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In this study, creep-fatigue (CF) tests on F82H at 823 K were conducted according to the standard specimen and requirement of ASTM. Tension holding (TH) showed higher lifetime than compression holding (CH). Compared with 9Cr-1Mo-V steels, CF lifetime degradation was not observed at the holding time less than 0.05 h in case of CH and 0.17 h in case of TH. CF damages were summarized from the CF test results by Campbell method. The obtained damages distributed around CF damage envelope of Grade 91 in ASME NH. CF damage of cylindrical water-cooled ceramic breeder (WCCB) test blanket module (TBM) container at the zenith of hemisphere body under the ITER thermo-mechanical load was calculated. The calculated damage located within of the damage envelope of Grade 91. It was indicated that the present design of cylindrical WCCB TBM might resist CF interaction under the ITER thermo-mechanical load conditions.

Water cooled ceramic breeder (WCCB) blankets have been regarded as a primary concept in Japan. We in-vestigated the tritium breeding capability of a WCCB blanket with a cylindrical structure, an advantageous shapefor withstanding high coolant pressure, in this study. The breeding area in the blanket was modeled as ahomogeneous mixture or heterogeneous structures. Nuclear analyses with Monte Carlo method were conductedfor evaluating the tritium breeding ratio (TBR) of the blanket. The neutron balance of the blanket was analyzedto elucidate the mechanism related to the increase in TBR when an additional thin breeding layer (envelope) wasapplied to the blanket. The neutron multiplication in (n, 2n) reaction increased concomitantly with increase ofthe beryllium volume ratio. However, numerous neutrons were not used efficiently for tritium production, butwere captured by the container, which was made of the reduced activation ferritic martensitic steel, F82H.Capture by the container can be reduced by introducing an envelope. The effect of the envelope was considerablewhen modeling the internal structure such as U-shaped pipes in the breeding area. The envelope was also appliedto a blanket with different container designs. An increase in TBR was shown irrespective of blanket design. Theenvelope effect was remarkable when it was difficult to achieve the internal configuration, which was equivalentto the homogeneous mixture in the breeding area

A water-cooled ceramic breeder blanket has been developed. Heat flux and coolant pressure are applied to the first wall of the blanket in a fusion reactor. A square cooling channel is adopted in the first wall in Quantum and Radiological Science and Technology (QST). This study specifically addressed the relation between the thermal mechanical responses with different cooling channel shapes and the allowable load of the first wall. Thermal mechanical responses of the first wall were evaluated using finite element method (FEM). Based on those results, the allowable loads for the structural integrity of the first wall were assessed in accordance with the requirements of ASME Sec. III NH. Among the failure modes the creep-fatigue damage was the most dominant on the allowable loads of the first wall. The allowable loads were determined by characteristics of the thermal mechanical responses with the cooling channel shape. The major determinants were the surface heat flux and the coolant pressure, respectively, for the circular and the square channels.

In this study, creep-fatigue (CF) tests on F82H at 823 K were conducted according to the standard specimen and requirement of ASTM. Tension holding (TH) showed higher lifetime than compression holding (CH). Compared with 9Cr-1Mo-V steels, CF lifetime degradation was not observed at the holding time less than 0.05 h in case of CH and 0.17 h in case of TH. CF damages were summarized from the CF test results by Campbell method. The obtained damages distributed around CF damage envelope of Grade 91 in ASME NH. CF damage of cylindrical water-cooled ceramic breeder (WCCB) test blanket module (TBM) container at the zenith of hemisphere body under the ITER thermo-mechanical load was calculated. The calculated damage located within of the damage envelope of Grade 91. It was indicated that the present design of cylindrical WCCB TBM might resist CF interaction under the ITER thermo-mechanical load conditions.

The development of a water cooled ceramic breeder (WCCB) test blanket module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and development of DEMO blanket, R&D has been performed on the module fabrication technology, breeder and multiplier pebble fabrication technology, tritium production rate evaluation, as well as structural and safety design activities. The fabrication of full-scale first wall, side walls, breeder pebble bed box and back wall was completed, and assembly of TBM with box structure was successfully achieved. Development of advanced breeder and multiplier pebbles for higher chemical stability was continued for future DEMO blanket application. From the view point of TBM test result evaluation and DEMO blanket performance design, the development of the blanket tritium transport simulation technology, investigation of the TBM neutron measurement technology and the evaluation of the tritium production and recovery test using D-T neutron in the fusion neutron source (FNS) facility has been performed. This paper provides an overview of the recent achievements of the development of the WCCB Blanket in Japan.

It is known that the chemical forms of tritium released from a ceramic breeder blanket are hydrogen form and water form. To recover tritiated water vapor, adoption of dryer that is packed column of synthetic zeolite has been proposed. On the other hand, synthetic zeolite is often used as a support of precious metal catalyst. Such catalysts usually have a capability of hydrogen isotope exchange between gas and water vapor. If this catalyst is used to dryer, the dryer may obtain a preferable function for tritium recovery by isotopic exchange reaction. To assess such functions, reaction rate should be estimated. The results of water adsorption experiment on cation-exchanged mordenite-type zeolite suggested the possibility that state of adsorbed water varied by exchanged cation. So, in this work, precious metal catalyst based on cation-exchanged mordenite was prepared, and the reaction rate of chemical exchange between hydrogen and tritiated water was investigated under temperature range between 30 °C and 80 °C by the steady-state approximation. In the case of platinum on Na-mordenite, the reaction between gaseous hydrogen and tritiated water vapor was almost expressed as first-order reaction concerning tritiated water vapor concentration.

