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Preliminary observation on the effect of baking soda volume on controlling odour from discarded organic waste

Highlights: • Approximately 50 g baking soda reduced odour concentration by 70%. • Reducing volatile acid concentration reduces odour concentration. • Ammonia has less effect on odour concentration. - Abstract: Food wastes with high moisture and organic matter content are likely to emit odours as a result of the decomposition process. The management of odour from decomposing wastes is needed to sustain the interest of residents and local councils in the source separation of kitchen wastes. This study investigated the potential of baking soda (at 50 g, 75 g and 100 g per kg food waste) to control odour from seven days stored food waste. It was found that 50 g of baking soda, spread at the bottom of 8 l food wastes bin, can reduce the odour by about 70%. A higher amount (above 100 g) is not advised as a pH higher than 9.0 may be induced leading to the volatilization of odorous ammonia. This research finding is expected to benefit the waste management sector, food processing industries as well as the local authorities where malodour from waste storage is a pressing issue.

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Evaluation of performance indicators applied to a material recovery facility fed by mixed packaging waste

Highlights: • Material Flows assessment of a Material Recovery Facility has been realized. • Performance Indicators for a generic MRF have been proposed. • A Dashboard has been utilized to measure the facility performance. • Experimental values of incoming waste and output products composition are reported. - Abstract: Most of the integrated systems for municipal solid waste management aim to increase the recycling of secondary materials by means of physical processes including sorting, shredding and reprocessing. Several restrictions prevent from reaching a very high material recycling efficiency: the variability of the composition of new-marketed materials used for packaging production and its shape and complexity are critical issues. The packaging goods are in fact made of different materials (aluminium, polymers, paper, etc.), possibly assembled, having different shape (flat, cylindrical, one-dimensional, etc.), density, colours, optical properties and so on. These aspects limit the effectiveness and efficiency of the sorting and reprocessing plants. The scope of this study was to evaluate the performance of a large scale Material Recovery Facility (MRF) by utilizing data collected during a long period of monitoring. The database resulted from the measured data has been organized in four sections: (1) data related to the amount and type of inlet waste; (2) amount and composition of output products and waste; (3) operating data (such as worked hours for shift, planned and unscheduled maintenance time, setting parameters of the equipment, and energy consumption for shift); (4) economic data (value of each product, disposal price for the produced waste, penalty for non-compliance of products and waste, etc.). A part of this database has been utilized to build an executive dashboard composed by a set of performance indicators suitable to measure the effectiveness and the efficiency of the MRF operations. The dashboard revealed itself as a powerful tool to support managers and engineers in their decisions in respect to the market demand or compliance regulation variation as well as in the designing of the lay-out improvements. The results indicated that the 40% of the input waste was recovered as valuable products and that a large part of these (88%) complied with the standards of the recycling companies. The evaluation of the indicators led to the decision to modify the layout to improve the interception of some polymers for which the performance indicators were poor. In particular, two additional optical sorters have to be inserted to increase the yield indicator and to the overall performance of the facility. Definitely, the results of the work allowed to: increase the yield and purity of products’ flows; ensure the compliance of waste flows; increase the workability.

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A conceptual framework for negotiating public involvement in municipal waste management decision-making in the UK

Highlights: • A review of public involvement in waste management decision-making was undertaken. • Public involvement seen as necessary to create stronger foundations for decisions. • The mode and level of public involvement explored in different decision contexts. • Public involvement can be negotiated based on the technological and social context. • Early public involvement favoured where issues are contentious or uncertain. - Abstract: The technical expertise that politicians relied on in the past to produce cost-effective and environmentally sound solutions no longer provides sufficient justification to approve waste facilities. Local authorities need to find more effective ways to involve stakeholders and communities in decision-making since public acceptance of municipal waste facilities is integral to delivering effective waste strategies. This paper presents findings from a research project that explored attitudes towards greater levels of public involvement in UK waste management decision-making. The study addressed questions of perception, interests, the decision context, the means of engagement and the necessary resources and capacity for adopting a participatory decision process. Adopting a mixed methods approach, the research produced an empirical framework for negotiating the mode and level of public involvement in waste management decision-making. The framework captures and builds on theories of public involvement and the experiences of practitioners, and offers guidance for integrating analysis and deliberation with public groups in different waste management decision contexts. Principles in the framework operate on the premise that the decision about ‘more’ and ‘better’ forms of public involvement can be negotiated, based on the nature of the waste problem and wider social context of decision-making. The collection of opinions from the wide range of stakeholders involved in the study has produced new insights for the design of public engagement processes that are context-dependent and ‘fit-for-purpose’; these suggest a need for greater inclusivity in the case of contentious technologies and high levels of uncertainty regarding decision outcomes.

