Ichihara, Akira; Abe, Yutaka*
JAEA-Conf 2022-001, p.175 - 180, 2022/11
Thermal neutron scattering law data were calculated for the heavy water molecule toward the fifth version of the Japanese evaluated nuclear data library, JENDL-5. The scattering laws for deuterium and oxygen atoms were computed using the molecular dynamics simulations. The simulations have been performed in the temperature range from 283.6 K to 600 K. The scattering law data have been evaluated in the neutron incident energies between 0.01 meV and 10 eV. With the obtained scattering laws, we calculated the cross sections for the heavy water molecule, and confirmed that the experimental data at room temperature were well reproduced. Moreover, in the computed temperature range, the cross sections were almost consistent with the ENDF/B-VIII.0 evaluations.
JAEA-Conf 2022-001, p.7 - 13, 2022/11
The partitioning and transmutation (P-T) technology has promising potential for volume reduction and mitigation of degree of harmfulness of high-level radioactive waste. JAEA is developing the P-T technology combined with accelerator driven systems (ADS). One of critical issues affecting the feasibility of ADS is the proton beam window (PBW) which functions as a boundary between the accelerator and the sub-critical reactor core. The PBW is damaged by a high-intensity proton beam and spallation neutrons produced in the target, and also by flowing high-temperature liquid lead bismuth eutectic alloy which is corrosive to steel materials. To study the materials damage under the ADS environment, J-PARC is proposing a plan of proton irradiation facility which equips with a liquid lead-bismuth spallation target bombarded by a 400 MeV - 250 kW proton beam. The facility is also open for versatile purposes such as soft error testing of semi-conductor devises, RI production, materials irradiation for fission and fusion reactors, and so on. Application to nuclear data research with using the proton beam and spallation neutrons is also one of such versatile purposes, and we welcome unique ideas from the nuclear data community.
JAEA-Conf 2022-001, p.97 - 102, 2022/11
In the space environment, radiation irradiate the semiconductors of the devices, and the atomic displacement caused by these radiation degrades the electrical performance of the devices. The atomic displacement of the semiconductor is proportional to the displacement damage (DDD), which is expressed by the non-ionizing energy loss (NIEL). In order to calculate the DDD of semiconductors for various radiation in space, we have developed a method for calculating the DDD in the PHITS code. When silicon was irradiated with protons, neutrons, and electrons, the results of the NIEL calculations by PHITS agreed with the numerical data obtained by the NIEL computer for semiconductors. The defect production efficiencies obtained from the recent molecular dynamic simulations for SiC, InAs, GaAs, and GaN semiconductors were also implemented in PHITS. The results show that GaAs is the most sensitive to displacement damage and SiC is the most resistant to damage when irradiated with 10 MeV protons.
Honda, Maki; Martschini, M.*; Wieser, A.*; Marchhart, O.*; Lachner, J.*; Priller, A.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
JAEA-Conf 2022-001, p.85 - 90, 2022/11
Accelerator mass spectrometry (AMS) is an analytical method that combines mass spectrometry with a tandem accelerator, which has been used mainly in nuclear physics experiments. AMS is used to measure radionuclides with half-lives of 10-10 years. For radionuclides with half-lives of this order, the method of measuring their mass is 10-10 times more sensitive than measuring their activity. Because of this advantage, AMS has been widely applied in Earth and planetary sciences, atomic energy research, and other fields. Among the various studies, Wallner et al. (2021, 2016) have achieved excellent work in Earth and planetary sciences. For example, they have attained the ultra-sensitive analysis of Fe and Pu in environmental samples. These are radionuclides produced by rapid-neutron-capture (r-process) nucleosynthesis. Our recent work shows that a new AMS system (VERA, University of Vienna), which combines laser isobaric separation and a typical AMS system, has been successfully applied to the ultra-sensitive determination of Sr and Cs in environment. For Sr in environmental samples, the -ray measurement by the milking of the daughter nuclide Y is still the principal method, which takes 3-6 weeks. The new AMS method has a detection limit of 0.1 mBq, which is comparable to that of -ray measurement, with a more straightforward chemical treatment than -measurement. Our achievement demonstrates that AMS can be a practical new method for determining Sr in the environment.
Konno, Chikara; Kwon, Saerom*
JAEA-Conf 2022-001, p.123 - 128, 2022/11
We found that a lot of nuclei in TENDL-2019 had no high-energy gamma peaks in secondary gamma spectra from the capture reaction and several nuclei in JEFF-3.3 also have. This problem causes not only drastically small damage energy production cross sections for radiation damage calculations at incident neutron energies below a few keV but also smaller gamma productions in shielding calculations. The problematic energy distribution data for secondary gammas in TENDL-2019 and JEFF-3.3 should be revised.
Iwamoto, Hiroki; Nakano, Keita; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
JAEA-Conf 2022-001, p.129 - 133, 2022/11
For accurate prediction of neutronic characteristics for accelerator-driven systems (ADS) and a source term of spallation neutrons for reactor physics experiments for the ADS at Kyoto University Critical Assembly (KUCA), we have launched an experimental program to measure nuclear data on ADS using the Fixed Field Alternating Gradient (FFAG) accelerator at Kyoto University. As part of this program, the proton-induced double-differential thick-target neutron-yields (TTNYs) and cross-sections (DDXs) for iron have been measured with the time-of-flight (TOF) method. For each measurement, the target was installed in a vacuum chamber on the beamline and bombarded with 107-MeV proton beams accelerated from the FFAG accelerator. Neutrons produced from the targets were detected with stacked, small-sized neutron detectors composed of the NE213 liquid organic scintillators and photomultiplier tubes, which were connected to a multi-channel digitizer mounted with a field-programmable gate array (FPGA), for several angles from the incident beam direction. The TOF spectra were obtained from the detected signals and the FFAG kicker magnet's logic signals, where gamma-ray events were eliminated by pulse shape discrimination applying the gate integration method to the FPGA. Finally, the TTNYs and DDXs were obtained from the TOF spectra by relativistic kinematics.
Watanabe, Shoto*; Minato, Futoshi; Kimura, Masaaki*; Iwamoto, Nobuyuki
JAEA-Conf 2022-001, p.103 - 108, 2022/11
JAEA-Conf 2022-001, p.63 - 67, 2022/11
This tutorial contains a role of accelerator-driven system (ADS) in the nuclear fuel cycle and necessity of nuclear data to realize the ADS. After an overview of Japanese nuclear fuel cycle and government direction, geological disposal concept of high-level waste (HLW) will be described. By partitioning problematic elements from the HLW and transmuting, utilizing or storing them, geological disposal can be changed. ADS plays a role of transmuting minor actinide (MA) separated from HLW to fission product (FP), which are less radio-toxic than MA. The principle of ADS will be introduced with technological issues, and finally utilization of nuclear data for R&D on ADS will be introduced.