We have performed the tritium release experiment on the fusion reactor blanket at JAEA/FNS since 2009, and then clarified the ratio of tritium release and the recovered tritium chemical form. In order to acquire the detailed tritium recovery performances, we have started a new blanket tritium recovery experiment with ionization chamber (IC) at JAEA/FNS. For the appropriate tritium measurement with IC, we improved the experimental container and carried out with an intense DT neutron source at JAEA/FNS. From our new experiment, the tritium recovery radioactivity from the LSC measurement corresponds with the calculation within 6%. However, it was pointed out that further improvement in the quantitative tritium measurement by IC method was needed.

Test Blanket Systems (TBS) will be operated in ITER in order to prepare the next steps towards fusion power generation. After the initial operation in H/He plasmas, the introduction of D and T in ITER will mark the transition to nuclear operation. The significant fusion neutron production will give rise to nuclear heating and tritium breeding in the in-vessel part of the TBS. The management of the activated and tritiated structures of the TBS from operation in ITER is described. The TBS specific features like tritium breeding and power conversion at elevated temperatures, and the use of novel materials require a dedicated approach, which could be different to that needed for the other ITER equipment.

The Water Cooled Ceramic Breeder Test Blanket module (TBM) has been developed for a demonstration of the major functions under the fusion reactor environment in ITER. Testing of the TBM shall neither hinder the ITER operation, nor threaten safety of operation even at water ingress into a box structure of the TBM (In-Box Loss of Coolant Accident, In-Box LOCA). In present study, the structural responses on the TBM under In-Box LOCA were evaluated by using Finite Element Method. Based on the analysis results, the TBM design was modified. The filled region and Tritium Breeding Ratio of the modified TBM design adding the fillet with 35 mm of radius increased by up to 20%, 12%, respectively, compared to the original TBM model without fillet.

Li2TiO3 with excess Li (Li2+xTiO3+y) has been developed as an advanced tritium breeder. With respect to the tritium release characteristics of the blanket, the optimum grain size after sintering was less than 5 μm. Therefore, an emulsion method was developed to fabricate pebbles with this target grain size. The predominant factor affecting grain growth was assumed to be the presence of binder in the gel particles; this remaining binder was hypothesized to react with the excess Li, thereby generating Li2CO3, which promotes grain growth. To inhibit the generation of Li2CO3, calcined Li2+xTiO3+y pebbles were sintered under vacuum and subsequently under a 1% H2–He atmosphere. The average grain size of the sintered Li2+xTiO3+y pebbles was less than 5 μm. Furthermore, the tritium release properties of Li2+xTiO3+y pebbles were evaluated, and deuterium–tritium (DT) neutron irradiation experiments were performed at the Fusion Neutronics Source facility in the Japan Atomic Energy Agency. To remove the tritium produced by neutron irradiation, 1% H2–He purge gas was passed through the Li2+xTiO3+y pebbles. The Li2+xTiO3+y pebbles exhibited good tritium release properties, similar to those of Li2TiO3 pebbles. In particular, the released amount of tritiated hydrogen gas for easier tritium handling was greater than the released amount of tritiated water.

The accurate measurement of behavior of bred tritium released from a tritium breeder is indispensable to understand the behavior for a design of a tritium extraction system. The tritium collection method combined a CuO bed and water bubbles was not suitable to measure transient behavior of tritium released from Li2TiO3 during neutron irradiation because tritium released behavior was changed to be delayed due to adsorption of oxidized tritium on the CuO. Hence, the tritium collection method with hydrophobic catalyst instead of the CuO was demonstrated and succeeded the accurate release measurement of tritium from Li2TiO3. With the method, we assessed the behavior of tritium release under the various conditions since tritium should be released from Li2TiO3 as the form of HT as much as possible from the view point of the fuel cycle. Our results indicated; promotion of isotopic exchange reaction on the surface of Li2TiO3 by addition of hydrogen in sweep gas is mandatory in order to release tritium smoothly from Li2TiO3 irradiated with neutrons; the favorable sweep gas to release as the form of HT was hydrogen added inert gas; and the temperature of Li2TiO3 was the dominant parameter to control the chemical form of tritium released from the Li2TiO3.

Damage cause and mechanism of the tungsten specimen under ELM-like heat pulse were examined by using a Nd:YAG laser experiment assuming the ITER divertor allowable heat load, 0.5 MJ/m2 and finite-element analysis in terms of thermal mechanical response. The thermal stress distribution with the heat load area was compared by FEM and the stress distribution by a Nd:YAG laser corresponded to that expected in the actual divertor target. The crack growth direction was changed from a perpendicular to parallel and this was caused by the thermal stress distribution in isotropic microstructure under ELM-like heat pulse. In addition the change of crack growth direction caused the deterioration of thermal conduction near the surface and it led to the local surface melting near cracks even at 0.51 MJ/m2 with 3000 heat load cycles.

