[en] Westinghouse is currently conducting the pre-application licensing of the International Reactor Innovative and Secure (IRIS). One of the key aspects of the IRIS design is its safety-by-designTM philosophy and within this framework the PRA is being used as an integral part of the design process. The most ambitious risk-related goal for IRIS is to reduce the Emergency Planning Zone (EPZ) to within the exclusion area by demonstrating that the off-site doses are consistent with the US Protective Action Guidelines (PAGs) for initiation of emergency response so that the required protective actions would be limited to the exclusion area. As a first step, a model has been developed to provide a first order approximation of the Large Early Release Frequency (LERF) as a surrogate predictor of the off-site doses. A key-aspect of the LERF model development is the characterization of the possible paths of release. Four main categories have been historically pointed out: (1) Core Damage (CD ) sequences with containment bypass, (2) CD sequences with containment isolation failure, (3) CD sequences with containment failure at low pressure and (4) CD sequences with containment failure at high pressure. They have been reevaluated to account for the IRIS design features

[en] The growth and structure of tellurium thin films deposited simultaneously onto the (001) surface of air-cleaved NaCl, KBr and KCl at various substrate temperatures were investigated. When the substrate temperature was increased, epitaxial growth with the tellurium c axis parallel to the [110] and [11-bar0] directions of the KBr and KCl substrates was observed, whereas films deposited onto NaCl gave no evidence of epitaxial growth. The temperature for epitaxial growth was found to decrease when vacuum-cleaved KBr was used as a substrate. (Auth.)

[en] The technology for the decomposition of trace amounts of halogenated pharmaceuticals/antibiotics was developed in wastewater by use of the combination method of zeolite adsorbent and ionizing radiation. Toxicity test was conducted using a luminescence bacterium on the irradiation of aqueous solution of 2-chlorophenol (2-ClPh) as a simple model of halogenated pharmaceuticals/antibiotics. Toxicity of 2-ClPh solution increased with the increase in γ-ray dose. The toxicity after γ-ray irradiation originates only in neither 2-ClPh nor primary products, but it is thought that it is based on a synergistic effect including organic acid or aldehyde. HMOR, a hydrophobic high-silica mordenite-type zeolite, was employed to concentrate 2-ClPh on it. HMOR adsorbed above 99% of 2-ClPh from dilute aqueous solutions. The yield of Cl⁻ production in HMOR mixture corresponded to the aqueous solution containing 10 fold higher concentration of dissolved 2-ClPh. Clofibrate and triclosan, one of chlorinated pharmaceuticals/antibiotics, in real wastewater were treated by use of the combination method of HMOR and ionizing radiation. Production yield of Cl^- by use of the adsorbent was about twice higher than that in aqueous solution, and HMOR was contributed for effective reduction of chlorinated pharmaceuticals/antibiotics in real wastewater. (author)

[en] In this paper, we review the detailed study of epitaxial growth of β-FeSi₂ films by reactive deposition epitaxy (RDE), multilayer technique and molecular beam epitaxy (MBE). The p- and n-type β-FeSi₂ was formed when it was grown under an Fe-rich and an Si-rich condition, respectively. The maximum electron and hole mobilities of the β-FeSi₂ epitaxial films reached 6900 and 13000 cm²/V·s for the n- and p-type β-FeSi₂, respectively, at around 50 K. Room temperature (RT) 1.6 μm electroluminescence (EL) was realized by optimizing the growth conditions for p-Si/β-FeSi₂ particles/n-Si structures prepared by RDE for β-FeSi₂ and by MBE for Si

[en] The mechanism of demethylenation of (methylenedioxy)benzene (MDB), (methylenedioxy)amphetamine (MDA), and (methylenedioxy)methamphetamine (MDMA) by purified rabbit liver cytochrome P450IIB4 has been investigated by using deuterium isotope effects. A comparison of the magnitude and direction of the observed kinetic isotope effects indicates that the three compounds are demethylenated by different mechanisms. The different mechanisms of demethylenation have been proposed on the basis of comparisons of the observed biochemical isotope effects with the isotope effects from purely chemical systems

