Search

SARS-CoV-2 infection has been reported to be associated with a positive direct antiglobulin test (DAT). In this study, an analysis of 40 consecutive coronavirus disease 2019 (COVID-19) cases from December 2020 to September 2021 in Japan revealed that patients of 70 years and over were predisposed to a positive DAT. DAT positivity was related to a decrease in the hemoglobin level. Anemia in DAT-positive COVID-19 patients was attributed to hemolysis, which was corroborated by high reticulocyte counts and an increase in the red blood cell distribution width. Human leukocyte antigen (HLA)-DRB1*12:01 and DRB1*12:02 were exclusively found in DAT-positive COVID-19 patients. In silico assays for the Spike protein of SARS-CoV-2 predicted several common core peptides that met the criteria for a B cell epitope and strong binding to both HLA-DRB1*12:01 and DRB1*12:02. Among these peptides, the amino acids sequence TSNFR, which is found within the S1 subunit of SARS-CoV-2 Spike protein, is shared by human blood group antigen Rhesus (Rh) CE polypeptides. In vitro analysis showed that the expression of HLA-DR in CD4

A 43-year-old Japanese male, who had undergone open liver surgery for tumor resection, presented with decreased hemoglobin levels on Day 13 post-emergency-release transfusion of 16 units of Fy(a +) red blood cells. As the anemia was accompanied by increased lactate dehydrogenase, indirect bilirubin, and reticulocytes, as well as decreased haptoglobin, it was attributed to hemolysis. In the diagnostic workup for hemolytic reaction, the direct antiglobulin test result for IgG was positive and the antibody dissociated from the patient's peripheral red blood cells was identified as anti-Fya (titer, 4). The hemolytic reaction was transient (approximately 10 days), of moderate severity, and did not result in any obvious organ damage. However, a single compatible red blood cell transfusion of 2 units was required on Day 17 after the causative transfusion. Notably, HLA typing revealed that the patient carried the HLA-DRB1*04:03 allele, which has been implicated in immunogenicity and induction of anti-Fya response in Caucasian populations. In summary, this is the first documented case of definitive anti-Fya-mediated delayed hemolytic transfusion reaction associated with HLA-DRB1*04:03 in the Japanese population.

In high-temperature plasmas, fast ion diagnostics is one of the important components for plasma heating. Therefore, it is important for fusion research to confirm and understand the physics of fast ions in experimental devices. Although conventional spectroscopy measurements have excellent energy resolution, it is difficult to measure fast deuterons with MeV order energy. The energy resolutions for neutron and $\gamma $ -ray measurements are low and need to be improved. A diagnostics method using the visible light (VIS) spectrum of 3He produced by the deuteron–deuteron reaction has been proposed. The previous studies did not consider the measurement line-of-sight (LOS) in the actual device. In this article, the observability of the proposed method is evaluated considering the spatial distribution of the temperature and density and the direction of ion motion in the deuterium beam-injected ITER deuterium plasma. It is shown that the change of the Doppler broadening of the VIS spectrum due to the formation of beam deuteron tails (non-Maxwell component) is sufficiently larger than the resolution of the spectrometer, it is strongly dependent on the LOS. The ratios of emissivity to bremsstrahlung are 40%–50% in the vertical LOS and 4%–7% in the tangential LOS.

Background The occurrence of transfusion-transmitted hepatitis B virus (HBV) infection has fallen dramatically due to continuous improvements in pre-transfusion laboratory testing. However, the characteristics of transfusion-transmitted HBV infection caused by individual donor nucleic acid amplification test (ID-NAT)-negative blood products are unclear. Case presentation A 76-year-old woman with acute myeloid leukemia was diagnosed with transfusion-transmitted HBV infection after receiving apheresis platelets derived from an ID-NAT-negative blood donation. This case was diagnosed definitively as transfusion-mediated because complete nucleotide homology of a 1556 bp region of the HBV Pol/preS1-preS2-S genes and a 23 bp region of the HBV core promoter/precore between the donor and recipient strains was confirmed by PCR-directed sequencing. The case is uncommon with respect to the unexpectedly prolonged HBV-DNA incubation period of nearly 5 months after transfusion (previously, the longest period observed since the recent implementation of ID-NAT pre-transfusion laboratory testing in Japan was 84 days). Slow-replicating HBV genotype A2 may contribute to the prolonged incubation period; also, the quantity of apheresis platelets delivered in a large volume of plasma, and/or the immune response of the recipient suffering from a hematological neoplasm, may have contributed to establishment of HBV infection in the recipient. This was supported by analysis of three previously documented cases of transfusion-transmitted HBV infection by blood products derived from ID-NAT-negative donations in Japan. Conclusion Continuous monitoring of HBV infection for longer periods (>3 months) may be required after transfusion of blood components from an ID-NAT-negative HBV window donation.