A Water-Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) System is being developed as one of the most important steps toward DEMO blanket in Japan. As for the ITER-TBM program, the conceptual design of WCCB-TBM system has been approved by the ITER organization (IO). And two years have already passed after the start of the preliminary design activity. WCCB TBM Team had a concern about TBM box structure withstanding over 15 MPa of the coolant pressure, and decided to change the design as the result of study on structural integrity. Recently, the design change of the TBM structure has been approved domestically. So, WCCB TBM Team has applied the design change to the IO, and agreed with the IO to receive the conceptual design review which is limited the scope to the TBM structure. This paper provides an overview of the recent achievements of the development of the WCCB Test Blanket Module System in Japan.

In test blanket module (TBM) program blanket major functions, which are tritium production, heat extraction for electric power production, and neutron shielding, will be demonstrated under fusion reactor environments in ITER. National Institutes for Quantum and Radiological Science and Technology (QST) has performed developments of water cooled ceramic breeder (WCCB) TBM as a primary concept in Japan. The container design of WCCB TBM was changed from the Box-shaped to a cylindrical structure to increase tritium breeding capability while maintaining pressure resistance under In-Box LOCA caused by water ingress into the container. The nuclear responses related to the blanket major functions would be changed with the container design change. The nuclear responses of WCCB TBM with the container design change were evaluated and the effects of the changed nuclear responses were described in this study. Tritium production rate increased by about 2 times with the container design changes. In contrast neutron shielding performance decreased due to the container design change. Degradation of neutron shielding in the cylindrical TBM led to an increase in nuclear heating of the TBM frame as well as an average of neuron flux behind TBM-set.

In this study, electromagnetic analyses of cylindrical water-cooled ceramic breeder test blanket module under the three types of ITER plasma disruption scenarios were conducted. Highest Lorentz force (LF) along radial direction was observed under plasma disruption scenario of MD-II. Symmetrical LF along two-eight o'clock position was observed in side wall (SW) of container and could be canceled in summation. Integrated LF of a container was mainly contributed by first wall and rear part of SW. Compared with previous design of box-shaped container, lower magnitude of LF was shown in current design of cylindrical container, which was mainly understood by difference in the volume of the solid structure. Maxwell force (MF) was additionally evaluated considering the ferromagnetic characteristic of F82H. Magnitude and distribution of MF was much higher than LF. Besides connection structure, the structural integrity of container should be taken into account when ferromagnetic characteristics were considered.

The temperature of Li 2 TiO 3 pebble breeder in a fusion DEMO blanket is assumed to be more than 1000 K. For the investigation of tritium release from a Li 2 TiO 3 pebble breeder blanket at such a high temperature, we have carried out a tritium release experiment with the DT neutron source at the JAEA-FNS. The Li 2 TiO 3 pebble (1.0–1.2 mm in diameter) of 70 g was put into a stainless steel container and installed into an assembly stratified with beryllium and Li 2 TiO 3 layers. During the DT neutron irradiation, the temperature was kept at 1073 K with wire heaters in the blanket container. Helium gas including 1% hydrogen gas (H 2 /He) mainly flowed inside the container as the purge gas. Two chemical forms, HT and HTO, of extracted tritium were separately collected during the DT neutron irradiation by using water bubblers and CuO bed. The tritium activity in the water bubbler was measured by a liquid scintillation counter. To investigate the effect of moisture in the purge gas, we also performed the same experiments with H 2 O/He gas (H 2 O content: 1%) or pure helium gas. From our experiment at 1073 K, in the case of the purge gas includes H 2 , it is indicated that the increasing tendency of HT release is similar to that of the dry H 2 /He.

Activities on Broader Approach (BA) were started in 2007. In Phase 2-2, many R&Ds, development of tritium accountancy technology, development of basic tritium safety research and tritium durability test, were implemented successfully by JAEA and Japanese Universities. In Phase 2-3, new collaborative study for tritium measurement and new R&D activities for JET ILW are started. R&D activities on BA have continued in Phase 2-3 (2014–2016).

It is revealed that binding position of fatty acid in triacylglycerol (TAG) deeply relates to the expression of its function. Therefore, we investigated the binding positions of individual trans-octadecenoic acid (trans-C18:1) positional isomers, known as unhealthy fatty acids, on TAG in partially hydrogenated canola oil (PHCO), milk fat (MF), and beef tallow (BT). The analysis was carried out by the sn-1(3)-selective transesterification of Candida antarctica Lipase B and by using a highly polar ionic liquid capillary column for gas chromatography-flame ionization detection. Trans-9-C18:1, the major trans-C18:1 positional isomer, was selectively located at the sn-2 position of TAG in PHCO, although considerable amounts of trans-9-C18:1 were also esterified at the sn-1(3) position. Meanwhile, trans-11-C18:1, the major isomer in MF and BT, was preferentially located at the sn-1(3) position. These results revealed that the binding position of trans-C18:1 positional isomer varies between various fats and oils.

