Publications

The design studies of Atmosphere Detirtiation System (ADS) have been carried out in Japan Atomic Energy Agency (JAEA) as a contribution of Japan to ITER. The performance of ADS has also been investigated under accidental conditions such as fire and co-existing of a poison gas for catalyst like SF6. There is no degradation of Detritiation Factor (DF) under co-existing of CO or CO2 up to 20% as a simulated fire condition. However, only 0.1% of SF6 degrades the DF from more than 1000 to 50, following reduction of water by SF4 etc. (decomposition products of SF6) at 773K of catalyst bed.For the tritium processing technologies, our efforts have been focused on the R & D of the tritium recovery system of breeding blanket. In case of ITER Test Blanket Module, a cryogenic molecular sieve bed system was designed and demonstrated. Furthermore, electro-chemical pumping system using a proton conductor is also investigated to design more effective system. The durability of electrolysis cell for Water Detritiation System (WDS) has been investigated and it is expected that the cell can endure more than 3 years’ operation under the ITER WDS design condition.A series of fundamental studies on tritium safety technologies has been carried out as another major activity of JAEA for ITER and future fusion demo reactors. Tritium behavior in various confinement materials, tritium monitoring & accountancy, and detritiation were studied under collaboration programs with universities, using Caisson Assembly for Tritium Safety study.

Abstract To assess the micrometeorological consequences of rice variety choices in relation to rising CO 2 associated to climate change, we quantified the interplay between rice architecture, physiology, and microclimate in current (~385 μmol mol −1 ) and future (~580 μmol mol −1 ) CO 2 microenvironments. Two rice varieties contrasting in canopy structure and physiology were grown embedded in irrigated rice paddies, under elevated CO 2 (using a Free‐Air CO 2 Enrichment facility) and ambient CO 2 conditions. The high‐yielding indica variety Takanari is more photosynthetically active and characterized by a more open canopy than a commonly cultivated variety Koshihikari . Our results show a strong diurnal interplay between solar angle, canopy structure, plant physiology, and the overlying atmosphere. Plant architecture was identified as a strong determinant of the relation between plant physiology and microclimate that in turn affects the surface forcing to the overlying atmosphere. Takanari was able to maintain lower canopy temperature both in current and future CO 2 owing to the greater atmospheric mixing and stomatal conductance than Koshihikari. In the perspective of food security, a shift to such a higher‐yielding variety would have consequences on the regional surface energy balance, which subsequently might alter regional weather.

4-Oxo-2-hexenal (4-OHE), which forms a 2′-deoxyguanosine (dG) adduct in a model lipid peroxidation system, is mutagenic in the Ames test. It is generated by the oxidation of ω-3 fatty acids and is commonly found in dietary fats, such as fish oil, perilla oil, rapeseed oil, and soybean oil. 4-OHE also forms adducts with 2′-deoxyadenosine (dA), 2′-deoxycytidine (dC), and 5-methyl-2′-deoxycytidine (5-Me-dC) in DNA. In this study, we characterized the structures of these adducts in detail. We measured the amounts of 4-OHE−DNA adducts in mouse organs by LC/MS/MS, after 4-OHE was orally administered to mice. The 4-OHE−dA, 4-OHE−dC, 4-OHE−dG, and 4-OHE−5-Me-dC adducts were detected in stomach and intestinal DNA in the range of 0.25−43.71/108 bases. After the 4-OHE administration, the amounts of these DNA adducts decreased gradually over 7 days. We also detected 4-OHE−dC in human lung DNA, in the range of 2.6−5.9/109 bases. No difference in the 4-OHE adduct levels was detected between smokers and nonsmokers. Our results suggest that 4-OHE−DNA adducts are formed by endogenous as well as environmental lipid peroxides.