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1
Report on analytical activities in potentially hazardous materials mitigation measures at the Plutonium Conversion Development Facility; 2015.12 $$sim$$ 2016.10
Horigome, Kazushi; Taguchi, Shigeo; Ishibashi, Atsushi; Inada, Satoshi; Kuno, Takehiko; Surugaya, Naoki
JAEA-Technology 2017-008, 14 Pages, 2017/05
The plutonium solution had been converted into MOX powder to mitigate the potential hazards of storage plutonium solution such as hydrogen generation at the Plutonium Conversion Development Facility. The plutonium conversion operations had been started in April, 2014, and had been finished in July, 2016. With respect to the samples taken from the conversion process, about 2,200 items of plutonium/uranium solutions and MOX powders had been analyzed for the operation control in the related analytical laboratories at the Tokai Reprocessing Plant. This paper describes the reports on analytical activities and related maintenance works in the analytical laboratories conducted from December, 2015 to October, 2016.
2
Sorption behavior of Np(V) on microbe pure culture and consortia
Onuki, Toshihiko; Kozai, Naofumi; Sakamoto, Fuminori; Utsunomiya, Satoshi*; Kato, Kenji*
Chemistry Letters, 2(5), p.771 - 774, 2017/05
The sorption behavior of Np(V) by the microbe consortia and by a single pure culture of Fe reducing bacterium was studied at pH between 3 and 7 in resting cell conditions. The sorption of Np(V) by the Fe reducing bacterium obtained in the inert condition and by the consortia in aerated condition were higher than by the Fe reducing bacterium in aerobic condition at pH below 5, strongly suggesting presence of other mechanism than the adsorption on microbial cell surface, i.e. reduction to Np(IV).
3
Preliminary assessment of the highest potential transmissivity of fractures in fault zones by core logging
Ishii, Eiichi
Engineering Geology, 221, p.124 - 132, 2017/04
Based on previous hydromechanical studies on fault zones, fault zones without development of tensile/hybrid damage-zone fractures have unlikely experienced faulting in highly brittle manner, and the highest potential transmissivity of fractures in such fault zones is assumed to be likely relatively low (transmissivity (T) $$leq$$ 10$$^{-8}$$m$$^{2}$$/s). To verify this assumption, this study investigated the relationship between the failure mode (tensile/hybrid/shear) of damage-zone fractures and the highest transmissivity of fractures in fault zones, using results from core logging and flowing-fluids electric conductivity logging in boreholes penetrating a Neogene siliceous mudstone of the Horonobe area, northern Hokkaido, Japan. In 96% (35/36) of fault zones where tensile/hybrid damage-zone fracture is not observed, the transmissivities of flow anomalies detected within the fault zones by FFEC logging are within a range of $$geq$$ 10$$^{-8}$$m$$^{2}$$/s. This result supports the above-mentioned assumption.
4
Completion of solidification and stabilization for Pu nitrate solution to reduce potential risks at Tokai Reprocessing Plant
Mukai, Yasunobu; Nakamichi, Hideo; Kobayashi, Daisuke; Nishimura, Kazuaki; Fujisaku, Sakae; Tanaka, Hideki; Isomae, Hidemi; Nakamura, Hironobu; Kurita, Tsutomu; Iida, Masayoshi*; et al.
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (DVD-ROM), 8 Pages, 2017/04
TRP has stored the plutonium in solution state for long-term since the last PCDF operation in 2007 was finished. After the great east Japan earthquake in 2011, JAEA had investigated the risk against potential hazard of these solutions which might lead to make hydrogen explosion and/or boiling of the solution accidents with the release of radioactive materials to the public when blackout. To reduce the risk for storing Pu solution (about 640 kg Pu), JAEA planned to perform the process operation for the solidification and stabilization of the solution by converted into MOX powder at PCDF in 2013. In order to perform PCDF operation without adaption of new safety regulation, JAEA conducted several safety measures such as emergency safety countermeasures, necessary security and safeguards (3S) measures with understanding of NRA. As a result, the PCDF operation had stared on 28th April, 2014, and successfully completed to convert MOX powder on 3rd August, 2016 for about 2 years as planned.
