The latest version of the Japanese Evaluated Nuclear Data Library, JENDL-5, was released at the end of 2021. JENDL-5 integrated the nuclear data released as the general-purpose and special-purpose files to meet the growing needs in various fields of nuclear energy and radiation applications [1]. The library consists of 8 nuclear related sub-libraries and 3 atomic related ones. While the atomic...
I was pleased to hear Drs. Osamu Iwamoto, Nobuyuki Iwamaoto and Ken-ichi Tada has been gotten the Awards for Science and Technology (Development Category), the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology in last April. This report is for its celebration lecture.
The Japanese Evaluated Nuclear Data Library (JENDL) has been being...
The JST-ERATO Sekiguchi Three-Nucleon Forces Project (TOMOE Project) is currently ongoing. This project aims to determine three-nucleon forces based on chiral effective field theory using high-precision scattering data from few-nucleon experiments. Establishing a quantum many-body calculation to describe nuclear properties with high predictive power is within the scope. I will present an...
Many important problem in physics can be attributed to solving accurately Schroedinger equation for 3- and 4-body problem.By solving the equation, i) we can predict various observable before measurement, and ii) we can obtain new understandings by comparing the observed data and our theoretical prediction. For this purpose, it is necessary 1) to develop the method to calculate 3- and 4-body...
It is not trivial to quantitatively reproduce nuclear saturation, the most fundamental property of atomic nuclei, which is often discussed together with the necessity of three-body forces. The density functional theory is known to reproduce the saturation property and gives quantitative descriptions from light to heavy nuclei with a single universal energy density functional. For instance, it...
RIKEN Transformative Research Innovation Platform of RIKEN Platforms (TRIP) project was launched in FY2023. The main objective of the TRIP project is to establish a next-generation research DX (digital transformation) platform by accumulating and integrating high-quality data to interconnect all RIKEN platforms. One of the experimental programs in the field of nuclear physics within the TRIP...
The study of three-nucleon forces (3NFs) is essential for clarifying various nuclear phenomena. The 3NFs arise naturally in the meson exchange model as well as in the framework of chiral effective field theory (EFT) [1]. In this framework, consistent two-, three- and many nucleon forces are derived on the same footing. The first non-vanishing 3NF diagrams appear at the third order, so called...
The Japan Atomic Energy Agency (JAEA) has developed and maintained several burnup calculation codes, such as SWAT4 [1] and MVP-BURN [2], which have been widely used for research and various nuclear evaluations. However, recent updates and expansions of evaluated nuclear data libraries have made it difficult to apply new nuclear data to these codes because of limitations in the number of...
JENDL-5 has been utilized in many fields including nuclear engineering since its release, and results of validation works have been also reported. Generally, validation of the evaluated nuclear data libraries is carried out using the measurement data on the integral parameters obtained at nuclear facilities. In the field of nuclear engineering, the radioactive decay data play important roles...
The details of the fuel debris generated in the Tokyo Electric Power Company Holdings’
Fukushima Dai-ichi Nuclear Power Station accident are still not fully understood, and its
critical properties are being evaluated using nuclear calculations with various parameters. On
the other hand, criticality experiments are required to validate these computations because the
fuel debris contains...
A neutron experimental system, called Nuclear Data Production System (NDPS) [1,2], has been constructed at RAON (Rare Isotope Accelerator complex for ON-line experiments) in Republic of Korea. It is designed to produce both white and mono-energetic neutrons, utilizing ion beams and proton beams with thick graphite and thin lithium targets, respectively. Neutrons are generated in the target...
Accurate nuclear cross-section data are essential for the design, safety assessment, and optimization of innovative nuclear reactor systems. Neutron-capture cross sections of minor actinides (MAs) and long-lived fission products (LLFPs) are particularly important for evaluating transmutation, production rates, and fuel-cycle sustainability in advanced nuclear systems [1-3]. However, precise...
At the Research Center for Accelerator and Radioisotope Science (RARiS), Tohoku University, we operate and maintain an electron linear accelerator (LINAC) and an AVF cyclotron, selecting between these accelerators according to the production purpose and the nuclide of interest. Through our joint-use program as a shared user facility, we carry out routine production and supply of radioisotopes...
Currently, a framework is required to examine the production method of a target nuclide while considering various boundary conditions based on nuclear reaction calculation codes and evaluated nuclear data libraries. To address this, we have developed a framework based on CCONE [1, 2], which had not been previously established. This framework enables the easy investigation of reactions that...
The use of radioactive isotopes (RIs) in medicine enables both the diagnosis and treatment of diseases, referred to as nuclear medicine imaging and nuclear medicine therapy, respectively. For example, drugs labeled with RIs can be administered to visualize or destroy cancer cells that selectively accumulate the compound. The physical and chemical properties required for RIs differ between...