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Characterization of brominated flame retardants from e-waste components in China

Highlights: • BFRs in housing plastics and PCBs from e-waste recycling enterprises in China were systematically examined. • Both PBDEs and TBBPA were detectable in most samples. • There is an apparent decreasing trend of BFRs from housing plastics and PCBs in China. • BFRs could be transferred into the recycled products those for other purpose use. - Abstract: Many studies show that high levels of many toxic metals and persistent and bio-accumulative chemicals have been found in electronic waste (e-waste) dismantling sites and their surrounding environmental media. Both flame-retardant plastic housing materials and printed circuit boards (PCBs) could be the major contributors. However, relatively little work has focused on the use or content of toxic substances and their changing in scrap housing materials and PCBs from home appliances. This study evaluated the existence of brominated flame retardants (BFRs, including polybrominated diphenyl ethers (PBDEs) and Tetrabromobisphenol-A (TBBPA)) in housing plastics and PCBs from home appliances collected from various e-waste recyclers in China. These were then analyzed for the potential migration of BFRs from the e-waste components into their recycled products. The results show that both PBDEs and TBBPA were found with high level in most of e-waste samples, indicating that the widespread use of BFRs in home appliances are entering into the end-of-life stage. For the plastics samples, CRT TVs and LCD monitors should be given priority for the control of BFRs. Regarding PBDEs, the dominant congeners of BDE-209 in the plastics samples contributed 90.72–93.54% to the total concentrations of PBDEs, yet there are large variations for PCBs samples: BDE-28, -47, -99, and -153 were also important congeners compositions, except for BDE-209. Compared with previous studies, the BFRs concentrations in current Chinese e-waste are trending to decline. This study also found that BFRs in housing plastics and PCBs will be transferred into the recycled products with other purpose use, and the new products could have highly enriched capacities for BFRs. The obtained results could be helpful to manage e-waste and their components properly in order to minimize associated environmental and health risks of BFRs, particularly for their further reuse.

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Enhanced HLW glass formulations for the waste treatment and immobilization plant

Current estimates and glass formulation efforts are conservative vis-a-vis achievable waste loadings. These formulations have been specified to ensure that glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet WTP Contract terms. The WTP's overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum, chromium, bismuth, iron, phosphorous, zirconium, and sulfur compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previous experience and current glass property models. DOE has a testing program to develop and characterize HLW glasses with higher waste loadings. This work has demonstrated the feasibility of increases in waste loading from 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. It is expected these higher waste loading glasses will reduce the HLW canister production requirement by 25% or more. (authors)

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Radionuclide inventory of vitrified waste after spent nuclear fuel reprocessing at La Hague

The primary aim of the present work was to determine the inventories of the radionuclides and stable elements in vitrified high-level waste produced at La Hague and delivered to Germany, which are of importance for long-term safety assessment of final repositories for radioactive wastes. For a subset of these radionuclides and stable elements, the inventories were determined - either by direct measurements or by involving established correlations - and reported by AREVA. This allowed verification of the validity of application of a model approach utilizing the data of burnup and activation calculations and auxiliary information on the reprocessing and vitrification process operated at La Hague. Having proved that such a model approach can be applied for prediction of inventories of actinides, fission and activation products in vitrified waste, the present work estimated the minimum, average and maximum inventories of the radionuclides, which are of importance for long-term safety assessment of final repositories for radioactive waste but were not reported by AREVA for delivered CSD-V canisters. The average and maximum inventories in individual CSD-V canisters predicted in the present approach were compared to the inventories predicted by Nagra for canisters with vitrified waste delivered from La Hague to Switzerland [1]. This comparison revealed a number of differences between these inventories despite the fact that the canisters delivered to Switzerland were produced in essentially the same way and from the common reprocessing waste stock as CSD-V canisters delivered to Germany. Therefore, a further work is required in order to identify the reason for the discrepancy in the present estimation versus the Nagra estimation [1]. Such a work should also address the recommendation by the international peer review of the Safety Report of the Project Opalinus Clay to obtain estimates of the inventories of long-lived mobile radionuclides (such as {sup 14}C, {sup 36}Cl, {sup 79}Se, and {sup 129}I), which contribute most to the dose estimates in the radiological safety assessments, if possible, in agreement with other countries with similar waste streams in order for a coordinated set of data to be generated [2]. Since vitrified waste from reprocessing of spent nuclear fuel at La Hague was delivered to several countries - Belgium, France, Germany, Japan, Netherlands, and Switzerland - an international effort can be recommended. (authors)