5
Current status of decommissioning activities at Ningyo-toge Environmental Engineering Center
Ishimori, Yuu
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (DVD-ROM), 7 Pages, 2017/04
This paper illustrates the current status of decommissioning activities at four facilities in the Ningyo-toge Environmental Engineering Center of Japan Atomic Energy Agency. (1) The Test milling facility was dismantled from 1999 to 2002. The dismantled materials are stored, and surveyed to determine the quantities of contaminants in the Dismantled materials storage facility. (2) Major equipment at the Refining and conversion facility was dismantled and removed from 2008 to 2013. About 530 t of dismantled materials were generated. Measures of other materials and equipment are taken for easier area managements. (3) A part of centrifuges in the Enrichment engineering facility was decontaminated with 5% of dilute sulfuric acid, and some of them were reused after clearance. Major equipment except centrifuges at the facility has been dismantled and removed since 2014. Dismantling activity will end in 2022. So far, about 270 t of dismantled materials were generated. (4) Centrifuges in the Uranium enrichment demonstration plant have been flushed by $$mathrm{IF}_7$$ gas since 2002 before dismantling. Decontamination efficiencies for DOP-1 and for DOP-2 were about 91% and 99%, respectively. Further plans for dismantling of centrifuges are under review. (5) Related techniques such as measurements are also explained.
6
Development and implementation of GloveBox Cleanout Assistance Tool (BCAT) to detect the presence of MOX by computational approach
Nakamura, Hironobu; Nakamichi, Hideo; Mukai, Yasunobu; Hosoma, Takashi; Kurita, Tsutomu; LaFleur, A. M.*
Proceedings of International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering (M&C 2017) (USB Flash Drive), 7 Pages, 2017/04
In order to maintain facility nuclear material accountancy (NMA) and safeguards properly, to understand where and how much holdup deposit in the process is presence is very important for the cleanout before PIT. JAEA and LANL developed a GloveBox Cleanout Assistance Tool (BCAT) to help cleanout (MOX powder recovering in a glovebox) for invisible holdup effectively by computational approach which is called distributed source-term approach (DSTA). The BCAT tool is a simple neutron measurement slab detectors and helps operator to find locations of holdup. To know the holdup location and the activity from the neutron measurements, the relation between BCAT measurements results at predetermined positions (57 positions) and source voxels (53 voxels) that we want to know the holdup activity was mathematically defined as a matrix by the MCNPX simulation. The model of MCNPX for entire process is very precisely established. We have implemented and experimentally proved that the BCAT tool can direct the operator to recoverable holdup that would otherwise be accounted for as MUF. Reducing facility MUF results in a direct improvement of the facility NMA. The BCAT enables the staff to significantly improve their knowledge of the locations of residual holdup in the process area. JAEA would like to use this application for dismantling of the glovebox with transparency in the future.
7
Comparison of classification performances between Random forests and Support vector machine for $$gamma$$-ray spectral data of uranium-bearing waste drums
Hata, Haruhi; Ishimori, Yuu
Radioisotopes, 66(4), p.149 - 158, 2017/04
For the estimation of radioactive inventory, the radioactive waste drums should be classified based on their radioactive composition. We compared the classification performances between random forests and support vector machine, both of which are machine learning methods. The tested uranium in waste drums included natural uranium from uranium ore, reprocessed uranium from nuclear fuel, and natural uranium with rich radium from the impurities in yellow cake. A total of 75 data in 1037 $$gamma$$-ray spectral data of these drums were trained, and 962 data were applied in the classification models. It was found that the random forests were advantageous in the shift of the channels.
8
Potassium-Argon (K-Ar) dating for fault gouge samples in the Tono Geoscience Center
Tamura, Hajimu*; Shibata, Kenji*; Takahashi, Naoya; Niwa, Masakazu
JAEA-Testing 2017-001, 52 Pages, 2017/03
It is essential to understand the activity of faults in and around a target area to assess the long-term geosphere stability for geological isolation. Potassium-Argon (K-Ar) dating of fault gouge has been conducted in Tono Geoscience Center as one of the dating technique for faulting. This report includes methods for sample preparation, analyses, and age calculation on the K-Ar dating. This can contribute to an evaluation of calculated K-Ar ages.
