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[en] Japan Atomic Energy Agency (JAEA) has been conducting 'geoscientific study' and 'research and development on geological disposal' in the Horonobe Underground Research Laboratory (URL) for safe geological disposal of high-level radioactive waste. Groundwater pressure and geochemical parameters such as pH and oxidation-reduction potential in the deep groundwater have been continuously monitored with monitoring systems which were developed in the Horonobe URL Project. This report presents the data of groundwater pressure which have been obtained by the monitoring systems installed at the 350 m gallery. The data obtained from April 1, 2016 until March 31, 2019 was summarized along with related information such as the specifications of boreholes and the excavation of the URL. A CD-ROM is attached as an appendix. (J.P.N.)
[en] The Mizunami Underground Research Laboratory (MIU) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies for geological disposal of High-level Radioactive Waste through investigations of the deep geological environment within the host crystalline rock at Mizunami City in Gifu Prefecture, central Japan. The project proceeds in three overlapping phases, 'Phase I: Surface-based investigation Phase', 'Phase II: Construction Phase' and 'Phase III: Operation Phase'. The MIU Project has been ongoing the Phase III, as the Phase II was concluded for a moment with the completion of the excavation of horizontal tunnels at GL-500m level in February 2014. The present report summarizes the research and development activities carried out mainly in the GL-500m stage during Third Medium to Long-term Research Phase. (author)
[ja]日本原子力研究開発機構核燃料・バックエンド研究開発部門東濃地科学センターでは、「地層処分技術に関する研究開発」のうち深地層の科学的研究(地層科学研究)の一環として、結晶質岩(花崗岩)を主な対象とした超深地層研究所計画を進めている。超深地層研究所計画は、「第1段階; 地表からの調査予測研究段階」、「第2段階; 研究坑道の掘削を伴う研究段階」、「第3段階; 研究坑道を利用した研究段階」の3段階からなる計画である。超深地層研究所計画では、「深部地質環境の調査・解析・評価技術の基盤の整備」および「深地層における工学技術の基盤の整備」について第1段階から第3段階までを通した全体目標として定め、調査研究を進めている。本報告書では、第3期中長期計画期間のうち、平成27年度から平成31年度までの深度500mまでの研究坑道を利用して実施した調査研究の成果を取りまとめた。具体的には、原子力機構改革の中で必須の課題として抽出した(1)地下坑道における工学的対策技術の開発、(2)物質移動モデル化技術の開発、(3)坑道埋め戻し技術の開発、の3つの研究開発課題の設定の考え方、必須の課題の内容、課題解決のために実施した調査研究の成果を取りまとめた。(著者)
[en] Horonobe Underground Research Center managed by Japan Atomic Energy Agency (JAEA) is the Japan's best environment to understand the project of geological disposal of high-level radioactive waste, because there is an Underground Research Laboratory (URL) in the center besides an exhibition facility which explains the content of research conducted in the URL. In the area of the center, there is also an exhibition facility for the full-scale model of engineered barrier system of geological disposal. JAEA takes advantage of this opportunity to conduct public hearing including questionnaire research regarding the questions, anxieties and comments by the visitors for geological disposal project. This report summarizes the result of statistical analysis of 3,349 visitors from April 2018 to January 2019. (author)
[en] After the Fukushima Daiichi Nuclear Power Station accident, large quantities of radiocesium-contaminated soil were generated from decontamination activities in the Fukushima prefecture. The removed soil has been stored in the prefecture until its final disposal. To complete the final disposal outside Fukushima prefecture, reducing the disposal volume through recycling can prove effective. The Ministry of the Environment, Japan (MOE) has presented a policy to recycle low-radioactive removed soil as recycled materials under the management of public authority. The recycling is limited to civil engineering structures in public projects. In this study, to contribute to guideline development for removed soil recycling by MOE, dose estimation in recycling of removed soil as embankment materials of seaside protection forest was conducted. First, additional doses to workers and the public in construction and service scenarios were evaluated. From the result, the radioactive cesium concentration level of recycled materials, where all additional doses meet the radiation criterion of 1 mSv/y, was derived to be 5,000 Bq/kg. Then, construction conditions were reviewed to reduce additional doses to the public in a service scenario. With the derived radioactivity level of 5,000 Bq/kg, the covered soil thickness of 39 cm or more limited the doses to less than 10 μSv/y. Finally, additional doses in a disaster scenario were evaluated. The doses were confirmed to be below 1 mSv/y when the removed soil of 5,000 Bq/kg was used. (author)
[en] We have been determining atmospheric radioactive cesium (134Cs and 137Cs) concentrations in the early period after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in 2011 using suspended particulate matter (SPM) collected hourly on a filter tape at many automated SPM monitoring stations located widely in eastern Japan. The hourly atmospheric 134Cs and 137Cs concentrations just after the FDNPP accident in wide areas of eastern Japan were first revealed in our study. The determined 134Cs and 137Cs concentrations are expected to play an important role in reducing uncertainties of estimations of the internal radiation dose rates from inhalation and time-series radionuclides release rates from FDNPP, and an evaluation of the atmospheric transport models. There are four steps for the determination of radioactive cesium; i.e., identification of the date and time of SPM samples collected on filter-tapes, preparation of samples for gamma-ray measurement, measurement of gamma-rays, and calculation of concentrations and screening of their values. In this article, we introduced the technical methods to conduct the quality assurance through these four steps, based on our experience for about 7 years. (author)