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Social scientist on board in long-term management of high level and/or long-lived radioactive waste in Belgium

In Belgium, the long-term management of radioactive waste is under the exclusive competence of the Belgian Agency for Radioactive Waste and Enriched Fissile Materials (knew as ONDRAF/NIRAS). Unlike low-level waste, no institutional policy has yet been formally approved for the long-term management of high level and/or long-lived radioactive waste (knew as B and C waste). In this context, ONDRAF/NIRAS considers the public and stakeholders' participation as an essential factor in the formulation of an effective and legitimate policy. This is why it has decided to integrate them in different ways during the elaboration of the Waste Plan (ONDRAF/NIRAS-document containing guidelines to make a principled policy decision about nuclear waste management). To do so, social scientists have been regularly mobilized either as external evaluators, follow-up committee members, or participatory observants. Hence, the Waste Plan is only the first step in a long decision-making process. For a PhD student under contract with ONDRAF/NIRAS, this mandate consists of thinking out a way to construct an inter-organizational innovative communication system that would be participative, transparent and embedded in a long-term perspective, thus integrating all the further legal steps to take throughout the decision-making process. In this regard, two paradoxical constraints must be taken into account: on the one hand, my own influence on the legal decision-making process should remain limited, because of a series of constraints, lock-ins and previous decisions which have to be respected; on the other hand, ONDRAF/NIRAS expects the research conclusions to be policy relevant and useful. In this paper, the purpose is twofold. Firstly, the issues raised by this policy mandate is an opportunity to question the per-formative dimensions of the social scientist in the decision-making process and, more specifically, to have a reflexive view on our position as PhD Student. Secondly, assuming the role of 'embarked' social scientist, numerous of answers will discuss to face the different dilemmas of the researcher 'in action'. Those reflections follow on, among others, those from previous papers discussed in Quimper in April 2013 and in Leuven in June 2013. (authors)

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Design of the Long-term Waste Management Facility for Historic LLRW Port Hope Project - 13322

The Municipality of Port Hope is located on the northern shores of Lake Ontario approximately 100 km east of Toronto, Ontario, Canada. Starting in the 1930's, radium and later uranium processing by Eldorado Gold Mines Limited (subsequently Eldorado Nuclear Limited) (Eldorado) at their refinery in Port Hope resulted in the generation of process residues and wastes that were disposed of indiscriminately throughout the Municipality until about the mid-1950's. These process residues contained radium (Ra- 226), uranium, arsenic and other contaminants. Between 1944 and 1988, Eldorado was a Federal Crown Corporation, and as such, the Canadian Federal Government has assumed responsibility for the clean-up and long-term management of the historic waste produced by Eldorado during this period. The Port Hope Project involves the construction and development of a new long-term waste management facility (LTWMF), and the remediation and transfer of the historic wastes located within the Municipality of Port Hope to the new LTWMF. The new LTWMF will consist of an engineered above-ground containment mound designed to contain and isolate the wastes from the surrounding environment for the next several hundred years. The design of the engineered containment mound consists of a primary and secondary composite base liner system and composite final cover system, made up of both natural materials (e.g., compacted clay, granular materials) and synthetic materials (e.g., geo-synthetic clay liner, geo-membrane, geo-textiles). The engineered containment mound will cover an area of approximately 13 hectares and will contain the estimated 1.2 million cubic metres of waste that will be generated from the remedial activities within Port Hope. The LTWMF will also include infrastructure and support facilities such as access roads, administrative offices, laboratory, equipment and personnel decontamination facilities, waste water treatment plant and other ancillary facilities. Preliminary construction activities for the Port Hope LTWMF commenced in 2012 and are scheduled to continue over the next few years. The first cell of the engineered containment mound is scheduled to be constructed in 2015 with waste placement into the Port Hope LTWMF anticipated over the following seven year period. (authors)