The JT interval of the myocardial repolarization time can be divided into Jpoint to T-peak interval (JTp) and T-peak to T-end interval (Tpe). It is well known that the JT interval is dependent on the heart rate, but little is known regarding heart rate dependence for JTp and Tpe. The aim of the present study was to clarify the heart rate dependence of JTp and Tpe and to elucidate the interference of autonomic nervous activity with these parameters.We evaluated 50 prepubertal children (mean age: 6.4 ± 0.5 years; male:female, 22:28) without heart disease. JTp, Tpe, and the preceding RR intervals were measured using 120 consecutive beats (lead CM5). First, the relationships between the RR interval and JTp and Tpe were evaluated by Pearson's correlation coefficient. Second, to evaluate autonomic interference with JTp and Tpe, the degree of coherence between RR interval variability and JTp or Tpe variability was calculated using spectral analysis.Significant positive correlations were observed between the RR interval and JTp (y = 0.116x + 105.5; r = 0.594, p0.001) and between the RR interval and Tpe (y = 0.037x + 44.7; r = 0.432, p0.001). Tpe variability had a lower degree of coherence with RR interval variability (range: 0.039-0.5 Hz) than with JTp variability (0.401 [interquartile range, 0.352-0.460] vs. 0.593 [0.503-0.664], respectively; p0.001).Tpe had lower heart rate dependence and a lower degree of autonomic nervous interference than did JTp.

Introduction Quantitative measurement of anti-A/-B antibody titers is important during ABO-incompatible living kidney transplantation (ABOi-LKT). Methods We conducted a multi-institutional study to measure the antibody titers using the automated column agglutination technique (auto-CAT) and tube test (TT) method in ABOi-LKT recipients. Statistical analysis was performed to evaluate the two methods. Results We examined 111 samples from 35 ABOi-LKT recipients at four institutions. The correlation coefficient of the two methods was >0.9; the concordance rate and clinically acceptable concordance rate for the IgG titers were 60.4% and 88.3%, respectively. Perioperative status did not influence the statistical significance. Parallel changes were observed in the IgG antibody titers measured using the auto-CAT or TT technique by desensitizing therapy in time-course monitoring. Conclusion Auto-CAT is comparable with the TT technique and is feasible for IgG anti-A/B antibody titration in ABOi-LKT recipients. This article is protected by copyright. All rights reserved.

A 43-year-old Japanese male, who had undergone open liver surgery for tumor resection, presented with decreased hemoglobin levels on Day 13 post-emergency-release transfusion of 16 units of Fy(a +) red blood cells. As the anemia was accompanied by increased lactate dehydrogenase, indirect bilirubin, and reticulocytes, as well as decreased haptoglobin, it was attributed to hemolysis. In the diagnostic workup for hemolytic reaction, the direct antiglobulin test result for IgG was positive and the antibody dissociated from the patient's peripheral red blood cells was identified as anti-Fy

Production of tritium using a high-temperature gas-cooled reactor (HTGR) has been studied for a prior engineering test with tritium handling and for the startup operation of a demonstration fusion reactor. For this purpose, the hydrogen absorption speed of Zr in a Li-loading rod for the reactor operation is experimentally measured, and an analysis model is presented to evaluate the tritium outflow from the Li rod in a high-temperature engineering test reactor (HTTR). On the basis of the presented model, the structure of the Li-loading rod for the demonstration test using the HTTR is proposed.