[en] Understanding spatial variation of rock and soil is important for capability precision as well as groundwater contamination or geopollution management. In view of waste dump/landfills, geoenvironmental hazards ravaging our land including surface and groundwater contamination, site suitability indexing, spatial distribution and characteristics of underlying rock and soil matter are studied. Rock and soil samples were collected in a systematic grid pattern using simple drill core rig and hand auger. Geostatistical and soil property analyses were conducted on each grid. Groundwater aquifer vulnerability to leachate was studied using depth to water table, recharge (precipitation), aquifer material, topographic slope, impact on vadose zone/vadose zone material and hydraulic conductivity (DRASTIC) and geophysical methods. Human population growth analysis indicates tremendous waste generation. Flash points of waste generation and dumping were noted. Geographical positioning system was used to take record of sampling point coordinates. Using a sufficient dataset, each grid indicative factor is objectively scaled, weighed and assigned a numerical rating according to their relative importance employing site suitability (S) analysis approach in an empirical equation. Results were imported into a geographic information system (GIS) platform to generate thematic maps. The results showed that subsurface rock and soil characteristics are neither spatially nor vertically homogeneously distributed. Thematic maps were generated and further interpolated in the GIS domain to produce a composite waste dump/landfill suitability index map.
[en] Recently, Jordan has introduced the integrated solid waste management (SWM) concept. Collection and sorting, composting, incineration of medical waste and sanitary landfills are starting to be implemented, while recycling, reuse and resource recovery are still in the initial stages. In Jordan, up to 50% of the generated waste goes uncollected, and the waste that is collected is mainly mixed with industrial and medical waste during handling and disposal. The typical method of municipal waste disposal in Jordan is landfill, which is poorly managed and lacks most of the basic engineering and sanitary measures for the collection and treatment of gas and leachate. The inability of the existing waste management systems to cope with the growing waste generation rates has led to significant health and environmental problems in Jordan. The problem represents a measurable threat to public health and environmental quality and requires national attention of the highest priority and urgency. The large influx of refugees, the increase of per capita solid waste (SW) generation rates, the impact of dumping SW in non-engineered landfills, the gaps in current related legislation, as well as the absence of proper practices for SW collection and management are the key challenges making this problem highly complicated for the government bodies responsible for handling and managing SW. Therefore, a fresh view is required. There is a need for action. A new integrated SW management system focusing on the overall SW management cycle (street-cleaning, collection, transfer and transport, treatment and disposal) and supplemented by legal, organisational and institutional recommendations is required to ensure optimum results throughout the Kingdom. The purpose of this thesis is to examine the MSW treatment practices in Jordan in order to submit possible treatment approaches, which could be adopted and implemented locally, for sustainable solid waste management in the future. This PhD was conducted in four phases. The first phase was the evaluation of the current situation of SWM practices in Jordan. In this phase, a comprehensive overview of the current situation of the waste management system in Jordan was undertaken. The second phase was an examination of the possibility of optimising the collection route by implementing a route-solving solution using advanced software, the ArcGIS Network Analyst tool, that can lead to benefits related to substantial cost savings, CO emissions and so forth. To this end, a Geographic Information System (GIS) has been created based on data collection involving GPS tracking (collection route/bin position). Both key performance and key operational costs indicators of the actual state (Scenario S0) were evaluated, and by modifying particular parameters, other scenarios were generated and analysed to identify optimal routes. The third phase was the assessment of the compost produced from source-separated organic materials. The study was conducted to explore the physical and chemical properties of compost made from different segregated bio-waste raw materials. The compost produced was monitored in terms of moisture content, bulk density, pH, EC, total organic carbon, total organic matter, total nitrogen, total phosphorus, total potassium and C/N ratio, heavy metal concentrations and compost respiration. Final product quality was examined and assessed against the quality specifications of the German End of Waste Criteria for bio-waste (BioAbfV) which has been subjected to composting. The fourth phase was the investigation of the potential for refuse-derived fuel (RDF) production and utilisation as an alternative