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Design and Testing of a Novel Wide Range - Segmented Gamma Scanner Incorporating Tomographic Gamma Scanning for Measuring Both Low and Intermediate Level Waste in Drums - 13470

This paper describes the design and testing of a novel automated Wide Range Segmented Gamma ray Scanning (WR-SGS) assay instrument that also incorporates Tomographic Gamma Scanning (TGS). The instrument is designed for the measurement of both Low and Intermediate Level Waste (LLW and ILW) in 200 litre drums and other waste containers covering a wide range of density. Like earlier ANTECH WR-SGS instruments, the system employs a single shielded and collimated high purity germanium (HPGe) detector to quantify the radionuclide content of the waste and like conventional SGS instruments it is suitable for the measurement of relatively homogeneous waste matrices. Also, like earlier WR-SGS systems the instrument incorporates an automated variable aperture collimator, which allows the vertical segment height to be adjusted in order to measure both high dose-rate and very low activity drums. The instrument employs both conventional discrete SGS vertical segment measurements as well as vertical segment measurement by continuous helical-scanning of the drum as it rotates. This latter method reduces measurement times for SGS measurements. In order to determine the density corrections for both low and high-density drums, a high activity Eu-152 transmission source is employed. When not in use, and in place of a conventional shutter mechanism, the shielded transmission source is moved to a shielded storage position to eliminate background radiation from the source. Due to its novel features, the WR-SGS is applicable to the measurement of both very low and very high activity waste drums as well as waste drums with a wide range of density. If located in a low background position and with the effective shielding of the strong transmission source, the instrument can be used to measure very low level or exempt waste. In order to extend the range of applicability to the measurement of heterogeneous drums, TGS measurement capability has been included in the basic WR-SGS design. This is achieved by adding horizontal motion to the waste drum rotation platform and incorporating TGS collimation into the variable aperture collimator, as well as a filter to reduce the detector signal when straight-through measurements are made using the strong transmission source. Test measurements are presented of the system operating in both SGS and TGS modes using different drum densities and source strengths. The test measurement results are compared with benchmarked MCNP Monte Carlo calculations. The Wide Range SGS - TGS instrument extends the range of both activity and density that can be measured in 200 and 340 litre drums. (authors)

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Reportable Nuclide Criteria for ORNL Radioactive Waste Management Activities - 13005

The U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee generates numerous radioactive waste streams. Many of those streams contain a large number of radionuclides with an extremely broad range of concentrations. To feasibly manage the radionuclide information, ORNL developed reportable nuclide criteria to distinguish between those nuclides in a waste stream that require waste tracking versus those nuclides of such minimal activity that do not require tracking. The criteria include tracking thresholds drawn from ORNL onsite management requirements, transportation requirements, and relevant treatment and disposal facility acceptance criteria. As a management practice, ORNL maintains waste tracking on a nuclide in a specific waste stream if it exceeds any of the reportable nuclide criteria. Nuclides in a specific waste stream that screen out as non-reportable under all these criteria may be dropped from ORNL waste tracking. The benefit of these criteria is to ensure that nuclides in a waste stream with activities which meaningfully affect safety and compliance are tracked, while documenting the basis for removing certain isotopes from further consideration. (authors)

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Industrial Program of Waste Management - Cigeo Project - 13033

