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Mycotic abdominal aortic aneurysms are rare but life-threatening, and no standard therapy has yet been established. Effective surgery with intensive antimicrobial therapy is crucial; however, this can be fatal in immunocompromised patients. Only a few reports of mycotic abdominal aortic aneurysm with concomitant autoimmune disease exist; therefore, we were concerned about our lack of experience and knowledge about appropriate treatment. We report a 69-year-old male with a mycotic abdominal aortic aneurysm secondary to septic shock after spinal fusion surgery. He had also been on long-term oral immunosuppressants for systemic lupus erythematosus. After preoperative cephazolin, we performed debridement of infected tissue, graft replacement with a rifampicin-bonded prosthesis, and omentopexy. On the 52nd postoperative day, he was transferred back to the previous attending hospital under oral antibiotics and prednisolone. Mycotic abdominal aortic aneurysm in patients with systemic lupus erythematosus should be treated with in situ replacement using an antimicrobial prosthetic or biological graft with thorough debridement and omentopexy, followed by antimicrobials and immunosuppressants, as needed.

A 78-year-old man underwent pacemaker implantation via the left internal jugular vein 36 years ago. After 30 years, a new device was implanted via the right subclavian vein and the old lead was cut and buried underneath the skin due to infection. This time, the patient presented with persistent lead infection of the left side. We chose open heart surgery to excise the old lead because of severe adhesion and surrounding calcification. The infected lead was completely removed using cardiopulmonary bypass without complication. Old pacemaker leads tend to develop adhesion and calcification within the innominate vein and superior vena cava, and therefore, it is often difficult to remove it with percutaneous technique. It was considered that open heart surgery was useful to excise a very old pacemaker lead.

Currently, several near-infrared spectroscopy oximetry devices are used for detecting cerebral ischemia during cardiopulmonary bypass (CPB) surgery. We investigated whether two different models of near-infrared spectroscopy oximetry devices affect the assessment of cerebral ischemia and its management during CPB. From January 2017 to August 2017, 70 adult cardiovascular surgery cases were randomly assigned to 1 of 2 different near-infrared spectroscopy oximetry devices. The devices were INVOS 5100C (Medtronic, Minneapolis, MN, USA) (group I; n = 35) and FORE-SIGHT ELITE (CAS Medical Systems, Branford, CT, USA) (group F; n = 35). There were no significant differences in patient characteristics. The rSO2 values were significantly higher for patients in group F than for patients in group I. Scalp–Cortex distance showed negative correlations with the mean rSO2 values in group I (P = 0.01). Interventions for low rSO2 during CPB for groups I and F were increase perfusion flow (13:5; P = 0.03), blood transfusion (7:1; P = 0.02), and both (6:1; P = 0.04), respectively. The Scalp–Cortex distance in group I was significantly longer in patients who required intervention than in patients who did not (17.1 ± 2.5 vs 15.1 ± 1.6 mm; P = 0.007). It is inappropriate to use the same intervention criteria for different near-infrared spectroscopy oximetry devices. Moreover, brain atrophy influence rSO2 values depending on device selection. It is important to note that inappropriate device selection may misguide perfusionists into performing unnecessary or excessive intervention during CPB.

Desmoid-type fibromatosis (DF) is a rare, locally infiltrative, and fibroblastic proliferative disease. DF usually arises from abdominal fascial tissue, but in rare cases, it can occur in extra-abdominal areas. A 73-year-old Japanese male complained of a painless, left anterior neck mass of 3-month duration. Computed tomography revealed the mass measured 9 × 7 × 6 cm and extended to the anterior mediastinum, with invasion of the left clavicle. En bloc resection of the tumor with the left sternoclavicular joint and the medial portion of the left clavicle was performed by cervico-thoracic approach with L -shaped partial sternotomy. Histopathologic examination showed fascicular growth of spindle-shaped cells separated by abundant collagen. Immunohistologic examination revealed nuclear staining of β-catenin and cytoplasmic staining of vimentin. Genetic analysis of 160 cancer-related genes by next-generation sequencing (NGS) demonstrated only a missense mutation in the CTNNB1 gene (c.133T>C, p.S45P). DF extending from the neck to the anterior mediastinum is rare. We report the complete resection of a large-sized DF with the clavicular invasion. A low-frequency CTNNB1 mutation of DF was identified. Genetic analysis with NGS was beneficial for the diagnosis.