fuel for the Jordanian cement industry by using the biodrying process as a solution for the conditions in Jordan to overcome some of its MSW management problems. During this study, laboratory analysis of RDF samples was carried out, to evaluate the RDF quality and compare it with criteria and limits set by some European countries. The biological drying process of solid waste by aerated windrow composting was used as a method of pre-treatment of mixed MSW prior to landfill, in order to produce high calorific material RDF and recover valuable material from the waste stream. Furthermore, the performance of the biological drying process of solid waste by aerated windrow composting was investigated as a pilot scale experiment carried out in Jordan. In conclusion, the findings indicate that GIS-based optimised scenarios could serve as an efficient management tool for the daily operations of solid waste collection and transportation. From an economic point of view, compared to the current situation, the results show that the proposed scenarios allow significant savings of about 23% in overall operational costs. Moreover, vehicle operating time was seen to decrease by 30%, in addition to other extra benefits related to CO emissions. A good alternative for Jordan is the composting of source-separated organic materials. A high quality compost with acceptable chemical properties (OM, TOC, TKN, total P, total K, heavy metals) and physical properties (bulk density, moisture content, etc.) was produced. The absence of local standards, monitoring systems and the legal barriers prevent the control of the sale and application of the compost produced to end users on agricultural/horticultural land. Overall, the results conclude that an efficient waste treatment system could be achieved with a fairly basic and low-cost MBT concept. This is by utilising the biological drying process to produce a substitute fuel for industrial processes. This would reduce the landfill areas required, as well as reduce the air emissions from the landfill, in particular greenhouse gases. High capital investment is needed to set up an RDF plant. However, return on investment is not guaranteed to treat the designated waste quantity for all cases. Therefore, the success of SWM is based on the partnership and cooperation between different parties involved (politicians, local private sector, public sector and international consultant companies). The selection of the appropriate solution for MSW must be based on many factors, such as the availability of land for disposal, the market for recyclable material and the need for energy production, and taking into account the economic and social aspects, with particular attention to environmental issues.
[en] The mobility and bioavailability of uranium in the environment, e.g. in the near field of a deep geological repository for high-level radioactive waste as well as in former uranium mining sites of Saxony and Thuringia, is controlled by important molecular reactions along the groundwater flow paths. These include both hydrolysis and complexation in aqueous solution as well as reactions at biogeochemical interfaces (sorption, diffusion). Detailed knowledge of the mechanisms taking place is essential to develop reliable long term safety analysis and remediation strategies. The required structural and thermodynamic information can be determined by various spectroscopic methods. The focus of this work is on the characterization of the aquatic speciation of tetravalent uranium present under reducing conditions with inorganic ligands in environmentally relevant micromolar concentrations. For this purpose, the complementary absorption and fluorescence spectroscopic methods UV-VIS, IR, fluorometry and (cryo-) time resolved laser- induced fluorescence spectroscopy (TRLFS) were combined with electrochemical and elemental analytical methods (ICP-MS) as well as with thermodynamic and quantum chemical calculations. In addition to the speciation, this combination allows stoichiometry and molecular structure of the aquatic U(IV) complexes to be characterized as well. To characterize the luminescent properties of U(IV), a laser-based measuring system was successfully set up to study U(IV) systems at room temperature (298.15 K) as well as in the frozen state at liquid nitrogen temperature (77 K). By reproducing previously published data on U(IV) luminescence [1, 2], the suitability of the established TRLFS system could be verified. Static and time-resolved luminescence spectra for the free U 4+ aquo ion could be detected with major peaks at 321, 410, and 523 nm and minor peaks at 337, 395, 447, 489, 511, and 564 nm, as well as an improved fine structure of the luminescence spectra. The associated luminescence lifetimes were determined in perchlorate and chloride with τ = 2.26 ± 0.1 ns at 298.15 K and with τHClO4 = 148.4 ± 6.5 ns and τHCl = 152.6 ± 8.3 ns at 77 K, respectively. Hydrolysis and sulfate complexation were shown to quench the U(IV) luminescence signal and the species UOH3+, USO4 2+ and U(SO4)2 do not luminesce upon excitation with λexc = 245 nm. However, the U(IV) sulfate species can be excited at a λexc higher than 245 nm. Furthermore, the influence of temperature on the absorption and luminescence spectroscopic properties of U(IV) was investigated. An increase in temperature shows a similar effect as an increase in pH since the formation of hydrolysis species is shifted to lower pH at elevated II temperature. Thus, the luminescence intensity decreases with increasing