The French Planning Act of 28 June 2006 prescribed that a reversible repository in a deep geological formation be chosen as the reference solution for the long-term management of high-level and intermediate-level long-lived radioactive waste. It also entrusted the responsibility of further studies and design of the repository (named Cigeo) upon the French Radioactive Waste Management Agency (Andra), in order for the review of the creation-license application to start in 2015 and, subject to its approval, the commissioning of the repository to take place in 2025. Andra is responsible for siting, designing, implementing, operating the future geological repository, including operational and long term safety and waste acceptance. Nuclear operators (Electricite de France (EDF), AREVA NC, and the French Commission in charge of Atomic Energy and Alternative Energies (CEA) are technically and financially responsible for the waste they generate, with no limit in time. They provide Andra, on one hand, with waste packages related input data, and on the other hand with their long term industrial experiences of high and intermediate-level long-lived radwaste management and nuclear operation. Andra, EDF, AREVA and CEA established a cooperation agreement for strengthening their collaborations in these fields. Within this agreement Andra and the nuclear operators have defined an industrial program for waste management. This program includes the waste inventory to be taken into account for the design of the Cigeo project and the structural hypothesis underlying its phased development. It schedules the delivery of the different categories of waste and defines associated flows. (authors)

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UP2 400 High Activity Oxide Legacy Waste Retrieval Project Scope and Progress-13048

The High Activity Oxide facility (HAO) reprocessed sheared and dissolved 4500 metric tons of light water reactor fuel the fuel of the emerging light water reactor spent fuel between 1976 and 1998. Over the period, approximately 2200 tons of process waste, composed primarily of sheared hulls, was produced and stored in a vast silo in the first place, and in canisters stored in pools in subsequent years. Upon shutdown of the facility, AREVA D and D Division in La Hague launched a thorough investigation and characterization of the silos and pools content, which then served as input data for the definition of a legacy waste retrieval and reconditioning program. Basic design was conducted between 2005 and 2007, and was followed by an optimization phase which lead to the definition of a final scenario and budget, 12% under the initial estimates. The scenario planned for the construction of a retrieval and reconditioning cell to be built on top of the storage silo. The retrieved waste would then be rinsed and sorted, so that hulls could subsequently be sent to La Hague high activity compacting facility, while resins and sludge would be cemented within the retrieval cell. Detailed design was conducted successfully from 2008 until 2011, while a thorough research and development program was conducted in order to qualify each stage of the retrieval and reconditioning process, and assist in the elaboration of the final waste package specification. This R and D program was defined and conducted as a response and mitigation of the major project risks identified during the basic design process. Procurement and site preparatory works were then launched in 2011. By the end of 2012, R and D is nearly completed, the retrieval and reconditioning process have been secured, the final waste package specification is being completed, the first equipment for the retrieval cell is being delivered on site, while preparation works are allowing to free up space above and around the silo, to allow for construction which is scheduled to being during the first semester of 2013. The elaboration of the final waste package is still undergoing and expected to be completed by then end of 2013, following some final elements of R and D required to demonstrate the full compatibility of the package with deep geological repository. The HAO legacy waste retrieval project is so far the largest such project entering operational phase on the site of La Hague. It is on schedule, under budget, and in conformity with the delivery requirements set by the French Safety Authority, as well as other stakeholders. This project paves the way for the successful completion of AREVA La Hague other legacy waste retrieval projects, which are currently being drafted or already in active R and D phase. (authors)

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Management of salt waste from electrochemical processing of used nuclear fuel

Electrochemical processing of used nuclear fuel involves operation of one or more cells containing molten salt electrolyte. Processing of the fuel results in contamination of the salt via accumulation of fission products and transuranic (TRU) actinides. Upon reaching contamination limits, the salt must be removed and either disposed or treated to remove the contaminants and recycled back to the process. During development of the Experimental Breeder Reactor-II spent fuel treatment process, waste salt from the electro-refiner was to be stabilized in a ceramic waste form and disposed of in a high-level waste repository. With the cancellation of the Yucca Mountain high-level waste repository, other options are now being considered. One approach that involves direct disposal of the salt in a geologic salt formation has been evaluated. While waste forms such as the ceramic provide near-term resistance to corrosion, they may not be necessary to ensure adequate performance of the repository. To improve the feasibility of direct disposal, recycling a substantial fraction of the useful salt back to the process equipment could minimize the volume of the waste. Experiments have been run in which a cold finger is used for this purpose to crystallize LiCl from LiCl/CsCl. If it is found to be unsuitable for transportation, the salt waste could also be immobilized in zeolite without conversion to the ceramic waste form. (authors)

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The safety improvement of Romanian radioactive waste facilities as an example for human and environmental protection

