for unloading, transport and lowering of waste containers into the silos and radiation shielded forklift trucks are also used, as appropriate, to minimize worker dose. The rock vaults fitted with shafts also have a concrete lid for further containment and reduction of doses to workers. A conservative approach has been taken in radiation protection and the use of shielding to minimize worker dose. During the conduct of waste operations at SFR a number of measures are taken for the protection of workers. Actions are taken to keep radioactive contamination under control. Such measures include dose rate mapping and wipe tests, contamination control of transport containers, and stationary dose-rate meters and airborne monitors within controlled areas to minimize the spread of contamination. Entrance controls to restricted areas are in place and workers are provided keys to doors for use in support of fire safety. Operations with the highest doses require detailed RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

15 planning and were found to be those associated with concrete backfilling of drums, molds and grouting around disposed steam separators, with a maximum dose of 5.6 mmansv. Maintenance is also another area of particular focus, particularly as a facility ages. Due to humidity and salt in underground facilities, metal items corrode more quickly (e.g. ventilation systems, doors and containers). Maintenance activities and schedules have to be planned carefully to optimize worker dose relative to frequency of maintenance, particularly in higher dose rate areas. Rare occurring events, such as the strengthening of barriers, typically in areas above 100 msv/h, also require careful planning to minimize worker dose. Operations have shown that worker doses decrease with the more experience the workers gain at the facility. The SFR has also taken measures to prepare for postulated accident events. Plans are in place to respond to and mitigate postulated events such as transport accidents, failure of mechanical equipment, fire in a vehicle and/or waste, and disposal of waste with high dose rates. The maximum dose for these postulated accidents is 15 mmansv. In the event of fire or increased diesel exhaust, the existing exhaust system can increase airflow to clear the air rapidly. Possible airborne releases are also manageable within the existing exhaust systems. Another occupational radiation exposure issue to be managed in the Swedish geological repository operations is radon ( 222 Rn) at concentrations up to approximately Becquerel per cubic meter (Bq/m 3 ). Radon exposures are not currently included in worker doses reported to the national register. The regulation of worker radon exposures by allowed air concentrations are provided in separate legislation. This approach will change, as appropriate, with the recent publication of new European and IAEA International Basic Safety Standards. The issue of retrievability of waste containers has also been investigated. The retrieval of waste containers can be associated with operational risks. Hundreds of containers may block access to the containers to be retrieved. Any retrieval should be justified and the impact substantiated. Concerning the issue of discharges, Swedish regulations require that releases be limited, measured and reported. The public dose should be limited to less than 0.1 msv per year for installations at one site. The SRF facility has no system for reduction of discharges, and inert gases and 222 Rn are not monitored. The drains from ILW storage are measured and drain water is transported to the adjacent nuclear power plant for treatment and release. Actions to establish a final repository for spent nuclear fuel (SNF) are progressing in Sweden. In March 2011, SKB applied for a license to build a final repository for Sweden s SNF. A facility for encapsulation of SNF is to be constructed at Clab and the application was submitted in The site for the SNF repository has been selected to be close to the Forsmark nuclear power plant in Östhammar municipality. The application is currently undergoing regulatory and legal review, in accordance with Sweden s Environmental Code and the Act on Nuclear Activities, before the Government s decision. The regulatory and legal authorities are to deliver their statements concerning the license application to the Government in In addition, in December 2014, SKB applied for a license to extend the SFR facility to meet future needs to accommodate anticipated decommissioning waste. In summary, Sweden has a long experience with underground facilities, both nuclear and nonnuclear. Operational radiation protection at existing facilities is working well. The focus of safety is on potential radiation doses, fire prevention, and radon exposures. The planned repository for SNF is being reviewed using an integrated systems approach to worker and environmental protection. The Swedish experience has demonstrated that radiation protection in underground nuclear waste repositories is manageable RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 15