Early extubation in the operating room after congenital open-heart surgery is feasible, but extubation in the intensive care unit after the operation remains common practice at many institutions. The purpose of this study was to evaluate retrospectively the adequacy of our early-extubation strategy and exclusion criteria through analysis based on the Risk Adjustment in Congenital Heart Surgery method (RACHS-1).This retrospective analysis included 359 cases requiring cardiopulmonary bypass (male, 195; female, 164; weight > 3.0 kg; aged 1 month to 18 years). Neonates and preoperatively intubated patients were excluded. Other exclusion criteria included severe preoperative pulmonary hypertension, high-dose catecholamine requirement after cardiopulmonary bypass, delayed sternal closure, laryngomalacia, serious bleeding, and delayed awakening. The early-extubation rates were compared between age groups and RACHS-1 classes.Overall, 83% of cases (298/359) were extubated in the operating room, classified by RACHS-1 categories as follows: 1, 59/59 (100%); 2, 164/200 (84%); 3, 61/78 (78%); and 4-6, 10/22 (45%). The early extubation rate in categories 1-3 (86%, 288/337) was significantly higher than for categories 4-6 (45.5%, 10/22) (P < 0.001). Because they met one of the exclusion criteria, 61 patients (17%) were not extubated in the operating room. Eight patients (2.7%) required re-intubation after early extubation in the operating room, and longer operation time was significantly associated with re-intubation (P < 0.001).Extubation in the operating room after congenital open-heart surgery was feasible based on our criteria, especially for patients in the low RACHS-1 categories, and involves a very low rate of re-intubation.

We describe a rare case of newborn with aortic atresia and transposition of the great arteries who underwent successful surgical repair. To the best of our knowledge, no such case has been previously reported. We demonstrated that, even with a complex diagnosis, the patient could survive after rapid two-stage Norwood procedure.

Cardiopulmonary bypass (CPB) elicits a systemic inflammatory response. Our previous reports revealed that prophylactic sivelestat administration at CPB initiation suppresses the postoperative acute inflammatory response due to CPB in pediatric cardiac surgery. The purpose of this study was to compare the effects of sivelestat administration before CPB and at CPB initiation in patients undergoing pediatric open-heart surgery. Twenty consecutive patients weighing 5-10 kg and undergoing ventricular septal defect closure with CPB were divided into pre-CPB (n = 10) and control (n = 10) groups. Patients in the pre-CPB group received a 24 h continuous intravenous infusion of 0.2 mg/kg/h sivelestat starting at the induction of anesthesia and an additional 0.1 mg/100 mL during CPB priming. Patients in the control group received a 24-h continuous intravenous infusion of 0.2 mg/kg/h sivelestat starting at the commencement of CPB. Blood samples were tested. Clinical variables including blood loss, water balance, systemic vascular resistance index, and the ratio between partial pressure of oxygen and fraction of inspired oxygen (P/F ratio) were assessed. White blood cell count and neutrophil count as well as C-reactive protein levels were significantly lower in the pre-CPB group according to repeated two-way analysis of variance, whereas platelet count was significantly higher. During CPB, mixed venous oxygen saturation remained significantly higher and lactate levels lower in the pre-CPB group. Postoperative alanine aminotransferase and blood urea nitrogen levels were significantly lower in the pre-CPB group than in the control group. The P/F ratio was significantly higher in the pre-CPB group than in the control group. Fluid load requirement was significantly lower in the pre-CPB group.Administration of sivelestat before CPB initiation is more effective than administration at initiation for the suppression of inflammatory responses due to CPB in pediatric open-heart surgery, with this effect being confirmed by clinical evidence.

Cardiopulmonary bypass (CPB) elicits a systemic inflammatory response. The neutrophil elastase inhibitor sivelestat is known to suppress this systemic inflammatory response, which can eventually result in acute organ failure. The prophylactic effect of sivelestat on acute lung injury, especially in pediatric cardiac surgery, remains unclear. This prospective double-blind, randomized study evaluated the perioperative prophylactic effect of sivelestat in patients undergoing elective pediatric open heart surgery with CPB. Thirty consecutive patients, weighing 5-10 kg and undergoing open heart surgery with CPB, were assigned to sivelestat (n = 15) or control (n = 15) groups. From CPB initiation to 24 h after surgery, patients in the sivelestat group received a continuous intravenous infusion of 0.2 mg/kg/h sivelestat, whereas patients in the control group received the same volume of 0.9% saline. Blood samples were collected, and levels of interleukin (IL)-6, IL-8, tumor necrosis factor alpha, polymorphonuclear elastase (PMN-E), C-reactive protein (CRP), as well as the white blood cell (WBC) count, platelet count, and neutrophil count (NC) were measured. PMN-E levels, IL-8 levels, WBC count, NC, and CRP levels were significantly lower, and platelet count was significantly higher in the sivelestat group, according to repeated two-way analysis of variance. The activated coagulation time was significantly shorter in the sivelestat group, similarly, blood loss was significantly less in the sivelestat group. In conclusion, Sivelestat attenuates perioperative inflammatory response and clinical outcomes in patients undergoing pediatric heart surgery with CPB.