The Nuclear Material Balance [1] (NMB) code is a nuclear fuel cycle simulator developed by the former Tokyo Institute of Technology (present Institute of Science Tokyo) and the Japanese Atomic Energy Agency. The code allows the simulation of the full nuclear fuel cycle, including front-end, reactor and back-end operations for an extended number of reactor designs, fuels, reprocessing and...
In fusion reactors, large angle neutron scattering reactions significantly affect neutronics calculations, particularly for the reactor blanket. Previous integral experiments for large angle scattering cross section data at JAEA/FNS revealed discrepancies between experimental and calculated values [1]. Therefore, benchmarking studies on large angle scattering cross sections were indispensable....
Currently, several approaches have been investigated for dose evaluation in the boron neutron capture therapy (BNCT). (1) In clinical practice, the absorbed dose is typically evaluated using the gold wire activation technique combined with pre-treatment PET scans, which provide both the neutron flux and boron concentration. (2) Another approach introduces MRI-sensitive structures, such as...
A series of critical experiments was implemented on a mockup PWR-type fuel assembly loaded with B4C neutron absorber rods (B4C rods) in a tank-type critical assembly (TCA) in 1983 [1]. The mockup assembly was a 15x15 lattice consisting of 204 UO2 fuel rods with 3.2 wt% enrichment and 21 water holes. It was surrounded by a driver lattice region composed of 2.6 wt% enrichment UO2 fuel rods. In...
Fast neutron detection plays an essential role in various fields, including nuclear data measurement, radiation shielding design and dose evaluation. In fast neutron measurements, gamma-rays are typically accompanied by neutrons in the radiation field, requiring effective neutron-gamma (n-g) discrimination. For this reason, organic scintillators are widely used because of their fast response...
In this study, we evaluated and improved the simulation method of the DD neutron field in the OKTAVIAN facility at Osaka University, aiming to establish it as a standard neutron field. In previous studies [1], discrepancies were observed between the experimental angular distribution of DD neutron intensity and simulation results. To address this issue, we developed a new 3D simulation method...
Ensuring the security of nuclear reactor facilities is one of the most pressing challenges in the nuclear field. Theft or illegal transport of nuclear materials, and sabotage of nuclear facilities, are serious threats to safety and stability. Addressing these risks requires technologies that can detect and identify nuclear materials without damaging them. However, existing approaches have been...
Charge-changing cross section ($\sigma_{\mathrm{CC}}$) measurements play an essential role in advancing our understanding of nuclear structure. In heavy-ion beam experiments, atomic number ($Z$) identification is performed by combining the measurement of energy loss ($\Delta E$) with that of the particle velocity ($\beta$). Under typical conditions, the flight path is long enough to determine...
To calculate reliably and accurately concentrations and activities for nuclides generated or depleted by neutron reactions and radioactive decays in nuclear fuel, it is necessary to use the updated nuclear decay data such as half-lives, branching ratios, and $\gamma$-ray spectra. The Evaluated Nuclear Structure Data File (ENSDF) contains required decay data for all nuclides, which is...
The electron linear accelerator at the Institute for Integrated Radiation and Nuclear Science, Kyoto University (KURNS-LINAC) is an L-band accelerator installed in 1965. In nuclear data measurements at KURNS-LIAC, pulsed neutron sources consisting of a water-cooled tantalum target as a photo-neutron source and light water moderators were used. The time resolutions of those pulsed neutron...
The charge radius of an atomic nucleus is an important physical quantity representing its size. By considering the charge distribution of nucleons, it can be converted into the radii of the proton density distribution within the nucleus. Charged radii have been derived from measurements of electron scattering and isotope shifts; however, due to experimental limitations, the measurable nuclides...
In heavy-ion beam experiments, the charge-state distribution of ions after passing through materials is an important quantity for improving the accuracy of beam transmission efficiency and interaction cross-section measurements. In the transmission method for measuring interaction cross sections, precise prediction or measurement of the charge-state distribution is essential to ensure...
As a material-damage index due to the radiation, displacement per atom (dpa) is used widely, which is given by the particle fluence and the displacement cross section, which can be obtained by the electrical resistivity change of target materials due to the proton irradiation by the Matthiessen rule. The sample had to be cooled at cryo-temperature to observe the very small resistivity change...
The interaction cross section (σI) is a fundamental observable that provides valuable information about the spatial extent of atomic nuclei and can be used to derive the nuclear matter radius. By determining nuclear radii, we can improve our understanding of nuclear structure and how nuclear size changes across the nuclear chart.
Traditionally, nuclear charge radii have been obtained from...
Se-79 produced during the operation of nuclear reactors needs to be disposed with transmutation technology due to its high radioactivity and geological migration. For developing reasonable transmutation scheme, it is important to improve the accuracy of Se-79 neutron capture cross section. Despite its importance, there is still almost no experimental data available for capture cross section...
In Accelerator-Driven systems (ADS), reliable cross-section data for fast neutron interacting with radioactive waste are essential for improving the prediction accuracy of transmutation performance [1]. Due to the high radiotoxicity of the waste, it is difficult to use it directly as a target; therefore, a neutron target is desired. However, the fabrication of a stable neutron target is not...
