Kyushu University · Engineering
Professor Yonghee Kim's research lab specializes in advanced nuclear reactor design and neutronics optimization, focusing on small modular reactors (SMRs) and micro modular reactors (MMRs) with enhanced safety, compactness, and long-life core performance. The lab explores innovative concepts such as soluble-boron-free cores, centrally-shielded burnable absorbers, and high-density fuels like U15N and UC to achieve high burnup, low reactivity swing, and improved neutron economy. Additionally, the lab investigates fundamental particle physics, particularly the spectroscopy of exotic hadrons like doubly heavy tetraquarks, using chiral quark-diquark models. The integration of advanced materials and device physics is also evident in their work on low-voltage organic transistors for next-generation wearable electronics.
Figures are computed from collected data and may differ slightly.
A complete solution for a soluble-boron-free (SBF) small modular reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity o
Energy spectrum of doubly heavy tetraquarks, ${T}_{QQ}$ ($QQ\overline{q}\overline{q}$ with $Q=c$, $b$ and $q=u,d,s$), is studied in the potential chiral-diquark model. Using the chiral effective theory of diquarks and the quark-diquark-based potential model, the ${T}_{bb}$, ${T}_{cc}$, and ${T}_{cb}$ tetraquarks are described as a three-body system composed of two heavy quarks and an antidiquark. We find several ${T}_{bb}$ bound states, while no ${T}_{cc}$ and ${T}_{cb}$ (deep) bound state is se
Abstract Low‐voltage operation and fast switching ability are necessary for wearable electronic devices. Recently, electrolyte dielectric materials have been widely used to decrease driving voltages; however, they often exhibit unwanted doping effects and power dissipation problems. Here, a method for dramatically lowering driving voltages is reported in organic electronics via source‐gated transistor (SGT) structures. SGTs are fabricated by evaporating asymmetric metals with different work func
A neutronics conceptual study of a supercritical CO2-cooled micro modular reactor (MMR) has been performed in this work. The suggested MMR is an extremely compact and truck-transportable nuclear reactor. The thermal power of the MMR is 36.2 MWth and it is designed to have a 20-year lifetime without refueling. A salient feature of the MMR is that all the components including the generator are integrated in a small reactor vessel. For a minimal volume and long lifetime of the MMR core, a fast neut
An optimization study of a single-pass transuranic (TRU) deep burn (DB) has been performed for a block-type modular helium reactor (MHR) proposed by General Atomics. A high-burnup TRU feed vector from light water reactors is considered: 50 GWd/tU burnup with 5-yr cooling. For three-dimensional equilibrium cores, the performance analysis is done by using McCARD, a continuous-energy Monte Carlo depletion code. The core optimization is performed from the viewpoints of the core configuration, fuel m
This paper presents a neutronics optimization study of a supercritical CO2-cooled micro modular reactor (MMR). The MMR is a fast-spectrum reactor designed to be an extremely compact, integrated, and truck-transportable reactor with 36.2-MWth power and a 20-year lifetime without refueling. The reactor uses a drum-type primary control system and a single absorber rod located at the core center as the secondary ultimate shutdown system. In order to maximize the fuel inventory in a compact fast reac
The mass spectra of singly charmed and bottom baryons, ${\mathrm{\ensuremath{\Lambda}}}_{c/b}(1/{2}^{\ifmmode\pm\else\textpm\fi{}},3/{2}^{\ensuremath{-}})$ and ${\mathrm{\ensuremath{\Xi}}}_{c/b}(1/{2}^{\ifmmode\pm\else\textpm\fi{}},3/{2}^{\ensuremath{-}})$, are investigated using a nonrelativistic potential model with a heavy quark and a light diquark. The masses of the scalar and pseudoscalar diquarks are taken from a chiral effective theory. The effect of ${U}_{A}(1)$ anomaly induces an invers
This paper presents the neutronics and transient studies of a supercritical CO2-cooled micro modular reactor (MMR). The suggested MMR is an extremely compact, integrated, and truck-transportable reactor with 36.2 MWth power and a 20-year lifetime without refueling. A salient feature of the MMR is that all the components including the generator are contained in a small reactor vessel. For a minimum volume and maximum lifetime of the MMR core, a fast neutron spectrum is utilized. To improve the fu
Chiral effective theory of scalar and vector diquarks is formulated according to the linear sigma model. The main application is to describe the ground and excited states of singly heavy baryons with a charm or bottom quark. Applying the potential quark model between the diquark and the heavy quark ($Q=c$, $b$), we construct a heavy-quark--diquark model. The spectra of the positive- and negative-parity states of ${\mathrm{\ensuremath{\Lambda}}}_{Q}$, ${\mathrm{\ensuremath{\Sigma}}}_{Q}$, ${\math
Open papers in the app to read, cite, and organize with AI.