Trans fatty acids (TFA) are considered risk factors for cardiovascular disease (CVD), while the details of distribution and metabolism of the individual isomers are not clear. Here we investigated the accumulation and catabolic rate of TFA positional isomers of octadecenoic acid (18:1) in mice. ICR mice were fed deuterium- and [1-(13)C] stable isotope-labeled trans-9-18:1 (9t-18:1*), trans-10-18:1 (10t-18:1*), or trans-11-18:1 (11t-18:1*) for 2 or 4 weeks, or a TFA mixture (9t-18:1*, 10t-18:1*, and 11t-18:1*) for 3 weeks. Analysis of whole-body tissues by gas chromatography-chemical ionization mass spectrometry revealed the highest 9t-18:1* levels in the heart. Significant differences in the accumulation of the respective trans-18:1 were observed in the heart and erythrocytes, where 9t- > 11t- > 10t-18:1*, but no significant difference was observed in the liver or white adipose tissue (WAT). Mice fed on 11t-18:1 demonstrated accumulation of endogenously synthesized conjugated linoleic acid in the liver, WAT, and heart, but any other metabolites were not found in other groups. Furthermore, we analyzed catabolic rates of single-dose-administered trans-18:1* isomers into [(13)C]-labeled CO2 using isotope-ratio mass spectrometry, and the 10t-18:1*catabolic rate was significantly higher than those of 9t- and 11t-18:1*. We found that the accumulation and catabolism of trans-18:1 positional isomers varied in these mice. Differential accumulation in tissues suggests that individual TFA positional isomers may play different roles in human health.

Since the current financial reporting uses various measurement attributes for measuring assets and liabilities, it is often referred to as the “mixed measurement model.” This paper addresses the issues related to why and how different measurement attributes, notably fair value and historical cost, are used in financial statements. The cost-benefit analysis is adopted as a research methodology throughout this paper by formalizing as mathematical functions the preparer’s measurement cost and the users’ benefits of accounting information that the preparer produces. The cost-benefit analysis suggests that the mixed measurement model can be justified through the preparer’s economic incentives for minimizing cost. It also suggests that the cost-minimization solution in the marketplace would represent a consensus among the interests of the preparer and the users within a constraint in which only one set of accounting information is provided. This paper also identifies the situations in which providing two sets of accounting information is preferable.

Behavior of tritium transfer through hydrophobic paints of epoxy and acrylic-silicon resin was investigated experimentally. The amounts of tritium permeating through their paint membranes were measured under the HTO concentration condition of 2–96 Bq/cm 3 . Most of tritium permeated through the paints as a molecular form of HTO at room temperature. The rate of tritium permeating through the acrylic-silicon paint was correlated in terms of a linear sorption/release model, and that through the epoxy paint was controlled by a diffusion model. Although effective diffusivity estimated by a diffusion model was obtained 1.1 × 10 −13 –1.8 × 10 −13 m 2 /s for epoxy membranes at the temperature of 21–26 °C, its value was found to be hundreds times larger than that for cement-paste coated with epoxy paint. Hence, resistance of tritium diffusion through interface between cement-paste and the epoxy paint was considered to be the most effective in the overall tritium transfer process. Clarification of tritium transfer behavior at the interface is important to understand the mechanism of tritium transfer in concrete walls coated with various paints.

Japan Atomic Energy Agency (JAEA) is performing the development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) as one of the most important steps toward DEMO blanket. Regarding the blanket module fabrication technology development using F82H, the fabrication of a real scale mockup of the back wall of TBM was completed. In the design activity of the TBM, electromagnetic analysis under plasma disruption events and thermo-mechanical analysis under steady state and transient state of tokamak operation have been performed and showed bright prospect toward design justification. Regarding the development of advanced breeder and multiplier pebbles for DEMO blanket, fabrication technology development of Li rich Li2TiO3 pebble and BeTi pebble was performed. Regarding the research activity on the evaluation of tritium generation performance, the evaluation of tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been performed. This paper overviews the recent achievements of the development of the WCCB Blanket in JAEA.

The Li2TiO3 is one of candidate breeding materials of a water cooled ceramic breeding (WCCB) blanket. In order to clarify the tritium recovery property of the WCCB blanket with the Li2TiO3 breeding material, we have performed the tritium recovery online experiment with the DT neutron source at the Fusion Neutronics Source facility in Japan Atomic Energy Agency (JAEA-FNS). We irradiated an experimental assembly simulating the WCCB blanket and recovered the tritium recovered from the Li2TiO3 pebbles put into the assembly with a heater system, sweep gases and bubblers. The activity of the recovered tritium was measured with a liquid scintillation counter. From our tritium recovery online experiment and calculation, the followings were found out: (1) the recovered tritium corresponded to the calculated tritium production within the experimental error in the range of 573–1073 K and (2) the recovered HTO tended to be easily recovered at lower temperature and high water moisture. The recovered HT increases at higher temperature and dry hydrogen circumstance. However, the maximum level of the tritium gas recovery is around 90% even at higher temperature and 1% H2 circumstance.

