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Sawaguchi, Takuma; Takai, Shizuka; Sasagawa, Tsuyoshi; Uchikoshi, Emiko*; Shima, Yosuke*; Takeda, Seiji
MRS Advances (Internet), 8(6), p.243 - 249, 2023/06
In the intermediate depth disposal of relatively high-level radioactive waste, a method to confirm whether the borehole for monitoring is properly sealed should be developed in advance. In this study, groundwater flow analyses were performed for the hydrogeological structures with backfilled boreholes, assuming sedimentary rock area, to understand what backfill design conditions could prevent significant water pathways in the borehole, and to identify the confirmation points of borehole sealing. The results indicated the conditions to prevent water pathways in the borehole and BDZ (Borehole Disturbed Zone), such as designing the permeability of bentonite material less than or equal to that of the host rock, and grouting BDZ.
fine-structure spectroscopy for studying nuclear structure of heavy nucleiAsai, Masato; Haba, Hiromitsu*; Sato, Nozomi; Kasamatsu, Yoshitaka*; Kaji, Daiya*; Morimoto, Koji*; Morita, Kosuke*; Shima, Yosuke*; Shibata, Michihiro*; Tsukada, Kazuaki; et al.
no journal, ,
We have developed high-resolution fine-structure spectroscopy for studying nuclear structure of short-lived heavy actinide nuclei. It has been demonstrated that spin-parities and single-particle configurations of the ground state of a parent nucleus as well as excited states in a daughter nucleus can be determined only through the measured singles spectrum. To achieve a good energy resolution of 
11 keV, conditions to make a thin source have been optimized. Using this technique, we have identified proton single-particle configurations of 
Lr, 
Lr, 
Lr, and 
Lr for the first time.
-decay spectroscopy for 
RfAsai, Masato; Tsukada, Kazuaki; Sato, Nozomi*; Sato, Tetsuya; Toyoshima, Atsushi; Ishii, Tetsuro; Miyashita, Sunao*; Kaneya, Yusuke*; Shibata, Michihiro*; Shima, Yosuke*
no journal, ,
We have performed -
coincidence and high-resolution -fine structure spectroscopy for Rf, and have obtained new information on nuclear structure of Rf. We have confirmed the existence of two transitions following the decay, and have succeeded in determining the -transition energy very accurately. On the basis of these experimental results, we have estimated the spin-parities and neutron single-particle configurations of the ground- and isomeric states of Rf, and have obtained information on the single-particle configurations and nuclear deformations for heavier superheavy nuclei.
RfAsai, Masato; Tsukada, Kazuaki; Sato, Nozomi*; Sato, Tetsuya; Toyoshima, Atsushi; Ishii, Tetsuro; Miyashita, Sunao*; Kaneya, Yusuke; Shima, Yosuke*; Shibata, Michihiro*
no journal, ,
Alpha-gamma coincidence and high-resolution fine-structure measurements were performed for the decay of Rf. Two lines associated with the decay of Rf were clearly observed, and more precise -energy spectrum than before were obtained. It was found that the literature value (8.28 MeV) of the -transition energy of Rf was incorrect, and that the -decay scheme of Rf should contain several low-energy cascade transitions. On the basis of these results and literature data of 
Rf, we will discuss nuclear structure of superheavy nuclei around this region as well as the level structure of Rf and its daughter nucleus No.
RfAsai, Masato; Tsukada, Kazuaki; Sato, Nozomi*; Sato, Tetsuya; Toyoshima, Atsushi; Ishii, Tetsuro; Miyashita, Sunao*; Kaneya, Yusuke*; Shima, Yosuke*; Shibata, Michihiro*
no journal, ,
We have obtained new experimental data for nuclear structure of Rf through -decay spectroscopy. We have reconfirmed existence of two transitions in the decay of Rf through - coincidence measurement, and determined the -transition energy very precisely through high-resolution -fine structure measurement. On the basis of these experimental results, we have estimated spin-parities and neutron single-particle configurations of the ground- and isomeric states of Rf, and have obtained information on the single-particle configurations and nuclear deformations for heavier superheavy nuclei.
Sato, Kaoru; Manabe, Kentaro; Shima, Yosuke*; Takahashi, Fumiaki
no journal, ,
ICRP published the 2007 fundamental Recommendations. The monitoring data is essential to internal dose assessment against workers and publics. In future, these dose assessments will be based on the 2007 Recommendations. Therefore, we started the conceptual design of calculation program for intake of radionuclides based on ICRP 2007 Recommendations. We also plan that the GUI function and calculation function of time dependent radioactivity in body will be are added to developing calculation program.
Takahashi, Fumiaki; Sato, Kaoru; Shima, Yosuke*; Manabe, Kentaro
no journal, ,
JAEA has developed a computation code for internal dosimetry based upon the ICRP 2007 Recommendations. In this year, the dose coefficient calculation function is updated to calculate dose coefficients for elements in OIR part3 of ICRP and designed to incorporate new data. Some models (e.g., biokinetic models in OIR part 3) are newly incorporated to the function. The algorithm is also updated to calculate dose coefficients for nuclides in decay series (U, Th and so on). Effective dose coefficients by the updated function agreed well with the data in OIR Data Viewer for most cases. The function gives information of biokinetic models to be published by files with ID number and then can correspond to models and data that are to be published by ICRP in future. In addition, directories are prepared for files that can be used in internal dosimetry based upon the ICRP 1990 Recommendations and parameters for Japanese.
Manabe, Kentaro; Shima, Yosuke*; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Intakes of radionuclides are estimated from monitoring results obtained by whole body counters or bioassay for personal dose management and internal dosimetry in case of an accident. In this study, we progressed the development of a function estimating intakes of radionuclides as part of development of an internal dosimetry code which is in accordance with the ICRP 2007 Recommendations. In FY2018, we built a basic function estimating intakes using the latest biokinetic models with a maximum likelihood method based on the conceptual design performed in HY2017. The quality of the basic function was assessed by comparison of the results by this function to literature data. In the presentation, we will report the method of estimating intakes and the result of quality assessment of this function.
