Showing papers by "Japan Atomic Energy Research Institute published in 1985"
TL;DR: In this article, the effects of electron beam irradiation on ten kinds of polymers containing various aromatic rings linked by functional groups in the main chain (aromatic polymer) were studied with reference to change in tensile properties.
95 citations
TL;DR: A new type of adsorbent containing amidoxime groups for the recovery of uranium from seawater was synthesized by the radiation-induced graft polymerization of acrylonitrile onto polymeric fiber followed by amidoximation with hydroxylamine as mentioned in this paper.
Abstract: A new type of adsorbent containing amidoxime groups for the recovery of uranium from seawater was synthesized by the radiation-induced graft polymerization of acrylonitrile onto polymeric fiber followed by amidoximation with hydroxylamine. When amidoxime groups were introduced superficially on the fiber, the amount of uranium adsorbed by the amidoxime groups was higher than that with the amidoxime groups introduced homogeneously in the fiber. The introduction of the poly(acrylic acid) chain and the increase in temperature and flow rate in the adsorption process were effective in increasing the amount of adsorbed uranium. Although alkali metals and alkaline earth metals were found in the adsorbent, the concentration factors for these metals were less than 1/103 of that for uranium. The present adsorbent had a high stability to various treatments such as contact with alkali and seawater.
78 citations
TL;DR: In this paper, a fibrous adsorbent for metal ions was synthesized by radiation-induced grafting of acrylonitrile followed by amidoximation of cyano groups with hydroxylamine.
Abstract: Amidoxime-group-containing fibrous adsorbents for metal ions were synthesized by radiation-induced grafting of acrylonitrile followed by amidoximation of cyano groups with hydroxylamine. The degree of amidoximation and the distribution of amidoxime groups in the fiber were follwed by means of electron probe X-ray microanalysis. The efficiency of adsorbing metal ions was increased by alkaline treatment of the adsorbent at high temperature for a short period before use. The order of adsorption for various bivalent metal ions was Hg > Cu > Ni > Co > Cd. From the distribution pattern of metal ions in the fibrous adsorbent, the adsorption was found to be controlled by the diffusion of the solution containing metal ions inside the adsorbent. It was found that confining amidoxime groups superficially and making short chain length of grafts were effective to obtain a high degree of adsorption.
70 citations
TL;DR: In this paper, experiments were carried out on DNB (Departure from Nucleate Boiling) heat flux for both upflow and downflow in a rectangular vertical channel simulating a subchannel in the fuel element of the research reactor JRR-3, which is scheduled to be upgraded with 20% low enriched uranium (LEU) fuel.
Abstract: Experiments were carried out on DNB (Departure from Nucleate Boiling) heat flux for both upflow and downflow in a rectangular vertical channel simulating a subchannel in the fuel element of the research reactor JRR-3, which is scheduled to be upgraded at 20MWt with 20% low enriched uranium (LEU) fuel. The experiments were carried out for the conditions of pressure and velocity which are important for the safety design of the JRR-3. With the investigation of the data of the present experiment along with already existing data for both rectangular channels and other channels, a scheme of DNB heat flux correlations was obtained for upflow and downflow. With the all available data, the errors of the correlations adopted in this scheme were so evaluated as to utilize these results in the safety analysis of the JRR-3. This scheme includes a new correlation of DNB heat flux for upflow and the identification of a region of high coolant flow rate where no remarkable differences in the DNB heat flux are observed bet...
61 citations
TL;DR: In this article, the dynamic mechanical relaxation of non-crystalline poly(aryl ether-ether-ketone) PEEK and the one irradiated with electron beam were studied and it was revealed from the study on the irradiation effects that three different molecular processes are overlapped in γ relaxation peak, i.e., molecular motion of water bound to main chain (peak temperature; at −100°C), local motion of main chain, and local mode of the aligned and/or oriented moiety (at −40°C).
54 citations
TL;DR: Preparation de deux oligomeres par polycondensation de l'acide DL-lactique sans amorceur de Des-Gly-[D-Leu]-LH-RH ethylamide.