According to IAEA classification, Romania with two nuclear research centres, with 2 Nuclear Power Units in operation at Cernavoda Town and with 2 new Units envisaged to be in operation soon, can be considered as a country with an average nuclear activity. In Romania there was an extensive interest in management of radioactive wastes generated by the use of nuclear technology in industry and research. Using the most advanced technologies in the mentioned time periods, Romania successfully accomplished to solve all management issues related to radioactive wastes being addressed all safety concerns. Every step of nuclear activity development was accompanied by the suitable waste management facilities. So that, in order to improve the existing treatment and disposal capacities for institutional waste, the existing Radioactive Waste Treatment Facility (STDR) and the National Repository Radioactive Wastes (DNDR) at Baita, Bihor, will be improved to actual requirements on the occasion of VVR-S Research Reactor decommissioning. This activity is in development into the frame of a National funded project related to disposal galleries filling improvement and repository closure for DNDR Baita, Bihor. All improvements will be approved by Environmental Protection Authority and Regulatory Body, being a guaranty of human and environmental protection. Also, in accordance with national specific and international policies and taking into account decommissioning activities related to the present operating NPPs, all necessary measures were considered in order to avoid unnecessary generation of radioactive wastes, to minimize, as much as possible, waste production and accumulation and the necessity to develop optimum solutions for a new repository with the assurance of improved nuclear safety. (authors)

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Feedback of the Dutch Historical Waste Management Program - 17085

This paper provides a feedback on the Dutch historical waste management program. Over the past decades, the High Flux Reactor located in Petten in the province of North Holland has tested numerous types of materials and fuels irradiation, for both medical and nuclear energy applications. A number of waste containers was accumulated on site, where the storage facility was initially built. Following Dutch political decisions in the 1980's, the contents of the waste storage facility in Petten must be transferred to another location. The consequences of this decision included the transportation of waste containers from Petten to the new location, which is located in the South-West of the Netherlands. This project was initiated and is now running. It includes a complex structure and can be described as follows: each historical-waste container will be opened, its contents segregated in three categories depending on the dose rate emission, characterized and repacked in new containers suitable for transportation and storage at the new site. The approach chosen is based on the final dose rate emitted by the repacked containers, which are sub-divided into 3 categories.. The lowest dose-emitting containers are transported directly to the new storage facility. The 2 other categories are first transported to a third party to be super compacted and subsequently transported to the new storage facility. So far, the segregation method is based on Co-60 gamma emission and nuclide vectors associated to the different materials. A pre-sorting has been established to fit as much as possible IAEA recommendations. Historical waste has then to be classified in families sharing common history. Thus, a set of canisters containing the pieces of the old reactor vessel, which was replaced in 1984 was the first challenge, followed by a set of canisters containing residues of instruments only and pieces coming from the top of the control rods of the reactor which were not directly irradiated in the reactor. So far, the two first sets of canisters are being treated and characterized as well as possible. Reporting and official documents have been filled up to comply to Dutch transport regulations and to define waste acceptance criteria for the storage facility. The first transports of containers with Low Level Waste occurred in October 2015, and another transport took place at the end of 2016. (authors)

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Optimization of Low Level Waste Disposal Policy, Strategies and Techniques - 17201

The mission of low level radioactive waste disposal facilities is to accept and dispose of waste in compliance with all applicable laws, regulations, license requirements, and social expectations. These facilities need to provide a cost effective disposal service to the waste generators, so that the cost savings could be passed down to business, industry, and ultimately, to the general public. To fulfil this mission, waste disposal facilities need to establish and maintain review and optimization mechanisms to respond to changing circumstances that may impact the long-term safe, cost effective operation of their facilities. Maintaining existing disposal resources available as long as possible, managing increased demand for disposal space as a consequence of growing number of nuclear facilities to be decommissioned, and developing capacity for future needs and uncertainties are some of the key challenges that drive optimization of disposal facilities. While the concept of optimization of low level waste disposal facilities is not new, the framework for holistic optimization of waste disposal facilities, enabling them to provide cost effective, sustainable services to the nuclear industry, as well as maintaining optimized safety and radiation protection systems is a notable gap in the current radioactive waste management body of knowledge. A comprehensive optimization framework is required to support the implementation of safe, effective, and sustainable integrated waste management strategies. (authors)