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17 4. LESSONS LEARNED This section of the document provides a summary of the experiences of the fire and radiological release event at the Waste Isolation Pilot Plant (WIPP) Repository, and the experience of the decommissioning of the Asse Mine in Germany. Events at the WIPP repository The Director of the Office of Program Management, Department of Energy (DOE) Carlsbad Office provided recent experiences at WIPP in Radiological Release Event at the Waste Isolation Pilot Plant (WIPP) Repository, New Mexico, USA. WIPP is a deep geologic repository for permanent disposal of transuranic (TRU) waste that is the by-product of the nation's nuclear defense program. The WIPP site was located in southeast New Mexico about 26 miles from the city of Carlsbad and was constructed in the 1980s. The underground nuclear waste repository was carved out of a 2,000-foot-thick salt bed formed 250 million years ago. TRU waste is disposed of 2,150 feet underground in rooms mined from the salt bed. WIPP has been disposing of legacy TRU waste from cleaning up 22 generator sites nationwide since On 5 February 2014, an underground salt haul truck caught on fire at WIPP. The fire was the subject of a DOE accident investigation with the final report published in March 2014 (DOE, 2014). The DOE Accident Investigation Report stated that: The Board identified the root cause of this accident to be the failure of Nuclear Waste Partnership LLC (NWP) and the previous management and operations (M&O) contractor to adequately recognize and mitigate the hazard regarding a fire in the underground. This includes recognition and removal of the buildup of combustibles through inspections and periodic preventative maintenance (e.g. cleaning), and the decision to deactivate the automatic onboard fire suppression system. (DOE, 2014) The report goes on to provide 22 conclusions and 35 judgments of need that recommended appropriate corrective actions be implemented by various involved organizations to further enhance the conduct of safe operations. On Friday evening, 14 February 2014, at 11:14 pm, a high airborne radioactivity alarm was received in the Central Monitoring Room (CMR) at WIPP. The alarm was from a continuous air monitor (CAM) in the WIPP underground that had been monitoring active TRU waste disposal in an area called Panel 7. The DOE Technical Assessment team concluded that a reaction between incompatible materials, including nitrate salt waste and organic absorbent materials, caused or contributed to the breach of drum number shipped to WIPP from Los Alamos National Laboratory (LANL). After months of investigation, DOE released its Phase 2 Accident Investigation Report of this event, coincidentally published the day after the joint session on 16 April The report stated that: The Board concluded that liquid prohibition alone was ineffective in preventing the shipment of ignitable wastes. Based upon the evidence gathered and analyzed during the investigation, the Board concluded that the release from the container(s) was preventable. If LANL had adequately developed and implemented repackaging and treatment procedures that incorporated suitable 2015 RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 17

18 hazard controls and included a rigorous review and approval process, the release would have been preventable. (DOE, 2015) The report also noted that: On 5 February 2014, a salt haul truck caught on fire in another location in the WIPP underground. The fire was the subject of a DOE accident investigation. The evacuation and subsequent investigation restricted access to the underground. There were no personnel in the underground at the time of the release event. The Board determined that the fire had no direct impact on waste stored in Panel 7. (DOE, 2015) The DOE Phase 2 Report provides 24 conclusions and 40 judgments of need. When these recommendations are evaluated and appropriate corrective actions are implemented by various organizations within LANL and DOE, as well as other DOE Laboratories sending waste to WIPP, it is envisioned that they will further enhance the conduct of safe operations. The Board investigating the accident also identified twelve contributing causes to the radiological release. The twelve contributing causes include the failure to: implement effective processes for procedure development, review and change control; implement adequate processes for hazard identification and control; comply with relevant regulations and permits; ensure LANL and DOE implemented a strong safety culture; resolve employee concerns; provide adequate oversight at all levels within organizations; provide adequate training and qualification of workers; and execute an effective stop work process. Although there were no workers underground at the time of the release accident, two leaking dampers allowed a small amount of airborne radioactive material to bypass the filtration system and be released to the environment. The damper seals were imperfect due to salt buildup. This release resulted in the potential exposure of 153 on-site personnel at the WIPP. Personnel were evaluated and all doses were determined to be less than the minimally detectable level of 0.1 msv for internal exposures due to inhalation of airborne particulates that leaked past the filters. Of these, 20 personnel were found to have positive fecal samples, and 18 were less than 0.4 msv (50-year committed effective dose equivalent). The two remaining workers had fecal sample results above the 0.4 msv threshold, but less than the recordable level of 1 msv. Airborne radioactive particulates positively attributable to the WIPP release event were detected at levels that would have resulted in the same low doses to workers (had there been any present) off site, and this was confirmed by independent monitoring. The two accidents/events at WIPP have had and will continue to have significant impacts. Disposal operations at the repository have been delayed for more than two years and recovery