Tritium recovery system using adsorption or catalytic isotope exchange has already been proposed for a solid breeding blanket system of a nuclear fusion reactor. Synthetic zeolite is often used as an adsorbent or a substrate of chemical exchange catalyst. And, it is well known that its property is changed easily by exchanging its cations. Synthetic mordenite is one of zeolites having fairly large silica/alumina ratio. There are many reports about hydrogen adsorption properties of cation-exchanged mordenite so far. And, the present authors also have reported that cation-exchanged mordenite with Ca ion (Ca–MOR) indicated fairly large hydrogen adsorption capacity at 77 K in comparison with Molecular Sieves 5A (MS5A). So, in this work, hydrogen adsorption properties of cation-exchanged mordenite with transition metal ion were investigated mainly. The cation-exchanged mordenite with Ag ion (Ag–MOR) has indicated considerably large hydrogen adsorption capacity in lower pressure range at 77 K in comparison with Ca–MOR. The discussion from the viewpoint of adsorption rate is still remaining, but more compact cryosorption column for tritium recovery system is possible to design if Ag–MOR is adopted.

Thalidomide (TM) induces limb defects in humans and some animal species including rabbits. Although the mechanism of TM-induced limb defects has been investigated for a long period, the limb development-related genes expressions have not been vigorously characterized in rabbits. In this study, we investigated the Fgf8, Bmp4 and Hoxa11 expressions in TM-treated JW rabbit embryos on gestation days (GDs) 10, 11 and 12 by whole mount in situ hybridization. On GDs 10 and 11, growth retardation of the embryo was induced by TM treatment. The Fgf8 expression lengths on GDs 10 and 11 in the forelimb bud were significantly or tended to be decreased in the TM-treated embryos, which was correlated to the growth retardation and was not considered to be directly relevant to the teratogenic effect of TM in the forelimb. The TM-induced characteristic changes in the expression pattern of Hoxa11 and Bmp4 on GDs 10 and/or 11 were not noted. On GD 12, TM-induced growth retardation was not noted and the Fgf8 and Bmp4 expressions were not changed. On the contrary, Hoxa11 expression was narrowed at the anterior region, which was located on the radial side, and was not changed at the middle and posterior regions in the forelimb bud and in all regions in the hindlimb bud. Because the radius malformations were induced by TM treatment, we concluded the decrease in the Hoxa11 expression was related to the TM-induced limb defects and can be a good marker for early prediction of the teratogenic effect of TM.

The effects of thalidomide on the embryo-fetal development (EFD) of rabbit fetuses and the sensitive periods (SP) for the various malformations were compared between Kbl:JW and Kbl:NZW rabbits to investigate possible strain differences. The post-implantation loss rate and number of placental remnants were increased and the number of live fetuses was decreased in both of the strains in the EFD study and in Kbl:NZW at 300 mg/kg dosed on GD 7-8 in the SP study. In the external and skeletal examinations, head, limb and tail malformations were observed in both the strains in the EFD and SP studies at the same dose levels in the same dosing period. In the visceral examination, hydrocephaly, cardiovascular malformations, absent pulmonary intermedial lobe, diaphragmatic hernia and/or abnormal liver lobation were also observed in both of the strains in the EFD and SP studies at the same dose levels and in the same dosing period. Plasma concentrations of thalidomide were equivalent between the two strains in the SP study. There were strain differences in some parameters, such as the post-implantation loss rate and the frequencies of malformations in forelimb and hindlimb and pulmonary intermedial lobe, but similar types of malformations or variations were induced at the same dose levels on the same dosing period in both strains. Therefore, it is concluded that there were no essential differences in sensitivity of the fetuses to thalidomide between Kbl:JW and NZW rabbits and both of the strains are useful to evaluate the teratogenic effects of thalidomide.

The multi-purpose RI facility has been constructed at Rokkasho site in DEMO R&D building until 2011. The facility is the first and quite unique facility in Japan, where tritium, beta and gamma RI species, and beryllium (Be) can simultaneously be used. The amounts of tritium used and stored are 3.7 TBq per glove box and 7.4 TBq, respectively. Some tritium water samples of 38 GBq has been stored at the equipment on March 2012. The material of the column of the micro gas chromatograph has been studied to develop a real time analysis tool for the hydrogen isotope composition in gas phase. The calorimeter has also been studied as a possible tritium measurement method in solid waste. A set of basic data on the interaction between materials and tritium has been measured by various methods. The behavior of tritium in Fe and W has been studied as a typical subject. As a study for the tritium durability, the endurance of ion exchange membrane has been tested by using high concentration tritium water. The curves of strength vs. dose for the Nafion membranes in tritium water were well consistent with those by gamma rays and electron beams irradiations.

Hydrogen isotope separation is important process in fusion reactor. Cryosorption is one of the methods for hydrogen isotope separation, and is often employed to gas chromatograph (GC) for hydrogen isotope analysis. Synthetic zeolite is used as the packing material of separation column for GC. And, it is well known that the retention time becomes long at 77 K. A zeolite having good separation capability at higher temperature may bring short retention time with good sensitivity. Mordenite type zeolite (MOR) in which cation was exchanged has been reported having comparatively good isotope separation capability. The present authors have investigated adsorption capacity of hydrogen isotope on cation-exchanged MORs at various temperatures. And, it has been shown that MOR with Ca 2+ as exchanged cation (Ca-MOR) has fairly large adsorption capacity. In this work, the breakthrough curves of hydrogen adsorption on Ca-MOR at 194, 175 K have been observed, and mass transfer coefficients or effective diffusivity in Ca-MOR particle have been estimated. The rate-controlling step is the diffusion process in the adsorbent particle. The isotope effect on hydrogen diffusion in Ca-MOR particle is larger than raw material (Na-MOR). Therefore, Ca-MOR is more suitable for the separation column than Na-MOR.