The neutron emission spectrum can be modified from Gaussian due to excited Alfven eigenmodes (AEs). We evaluate the neutron emission spectrum when the fuel-ion velocity distribution functions are distorted by AEs, assuming an ITER-like deuterium–tritium tokamak plasma. When shear AEs are excited by energetic particles in a plasma, the non-Maxwellian tails are created in the fuel-ion distribution functions in directions that are parallel and antiparallel to the magnetic field lines. Due to formation of these tails, the non-Gaussian components are formed in the neutron emission spectrum in the same and opposite directions of the toroidal axis. The anisotropic, non-Gaussian neutron emission spectrum can be used for experimental verification and diagnostics of the non-Maxwellian tails in the fuel-ion velocity distribution functions formed by AEs.

Analysis and experimental validation of energetic non-Maxwellian components formed in ion velocity distribution functions enhance our understanding of important physical phenomena in burning plasmas. As one such energetic component, knock-on tails appear due to nuclear elastic scattering (NES). It is important to experimentally validate the NES effects and analysis model of knock-on tails. For this purpose, we propose a method for determining the shape and size of a knock-on tail from the Doppler-broadened γ-ray emission spectrum in a proton-beam-injected deuterium plasma confined in an ITER-like experimental fusion device. In the proposed method, we adopt a two-temperature Maxwellian model and utilize the γ-ray-generating 6Li(d,nγ)7Be and 6Li(d,pγ)7Li nuclear reactions. We discuss both the validity of the proposed method and the expected accuracy of the shape and size of the measured knock-on tail.

It is well known that the influence of nuclear force, e.g., nuclear elastic scattering (NES), appears in an ion scattering process when ion energy increases. NES caused by high-energy particles forms the non-Maxwellian component in the ion distribution function. The non-Maxwellian component is named knock-on tail. The knock-on tail gives various effects on fusion plasma. Therefore, it is important to conduct an experiment in order to understand the impact of the NES effects. The NES effects are affected by the “shape and size” of the knock-on tail and the “shape and size” of the knock-on tail depends on plasma conditions. Therefore, we newly propose the method to observe the correlation between the NES effects and the plasma conditions by using Doppler effects for the γ-ray-generating reaction, i.e., 6 Li(d, p) 7 Li nuclear reaction, in ITER-like deuterium plasma. We can capture the impact of the NES effect caused by the change in the plasma conditions, i.e., electron temperature, deuteron density, proton beam power, and proton beam energy by capturing the change in the γ-ray spectrum. On the basis of the Boltzmann-Fokker-Planck model, we showed the validity of the method by simulation.

Tritium is required for research and development activities for the deuterium–tritium (DT) fusion reactor and fueling the DEMOnstration Power Station (DEMO). However, tritium is a very rare nuclide and must be produced artificially. Tritium production by loading Li compounds (Li rods) into burnable poison holes of a high-temperature gas-cooled reactor (HTGR) has been proposed (H. Matsuura, et al., Nucl. Eng. Des. 243 (2012) 95–101.). Al2O3 and Zr are used to prevent tritium leaks. Nuclear reaction heat caused by the nuclear reaction (e.g., 6Li(n,α)T reaction) can cause a spatial temperature profile in the Li rods and may change its tritium containment performance, because Al2O3 and Zr performance strongly depend on these temperatures. The effect of nuclear reaction heat by the 6Li(n,α)T reaction on the tritium containment performance of the Li rods was evaluated by simulation. The temperatures of the Li rods for the high-temperature engineering test reactor (HTTR) and gas turbine high-temperature reactor 300 (GTHTR300) increased by 36 K and 46 K, and the leaked tritium decreased by 32% and 37% via nuclear reaction heat, respectively.

A high-temperature, gas-cooled reactor (HTGR) is proposed as a tritium production device that has the potential to produce a large amount of tritium using the 6Li(n,α)T reaction without major changes to the original reactor core design. In an HTGR design, generally, boron is loaded into the core as a burnable poison to suppress excess reactivity. In this study, lithium is loaded into the HTGR core aiming to produce thermal energy and tritium simultaneously and is loaded instead of boron as a burnable poison. The nuclear characteristics and fuel temperature were analyzed to confirm the nuclear and thermal feasibility of a lithium-loaded HTGR. It was shown that the analysis results satisfied the design requirements and hence the nuclear and thermal feasibility was confirmed for a lithium-loaded HTGR that produces thermal energy and tritium.

