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Journal Articles

Development of waste acceptance criteria and current challenges relating to the disposal project of LLW generated in research, medical and industrial facilities

Nakata, Hisakazu; Amazawa, Hiroya; Izumo, Sari; Okada, Shota; Sakai, Akihiro

Dekomisshoningu Giho, (58), p.10 - 23, 2018/09

Low level radioactive wastes are generated in the research and development of the nuclear energy, medical and industrial use of radioisotope except NPP in Japan. The disposal of wastes arising from NPP has already been implemented while not the one for wastes from research institutes etc. Japan Atomic Energy Agency therefore has been assigned an implementing organization for the disposal legally in 2008 in order to promote the disposal program as quickly and firmly as possible. Since then, JAEA has conducted their activity relating to the disposal facility design on generic site conditions and developing Waste Acceptance Criteria for LLW from research institutes. This report summarizes the WAC and current challenges.

Journal Articles

Development of the reasonable confirmation methods concerning radioactive wastes from research facilities

Hayashi, Hirokazu; Okada, Shota; Izumo, Sari; Hoshino, Yuzuru; Tsuji, Tomoyuki; Nakata, Hisakazu; Sakai, Akihiro; Amazawa, Hiroya; Sakamoto, Yoshiaki

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

A near surface disposal for low-level radioactive waste (LLW) generated from commercial nuclear power plants (NPP) is operating in Japan. However, the disposal of LLW from other nuclear facilities and radioisotope utilization facilities has not yet been implemented. Japan Atomic Energy Agency (JAEA) plans to implement the near surface disposal. In order to be disposed of these wastes, it must be confirmed by the regulator that each waste package (radioactive waste solidified with filling materials, such as cement, in a container by a regulated method is termed a waste package) conforms to technical standards that aim for safe disposal. JAEA has studied reasonable confirmation methods to demonstrate the conformity of the waste package to the technical standard as NPP operators have studied it. This report describes the outline of our activities focused on development of the confirmation method applicable to radioactive wastes from research facilities.

JAEA Reports

Waste acceptance criteria for waste packages destined for near surface disposal containing radioactive waste from research, industrial and medical facilities

Okada, Shota; Izumo, Sari; Nakata, Hisakazu; Tsuji, Tomoyuki; Sakai, Akihiro; Amazawa, Hiroya

JAEA-Technology 2016-023, 129 Pages, 2016/11

JAEA-Technology-2016-023.pdf:8.95MB

Waste packages must meet the technical requirements. This is because JAEA has been preparing an operating procedure manual for quality control of radioactive waste disposal to be applied to the processing of the waste packages. Raw wastes generated by JAEA are segregated and stored by a method specified in the manual. The composition of raw wastes was characterized on the basis of records of the segregation process. Simulated waste packages were produced by placing the waste materials in a 200 liter drum, which was then filled with mortar, followed by curing in a controlled manner. The static load test was conducted to measure deformation and strain performance of the simulated waste package. Compression apparatuses which can imitate loading conditions in pit-type and trench-type facility that are planned by JAEA were used. Based on the test result, waste packages produced in accordance with the manual met the technical requirement under the condition.

JAEA Reports

Design study for impermeable function of trench disposal facility for very low level waste generated from research, industrial and medical facilities (Joint research)

Sakai, Akihiro; Kurosawa, Ryohei*; Nakata, Hisakazu; Okada, Shota; Izumo, Sari; Sato, Makoto*; Kitamura, Yoichi*; Honda, Yasutake*; Takaoka, Katsuki*; Amazawa, Hiroya

JAEA-Technology 2016-019, 134 Pages, 2016/10

JAEA-Technology-2016-019.pdf:8.25MB

Japan Atomic Energy Agency has been developing to design trench disposal facility with impermeable layers in order to dispose of miscellaneous waste. Geomembrane liners have a function that prevent seepage of leachant and collect the leachant. However, the geomembrane liners do not necessarily provide the expected performance due to damage generated when heavy equipment contacts with the liner. Therefore, we studied the impermeable layers having high performance of preventing seepage of leachant including radioactivity taking into account characteristics of low permeable materials and effect of multiple layer structure. As results, we have evaluated that the composite layers composed by a drainage layer, geomembrane liners and a low permeable layer are most effective structure to prevent seepage of leachant. Taking into account disposal of waste including cesium, we also considered zeolite containing sheets for adsorption of cesium were installed in the impermeable layers.

JAEA Reports

Waste acceptance criteria for waste packages destined for near surface disposal containing radioactive waste from research, industrial and medical facilities

Nakata, Hisakazu; Sakai, Akihiro; Okada, Shota; Izumo, Sari; Tsuji, Tomoyuki; Kurosawa, Ryohei; Amazawa, Hiroya

JAEA-Technology 2016-001, 112 Pages, 2016/03

JAEA-Technology-2016-001.pdf:16.71MB

The waste packages must meet the technical requirements that radioactive waste shall be solidified in a container by a method determined by the Nuclear Regulation Authority to prevent from radiation hazards. JAEA has been preparing operating procedure manual on quality control for radioactive waste disposal in order to promote the manufacturing the waste package. This report presents that simulant waste packages were produced by placing wastes in a 200 liter drum, which was then filled with mortar of a novel mix proportion, followed by curing in a controlled manner. Determination of the presence of harmful voidage and raw waste immobility were performed by direct measurement and visual inspection of a vertical cross section of the waste packages respectively.