Abstract: Preparation de deux oligomeres par polycondensation de l'acide DL-lactique sans amorceur. Liberation controlee de Des-Gly-[D-Leu]-LH-RH ethylamide
51 citations
TL;DR: In this article, a spin-lattice relaxation with nuclear magnetic resonance and ionic conductivity was used to measure the ionic properties of a solid breeder material under irradiation.
51 citations
TL;DR: In this paper, the stored energy release spectra have been measured using the linear-rise method for pyrolytic graphite samples, neutron-irradiated to a fluence of 4 × 10 17 n/cm 2 at about 80°C.
47 citations
TL;DR: In this article, surface chemical states were studied for Zr and Nb metals exposed to 8-keV hydrogen molecular ions, and X-ray photo-emission spectroscopy (XPS) measurements revealed that chemical shifts of the binding energies for the ion-implanted Zr from the metallic states are 0.6-1.4 eV, consistent with the core-line shifts for thermally synthesized NbH.
Abstract: Surface chemical states were studied for Zr and Nb metals exposed to 8-keV hydrogen molecular ions. X-ray photoemission spectroscopy (XPS) measurements revealed that chemical shifts of the binding energies for the ion-implanted Zr from the metallic states are 0.6--1.4 eV, consistent with the core-line shifts for thermally synthesized ${\mathrm{ZrH}}_{1.64}$. In the case of the ion-implanted Nb, the corresponding shifts are 0.6--0.8 eV, in good agreement with those for thermally synthesized ${\mathrm{NbH}}_{0.86}$. On the other hand, the ion implantation provided XPS spectra with a distinct photopeak attributable to a metal 4d--H 1s bond near the Fermi level, 3.4 eV for Zr and 4.6 eV for Nb, respectively. The peak positions are \ensuremath{\sim}2.5 eV lower than those calculated previously for the dihydrides. The photopeaks grew upon thermal annealing to 610 \ifmmode^\circ\else\textdegree\fi{}C. The observations are discussed in relation with the peculiarity of hydrogen sites in the crystal lattice and partial recovery of the ion-induced surface damage.
45 citations
TL;DR: The magnetic susceptibility of UO 2 ThO 2 solid solutions has been measured from room temperature to 2.0 K in this article, and the magnetic moment and the Weiss constant have been determined in the temperature range in which the Curie-Weiss law holds.
44 citations
TL;DR: In this paper, the Suzuki-Trotter formula has been used to get the mth approximant to the classical representation of the partition function of the one-dimensional N-spin 5+ quantum spin systems.
Abstract: , ' The Suzuki-Trotter formula has been used to get the mth approximant to the classical representation of the partition function of the one-dimensional N-spin 5=+ quantum spin systems. The equivalent two-dimensional (NX2m) Ising model with four-spin interactions has been studied in detail by using the numerically exact transfer-matrix method for T;;;;O.05 and m~8. The convergence properties have been examined in two different representations; checkerboard decomposition (CBD) and real-space decomposition (RSD). The spin correlation functions in RSD converge much faster than those in CBD. The limiting m --+ 00 behavior has been estimated from the extrapolation formula of the form: E( m) = E( 00 ) +a/m 2 • The limiting values of the energy derived from the nearest-neighbor correlation agree with: the correct values excellently.
TL;DR: In this article, the diffusivity of tritium was studied as a function of the degree of the preferred orientation utilizing pyrolytic carbons deposited on alumina substrates.
TL;DR: In this paper, the authors derived the first region of stability for n = ∞ ballooning modes in advanced-shaped tokamaks and showed that Dee or bean shapes with sharply tipped cross-sections are more favorable for achieving high beta values than those with round-tip crosssections having nearly the same safety factor profile.