No abstract available

[en] By using an ultra-fast pulse radiolysis based on pulse-and-probe method, initial yields and transient behaviors of pre-solvated and solvated electrons in variety kinds of alcohols were measured. The system consists of a 22 MeV S-band electron linac and a femtosecond Ti: sapphire laser. A laser driven photocathode is installed at the linac, to which a third harmonics of the femtosecond fundamental laser (795 nm) is injected. 30% of the fundamental laser, after split by a beam splitter, is guided to a sample and used as probe light for transient absorption spectroscopy. It is possible to measure between 400 - 1100 nm by generating white light continuum using D₂O cell, while replaced by an optical parametric amplifier (TOPAS, Quantronix Co., Ltd), measurements at near infrared region (535-2600 nm) can be more efficiently done. Initial G-values (molecules/100 eV) of solvated electrons in various alcohols, n-alcohols, diols, and triols were estimated by the following processes: (i) absorption measurement of hydrated electron at 700 nm; (ii) absorption measurement of solvated electrons in alcohols, where time and wavelength were chosen appropriately for each alcohols; (iii) calculation of G-values of solvated electrons using (i) and (ii), and taking into account the initial G-value of the hydrated electron (G(e_aq) = 4.15 at 20 ps), density as well as the molar absorption coefficients of each alcohols. The results show that G-value of the solvated electrons in methanol was very close to that in water, while it gradually decreased for longer alcohols (C_nH_2n+1OH, n=1-10). G-values of diols (ethylene glycol, 1,2-propanediol, and 1,3-propanediol) seems to be systematically higher than previously reported values. Although this might be partly due to the use of disputable molar absorption coefficients, it is believed that the molecular structure should play a very important role. In spite of rather high viscosity, transient absorption at near IR implies that the solvation processes of electron in diols complete quickly. In fact, for the diols, the absorption of pre-solvation state seems to exist at lower wavelength (closer to solvation states) than n-alcohols, and the absorption at near IR by pre-solvated electron is rather small. This strongly suggests that, in diols, because of the higher concentration of OH-sites, more stable pre-solvated states (or even pre-existing trapping sites) are created. (authors)

[en] We have developed a vegetation monitoring lidar called a laser-induced fluorescence spectrum (LIFS) lidar which is able to get the living status of plants by observing their fluorescence remotely. The features of its operation are; daytime observations possible even outdoors, mobility and self-sufficiency, capability of mapping plant living information, and a user-friendly operation by unifying the controls of different equipment of the lidar using software. These features make observations by our LIFS lidar possible at any time and any place. In forest observations, we could depict three-dimensional structures of fluorescence spectrums. We also discuss in this work the possibility of monitoring other plant physiological information such as the concentration of chlorophyll and photosynthesis secondary metabolites in this work.

[en] Complete text of publication follows. Increase in the yields of H₂ production and reduction of oxidative metal ions has been reported in mixed systems of silica particles and aqueous solutions. The understanding of the mechanisms of this effect enables to control the radiation-induced reactions. Concerning this effect, radiolysis of water in the presence of silica has been studied. Little is known of the reaction leading to increase in production of H₂ or reduction of metal ions. Thus the effect of silica on radiation-induced reactions was studied by pulse-radiolysis using pulsed electron beam from LINAC at UTNL (10 ns, 10 Gy/pulse). Decay kinetics of hydrated electron and formation kinetics of Fe(CN)₆^3- produced by reaction of OH and Fe(CN)₆^4- were studied in the presence of nano-sized colloidal silica (2.5 ± 0.5 nm in diameter) prepared by hydrolysis of Si(OC₂H₅)₄. In Ar saturated water added 50 mM t-butanol as scavenger of OH radical, little change in decay kinetics of hydrated electron was observed. In the aqueous solution of K₄Fe(CN)₆ saturated by N₂O to convert hydrated electron to OH radical, decrease in absorbance of Fe(CN)₆^3- was observed as the concentration of colloidal silica increased (Figure 1). This decrease is considered to be due to the interaction of silica particles with OH radical and it competes with reaction of Fe(CN)₆^4- to reduce the yield of Fe(CN)₆^3-.

[en] In combination of a laser driven photocathode RF-gun and a femtosecond laser, a highly time-resolved pulse radiolysis system has been developed. Time resolution < 10 ps has been attained and the system has been used to determine the initial yields and time behaviors of pre-solvated and solvated electrons in variety of alcohols systematically in ps time range. (author)