9
Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2015); Development of design and construction planning and countermeasure technologies (Contract Research)
Toguri, Satohito*; Kobayashi, Shinji*; Tsuji, Masakuni*; Yahagi, Ryoji*; Yamada, Toshiko*; Matsui, Hiroya; Sato, Toshinori; Mikake, Shinichiro; Aoyagi, Yoshiaki
JAEA-Technology 2017-005, 43 Pages, 2017/03
The study on engineering technology in the Mizunami Underground Research Laboratory (MIU) project roughly consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration and mitigating of the excavation effect. In FY2015, as a part of the important issues on the research program, water-tight grouting method has been developed. Grouting methods utilized in the MIU were evaluated and the post-excavation grouting at the -500m Access/Research Gallery-South was planned based on these evaluation results. Also, technology development from the viewpoint of geological disposal was summarized, and information on the alternative method to the grouting method was collected and organized.
10
Rearrangement works of unbalanced waste packages by influence of the Great East Japan Earthquake
Ishihara, Keisuke; Kanazawa, Shingo; Kozawa, Masachiyo; Mori, Masakazu; Kawahara, Takahiro
JAEA-Technology 2017-002, 27 Pages, 2017/03
At radioactive waste management facilities in the Nuclear Science Research Institute, solid radioactive wastes are stored by using containers such as 200L drums and pallets to tier containers in 2 to 4 stacks in the height direction in waste storage facilities (Waste Storage Facility No.1, Waste Storage Facility No.2 and Waste Size Reduction and Storage Facility). On March 11, 2011, the Great East Japan Earthquake was happened, and some waste packages dropped from their pallets and large number of waste packages moved from their original position and inclined due to the influence of the earthquake in the waste storage facilities. There was no experience of rearrangement works to set those dropped and unbalanced waste packages in their original position and it was necessary to prepare detailed work procedures and progress for this task to prevent the occurrence of industrial accidents. Therefore, we prepared detailed work manual and repeatedly carried out mock-up test. And then, we started rearrangement work from April 2011 after confirmation of workers skill and adequacy of the work manual. Finally, all rearrangement works for stored waste packages took about four and half years and were completed in September 2015 without any accident and shutdown of storage function. This report summarizes the countermeasures to reduce exposure doses of workers and to prevent the occurrence of industrial accidents during the rearrangement works.
11
Evaluation of nuclides migration for trench-type disposal by a calculation method taking leaching into consideration
Totsuka, Masayoshi; Kurosawa, Ryohei*; Sakai, Akihiro; Nakata, Hisakazu; Hayashi, Hirokazu; Amazawa, Hiroya
JAEA-Technology 2017-001, 40 Pages, 2017/03
Japan Atomic Energy Agency is planning for the near surface disposal of low level radioactive wastes generated from research, industrial and medical facilities industry in Japan. This document provides the values of radioactivity concentrations equivalent to dose criterion for trench-type disposal. These values are derived based on the safety assessment for ground water scenarios by using a model which describes the release of radionuclides from wastes to a cover soil caused by elution. These concentrations are compared with the one calculated by a model that describes the nuclide release mechanisms as solid-liquid partitioning equilibrium. Additionally, the change in the concentrations is evaluated when the amount of water percolating into a disposal facility varies.
12
Measurement of rock mass deformation around the closure test drift during groundwater recovery experiment at 500m depth of Mizunami Underground Research Laboratory
Kuwabara, Kazumichi*; Aoyagi, Yoshiaki; Ozaki, Yusuke; Matsui, Hiroya
JAEA-Research 2017-002, 39 Pages, 2017/03
Authors developed a displacement meter using optical fiber sensor. The displacement meter can be set at any locations in a borehole and guarantee the measurement accuracy up to 5MPa. Total twelve displacement meters were installed in three boreholes to measure the rock mass displacement during groundwater recovery test. The measurement of the rock mass displacement was stated on March, 27, FY 2014. During the first and second groundwater recovery experiments, compressive displacements were observed close to the closure test drift wall. Magnitude of the measured displacements, except vicinity of test drift wall, was smaller than that of calculated under the assumption of it is an isotropic elastic material.