Cardiopulmonary bypass (CPB) evokes activation of a systemic inflammatory response. Sivelestat has been used clinically to treat acute lung injury associated with systemic inflammatory response syndrome. This prospective, doubleblind, randomized study was designed to evaluate the effects of sivelestat in the perioperative period of elective pediatric open-heart surgery with CPB. Twenty-six consecutive pediatric patients weighing between 5 and 10 kg and undergoing open-heart surgery with CPB were divided into a sivelestat group (n = 13) and a control group (n = 13). The patients in the sivelestat group were administered a continuous intravenous infusion of 0.2 mg/kg/hour of sivelestat, and the patients in the control group were administered the same volume of 0.9% saline from the initiation of CPB to 24 hours after surgery. Blood samples were drawn for the measurement of cytokines, polymorphonuclear elastase (PMN-E), white blood cell count (WBC), neutrophil count (NC), and C-reactive protein (CRP). There were no significant differences in cytokine data between the two groups. The peak PMN-E and WBC levels were significantly increased in the control group (P = 0.049, P = 0.039). The WBC and NC levels immediately after surgery in the control group were significantly greater than those in the sivelestat group (P = 0.049, P = 0.044). The peak CRP level in the control group was significantly greater than the sivelestat group (P = 0.04), and the CRP level on postoperative day 4 in the control group was significantly greater than in the sivelestat group (P = 0.014). This study showed that sivelestat attenuates the perioperative inflammatory response in pediatric heart surgery with CPB.

Corresponding to the world nuclear security concerns, future nuclear fuel cycle (NFC) should have high proliferation-resistance (PR) and physical protection (PP), while promotion of the peaceful use of the nuclear energy must not be inhibited. In order to accomplish nuclear non-proliferation from NFC, a few models of the well-PR systems should be developed so that international community can recognize them as worldwide norms. To find a good balance of ‘safeguard-ability (so-called extrinsic measure or institutional barrier)’ and ‘impede-ability (intrinsic feature or technical barrier)’ will come to be essential for NFC designers to optimize civilian nuclear technology with nuclear non-proliferation, although the advanced safeguards with high detectability can still play a dominant role for PR in the states complying with full institutional controls. Accomplishment of such goal in a good economic efficiency is a future key challenge.

Background: For management of bowel obstruction due to colorectal cancer, endoscopic trans-anal decompression technique has been first reported by Lelcuk et al. in 1986 using balloon dilatation technique. Since then, various types of trans-anal decompression tubes have been clinically used for patients suffering from left side obstructing colorectal cancer as an emergent decompressing device. At present, two types of trans-anal ileus tube (trans-anal decompression tube) have been available for clinical use, but they have two main problems that are late colon perforations caused by the tip of the tube and tube obstruction by stool. Methods: Analysis on three late colon perforations experienced with the use of conventional devices drew possible improvements to make a trans-anal ileus tube less harmful. To overcome the pitfalls inherent to conventional tubes, the author has developed an improved trans-anal ileus tube with a balloon installed at the very end of the tube (‘balloon-tipped type’) made of silicone, measuring 1200 or 1700 mm in total length and 22 Fr in outer diameter. It has been used for 12 cases with obstructing colorectal cancer etc. and its outcomes were compared with those obtained by the use of conventional trans-anal ileus tube. Results: No late perforations have been encountered, but tube obstruction did occur in one of 12 cases. Conclusion: The new trans-anal ileus tube with a balloon installed at the tip of ileus tube is considered to be safer and especially effective in preventing late colon perforation and tube obstruction.

The mission of the National Centralized Tokamak (NCT) is to establish high-beta steady-state plasma operation for DEMO and to contribute to ITER. Plasma performance with high-beta conditions is discussed. It is found that near break-even class plasma ( Q DT eq ≥ 0.7 ) with high beta ( β N ≥ 3.5) is achievable with 25 MW of NB power at I P = 4.0 MA and an aspect ratio of 2.6. High beta with steady-state full current drive is possible with 13 MW of NB power at I P = 1.5–1.7 MA. In the engineering design activity of NCT, the strength of the support structure and strength of material for the conductor is confirmed for the superconducting coils, and the successful progress of R&D of boron-loaded resin for neutron shielding is discussed.