JAEA Reports

Method and result for calculation of radioactivity concentration of radionuclide corresponding to dose criterion for near surface disposal of radioactive waste generated from research, medical, and industrial facilities

Okada, Shota; Kurosawa, Ryohei; Sakai, Akihiro; Nakata, Hisakazu; Amazawa, Hiroya

JAEA-Technology 2015-016, 44 Pages, 2015/07

JAEA-Technology-2015-016.pdf:5.8MB

In this report, we calculated radioactivity concentration of radionuclides potentially contained in low level radioactive waste (LLW) generated from research, medical, and industrial facilities corresponding to dose criterion (10 $$mu$$Sv/y) for near surface disposal. 220 kinds of nuclides whose half-life are more than 30 days were selected. Radioactivity concentrations corresponding to dose criterion of 40 nuclides among 220 ones were calculated by using the representative model because the concentrations of 40 nuclides had not been calculated yet. Skyshine dose from each of 19 nuclides, whose radioactivity concentration were invalid values that are larger than the specific radioactivity of nuclides, during operation of disposal facility was calculated. These radioactivity concentrations can be used as criteria of categorization of LLW between trench type and concrete vault type disposal and of preliminary selection of important nuclides of these disposals in the generic conditions.

JAEA Reports

Development of calculation tool of neutron flux used for evaluation of radioactivity inventory in radioactive waste generated from research, medical and industrial facilities

Kurosawa, Ryohei; Okada, Shota; Sakai, Akihiro; Nakata, Hisakazu; Amazawa, Hiroya

JAEA-Data/Code 2015-005, 82 Pages, 2015/06

JAEA-Data-Code-2015-005.pdf:3.47MB

The calculation tool of neutron flux at materials within and around the research reactor was developed so that the user more easily evaluate radioactivity inventory in radioactive waste generated from the decommissioning of research reactors at various conditions. The tool consists of some computer programs which calculate macroscopic effective cross section at materials, calculate the neutron flux at materials within and around the research reactor, and edit the neutron flux to evaluate the radioactive inventory. This report describes the outline of evaluation method of neutron flux at materials within and around the research reactor, the structure and functions of the calculation tool of neutron flux, input and output data, and sample run with the tool.

Journal Articles

Effect of proton irradiation on AlGaN/GaN micro-Hall sensors

Abderrahmane, A.*; Koide, Shota*; Okada, Hiroshi*; Takahashi, Hiroki*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

Applied Physics Letters, 102(19), p.193510_1 - 193510_4, 2013/05

 Times Cited Count:6 Percentile:61.82(Physics, Applied)

The magnetoelectric properties of AlGaN/GaN micro-Hall effect sensors were studied after 380 keV proton irradiation. After irradiation the current-voltage measurements, stability of the magnetic sensitivity of the sensors, and the sheet electron density were degraded with a dramatic decrease of the electron mobility at high temperatures. Raman spectroscopy showed a degradation in the crystalline quality of GaN crystal, but there was no change in the strain.

Journal Articles

Effect of Proton Irradiation on 2DEG in AlGaN/GaN Heterostructures

Abderrahmane, A.*; Koide, Shota*; Tahara, Tomoyuki*; Sato, Shinichiro; Oshima, Takeshi; Okada, Hiroshi*; Sandhu, A.*

Journal of Physics; Conference Series, 433, p.012011_1 - 012011_8, 2013/04

 Times Cited Count:4 Percentile:14.27

We investigated the effect of high energy and high fluence proton irradiation on magnetoelectric properties of AlGaN/GaN micro-Hall sensors from 5.4 K to room temperature. The sensors show good resistance versus the irradiation translated by the stability of the sheet density therefore the stability of the absolute sensitivity of the sensor. However, the proton irradiation damaged the electrical properties of the sensor indicated by the dramatically decrease of the mobility at low temperature by rate of about 81% at 5.4 K. The existing of the 2DEG system either after irradiation with high energy was confirmed by investigation the magnetotransport measurements at low temperature and which show Shubnikov de Haas oscillations at high magnetic field. Damping of the Shubnikov de Haas oscillations and disappearance of Landau plateaus after irradiation were related to the degradation in the mobility causing by increasing the scattering at the interface.