costs are estimated to be in excess of USD 240 million. It is also estimated that additional capital asset costs ranging from USD 65 million to over USD 260 million will be needed in order to return WIPP to full operation. It is worth noting that WIPP s mine and safety systems functioned as designed to ensure that the maximum exposure to workers would be less than 0.1 msv. As a result of this accident, releases to the environment were very low, dropped off quickly and no public health impacts were noted or anticipated. Nevertheless, the accident reports found that the fire and radiation release events were both preventable. The fire was a result of the aged equipment and lack of maintenance and training. The radiological release was from a single drum of incompatible materials and both events revealed weaknesses in the safety systems and safety culture that are now being addressed. As WIPP has an important U.S. national mission for the permanent removal of defense-related TRU waste from the biosphere, the full recover of the WIPP facility is anticipated within the next two years. Decommissioning of the Asse Mine The Head of the Federal Office for Radiation Protection at the Bundes Schweizerischer Frauenvereine (BfS), Germany provided their experience in decommissioning at, The Asse Mine Radiological Protection from Mining Law to Atomic Law RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT

19 During the period 1909 to 1964, the Asse Mine, in Germany, was used to extract potash and rock salt. In 1965, the Federal Ministry of Scientific Research and Technology charged Helmoholtz Zentrum München (HMGU) with exploring radioactive waste disposal in the abandoned mine. Portions of the mine were to be used for the placement of medium or intermediate activity and low activity radioactive waste from 1967 to From 1978 to 1992, there was no waste disposal, but research was conducted to explore the mine at greater depths for possible emplacement of waste. To enhance mechanical stability of the mine, backfilling of a portion of the mine, with 2.2 million tons of salt grain, was accomplished from 1995 to As of 31 December 2014, there was a total activity of Bq in the Asse Mine, including Bq (13.6%) of long-lived alpha emitting isotopes of americium, uranium and plutonium. During this period, the mine was operated under the national laws for mining operations. The backfilling operations, which used compressible salt, had resulted in clefts in the backfilled cavities and brine from above had caused progressive deformation and degradation of the overburden rock that risked an increased flow of brine into the waste chambers. With the original goal of mining to extract the maximum product, chambers were typically placed close together, both vertically and horizontally, which increased the risk of collapse for future use. Effective 01 January 2009, the operatorship of the mine was transferred from HMGU to the BfS as the competent authority for radioactive waste disposal. The BfS was to conduct operations and decommissioning in accordance with nuclear law standards, adapt nuclear engineering standards as appropriate, and to stabilize the mine to reduce the risk of increasing brine inflow. During 2009 and 2010, existing operational regulations were combined and supplemented. This resulted in an extensive review process as required by law in order for approval of licensed operation. It was found that the existing regulations for nuclear power plants were difficult to adapt to the mine/repository situation, as there were difficulties in identifying the radiation protection relevant requirements for operations. In addition, there was pressure to establish an appropriate radiation protection program. Other challenges were identified in moving from mine-safety operations to nuclear operations and establishing a relevant radiation protection program. In particular, the radiation protection program now needed to include: methods for monitoring radon buildup on exhaust filters from the collection of dust; identification and placement of samplers to monitor emissions; and placement of a meteorological station to meet regulatory requirements. Another key challenge was establishing the criteria for the clearance and removal of items from the mine. Progress was made in July 2012, with the Federal Ministry of Environment providing new simplified clearance and removal procedures. The law to accelerate the retrieval of radioactive waste and the decommissioning of the Asse mine, Lex Asse, entered into force on April 25, The law requires the retrieval of the radioactive waste before the decommissioning of the mine. An English translated copy of the legislation can be found at: AtG.pdf? blob=publicationfile&v=7. One of the main lessons learned from moving from mine safety to establishing a radiation protection program at the Asse mine was that the regulatory framework, mainly written for nuclear power plants, was difficult to adapt for a mine/repository operation. In addition, conditions in a mine/repository are substantially different from a clean, aboveground nuclear installation due to dust from mining activities and the corrosive atmosphere in a salt mine. This experience has also shown that it is important that documentation for an extensive radiation protection relevant program that may need to be revised frequently due to changing situations requiring extensive approvals should be avoided. License requirements that are to be fulfilled at a later time should also be avoided RWMC/CRPPHH JOINT TOPICAL SESSION SUMMARY REPORT 19