temperature due to formation of not luminescent hydrolysis species combined with increasing dynamic quenching processes. The detection limit for U(IV) fluorescence was improved by two orders of magnitude to 5·10−6 M U(IV) at 25°C/298.15 K and 10−6 M U(IV) at 77 K. The suitability of TRLFS as a sensitive, non-invasive analytical technique for the detection of U(IV) in aqueous solution with environmentally relevant uranium concentrations was verified. However, this method is currently not suitable for speciation studies of U(IV) by reason that the U4+ ion is the only U(IV) species in solution to show a characteristic luminescence signal. Based on its absorption properties, the aqueous speciation of the U(IV) sulfate system in the pH range 0 to 2 could be characterized. Since U(IV) hydrolyzes already at low pH values, a complex multicomponent system consisting of the free U(IV) aquo ion, hydrolysis products and U(IV) sulfate complexes was considered here. Single component spectra for U 4+, UOH3+ , US 2+ and U(So)2 as well as their extinction coefficients of 61.7, 19.2, 47.6 and 40.3 L mol−1 cm−1 were calculated using HypSpec for numerical modeling. Under the experimental conditions, no further hydrolysis and sulfate species were detected. The following complex formation constants for infinite dilution were calculated for the two species USO4 2+ and U(SO4)2 present in aqueous solution and for the hydrolysis species UOH3+: log β⦵101 = 6.9 ± 0.3, log β⦵102 = 11.84 ± 0.5, log β⦵110 = −(0.4 ± 0.1). These were first determined by spectroscopic methods and are in good agreement with literature values from indirect investigation methods or analogies to other tetravalent actinides.[3, 4] Compared with previous experiments, the methodology presented here offers the advantages of direct and non-invasive detection of the species as well as its application to micromolar uranium concentrations. By combining these results with vibration spectroscopic investigations and quantum mechanical calculations, it was additionally possible to show that the species USO4 2+ has a monodentate structure in solution. These results serve as a reference for synthetic and natural systems. In addition, the presented methodology can be applied to other inorganic U(IV) species as well as for other actinides and tetravalent metal ions. As examples of application to real systems, this work photometrical investigates the U(IV) speciation in waters of the Asse II mine and the former uranium mine Königstein. For mine water of the Asse II it was shown that U(IV) remains under reducing conditions stable in solution for several weeks despite a pH of 4.7, since it is stabilized by high ionic strength. The dominant U(IV) species in solution are USO4 2+ and U(SO4)2. For the flooding water from Königstein, after both electrochemical and biochemical reduction of the naturally dissolved uranium, U(IV) in solution could be detected. The dominant U(IV) species in solution is U(SO4)2. Since U(IV) remains stable in solution under the prevailing conditions, remediation strategies based on immobilization through uranium reduction require an increase in pH as well.
[en] Japan Atomic Energy Agency (JAEA) has been conducting a wide range of geoscientific research in order to build scientific and technological basis for geological disposal of nuclear wastes. This study aims to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. The Regional Hydrogeological Study (RHS) project is a one of the geoscientific research program at Tono Geoscience Center. This project started since April 1992 and main investigations were finished to FY2004. Since FY2005, hydrogeological and hydrochemical monitoring have been continued using the existing monitoring system. Furthermore, these monitoring were ceased at the end of FY2019 due to the completion of the RHS project. This report describes the results of the long term hydro-pressure monitoring for FY2019. A CD-ROM is attached as an appendix. (J.P.N.)
[en] Comparing the costs of different power generation technologies has become one of the main arguments used by proponents of specific sources and those seeking to find the best approach to plan the expansion of electrical systems. However, this approach, taken alone for public energy policy making, is far from simple and can lead to unwanted and unexpected results. How much does it cost? It seems like a simple question. However, when it comes to competing power generation technologies, it is an extremely challenging question. Generation costs include many variables: capital, fuel, location, waste disposal, environmental impact, interconnection, reliability, intermittency, and other external and systemic costs. No two technologies are alike. System costs are often divided into the following four broadly defined categories of profile costs (also referred to as utilization costs or backup costs), balancing costs, grid costs and connection costs: – Profile costs refer to the increase in the generation cost of the overall electricity system in response to the variability of VRE output. – Balancing costs refer to the increasing requirements for ensuring the system stability due to the uncertainty in the power generation (unforeseen plant outages or forecasting errors of generation). – Grid costs reflect the increase in the costs for transmission and distribution due to the distributed nature and locational constraint of VRE generation plants. – Connection costs consist of the costs of connecting a power plant to the nearest connecting point of the transmission grid.