Journal Articles

Robust Hall effect magnetic field sensors for operation at high temperatures and in harsh radiation environments

Abderrahmane, A.*; Koide, Shota*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*; Okada, Hiroshi*

IEEE Transactions on Magnetics, 48(11), p.4421 - 4423, 2012/11

 Times Cited Count:12 Percentile:34.43(Engineering, Electrical & Electronic)

Recent industrial trends indicate increasing demand for Hall effect sensors for monitoring magnetic fields under extreme conditions such as high temperatures and under harmful radiation conditions. In this study, robust and high sensitivity Hall effect sensors using AlGaN/GaN heterostructures with a two-dimensional electron gas at the heterointerface were fabricated, and their magnetic properties were investigated. The AlGaN/GaN 2DEG Hall sensors were stable to at least 400 $$^{circ}$$C and even after irradiation of 380 keV protons at the fluence of 1 $$times$$ 10$$^{14}$$ /cm$$^2$$. The results showed that the AlGaN/GaN 2DEG Hall sensors had superior radiation tolerance to AlGaAs/GaAs and AlInSb/InAsSb/AlInSb magnetic sensors.

Journal Articles

Effects of proton irradiation on the magnetoelectric properties of 2DEG AlGaN/GaN micro-hall sensors

Okada, Hiroshi*; Abderrahmane, A.*; Koide, Shota*; Takahashi, Hiroki*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*

Journal of Physics; Conference Series, 352, p.012010_1 - 012010_5, 2012/03

 Times Cited Count:5 Percentile:8.64

Oral presentation

Laser-driven proton generation from a thin-foil target with a high-intensity laser

Sagisaka, Akito; Nishiuchi, Mamiko; Pirozhkov, A. S.; Ogura, Koichi; Sakaki, Hironao; Maeda, Shota; Pikuz, T.; Faenov, A. Ya.*; Fukuda, Yuji; Yogo, Akifumi; et al.

no journal, , 

High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical and other applications. We have performed several high intensity laser-matter interaction experiments using a thin-foil target irradiated by Ti:sapphire laser (J-KAREN) at JAEA. The pulse duration was typically $$sim$$ 40 fs (FWHM). The electron density profiles of the preformed plasma were observed with the interferometer. The high temporal contrast laser system could reduce the preformed plasma. The maximum proton energy gradually increased as the laser performance improved and finally protons of $$sim$$ 40 MeV energy were observed at the peak laser intensity of $$sim$$ 1 $$times$$ 10$$^{21}$$ W/cm$$^{2}$$.

Oral presentation

Laser driven ion acceleration experiment by high contrast high intensity laser J-KAREN system

Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Maeda, Shota; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.

no journal, , 

no abstracts in English

Oral presentation

Measurement of electron spectrum generated by irradiating thin-Foil target with Ultra-intense Ultra-short pulse laser

Maeda, Shota; Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.

no journal, , 

In JAEA, the high energy ions generated by the interaction between Ultra-intense Ultra-Short pulse laser and thin-foil target is being studied. Irradiating condition must be optimized to generate higher energy ions while suppress the becoming gigantic of laser. It is necessary to know the physical phenomenon in plasma to determine the parameter to optimize from the information on the electron and neutron, X-rays, which are generated simultaneously with ion. In this study, in order to measure electron temperature accurately, an electron spectrometer was developed which have broad range (1-200 MeV). The detector is comprised of permanent magnets and a fluorescent plate, CCD camera. In the presentation, the result of the calibration experiment carried out using 4, 9, 12, 15 MeV quasi-monoenergetic electron beam in HIBMC will be reported. Moreover, response analysis method was inspected using PHITS which is particle transporting Monte Carlo simulation code, and will also report the result.

Oral presentation

Laser-driven proton acceleration with a thin-foil target

Sagisaka, Akito; Nishiuchi, Mamiko; Pirozhkov, A. S.; Ogura, Koichi; Sakaki, Hironao; Maeda, Shota; Pikuz, T.; Faenov, A. Y.*; Fukuda, Yuji; Kanasaki, Masato; et al.

no journal, , 

High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical and other applications. We have performed several high intensity laser-matter interaction experiments using a thin-foil target irradiated by Ti:sapphire laser (J-KAREN) at JAEA. The pulse duration was typically $$sim$$40 fs (FWHM). The high-order harmonics (2nd$$sim$$4th) were observed with the spectrometer in the reflected direction. The maximum proton energy of $$sim$$40 MeV energy were observed at the peak laser intensity of $$sim$$1$$times$$10$$^{21}$$W/cm$$^{2}$$.

Oral presentation

Proton generation from a thin-foil target with a high-intensity laser

Sagisaka, Akito; Nishiuchi, Mamiko; Pirozhkov, A. S.; Ogura, Koichi; Sakaki, Hironao; Maeda, Shota*; Pikuz, T.; Faenov, A. Ya.*; Fukuda, Yuji; Kanasaki, Masato*; et al.

no journal, , 

High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical and other applications. We have performed several high intensity laser-matter interaction experiments using a thin-foil target irradiated by Ti:sapphire laser (J-KAREN) at JAEA. The pulse duration was typically $$sim$$40 fs (FWHM). The high-order harmonics (2nd $$sim$$ 4th) were observed with the spectrometer in the reflected direction. The maximum proton energy of $$sim$$40 MeV energy were observed at the peak laser intensity of $$sim$$1$$times$$10$$^{21}$$ W/cm$$^{2}$$.

Oral presentation

17 (Records 1-17 displayed on this page)
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