13
Horonobe Underground Research Laboratory Project; Synthesis of Phase II (Construction Phase) investigations to a depth of 350m
Sato, Toshinori; Sasamoto, Hiroshi; Ishii, Eiichi; Matsuoka, Toshiyuki; Hayano, Akira; Miyakawa, Kazuya; Fujita, Tomoo*; Tanai, Kenji; Nakayama, Masashi; Takeda, Masaki; et al.
JAEA-Research 2016-025, 313 Pages, 2017/03
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. This report summarizes the results of the Phase II investigations carried out from April 2005 to June 2014 to a depth of 350m. Integration of work from different disciplines into a "geosynthesis" ensures that the Phase II goals have been successfully achieved and identifies key issues that need to made to be addressed in the Phase II investigations Efforts are made to summarize as many lessons learnt from the Phase II investigations and other technical achievements as possible to form a "knowledge base" that will reinforce the technical basis for both implementation and the formulation of safety regulations.
14
Hydrochemical investigation at the Mizunami Underground Research Laboratory; Compilation of groundwater chemistry data in the Mizunami group and the Toki granite (fiscal year 2015)
Hayashida, Kazuki; Kato, Toshihiro; Munemoto, Takashi; Aosai, Daisuke*; Inui, Michiharu*; Kubota, Mitsuru; Iwatsuki, Teruki
JAEA-Data/Code 2017-008, 52 Pages, 2017/03
Japan Atomic Energy Agency has been investigating groundwater chemistry to understand the effect on excavating and maintenance of underground facilities as part of the Mizunami Underground Research Laboratory (MIU) Project in Mizunami, Gifu, Japan. In this report, we compiled data of groundwater chemistry obtained at the MIU in the fiscal year 2015. In terms of ensuring traceability of data, basic information (e.g. sampling location, sampling time, sampling method, analytical method) and methodology for quality control are described.
15
Data of geophysical logging based on the deep borehole investigations in the Horonobe Underground Research Laboratory Project (Phase I)
Miyara, Nobukatsu; Matsuoka, Toshiyuki
JAEA-Data/Code 2017-005, 34 Pages, 2017/03
Japan Atomic Energy Agency (JAEA) is performing the Horonobe Underground Research Laboratory Project, which includes a scientific study of the deep geological environment as a basis of research and development for geological disposal of high level radioactive wastes (HLW), in order to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in the sedimentary rock. This report integrates geophysical logging data obtained from the deep borehole investigations (HDB-1 $$sim$$ HDB-11) conducted in the Horonobe Underground Research Laboratory Project (Phase I).
16
Monitoring of groundwater inflow into research galleries in the Mizunami Underground Research Laboratory Project (MIU Project); From fiscal year 2014 to 2015
Ueno, Tetsuro; Takeuchi, Ryuji
JAEA-Data/Code 2017-003, 46 Pages, 2017/03
Tono Geoscience Center of Japan Atomic Energy Agency (JAEA) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction Phase (Phase II), and Operation phase (Phase III). As for The MIU Project (Phase II) was carried out from 2004 fiscal year, and has been started the Phase III in 2010 fiscal year. The groundwater inflow monitoring into shafts and research galleries, has been maintained to achieve the Phase II goals, begins in 2004 fiscal year and follow now. This document presents the results of the groundwater inflow monitoring from fiscal year 2014 to 2015.