背景:術中迅速診断に圧挫細胞診が有用であった乳頭型髄膜腫を経験したので報告する.症例:18歳, 女性.約8ヵ月前より頭痛, ふらつきが出現し, CT, MRIで左小脳橋角部から中頭蓋窩に6×5cm大の腫瘤と水頭症が認められた.神経鞘腫や髄膜腫などの頭蓋底腫瘍を疑い, 腫瘍摘出手術を施行した.確定診断のため, 術中迅速検査が施行された.材料より凍結切片の組織標本と圧挫による細胞診標本を作成した.凍結組織標本では大小不同のみられる核と広い細胞質をもつ細胞が, 一部に偽ロゼット様構造をもちシート状増殖を示し, 良性・悪性および病理診断に苦慮したが, 同時に施行した圧挫細胞診標本では線維血管を軸とした乳頭状構造が明瞭で, 核異型, 核クロマチン増量は乏しく, 乳頭型髄膜腫と術中報告をした.永久組織標本では腫瘍細胞が線維血管周囲に乳頭状に増殖する所見が明瞭で, 免疫染色ではEMA陽性, GFAP陰性で, 最終診断は乳頭型髄膜腫とした.結語:術中迅速診断において, 人工的修飾が加わりにくい圧挫細胞診は組織検査の補助診断として有用である.

To reveal interaction between boron coating film and energetic hydrogen isotopes, chemical states of deuterium implanted into the boron coating films deposited on graphite by using DC glow discharge in a diborane diluted helium have been studied. The XPS measurements showed the possibility of the formation of B–D and C–D bonds by D2+ ion implantation. The TDS experiments indicated that deuterium desorption took place in two stages, which were attributed to the desorption processes from the trapping sites of B–D and C–D bonds. The results of the XPS measurements after D2+ ion implantation revealed that the peak areas of the B–D and C–D bonds began to decrease at 310 and 473 K and the peaks almost disappeared at 873 and 1073 K, respectively. These results suggest that the trapping site of the B–D bond is largely influenced by thermal annealing effects compared with that of the C–D bond.

The in situ measurements of hardness and X-ray diffraction have been performed at high temperature for Fe–Cr–W steels. The effect of tungsten concentration was investigated by comparing Fe–9Cr–2W–V–Ta steel and Fe–9Cr–3W–V–Ta steel. The tungsten addition increases hardness below 873 K. An aging test for 3600 s at 873 and 1073 K showed no clear change of hardness. A structural change from bcc to fcc and tungsten carbide coarsening are observed by X-ray diffractometry.

The present fusion program of Japan is based on the ''Third Phase Basic Program of Fusion Research and Development,'' determined by the Japan Atomic Energy Commission in 1992. This paper describes the Third Phase Basic Program and the overview of the relevant present research status.

A three-month-old girl weighing 4.2 kg, diagnosed with transposition of the great arteries (TGA) and ventricular septal defect (VSD) was referred to us. She had normal-sized pulmonary annulus and moderate pulmonary regurgitation. Because her pulmonary valve was not suitable for systemic circulation due to valvular incompetence, the half-turned truncal switch operation was selected. The postoperative course was uneventful without left or right ventricular outflow obstructions over a year of follow-up. Our report demonstrated that the TGA and VSD with normal pulmonary annulus is not contraindicated for half-turned truncal switch operation.

Fenestration-related massive aortic regurgitation is rare. The underlying mechanism is reported to be rupture of the fenestrated fibrous strand, and most ruptured cords have been reported in the bicuspid valve or in the right coronary cusp of the tricuspid aortic valve. We encountered a rare case of acute aortic regurgitation due to fibrous strand rupture in the fenestrated left coronary cusp. Preoperative echocardiography detected left coronary cusp prolapse, and operative findings revealed rupture of a fibrous strand in the left coronary cusp. For cases such as this, preoperative echocardiography would be useful for appropriate diagnosis.