In high-temperature plasma sustained by neutral beam injection heating, the emission spectrum of the neutrons produced by fusion reactions is known to have a modified Gaussian distribution. In this study, neutron transport simulation is carried out for a plasma source that emits neutrons with a modified spectrum and the influence of this modified neutron emission spectrum on the tritium production performance is investigated. The results show that in tritium production using D(d,n)3He neutrons, the rate of the 9Be(n,2n)2α neutron multiple reactions, which has a threshold energy of 2.0 MeV, is significantly enhanced compared with that when a source with a Gaussian neutron emission spectrum was assumed. In addition, the influence of the blanket composition on the tritium production performance is discussed.

Large quantities of tritium are required to start up fusion reactors and conducts engineering tests using tritium for a fusion blanket system. However, tritium is very rare and kg orders of tritium must be produced artificially. Tritium production, by 6Li(n,α)T reaction using a high temperature gas-cooled reactor (HTGR) has been proposed. This method considers the loading of Li rods into burnable poison holes in the HTGR. In this paper, the Li rod suited for use in the High Temperature engineering Test Reactor (HTTR) was designed, and tritium production and leakage from Li-rod capsules were evaluated by adjusting the thicknesses of LiAlO2, alumina, and Zr layers. An irradiation test scenario to be conducted in the HTTR for demonstration of the Li rod’s tritium production and containment performance was presented.

Background and objectives Determination of the anti-A/-B titre pre- and post-transplantation is beneficial for treatment selection. Currently, the recommended method for antibody titration is the tube test (TT) assay. Dithiothreitol (DTT) is used for IgM antibody inactivation. Recently, a fully automated antibody titration assay using the column agglutination technique (CAT) was developed (auto-CAT). Our aim was to compare the auto-CAT and TT techniques for ABO antibody titration, to evaluate the effectiveness of DTT-treated plasma for use with auto-CAT and to define the cut-off value for antibody titration by auto-CAT. Materials and methods We enrolled 30 healthy individuals, including 10 each for blood types A, B and O. We performed antibody titre measurement using the TT technique and auto-CAT simultaneously. Auto-CAT uses the bead column agglutination technology. Results With the auto-CAT cut-off value set to weak (w)+ with DTT treatment plasma, the concordance rate was 45%, and the weighted kappa value between TT and auto-CAT results was 0·994 in all subjects. Furthermore, there was a significant positive correlation between the anti-A/-B titre results obtained using the TT technique and auto-CAT in all blood types. Moreover, a positive bias (falsely elevated end-points due to agglomeration of A/B cells) was not observed in auto-CAT testing using DTT-treated plasma. Conclusion Our results show that 1+ agglutination using the TT technique is equivalent to w+ agglutination obtained using auto-CAT. We recommend that DTT may be used with auto-CAT to measure antibody titres. Thus, we suggest that auto-CAT is useful for antibody titration in routine examination.

To launch a fusion reactor stably, it is necessary to prepare sufficient amount of tritium by an external tritium source. Tritium production using nuclear reactions by neutron and Li in a high temperature gas-cooled reactor (HTGR) is an attractive method. An important issue is tritium confinement in high temperature conditions of HTGR. Covering Li compound by Al2O3 is a promising method because hydrogen permeability in Al2O3 is quite low. Furthermore, it is expected that inserting Zr between Li compound and Al2O3 suppresses tritium permeation because Zr has a large hydrogen absorption capacity. For example, a cylindrical multilayer structure consisted of Zr – Li compound – Zr – Al2O3 is a candidate structure to confine generated tritium. To evaluate hydrogen permeation rate through cylindrical Zr material, in this work, hydrogen permeation experiments were carried out for two samples of one-side sealed Zr pipe. Hydrogen permeation rate in one sample was proportional to as the square root of hydrogen pressure but that in another sample, which had retained a certain amount of hydrogen before the experiment, did not indicate an obvious pressure dependence regardless of almost the same experimental procedure except hydrogen permeation direction. Since observed hydrogen permeation rate in Zr was faster than that in Al2O3, under the multi confinement structure by Zr – Li compound – Zr – Al2O3, the generated tritium in Li compound diffuses promptly in whole Zr inside Al2O3 layer and it is expected tritium is stored stably in the structure. Keywords: Hydrogen, Permeation, Zirconium, Pipe