17
In situ stress measurement at the 350 m Loop Gallery East at the Horonobe Underground Research Laboratory
Aoyagi, Kazuhei; Sakurai, Akitaka; Niunoya, Sumio*
JAEA-Data/Code 2016-022, 91 Pages, 2017/03
The objective of this report is to investigate the three dimensional stress state in the 350 m Loop Gallery (East) at the Horonobe Underground Research Laboratory. For the measurement, three boreholes, which are 17.0 m in length, were drilled. Hydraulic fracturing was applied as a stress measurement method. For the analysis, shut-in pressure of a transverse fractures, reopening pressure of longitudinal fractures and stress condition causing borehole breakouts were integrated into the equation; then stress state was calculated by inversion technique. As a result, considering the stress condition causing breakouts, the value of the maximum principal stress was 3.73 MPa, which is much smaller than the overburden pressure (about 6.0 MPa). The orientation of the maximum horizontal stress is almost vertical. The stress state is normal faulting.
18
Gas composition related to the Horonobe Underground Research Laboratory Project
Miyakawa, Kazuya; Tamamura, Shuji*; Nakata, Kotaro*; Hasegawa, Takuma*
JAEA-Data/Code 2016-021, 60 Pages, 2017/03
The Japan Atomic Energy Agency has been involved in ongoing research in the Horonobe area for the purposes of geoscientific research, and research and development (R&D) on technologies to be used for the geological disposal of high-level radioactive waste. The chemistry of groundwater and dissolved gas from deep boreholes has been obtained since H13 fiscal year for R&D on technologies related to geological characterization. Horonobe Research Institute for the Subsurface Environment (H-RISE) has investigated a resources development on promoting effective use of coal bed buried in Hokkaido including the Horonobe area using microbial communities. The data of dissolved gas from the Horonobe groundwater have also been obtained along with the microbiological research by H-RISE. Central Research Institute of Electric Power Industry (CRIEPI) has conducted R&D on technology of groundwater geochronology which is one of technologies to be used for the geological disposal, and noble gas data from the Horonobe groundwater have been obtained by CRIEPI. This report shows a data set which comprises gas data obtained from the Horonobe underground research project during the period from H13 fiscal year to H27 fiscal year.
19
Compilation of information on uplift of the last hundred thousand years in the Japanese Islands
Nomura, Katsuhiro; Tanikawa, Shinichi*; Amamiya, Hiroki; Yasue, Kenichi
JAEA-Data/Code 2016-015, 49 Pages, 2017/03
The uplift of the last hundred thousand years in the Japanese Islands has been acquired mainly using marine and river terraces. We arranged information regarding the uplift in a table. This data is one of the useful information for the development of the investigation technology of uplift and for the research of the landform evolution in Japanese islands.
20
Mineralogical, physical and chemical investigation of compacted Kunigel V1 bentonite in contact with a steel heater in the ABM test package 1 experiment, $"A$sp$"o$ Laboratory, Sweden
Sasamoto, Hiroshi; Isogai, Takeshi*; Kikuchi, Hirohito*; Sato, Hisao*; Svensson, D.*
Clay Minerals, 52(1), p.127 - 141, 2017/03
Compacted bentonite has been considered as a candidate of engineering barrier material in many countries for the safe disposal of high-level radioactive waste. SKB set up an in situ experiment (named ABM project) to compare the stability of different bentonites under the conditions exposed to an iron source and elevated temperature (up to 130$$^{circ}$$C as maximum) at the $"A$sp$"o$ Hard Rock Laboratory, Sweden. Results for the Japanese bentonite (Kunigel V1) are summarized in the present paper. Mineralogical investigation using X-ray diffraction (XRD) and X-ray spectroscopy (SEM-EDX) suggested that no indication of smectite transformation or newly formed clay phases were observed. However, a distinct change of exchangeable cations of smectite was indicated (i.e., from Na type to Fe type) in the bentonite at the vicinity of the steel heater. Physical investigation by measurements of hydraulic conductivity and swelling property suggested that no significant change occur in the bentonite even at the vicinity of the steel heater. Such results might be considered due to the limited portion affected by the iron-bentonite interactions and partially occurred ion exchange reactions. Chemical investigation based on the measurements of methylane blue (MB), cation exchange capacity (CEC) and exchangeable cations showed that the lateral distribution for these parameters were basically constant without the significant gradient.