Cardiopulmonary bypass (CPB) elicits a systemic inflammatory response. Our previous reports revealed that prophylactic sivelestat administration at CPB initiation suppresses the postoperative acute inflammatory response due to CPB in pediatric cardiac surgery. The purpose of this study was to compare the effects of sivelestat administration before CPB and at CPB initiation in patients undergoing pediatric open-heart surgery. Twenty consecutive patients weighing 5-10 kg and undergoing ventricular septal defect closure with CPB were divided into pre-CPB (n = 10) and control (n = 10) groups. Patients in the pre-CPB group received a 24 h continuous intravenous infusion of 0.2 mg/kg/h sivelestat starting at the induction of anesthesia and an additional 0.1 mg/100 mL during CPB priming. Patients in the control group received a 24-h continuous intravenous infusion of 0.2 mg/kg/h sivelestat starting at the commencement of CPB. Blood samples were tested. Clinical variables including blood loss, water balance, systemic vascular resistance index, and the ratio between partial pressure of oxygen and fraction of inspired oxygen (P/F ratio) were assessed. White blood cell count and neutrophil count as well as C-reactive protein levels were significantly lower in the pre-CPB group according to repeated two-way analysis of variance, whereas platelet count was significantly higher. During CPB, mixed venous oxygen saturation remained significantly higher and lactate levels lower in the pre-CPB group. Postoperative alanine aminotransferase and blood urea nitrogen levels were significantly lower in the pre-CPB group than in the control group. The P/F ratio was significantly higher in the pre-CPB group than in the control group. Fluid load requirement was significantly lower in the pre-CPB group.Administration of sivelestat before CPB initiation is more effective than administration at initiation for the suppression of inflammatory responses due to CPB in pediatric open-heart surgery, with this effect being confirmed by clinical evidence.

Direct measurements of localized electric fields have been made by the laser induced fluorescence (LIF) method using the Stark effect in the central cathode core region of an inertial electrostatic confinement fusion (IECF) neutron (proton) source. These are expected to have various applications, such as luggage security inspection, non-destructive testing, land mine detection and positron emitter production for cancer detection, currently producing continuously about 107 n/s D-D neutrons. Since 1967, when the first fusion reaction was successfully proved to have taken place in a very compact IECF device, potential well formation due to the space charge associated with spherically converging ion beams has been a central key issue remaining to be clarified in beam-beam collision fusion, which is the major mechanism of the IECF neutron source. Many experiments, although indirect, have been done so far to clarify the nature of the potential well, but none of them has produced definitive evidence. The results found by the present LIF method show a double well potential profile with a slight dip for ion beams with relatively larger angular momenta, whereas for ions with smaller angular momenta, a much steeper potential peak develops.

Performance characteristics of an inertial electrostatic confinement fusion triple-grid system are experimentally studied to provide an ample fusion reaction rate under a lower-gas-pressure region to make the operation free from glow discharge restrictions between the discharge voltage, current, and gas pressure. With a filament to provide sufficient electrons, the operating gas pressure is found to reduce down to 1/5 for the same discharge current and voltage. Although the gas pressure region that was achieved still remains the region where the fusion reaction between the ion beam and background gas is dominant, the neutron yield normalized by the gas pressure in the triple-grid system shows higher value than the conventional single-grid system.

The effects of beam convergence on the fusion reaction rate in the cylindrical inertial electrostatic confinement fusion device are investigated using a two-dimensional simulation code and experiments. It is found from the simulation that the fusion reaction rate increases significantly with an increase of beam convergence; therefore, there is an increase of ion densities at the center region. In the experiments designed to confirm these results using different electrode shapes, the effects of the anode shape are clearly observed.

Strongly localized electric fields were measured in the central cathode helium plasma core region of an inertial electrostatic confinement fusion device by using laser-induced fluorescence (LIF) by the degree of polarization and by the longitudinal alignment methods. Both results show double well potential formation with a slight concave at the center in excellent agreement. The decay time of the excited states is found to indicate least effects by the collisions to ensure the LIF method.

Possibility of helical device as a high current electron source by utilizing a new method of runaway electrons extraction has been investigated. Magnetic force lines of the helical system with extraction coils and electron orbits in the given magnetic configuration have been calculated to design an experimental device for demonstrate electrons extracting from the helical device. Numerical results show it can be made.

Simultaneous measurements of neutrons and protons were carried out to identify D-D fusion reactions in an Inertial-Electrostatic Confinement Fusion (IECF) device, which is theoretically expected to produce D-D protons and neutrons in a dense plasma core at the center. Experimental results showed an excellent agreement of a measured proton energy with the predicted one, and a strong linear correlation between neutron and proton yields, both indicating conclusively D-D fusion reactions in the IECF device. It is also found, through comparison between neutron and collimated proton yields, that more than 98 % of the fusion reactions take place outside the central core region under the present experimental conditions.