In the large helical device (LHD) deuterium plasma experiment, the neutron emission rate and the shot-integrated neutron yield are measured with the neutron flux monitor (NFM) and the neutron activation system (NAS), respectively, where the neutron emission is assumed to be isotropic in the plasma. The differential cross section of the D(d,n) 3 He reaction has a large anisotropy for the forward direction of the incident deuteron direction. LHD has intensive tangential neutral beam injectors (NBIs), which may cause an anisotropic neutron emission in the plasma. The angular distribution of the neutron emission is calculated from the fast-ion distribution function evaluated by a code that solves Fokker-Plank equations for the 180-keV tangential NBI. The effect of the anisotropic neutron emission on the NFM and NAS measurements is estimated by a general-purpose Monte Carlo N-particle (MCNP) code calculations. Also, the effect is confirmed experimentally. The neutron emission rate measured with the NFM near the equatorial port is about 10% larger than that with the NFM at the top of the LHD center axis. The shot-integrated neutron yield measured with NAS is 25% larger than that with NFM at the top of the LHD center axis in the case of the tangential neutral beam injection, which is consistent with the MCNP calculation.

A possible scenario to observe a knock-on tail using anisotropic neutron emission spectrum in a proton-beam injected deuterium plasma is presented. On the basis of the ion trajectory analysis in ITER-like magnetic configuration, Boltzmann collision integral and Fokker-Planck simulation, the knock-on tail formation in deuteron distribution function due to nuclear elastic scattering, and the resulting modification of the “double differential” neutron emission spectrum are examined. As a result of the beam injection with a specific direction, the neutron emission spectrum is modified in 2-D phase space. It is shown that the ratio of neutron emission rate with >2.8-MeV energy to the 2.45-MeV peak is increased almost 10 times compared with the 1-D modified neutron emission spectrum integrated over the emission angle, which implies the improvement of the accuracy in the neutron measurement. By using the anisotropic neutron emission adjusting the relative positions between beam-injection port and the neutron detector, the possibility to catch the knock-on tail for various plasma conditions can be increased.

The production of tritium (T) using high-temperature gas-cooled reactors (HTGRs) has been studied for a prior engineering research with T handling and initial T possession in demonstration fusion reactors. Stable containment of T in Li-loading rods during HTGR operation is a critical issue. This study investigates this for an irradiation test to examine T-containment performance in Li-loading rods and develops an analytical model of evaluating the amount of T outflow to a He coolant. The hydrogen absorption characteristics, including the deterioration of the hydrogen absorption speed after Zr has sufficiently absorbed the hydrogen, is experimentally measured assuming an HTGR setting. We present an analytical model of evaluating the T outflow from a Li rod and, on the basis of this model, estimate the total T outflow, assuming the presence of a gas-turbine high-temperature reactor of 300 MWe with a nominal capacity and a high-temperature engineering test reactor. It is demonstrated that, by loading a sufficient amount of Zr into the Li rod, the T outflow can be suppressed to less than a small percent of the total T produced during 360 days of reactor operation.

A high temperature gas cooled reactor is proposed as an external tritium source for stably starting up of fusion reactors. A Li rod coated with zirconium and alumina have been proposed to confine produced tritium. Although the tritium leakage from the Li rod has been estimated by the simulation, it is necessary to evaluate the tritium confinement performance experimentally. In this study, the test assembly simulating the Li rod composed of Inner Zr tube - Outer Zr tube - Al2O3 tube was built up, and tritium confinement experiments were conducted. The test assembly successfully confined tritium, which was contained in the Ar gas mainly as HTO and slightly as HT, for 12 h and 87 h at a high temperature of 700 °C. It was suggested that an oxide layer formed on the Zr tube contributed to suppress tritium permeation in HTO.

Performance of tritium production for fusion reactors, using a high-temperature gas-cooled reactor (HTGR) is examined. From the viewpoints of tritium recovery and environmental safety, tritium outflow from Li rods should be suppressed to the same level as the liquid radioactive waste from the pressurized water reactors (PWRs) in Japan. Methods for suppressing tritium leakage from Li rods are studied. The tritium outflow is reevaluated accurately on the basis of non-equilibrium simulations and the influence of coolant temperature on tritium leakage is clarified. The approach using Zr in the Li rod to reduce the tritium pressure and the resulting suppression of tritium leakage are also investigated.The results of the non-equilibrium simulation show that the tritium outflow is approximately 40% lower than the outflow reported in a previous study. Although the electric power generation efficiency is reduced, lowering the coolant temperature to 600 K results in a reduction of the tritium outflow to ~1/...