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. In Japan, fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. Important key technologies are almost clarified for the fabrication of the real scale TBM module mockup. From the view point of testing and evaluation, development of the technology of the blanket tritium recovery, development of advanced breeder and multiplier pebbles and the development of the blanket neutronics measurement technology are also performed. Also, tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been started as the verification test of tritium production performance. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.

In a fusion reactor, the prediction of tritium release behavior from breeder blanket is important to design the tritium recovery system, but the amount of tritium generated is necessary information to do that. Hence, tritium generation and recovery studies on lithium ceramics packed bed have been started by using fusion neutron source (FNS) in Japan Atomic Energy Agency (JAEA). Lithium titanate (Li 2 TiO 3 ) was selected as tritium breeding material, and its packed bed was enclosed by the beryllium blocks, and was kept at certain temperature during fusion neutron irradiation. During irradiation, the packed bed was purged with the sweep gas continuously, and tritium released was trapped in each gas absorber selectively by chemical form. In this work, the effect of sweep gas species on tritium release behavior was investigated. In the case of sweep by helium with 1% of hydrogen, tritium in water form was released sensitively corresponding to the irradiation. This is due to existence of the water vapor in the sweep gas. On the other hand, in the case of sweep by helium without water vapor, tritium in gaseous form was released first, and release of tritium in water form was delayed from gaseous tritium and was gradually increased.

In JAEA, the tritium processing and handling technologies have been studied at TPL (Tritium Process Laboratory). The main RD the basic tritium behavior in confinement materials; and detritiation and decontamination. The R&D activities on tritium processing and handling technologies for a demonstration reactor (DEMO) are also planned to be carried out in the broader approach (BA) program by JAEA with Japanese universities. The ceramic proton conductor has been studied as a possible tritium processing method for the blanket system. The BIXS method has also been studied as a monitoring of tritium in the blanket system. The hydrogen transfer behavior from water to metal has been studied as a function of temperature. As for the behavior of high concentration tritium water, it was observed that the formation of the oxidized layer was prevented by the presence of tritium in water (0.23 GBq/cc). A new hydrophobic catalyst has been developed for the conversion of tritium to water. The catalyst could convert tritium to water at room temperature. A new Nafion membrane has also been developed by gamma ray irradiation to get the strong durability for tritium.

Electrochemical hydrogen pump can extract hydrogen isotopes selectively from a blanket sweep gas, because one of its driving forces of hydrogen transportation is electric potential difference. In this work, transportation properties of multi-component hydrogen isotopes including tritium were investigated experimentally. Ceramic proton conductor membrane used in this work was SrCe 0.95 Yb 0.05 O 3− α made by TYK Co. H 2 –D 2 mixture balanced with He was supplied to the hydrogen pump, that was kept at 873 K and applied the voltage between 0 and 1000 mV, and the permeated gas was analyzed with a gas chromatograph. The rate-determining step of hydrogen transfer via ceramic membrane seems to be close to the diffusion step in the bulk of ceramic with increase of the applied voltage. HT–H 2 mixture balanced with He was also supplied to the hydrogen pump, and recovery of tritium via ceramic membrane was done. Diffusivity of hydrogen in the proton conductor ceramic is larger than that of tritium. Hence, hydrogen is enriched in the gas of the permeation side. In this experimental condition, about 40% of tritium supplied was recovered and the decontamination factor was 1.5.

The RD (2) basic tritium safety research; and (3) tritium durability test. The EU joins the discussions and assessment of the R&D results. As the recent activities on the tritium technologies of the BA program, a multi-purpose RI facility, where the above R&D subjects will be carried out, has been designed in detail. A preliminary safety study has also been carried out for the amount of tritium released to the environment and for the radiation dose of workers. The facility is now under construction at Rokkasho in Aomori. The main subjects of the R&D of tritium analysis are the technologies for real-time analysis for hydrogen isotopes, gas, liquid and solid (such as microGC and calorimeter). The materials of interest include F82H, SiC, ZrCo, solid and liquid advanced breeder and multipliers. In the tritium durability tests, organic materials and metals planned to be used in a DEMO plant are studied for the radiation and the corrosion damage. A series of preliminary studies for the above subjects has been started.

PIWI-interacting RNAs (piRNAs) protect genome integrity from transposons. In Drosophila ovarian somas, primary piRNAs are produced and loaded onto Piwi. Here, we describe roles for the cytoplasmic Yb body components Armitage and Yb in somatic primary piRNA biogenesis. Armitage binds to Piwi and is required for localizing Piwi into Yb bodies. Without Armitage or Yb, Piwi is freed from the piRNAs and does not enter the nucleus. Thus, piRNA loading is required for Piwi nuclear entry. We propose that a functional Piwi–piRNA complex is formed and inspected in Yb bodies before its nuclear entry to exert transposon silencing.