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Performance Assessment for the Waste Management Area C at the Hanford Site in Southeast Washington - 17515

An initial performance assessment (PA) of Single-Shell Tank (SST) Waste Management Area C (WMA C) located at the U.S. Department of Energy's (DOE) Hanford Site in southeastern Washington has been completed to satisfy the requirements of the Hanford Federal Facility Agreement and Consent Order (HFFACO), as well as other Federal requirements and State-approved closure plans and permits. The WMA C PA assesses the fate, transport, and impacts of radionuclides within residual wastes left in tanks and ancillary equipment and facilities in their assumed closed configuration, and the subsequent risks to humans into the far future. This PA focused on radiological impacts has been developed to meet the requirements for a closure authorization under DOE O 435.1 that includes a waste incidental to reprocessing determination for residual wastes remaining in tanks, ancillary equipment, and facilities. PA results indicate that the performance objectives and measures for the all-pathways dose, the air pathway dose, the radon flux, and groundwater protection are met for both the 1,000-year compliance time period (2020 to 3020) and the post-compliance period (3020 to 12020). The peak dose for the all-pathways analysis in the 1,000-year compliance period is associated with the air pathway, with the peak dose of 4 x 10{sup -5} mSv/yr dominated by tritium resulting from upward gaseous diffusive flux from the residual waste. The peak dose within the sensitivity/uncertainty analysis time period (1,000 to 10,000 years after closure) occurs at about 1,500 years after closure, and results primarily from a peak in {sup 99}Tc groundwater concentration at 100 m down-gradient of the facility. The peak total dose within the sensitivity/uncertainty analysis time period is 0.001 mSv/yr. For all of the sensitivity analyses and uncertainty analyses evaluated, the disposal system also met the performance objectives. In the uncertainty analysis performed with the system level model based on GoldSim{sup C}, the highest calculated groundwater dose in the compliance period was about 7 x 10{sup -4} mSv/yr, and the highest calculated peak dose in the sensitivity/uncertainty analysis period was 0.025 mSv/yr.Doses associated with hypothetical inadvertent human intrusion were calculated for all sources in WMA C and compared to the acute and chronic performance measures in DOE O 435.1. The calculated doses for acute and chronic exposure scenario from potential intrusion into a waste transfer pipeline remain below the DOE O 435.1 performance measure for the time period evaluated beyond 100 years after closure. Acute exposure from drilling into the waste yielded a dose of about 0.36 mSv after the assumed 100-year institutional control period, well below the 5 mSv performance measure for acute exposure. Chronic exposure to waste from drill cuttings in a rural pasture scenario resulted in a dose of about 0.08 mSv/yr after the assumed 100-year institutional control period, well below the 1 mSv/yr performance measure for chronic exposure. (authors)

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Development of understanding of disposability of high-heat-generating wastes in the UK - 15359

The inventory of radioactive wastes planned for geological disposal in the UK is diverse. This inventory includes a range of high-heat-generating wastes and potentially some other nuclear materials (some spent fuel, uranium and plutonium) that are subject to government policy decisions and therefore may be declared as wastes for geological disposal in the future. To ensure that safe disposal solutions can be developed, it will be necessary to understand the influence of this heat on engineered barrier systems for the range of generic disposal concepts being considered in the UK. Furthermore, waste producers need to develop packaging solutions for these materials that take account of any thermal constraints. For these reasons, RWM has established the High-heat-generating Wastes Project (Project Ankhiale), a dedicated project to enhance understanding of the factors affecting geological disposal of high-heat-generating wastes with a view to supporting future decision making and concept selection. The project has been established around a multi-disciplinary Integrated Project Team (IPT), comprising members of RWM, Amec Foster Wheeler and external experts, to provide a comprehensive approach across a range of technical disciplines. Phase 2 of the project, which comprises a series of specific technical activities, commenced in March 2013 and, since then, progress has been made across the following five broad categories: - Compilation of the inventory of UK high-heat-generating wastes;- Waste package performance work; - Development of a better understanding of thermal constraints for different buffer materials; - Exploration of the range of disposal parameters using a thermal dimensioning modelling tool; and - Concept engineering design work. (authors)

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