Abstract: Numerical studies of the beta limit in the first region of stability for n = ∞ ballooning modes in advanced-shaped tokamaks are presented. A higher beta value than corresponds to the present conventional beta scaling is expected for advanced-shaped tokamaks with sufficient triangularity/indentation. Extremely elongated configurations without appropriate triangularity do not lead to an increase in critical beta. Dee or bean shapes with sharply tipped cross-sections are more favourable for achieving high beta values than those with round-tip cross-sections having nearly the same safety factor profile. A new beta scaling for elongated ellipse, Dee- and bean-shaped tokamaks is derived.
TL;DR: The chemical fate of tritium produced by the 6Li(n, α)T reaction in Li2O has been studied in this paper, with the emphasis on the thermal release behavior of the trite.
TL;DR: In this article, a Doublet III 2.4 MW neutral-beam-heated limiter discharge at a line-averaged density of 1 × 1014 cm−3 was compared to a conventional gas-fuelled plasma at similar density.
Abstract: A centrifuge injector that repetitively fires 1.3 mm deuterium pellets (1 torr⋅L per pellet) at a rate of 32 pellets per second was used to build up and maintain a Doublet III 2.4 MW neutral-beam-heated limiter discharge at a line-averaged density of 1 × 1014 cm−3. When compared to a conventional gas-fuelled plasma at similar density, the pellet-fuelled plasma was characterized by a factor-of-three reduction in edge neutral density and limiter recycling, a centrally peaked profile, a 70% increase in global energy confinement, and a tenfold increase in the fusion reaction rate.
TL;DR: Gamma-ray exposure buildup factors are calculated using a discrete ordinates direct integration code, PALLAS-PL, SP-Br, for water, concrete, iron, and lead for point isotropic sources as discussed by the authors.
Abstract: Gamma-ray exposure buildup factors are calculated using a discrete ordinates direct integration code, PALLAS-PL, SP-Br, for water, concrete, iron, and lead for point isotropic sources. These data i...
TL;DR: In this paper, the degree of degradation by γ-ray and electron beam irradiations of homopolypropylene, copolypropylene and polymethylpentene were compared, and chemiluminescence (CL) of irradiated polymers were measured.
Abstract: In relation to sterilization of medical supplies, the degree of degradation by γ-ray and electron beam irradiations of homopolypropylene (HP), copolypropylene (CP, coplymer including 6% of ethylene unit) and polymethylpentene were compared, and chemiluminescence (CL) of irradiated polymers were measured. HP degraded extremely around the sterilization dose (2.5 Mrad) by either γ-ray or electron beam irradiations. In the case of CP and polymethylpentene, stabilities of polymers far differed between γ-ray and electron beam irradiations. The polymethylpentene was more stable than the polypropylenes against irradiation. The counts of CL emitted by recombination of peroxy radical (ROO ·) increased with increasing dose, reflecting degrees of oxidation of polymers. The degradation of polymers was independent of irradiation sources, rather it depended on the degree of oxidation. It was found that CL analysis are favorable for estimation of degradation in irradiated polymers.
TL;DR: The recent progress on the research field of immobilization of biocomponent mainly by means of radiation-induced polymerization is reviewed in this paper, where the characteristics of the technique and some results of application such as drug delivery system and cell culture are described.
TL;DR: In this article, the differences in the single-phase forced-convection heat transfer characteristics between upflow and downflow were investigated experimentally with a narrow vertical rectangular channel, which is simulating a subchannel of 2.25 mm in gap and 750 mm in length in the fuel element of the research reactor, JRR-3.
Abstract: The differences in the single-phase forced-convection heat transfer characteristics between upflow and downflow were investigated experimentally with a narrow vertical rectangular channel. The objectives of the experiment were to investigate in both laminar and turbulent flow regions the applicability of existing correlations to and the effects of buoyant force on the heat transfer characteristics in the narrow vertical rectangular channel, which is simulating a subchannel of 2.25 mm in gap and 750 mm in length in the fuel element of the research reactor, JRR-3 to be upgraded at 20 MWt. As the results, it was revealed that (1) by use of equivalent hydraulic diameter, existing correlations are applicable to a channel as narrow as 2.25 mm in gap for turbulent flow though the precision and critical Reynolds number are different among the correlations, and (2) in the laminar flow, the difference in heat transfer characteristics arises between upflow and downflow with Reynolds number less than about 700 and Gr...