Nuclear reactors produce a great number of electron antineutrinos mainly from beta-decay chains of fission products (FP). Such neutrinos have energies mostly in MeV range. We are interested in neutrinos in a region of keV, since they may have information on fuel burn-up and may be detected in the future with advanced measurement technology. We calculate reactor antineutrino spectra especially in the low-energy region. In this work, we present neutrino spectra from various reactors such as typical pressurized water reactor and others types of reactors for comparison. Our result shows the electron antineutrino flux in the low-energy region increases with burn-up of nuclear fuel by accumulated nuclides with low Q values in beta-decay.

The fast deuteron (non-Maxwellian component) diagnostic method, which is based on the higher resolution optical spectroscopic measurement, has been developed as a powerful tool. Owing to a decrease in the D–H charge-exchange cross section, the diagnostic ability of conventional optical diagnostic methods should be improved for ∼MeV energy deuterons. Because the 3He–H charge-exchange cross section is much larger than that of D–H in the ∼MeV energy range, the visible light (VIS) spectrum of 3He produced by the dueteron–dueteron (DD) reaction may be a useful tool. Although the density of 3He is small because it is produced via the DD reaction, improvement of the emissivity of the VIS spectrum of 3He can be expected by using a high-energy beam. We evaluate the VIS spectrum of 3He for the cases when a fast deuteron tail is formed and not formed in the ITER-like beam injected deuterium plasma. Even when the beam energy is in the MeV energy range, a large change appears in the half width at half maximum of the VIS spectrum. The emissivity of the VIS spectrum of 3He and the emissivity of bremsstrahlung are compared, and the measurable VIS spectrum is obtained. It is shown that the VIS spectrum of 3He is a useful tool for the MeV beam deuteron tail diagnostics.

Background: Nuclear reactors produce a great number of antielectron neutrinos mainly from beta-decay chains of fission products. Such neutrinos have energies mostly in MeV range. We are interested in neutrinos in a region of keV, since they may take part in special weak interactions. We calculate reactor antineutrino spectra especially in the low energy region. In this work we present neutrino spectrum from a typical pressurized water reactor (PWR) reactor core. Materials and Methods: To calculate neutrino spectra, we need information about all generated nuclides that emit neutrinos. They are mainly fission fragments, reaction products and trans-uranium nuclides that undergo negative beta decay. Information in relation to trans-uranium nuclide compositions and its evolution in time (burn-up process) were provided by a reactor code MVP-BURN. We used typical PWR parameter input for MVP-BURN code and assumed the reactor to be operated continuously for 1 year (12 months) in a steady thermal power (3.4 GWth). The PWR has three fuel compositions of 2.0, 3.5 and 4.1 wt% 235U contents. For preliminary calculation we adopted a standard burn-up chain model provided by MVP-BURN. The chain model treated 21 heavy nuclides and 50 fission products. The MVB-BURN code utilized JENDL 3.3 as nuclear data library. Results and Discussion: We confirm that the antielectron neutrino flux in the low energy region increases with burn-up of nuclear fuel. The antielectron-neutrino spectrum in low energy region is influenced by beta emitter nuclides with low Q value in beta decay (e.g. 241Pu) which is influenced by burp-up level: Low energy antielectron-neutrino spectra or emission rates increase when beta emitters with low Q value in beta decay accumulate Conclusion: Our result shows the flux of low energy reactor neutrinos increases with burn-up of nuclear fuel.

In order to investigate the potential of high temperature gas-cooled reactors (HTGRs) for transmutation of long-lived fission products (LLFPs), numerical simulation of four types of HTGRs were carried out. In addition to the gas-turbine high temperature reactor system “GTHTR300”, which is the subject of our previous research, a small modular HTGR plant “HTR50S” and two types of plutonium burner HTGRs “Clean Burn with MA” and “Clean Burn without MA” were considered. The simulation results show that an early realization of LLFP transmutation using a compact HTGR may be possible since the HTR50S can transmute fair amount of LLFPs for its thermal output. The Clean Burn with MA can transmute a limited amount of LLFPs. However, an efficient LLFP transmutation using the Clean Burn without MA seems to be convincing as it is able to achieve very high burn-ups and produce LLFP transmutation more than GTHTR300. Based on these results, we propose utilization of variety of HTGRs for LLFP transmutation and storage.