Effects of electrode shape on fusion reaction rate in the cylindrical IECF device are investigated by the experiments to verify simulation results. The effects of the cylindrical edge of anodes are clearly observed, but the effect of cathode length and radius is not clear in the preliminary experiments. The maximum neutron generation rate of ∼47 thousand neutrons per second is obtained with 37.5kV, 6mA discharge using an anode with 40-mm depth edge.

Strongly localized electric fields were measured in the central cathode He plasma core region of an Inertial-Electrostatic Confinement Fusion (IECF) device by using the laser-induced fluorescence (LIF) method as well as plasma core diameter to examine their correlations. It was found that the FWHM of plasma core diameter increases slightly with the increasing ion beam perveance. Comparison of the intensity profile of the plasma core is made with that of the electric quadrupole moment (QDP) component. For the cases of potential profiles with one peak, the peak positions show good correspondence with each other, while the profiles themselves are vastly different to each other.

The large helical device (LHD) is the largest heliotron type superconducting device. Its operation was started on 31 March 1998. Three experimental campaigns have been completed until the end of 1999. Wall conditioning mainly by cleaning discharges using ECRF or glow discharges worked well even without high temperature baking. The plasma production with ECRH and auxiliary heating with NBI and/or ICRF in the LHD configuration equipped with open helical divertor were well performed. The divertor material was SS316L in the first and second campaigns, and was replaced by the graphite in the third campaign. The influences of the different divertor materials were investigated. Our understanding of the edge and the divertor plasma has progressed. Long-pulse discharges 80 and 68 s heated by NBI (0.5 MW) or ICRF (0.9 MW) have been achieved, respectively. No severe limitation of the duration has appeared.

The first and second experimental campaigns in large helical device (LHD) were carried out from March to December 1998. Before the each campaign, the material probes were placed at the inner wall of vacuum vessel along the poloidal direction. After each campaign, change of surface morphology, impurity depth profile and gas desorption of the samples were examined. In the first experimental campaign, the ECR discharge cleanings were employed. After the first experimental campaign, the surface was modified by the deposition of sub-micron particles, and the concentrations such as oxygen and carbon were still high. Impurity gas desorption was also large in the sample at the port. In the second experimental campaign, the glow discharge cleanings were employed and the number of main discharge shots increased. After the second experimental campaign, no significant deposition took place except for the position close to the divertor leg, and the oxygen impurity level was reduced. In every sample, the helium was retained by the helium glow discharge. In addition, the amount of gas desorption was considerably reduced even in the sample at the port. In the second experimental campaign, the wall conditionings largely progressed by using the glow discharge cleanings and the increase of main discharge shots with a high heating power.

In the large helical device (LHD) radiation profiles measured using arrays of resistive metal, foil bolometers are used to investigate the change in radiation resulting from a replacement of stainless steel divertor plates with graphite tiles between the second and third experimental campaigns. In particular, for the magnetic configuration of R axis = 3.6 m and at line averaged densities below 3 x 10 19 m 3 , a reduction of the radiated power fraction from 35% in the second campaign to down to 12% in third campaign was observed. Comparing similar shots (in terms of discharge parameters) from the second and third cycles the core (0 < r/a < 0.79) radiation fraction was reduced from 44% to 30% of the total radiation. Spectroscopic measurements show a corresponding decrease in radiation from iron. Comparing long pulse discharges the radiated power fraction reduced from greater than 67% during the density limiting oscillation observed in the second campaign to 20% during the third campaign with a reduction in the respective core radiation fractions from 63% to 37%.

Japanese fusion program emphasizes development of fusion as a candidate of an innovative future energy source, and the ITER project is regarded as the core program in the current strategy. Extensive program review is currently performed to make a decision on the next phase activity of ITER toward construction, and some committees are reporting the results of their assessment. Major decision will be made within a year. Fusion program is also important from the aspect of basic study of science, practical application of advanced technology, and education. Alternative confinement studies and broad range of fusion related technical activities are performed under the overall fusion policy in Japan. One of the highlight is the successful initial operation of superconducting helical device, LHD. Large tokamak JT-60 plan a major modification to equip superconducting magnets in near future. Technology development is focused on blanket research and material study. As a whole, Japanese program encompasses power reactor development through ITER, and contribution to the international society by its research activity on science and technology.

Effects of beam convergence on fusion reaction rate in the cylindrical IECF device are investigated using 2-D simulation code by changing electrode shape. Simple simulation well reproduces experimentally obtained dependences of neutron production rate vs. discharge voltage and current, and it is found that almost all reactions occur by beam-background gases collisions, not beam-beam collisions. Results show that fusion reaction rate increases significantly with increase of beam convergence, therefore, increase of ion densities in the center, even in the devices where beam-background gas collision is dominate.