The nuclear force that forms the nuclei is described as interactions between nucleons. The three-nucleon force (3NF) acting among three nucleons is essential to provide descriptions for various nuclear phenomena with high precision. Among the components of the 3NF, the spin-dependent part is still insufficiently understood [1]. To investigate spin-dependent parts of 3NFs, we are planning the...
The three-nucleon force (3NF) is crucial for understanding various nuclear properties, including the binding energy of light nuclei and observables in few-nucleon scattering. In few-nucleon scattering, 3NF effects have been observed in the cross section for deuteron-proton elastic scattering at around 100 MeV/nucleon [1]. 3NF effects have been observed in the cross section for deuteron-proton...
Accurate fission product yield (FPY) data are essential for reactor design and safety studies. Existing nuclear data libraries provide FPY only at limited neutron energies, leaving large gaps in the intermediate region that affect predictions for accelerator-driven systems (ADS) and advanced reactors. We developed a physics-informed machine-learning model using a Bayesian Neural Network (BNN)...
A preliminary benchmark study has been conducted to investigate the large-angle neutron scattering cross section of liquid nitrogen (LN₂). This work is motivated by the crucial role of nitrogen as a constituent nuclide in several materials used for the blanket and shielding systems of fusion reactors. Despite its importance, existing nuclear data for nitrogen remain insufficiently accurate,...
Isomer production is important in nuclear applications, such as radiation safety and radioactive waste management, and theoretical nuclear physics, such as level structure. Although the isomer production can be described by EBITEM [1] in PHITS [2], the number of reactions used as benchmarks is limited. Thus, further verification of the EBITEM’s performance is essential.
To confirm the...
Chromium (Cr) matters from two perspectives. In reactors, Cr is a major alloying element in stainless steels throughout cores and internals. Its 1--100 keV neutron-capture cross section directly affects reaction rates and $k_{\mathrm{eff}}$ [1]. In astrophysics, accurate MACS are crucial for modeling nucleosynthesis [2]. However, current datasets and evaluations show discrepancies in this...
The cross sections of neutron-induced charged-particle emission reactions such as (n,p) and (n,α) for many nuclides have not been measured as well as those of the neutron capture reaction. In the present work, building upon our previous confirmation of the feasibility of the sample-added scintillator technique for detecting neutron-induced charged-particle emission reactions, we plan to extend...
The history of element synthesis (Z>92) began with the discovery of $_{93}$Np in 1940. Since then, elements up to $_{118}$Og have been officially recognized. The superheavy elements from $_{114}$Fl to $_{118}$Og were first successfully synthesized directly using a $^{48}\text{Ca}$ projectile. However, this approach is considered impractical for element 119 due to the extreme difficulty in...
This study used the CoH$_3$ code [1] to perform a theoretical interpretation of neutron double-differential cross-sections (DDXs) for two nuclei, Tantalum (Ta) and Bismuth (Bi) [2-3], with the goal of investigating the underlying reaction mechanisms. We modified the exciton model by introducing a phenomenological factor to govern the transition rate from the initial, simple configuration to...
As I approach retirement at the end of this fiscal year, I would like to take this opportunity to review my research journey in the fields of nuclear physics and nuclear data. I will begin by looking back on the history of education and research in the Department of Nuclear Engineering, Faculty of Engineering, at Kyushu University, where I spent my early academic years. I will then trace the...
In memory of Mr. Tsuneo Nakagawa, who passed away in May of this year, we would like to express our sincere gratitude to Mr. Nakagawa for his highly technical and skillful editing efforts And also in swiftly disseminating and exchanging of information in the community through the regular publication of Nuclear Data News. It would be OK Mr. Nakagawa MR.JENDL
To describe nuclear fission, phenomenological approaches, including statistical models and the Langevin method, have been widely employed. On the other hand, microscopic theories of nuclear fission are still under development and contain many aspects that require improvement. In particular, no method has been established for deriving nuclear fission cross sections from a microscopic nuclear...
Previous studies have revealed the importance of introducing surface correction into a phenomenological model for inclusive ($n,xn$) and ($p,xp$) reactions [1]. These findings have contributed significantly to the improvement of nuclear data evaluation. However, the necessity for the surface correction in an inclusive ($d,xd$) reaction has hardly been investigated.
The purpose of this study...
Reliable nuclear data are essential for both basic research and practical applications in nuclear science and technology. Recent advances in microscopic nuclear reaction theories have enabled a more unified and consistent description of nuclear structure and reaction dynamics. In this work, we present applications of such theoretical frameworks to nuclear data evaluation. In particular, we...
We are performing nuclear data measurements at the 3NBT facility of J-PARC.
In this symposium, we will present an overview of a series of experiments, including measurements of (1) neutron energy spectra at 180 degrees from the beam direction from the mercury target at the MLF, (2) nuclide production cross sections induced by the proton beam, (3) proton scattering spectra through an aluminum window.