In this work, energetic-ion confinement and loss due to energetic-ion driven magnetohydrodynamic modes are studied using comprehensive neutron diagnostics and orbit-following numerical simulations for the Large Helical Device (LHD). The neutron flux monitor is employed in order to obtain global confinement of energetic ions and two installed vertical neutron cameras (VNCs) viewing different poloidal cross-sections are utilized in order to measure the radial profile of energetic ions. A strong helically-trapped energetic-ion-driven resistive interchange mode (EIC) excited in relatively low-density plasma terminated high-temperature state in LHD. Changes in the neutron emission profile due to the EIC excitation are clearly visualized by the VNCs. The reduction in the neutron signal for the helical ripple valley increases with EIC amplitude, which reaches approximately 50%. In addition to the EIC experiment, orbit-following simulations using the DELTA5D code with EIC fluctuations were performed to assess the energetic-ion transport and loss. Two-dimensional temporal evolution results show that the neutron emissivity at the helical ripple decreases significantly due to the EIC. The rapid reduction in neutron emissivity shows that the helically-trapped beam ions immediately escape from the plasma. The reduction in the VNC signals for the helical ripple valley and the total neutron emission rate increase with increasing EIC amplitude, as observed in the experiment. Calculated line-integrated neutron emission results show that the profile measured by VNC1 has one peak, whereas the profile measured by VNC2 has two peaks, as observed in the experiment. Although the neutron emission profile for VNC2 has a relatively wide peak compared with the experimental results, the significant decrease in neutron signal corresponding to the helical ripple valley was successfully reproduced.

In the Force Free Helical Reactor FFHR-d1 (R∼15.7 m, a∼2.5 m, Bo ∼4.5 T, 〈β〉∼5 % and the fusion power of 3 GW) [1, 2], it is demonstrated that the thermally unstable operation is better to achieve the higher density and lower temperature plasma (n(0)∼ 9 × 1020 m−3 and T(0)∼7 keV) than the impurity injection method. One drawback of the thermally unstable operation is a possibility of the thermal runaway when fueling systems have failures. However, we have found that the inherently safe function exists owing to the plasma outward shift during the thermal runaway. Thus we continue to pursue this high-density operation scenario for FFHR-d1. Preliminary estimation of the alpha energy loss fraction of ∼3 % is obtained for a broad density profile in the high-density ignition regime.

A first attempt to observe a nuclear-elastic-scattering (NES) effect caused by energetic protons on deuteron slowing-down behaviour was made on the Large Helical Device located at the National Institute for Fusion Science. The NES effect on the slowing-down of fast ions can influence the confinement of fast ions, ion heating, fusion reaction rate coefficient, etc. An intense hydrogen beam was injected into a deuterium plasma to create a knock-on tail, i.e. a non-Maxwellian energetic component in the deuteron velocity distribution function. We conducted two types of experiment: (1) observation of the slowing-down of the knock-on tail and (2) observation of the NES effect on the slowing-down time of fast ions. The phenomena are discussed in terms of the difference in the decay process of the D(d,n)3He neutron generation rate after neutral beam heating is terminated between the cases when the knock-on effect is influential and not influential, and also from the difference in the neutron decay times. The results of a series of experiments indicate that the NES effect caused by energetic protons can have an impact on the slowing-down of fast deuterons.

The ratio of the left atrial volume index (LAVI) and late diastolic mitral annular velocity (A') is a useful echocardiographic index for identifying advanced left ventricular (LV) diastolic dysfunction in patients with dyspnoea. We investigated the clinical implications and prognostic value of the aforementioned ratio (LAVI/A') in patients with ST elevation (STE) or non-STE (NSTE) acute coronary syndrome (ACS).We studied 212 patients with ACS. All patients underwent electrocardiography, echocardiography and measurement of plasma B-type natriuretic peptide (BNP) level on admission. The study endpoints were hospitalisation and mortality because of heart failure (HF).There was a significant, moderate positive correlation between LAVI/A' and natural logarithm (Ln) BNP level among the participants (r=0.48, p0.0001). During a mean follow-up of 17 months, eight patients died and nine patients were hospitalised because of HF. The receiver operating characteristics curve indicated that LAVI/A'≥3.0 predicted these events (log-rank, p=0.0021). A significant and moderate positive correlation existed between LAVI/A' and Ln BNP level in the NSTE-ACS group (n=128; r=0.58, p0.0001). However, the correlation between LAVI/A' and Ln BNP level was weaker in the STE-ACS group (n=84; r=0.33, p=0.0017).LAVI/A' was related to plasma BNP levels in patients with ACS, particularly in those with NSTE-ACS. This index was useful for predicting cardiac events in patients with ACS.