TL;DR: In this paper, the equilibrium pressure of hydrogen and deuterium over titanium (420-970°C), zirconium (480-940°C) and hafnium (445-635°C") was measured in the pressure range from 0.013 to 133 Pa.
TL;DR: In this paper, the conductivity of a sintered pellet of Li 8 ZrO 6 was measured in dry or wet argon atmosphere by the two-terminal technique with an AC Wheatstone bridge in the temperature range 350-1050 K.
Abstract: Single crystals of monoclinic Tl 2 ZnI 4 were grown, and dielectric properties were measured. The crystal exhibits ferroelectricity below the Curie temperature of 209 K where the dielectric constant along the b -direction shows a λ-type maximum with the peak value of about 530. The spontaneous polarization at 180 K is about 1.2×10 -2 C m -2 .
TL;DR: In this paper, single crystals of Rb 2 CoCl 4 and CoX 4 were grown from melt, and dielectric constants were measured along the three crystallographic axes down to liquid helium temperature.
Abstract: Single crystals of Rb 2 CoCl 4 and Rb 2 CoBr 4 were grown from melt, and dielectric constants were measured along the three crystallographic axes down to liquid helium temperature. Below the ferroelectric Curie temperature T c ( T c =192 K for Rb 2 CoCl 4 and 180 K for Rb 2 CoBr 4 ) there are one phase transition at 66 K in Rb 2 CoCl 4 and two transitions at 95 K and 65 K in Rb 2 CoBr 4 . Dielectric anomalies at these low temperature transitions in Rb 2 CoX 4 (X: Cl, Br) are quite similar to those in the corresponding Rb 2 ZnX 4 crystals.
TL;DR: A ceramic electrolysis cell and a palladium diffuser have been developed in Japan and tested with tritium at the Tritium Systems Test Assembly (TSTA) at the Los Alamos National Laboratory, to test their feasibility as possible upgrades for the fuel cleanup system (FCU).
Abstract: A ceramic electrolysis cell and a palladium diffuser have been developed in Japan and tested with tritium at the Tritium Systems Test Assembly (TSTA) at the Los Alamos National Laboratory, to test their feasibility as possible upgrades for the fuel cleanup system (FCU). The ceramic electrolysis cell, made of stabilized zirconia, was operated at 630/sup 0/C for an extended period with a mixture of 3% T/sub 2/O in He carrier gas in a circulation system with an oxidizing catalyst bed. The palladium diffuser was tested with pure tritium gas, circulated at 280/sup 0/C, to verify the compatibility of the alloy with tritium, since the /sup 3/He produced in the metal could cause degradation. The isotopic effects were also measured for both devices.
TL;DR: In this paper, phase relations and defect structures were studied in a PrO1.5-UO2-O2 ternary system in the temperature range from 1200 to 1500°C.
TL;DR: In this article, an optical absorption technique was used to study the irradiation defects in lithium oxide, irradiated by oxygen ions with energies of 0.5, 0.75, 1.25 and 100 MeV.
TL;DR: In this paper, the relationship between the equilibrium hydrogen pressure and the hydrogen concentration in liquid Li17Pb83 was carried out by a hot-extraction method, using specimens of about 10 g. The relationship was valid and its constant ( Ks = √P /XH) was obtained as 2.9 × 103 √atm on average.
TL;DR: Effectiveness and usefulness of the STP analysis is suggested not only as a noise analysis technique but also as a tool for reactor diagnosis.
TL;DR: In this paper, the authors developed a new type plasma CVD (TP-CVD method) for molybdenum and a new HCD-ARE method for Inconel 625 which could successfully reduce the deposition temperature to 900°C and 500°C, respectively.
TL;DR: In this article, a technique of combined thermal desorption and chemical treatment with corrosive solutions was used to decontaminate Type 316 stainless steel surfaces exposed to gaseous tritium.