At Tritium Process Laboratory (TPL) of Japan Atomic Energy Agency (JAEA), tritium technologies for a fusion reactor have been carried out up to date. The design studies of Air Detrtiation and Vent Detritiation System (ADS/VDS) of ITER have been carried out in JAEA as a contribution of Japan to ITER. For the tritium processing technologies, our efforts have been focused on the R&D of the tritium recovery system of ITER test blanket system. A ceramic proton conductor has been studied as an advanced blanket system. A series of fundamental studies on tritium safety technologies for ITER and for fusion DEMO plants has also been carried out. The main R&D activities in this field are the tritium behavior in a confinement and its barrier materials, monitoring, accountancy, detritiation and decontamination, etc. Especially, for the fundamental studies for a DEMO plants, a part of the studies will be carries out a new facility at Rokkasho in Aomori in the Broader Approach (BA) program in coming 10 years. For this purpose, a design study of the facility at Rokkasho has first been started.

A gas chromatography using a cryogenic separation column is one of the methods for hydrogen isotope analysis. However, the use of the refrigerant such as liquid nitrogen is the cause of long analysis time and is not suitable for easy installation. The development of the column material having separation capability at comparatively high temperature region is one of the solutions for these weak points. Mordenite (MOR) is a kind of a zeolite, and it has been reported that the separation column using MOR has possibility to separate hydrogen isotope mixture at comparatively high temperature. In this work, the separation columns using MOR were made and tested. The peaks of H2 and D2 were mostly separated at 144 K, but they were not separated at 195 K. MOR column adjusted in this work was still not for the practical use. However, this result suggests the possibility of the existence of the synthetic zeolite that can separate hydrogen isotope mixture at comparatively high temperature.

RNA silencing is a conserved mechanism in which small RNAs trigger various forms of sequence-specific gene silencing by guiding Argonaute complexes to target RNAs by means of base pairing. RNA silencing is thought to have evolved as a form of nucleic-acid-based immunity to inactivate viruses and transposable elements. Although the activity of transposable elements in animals has been thought largely to be restricted to the germ line, recent studies have shown that they may also actively transpose in somatic cells, creating somatic mosaicism in animals. In the Drosophila germ line, Piwi-interacting RNAs arise from repetitive intergenic elements including retrotransposons by a Dicer-independent pathway and function through the Piwi subfamily of Argonautes to ensure silencing of retrotransposons. Here we show that, in cultured Drosophila S2 cells, Argonaute 2 (AGO2), an AGO subfamily member of Argonautes, associates with endogenous small RNAs of 20-22 nucleotides in length, which we have collectively named endogenous short interfering RNAs (esiRNAs). esiRNAs can be divided into two groups: one that mainly corresponds to a subset of retrotransposons, and the other that arises from stem-loop structures. esiRNAs are produced in a Dicer-2-dependent manner from distinctive genomic loci, are modified at their 3' ends and can direct AGO2 to cleave target RNAs. Mutations in Dicer-2 caused an increase in retrotransposon transcripts. Together, our findings indicate that different types of small RNAs and Argonautes are used to repress retrotransposons in germline and somatic cells in Drosophila.

Electrochemical hydrogen pump with ceramic proton conductor membrane has been proposed to apply for a blanket tritium recovery system (BTR) of a fusion reactor. The advantage of this system is that it can apply to the system of low hydrogen pressure, because the driving force of hydrogen permeation is the electric potential difference. Perovskite-type ceramic such as SrCe0.95Yb0.05O3−α (SCO) is one of the candidates of membrane. To apply hydrogen pump to BTR, the enhancement of the hydrogen transportation capability is necessary. Modification of electrode is one of the methods to enhance the hydrogen transportation capability. In this work, the electrodes of platinum (Pt) and palladium (Pd) were attached to the SCO sample by the sputtering method (sputtering electrode), and its electric conductivity and proton conductivity were measured. Then, they were compared with that of the usual Pt paste electrode. Hydrogen transportation capability was enhanced when the sputtering electrode was applied. Especially, in case of the Pd sputtering electrode, the current density which was about 4 or 5 times larger than the usual Pt paste electrode was observed at 0.1% of H2 concentration.

In a fusion reactor system, a monitoring of hydrogen isotopes including tritium is necessary for the safety of system control and operation. A gas chromatography using a cryogenic separation column is one of the methods for hydrogen isotope analysis. Synthesis zeolite such as molecular sieve 5A (CaA) is a candidate material of the separation column, and its property varies by the ratio of silica to alumina, the kinds of cation and so on. If the factor affected the hydrogen adsorption property of the synthesis zeolite is clarified, it may lead to the development of the new zeolite optimized to the separation column. So, in this work, adsorption capacity of hydrogen (H2) and deuterium (D2) for mordenite (MOR) and NaY type zeolite (NaY) were investigated at various temperatures, and were compared with CaA. The amount of adsorption per unit weight of MOR was larger than that of CaA, and that of NaY was smaller than that of CaA. The adsorption isotherms were expressed by sum of two Langmuir equations, and the Langmuir coefficients of H2 and D2 were proposed. Furthermore, the Langmuir coefficients of HD, HT, DT and T2 were estimated by the reduced mass. The correlation between the adsorption properties and the physical parameters of the zeolite were not confirmed.