This study examines numerical analysis of particle velocity and temperature distribution of struck material surface in fine particle peening. When the particle is accelerated using a direct-pressure type, the velocity of a 50 μm particle, just before striking the metal surface, was calculated to be 222 m/s. In applying air pressure, the acceleration of fine particles show significant increase compared to larger sizes. Moreover, the experimental values agree well with the calculated ones. On the other hand, the temperature distributions show the maximum surface temperature to be 1500 K and cools instantly.

The neutral beam (NB) shine-through profile is routinely monitored on the Large Helical Device (LHD) both to calibrate the port-through power of the NB and to evaluate the NB-deposition power to LHD plasmas. The profile is measured with a calorimeter (CM) array on an armor plate of the NB counter wall inside the LHD vacuum vessel. An infrared camera is also used to check the beam profile where CMs are not located, and measures a temperature increase of the armor plate due to the NB heat load. The measured beam profile is compared to the calculated NB profile at the armor plate. The measurement indicates that the beam is not uniform at the exit of the ion source and that the steering angle of the beam in the horizontal direction is not the same as the designed value. It is found that the monitoring of the NB shine-through profile is important to estimate the NB port-through power and the NB deposition power, especially when the neutral beam injector (NBI) is based on a large negative-hydrogen ion source.

Characterization of a weld joint of a Fe–Cr–W ferritic steel (JLF-1) has been carried out in comparison with heat-treated specimens. The heat-treatment was carried out to simulate heating history effects of the base metal (BM), the heat-affected zone (HAZ) and the weld metal (WM) of the joint. Change in X-ray diffraction patterns and hardness of the weld joint and the heat-treated samples are compared and discussed. The results of X-ray diffractometry and the hardness measurements suggest that phase transformation should occur around the heat-treatment temperature of 820–830°C, and that the transformation does not necessarily cause hardening. Although the hardness of the HAZ changes with the distance from fusion line, the internal strain and the residual stress do not change significantly throughout the HAZ. The single heat-treatment test seems insufficient to correlate directly to the HAZ of the weld joint, because repeated heating with different maximum temperatures and different cooling rates would have been applied to the HAZ.

Conceptual design of a tritium breeding blanket for CREST-1 was conducted. CREST-1 (Compact REversed Shear Tokamak), a conceptual design of water-cooled commercial reactor based on a reversed shear high beta equilibrium, has been proposed as a possible scenario to an economical and feasible reactor succeeding the ITER project. In the present design study, a possibility of cost competitive fusion power plants with water-cooled concept, which has much experience in nuclear power plants, was examined. The new blanket design is based on the low activation ferritic steel components and an advanced super-heated steam cycle, which is used to realize a high thermal efficiency. High value of the thermal efficiency is very effective for reduction of the cost of electricity. On designing the blanket, allowable temperature range of the structure material, low activation ferritic steel is assumed to be 350–900 K with an expectation of the material research and development. Mixture of lithium oxide pebbles and beryllium pebbles is installed in the breeding zone for high tritium breeding ratio and high thermal conductivity of the breeding zone. Mixture ratio of beryllium and lithium-6 enrichment were optimized from viewpoints of temperature distribution in the breeding zone, achievable tritium breeding ratio and its reduction due to burn up. The designed blanket system has approximately 1.4 of local tritium breeding ratio with a 1.0 mm thickness of zirconium plate which is placed at 24 cm from the plasma surface as a conducting shell for kink stabilization. Arrangements of cooling channels and breeding zones and flow rate and inlet temperature of the coolant were also optimized to keep the temperatures of structure materials, breeding materials and coolant in the allowable range. The first wall is cooled by pressurized water at about 570 K. The coolant out of cooling channels of the first wall is lead to those of breeding zone and starts partially boiling. The steam is super-heated up to 750 K in the blanket. This high temperature raises the thermal efficiency of turbine to 41%. Our cost assessment has shown that CREST-1 generates about 1.16 GWe electric power within a competitive COE range.

The compact reversed shear tokamak CREST is a cost competitive reactor concept based on a reversed shear high β plasma and water cooled ferritic steel components. The moderate aspect ratio A = 3.4 and the elongation κ = 2.0 of CREST are very similar to the case of the ITER advanced mode plasma. Presentation of such a concept based on the ITER project should be worth while for formulating a fusion development strategy. The achievement of a competitive cost of electricity (COE) is the first priority for electric power industries. High β and high thermal efficiency are the most effective parameters for achieving a competitive COE. In order to achieve a high efficiency power plant, a superheated steam cycle has been adopted which permits a high thermal efficiency (η = 41%). Current profile control and high speed plasma rotation by neutral beam current drive stabilize the ideal MHD activity up to the Troyon coefficient βN = 5.5. A cost assessment has shown that CREST could generate about 1.16 GW(e) electric power at a competitive cost.