Tritium production utilizing nuclear reactions by neutron and lithium in a high-temperature gas-cooled reactor is attractive for development of a fusion reactor. From viewpoints of tritium safety a...

Tritium production using high-temperature gas-cooled reactors and its outflow from the region loading Li compound into the helium coolant are estimated when considering the suppression of tritium outflow. A Li rod containing a cylindrical Li compound placed in an Al 2 O 3 cladding tube is assumed as a method for loading Li compound. A gas turbine high-temperature reactor of 300 MW electrical nominal capacity (GTHTR300) with 600 MW thermal output power is considered and modeled using the continuous-energy Monte Carlo transport code MVP-BURN, where burn-up simulations are carried out. Tritium outflow is estimated from equilibrium solution for the tritium diffusion equation in the cladding tube. A GTHTR300 can produce 400–600 g of tritium over a 180-day operation using the chosen method of loading the Li compound while minimizing tritium outflow from the cladding tube. Optimizing tritium production while suppressing tritium outflow is discussed.

To start up a fusion reactor, it is necessary to provide a sufficient amount of tritium from an external device. The fusion DEMO reactor is planned to start up in the 2030s. Herein, methods for supplying the reactor with tritium are discussed. For the initial startup of the fusion reactor, use of a high temperature gas-cooled reactor (HTGR) as a tritium production device has been proposed. So far, the analyses have been focused only on the operation in which fuel is exchanged at stated periods (batch) using the block type HTGR. In this paper, to improve the performance of tritium production, properties of the HTGR are studied from the viewpoint of continuous operation for several conditions. In continuous operation, for example, in the pebble bed type HTGR, it is possible to design an operation that has no time loss for refueling. The pebble bed modular reactor (PBMR) and the gas turbine high temperature reactor of 300 MWe nominal capacity (GTHTR300) are assumed as the calculation and comparison targets, ...

The concentration of extracellular potassium in red blood cell concentrates (RCCs) increases during storage, leading to risk of hyperkalemia. A potassium adsorption filter (PAF) can eliminate the potassium at normal blood transfusion. This study aimed to investigate the potassium adsorption capacity of a PAF during rapid blood transfusion. We tested several different potassium concentrations under a rapid transfusion condition using a pressure bag. The adsorption rates of the 70-mEq/l model were 76·8%. The PAF showed good potassium adsorption capacity, suggesting that this filter may provide a convenient method to prevent hyperkalemia during rapid blood transfusion.

We developed an analysis model to predict and describe neutron emission anisotropy caused by anisotropy of energetic deuterons in the large helical device (LHD), by considering energetic-ion distribution functions, the differential cross-section of fusion reactions, and the exact shape of the vacuum vessel of the LHD. Neutron emission anisotropy that can be observed by the neutron activation system is evaluated numerically assuming deuterium-beam-injected deuterium plasmas confined by the LHD using the model. We demonstrate the dependence of neutron emission anisotropy on the beam-injection direction and the electron temperature. Based on this estimation, we propose an experimental scenario to validate the analysis model and easily understand energetic-ion anisotropy caused by the neutral beam injection.

The performance of a high-temperature gas-cooled reactor as a tritium production with continuous tritium recovery system is examined. A gas turbine high-temperature reactor of 300-MWe (600 MW) nominal capacity (GTHTR300) is assumed as the calculation target, and using the continuous-energy Monte Carlo transport code MVP-BURN, burn-up simulations for the three-dimensional entire-core region of the GTHTR300 were performed. A Li loading pattern for the continuous tritium recovery system in the gas-cooled reactor is presented. It is shown that module gas-cooled reactors with a total thermal output power of 3 GW in all can produce ∼6 kg of tritium maximum in a year.