In Drosophila , repeat-associated small interfering RNAs (rasiRNAs) are produced in the germ line by a Dicer-independent pathway and function through the PIWI subfamily of Argonautes to ensure silencing of retrotransposons. We sequenced small RNAs associated with the PIWI subfamily member AGO3. Although other members of PIWI, Aubergine (Aub) and Piwi, associated with rasiRNAs derived mainly from the antisense strand of retrotransposons, AGO3-associated rasiRNAs arose mainly from the sense strand. Aub- and Piwi-associated rasiRNAs showed a strong preference for uracil at their 5′ ends, and AGO3-associated rasiRNAs showed a strong preference for adenine at nucleotide 10. Comparisons between AGO3- and Aub-associated rasiRNAs revealed pairs of rasiRNAs showing complementarities in their first 10 nucleotides. Aub and AGO3 exhibited Slicer activity in vitro. These data support a model in which formation of a 5′ terminus within rasiRNA precursors is guided by rasiRNAs originating from transcripts of the other strand in concert with the Slicer activity of PIWI.

The blanket tritium recovery system using the electrochemical hydrogen pump with proton conductor membrane has been proposed. The feature of the electrochemical hydrogen pump is that the driving force of hydrogen transportation is a potential difference. Therefore, it might be effective to apply the hydrogen pump to the blanket sweep gas (the low hydrogen and water vapor pressure). Perovskite-type ceramic such as SrCe 0.95 Yb 0.05 O 3− α , is one of the candidate proton conductor for hydrogen pump and its ionic hydrogen transportation properties have been investigated. In this work, the basic mass transfer equation for hydrogen, in which the apparent proton conductivity is used as the over-all mass transfer coefficient, is proposed. And then, the apparent proton conductivities were estimated from experimental data using these equations, and mass transfer of hydrogen via proton conductor membrane was discussed by using the apparent conductivity.

Automation is an important issue in industry, particularly in inspection of underground facilities. This paper describes an intelligent system for automatically detecting faulty areas in a sewer pipe system based on images. The proposed system can detect various types of faults and be implemented in a real time system. The present paper describes system architecture and focuses on two modules of image preprocessing and detection of faulty areas. The proposed approach demonstrates high performance in detection and reduction of time and cost.

Trans fatty acids (TFA) are considered risk factors for cardiovascular disease (CVD), while the details of distribution and metabolism of the individual isomers are not clear. Here we investigated the accumulation and catabolic rate of TFA positional isomers of octadecenoic acid (18:1) in mice. ICR mice were fed deuterium- and [1-(13)C] stable isotope-labeled trans-9-18:1 (9t-18:1*), trans-10-18:1 (10t-18:1*), or trans-11-18:1 (11t-18:1*) for 2 or 4 weeks, or a TFA mixture (9t-18:1*, 10t-18:1*, and 11t-18:1*) for 3 weeks. Analysis of whole-body tissues by gas chromatography-chemical ionization mass spectrometry revealed the highest 9t-18:1* levels in the heart. Significant differences in the accumulation of the respective trans-18:1 were observed in the heart and erythrocytes, where 9t-11t-10t-18:1*, but no significant difference was observed in the liver or white adipose tissue (WAT). Mice fed on 11t-18:1 demonstrated accumulation of endogenously synthesized conjugated linoleic acid in the liver, WAT, and heart, but any other metabolites were not found in other groups. Furthermore, we analyzed catabolic rates of single-dose-administered trans-18:1* isomers into [(13)C]-labeled CO2 using isotope-ratio mass spectrometry, and the 10t-18:1*catabolic rate was significantly higher than those of 9t- and 11t-18:1*. We found that the accumulation and catabolism of trans-18:1 positional isomers varied in these mice. Differential accumulation in tissues suggests that individual TFA positional isomers may play different roles in human health.

In Drosophila, Piwi (P-element-induced wimpy testis), which encodes a protein of the Argonaute family, is essential for germ stem cell self-renewal. Piwi has recently been shown to be a nuclear protein involved in gene silencing of retrotransposons and controlling their mobilization in the male germline. However, little is known about the molecular mechanisms of Piwi-dependent gene silencing. Here we show that endogenous Piwi immunopurified from ovary specifically associates with small RNAs of 25–29 nucleotides in length. Piwi-associated small RNAs were identified by cloning and sequencing as repeat-associated small interfering RNAs (rasiRNAs) derived from repetitive regions, such as retrotransposon and heterochromatic regions, in the Drosophila genome. Northern blot analyses revealed that in vivo Piwi does not associate with microRNAs (miRNAs) and that guide siRNA was not loaded onto Piwi when siRNA duplex was added to ovary lysate. In vitro, recombinant Piwi exhibits target RNA cleavage activity. These data together imply that Piwi functions in nuclear RNA silencing as Slicer by associating specifically with rasiRNAs originating from repetitive targets.