This study examines the effect of hybrid surface modification by vacuum carburizing and fine particle peening on fatigue strength behaviors of SCM 415 material. We used quenched vacuum carburized and hybrid, vacuum carburized and fine particle peened, specimen made of SCM 415 and measured their hardness distribution, mechanical properties, fatigue strength and crack propagation. In terms of the fatigue behaviors, we investigated the relationship between the crack propagation rate da/dN and stress intensity factor range △K, da/dN and effective stress intensity factor range △Keff, as well as the fatigue crack initiation life Ni and crack failure life Nf of specimens. The results show specimens with hybird surface modification are effective in the prevention of fatigue crack initiation and fatigue crack propagation.

The effect of oxygen contamination on hydrogen absorption and desorption behavior from a boron coating film has been studied. Oxygen atoms were implanted by glow discharge in an O2/He gas mixture until near saturation, into the boron film deposited by PCVD. The depth profile measurement by AES showed that O atoms were retained up to the depth of 20 nm. Hydrogen discharges were carried out to investigate the H absorption behavior. The capability of H absorption decreased for 30–50% compared to the pure boron film without O contamination. After the discharge, the depth profile of the oxygen atoms was not changed, which means that a stable oxide layer had formed. The reduction of the H absorption capability occurs probably because the formation of the boron oxide prevents H atoms from trapping in the form of B–H bonding. Most of the retained H atoms can be released by a heating up to 500°C with the O contamination. The required temperature for H evacuation is slightly higher than that for pure boron film. In addition, a small peak was observed at around 200°C. From these results, the applicability of boronization to future long term discharges was discussed, in which the boron film saturates with O contamination.

A thin boron film is attractive as a deuterium/tritium free wall, and as a protecting layer against impact of energetic charge-exchange neutrals in future fusion devices with long pulse operation. New experimental evidence is given for desorption of hydrogen isotopes from these films at relatively low temperature. Most hydrogen atoms in a boron-coated layer are re-emitted to the plasma side below 400°C without penetration into the substrate of stainless steel. The maintainability of a thin boron layer during a long pulse operation may be a problem. Boron atoms are hardly removed by pumping because their hydrides are easily disintegrated and redeposited. Gross migration of boron atoms inside the vessel is a concern. A condition required for avoiding the migration is discussed.

The LHD experiment has just begun. A scenario is presented for LHD divertor experiments. It includes development of LHD divertor components particularly efficient pumping system, local island divertor as a closed pumped divertor, simultaneous achievement of H-mode and radiative cooling (SHC operation) as an H-mode approach in the helical device, high temperature divertor plasma operation for enhancement of the energy confinement.

Fe–Cr–W ferritic steels are candidate low activation materials for fusion reactor structural components. Under a surveillance test program of the Japanese low activation Fe–9Cr–2WVTa steel (JLF-1), JLF-1-HEAT2 was made by Japanese universities. The present paper reports the results of microstructural observation and hardness testing of JLF-1-HEAT2 and its weld joint. The relation of microstructure with local hardness and tensile properties at various positions on the weld joint was investigated, and the correlation qualitatively interpreted in terms of the martensitic lath width.

We designed a volumetric neutron source for testing large-scale blanket components, based on a steady-state tokamak device with superconducting coils. It is found that a neutron flux of approximately 1.0 MW m −2 is available in the medium-size device ( R =4.5 m, a =1.0 m, κ =1.8, I p =5.6 MA) under the conditions of H ∼2 and β N ∼3 with a neutral beam injection (NBI) power of about 60 MW. We demonstrate the controllability of the current profiles required for high-beta plasma up to β N =3–3.8 with the combination of bootstrap current and NB-driven current ( E b =1.0 MeV). If an advanced performance scenario such as a reversed shear configuration is available, a neutron flux of 1.4 MW m −2 is achievable. We install the breeding blanket of Li–Pb only at outboard and upper regions, and find that a local tritium breeding ratio (TBR) of 1.5 is achievable and a net TBR of 0.8 could be available. The analysis of shielding materials at the inboard region shows that the proper combination of tungsten, steel and boric water yields a reduction of the nuclear irradiation of TF coil by a factor of approximately 10.