Vol.08,

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The low aspect ratio Tokamak is proposed for the driver of a transmutation reactor. The main parameters of the reactor core, neutronic analysis of the blanket are given. The neutron wall loading can be lowered from the magnitude order of 1 MW/m² to 0.5 MW/m² which is much easier to reach in the near future, and the transmutation efficiency (fission/absorption ratio) is raised further. The blanket power density is about 200 MW/m³ which is not difficult to deal with. The key components such as diverter and center conductor post are also designed and compared with conventional Tokamak. Finally, by comparison with the other drivers such as FBR, PWR and accelerator, it can be anticipated that the low aspect ratio transmutation reactor would be one way of fusion energy applications in the near future.

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Sonoluminescence (SL) observed in the cavitation of water is explained by the Planck theory of SL that treats the bubbles as miniature masers converting the velocity of bubble collapse to electromagnetic (EM) waves at microwave (MW) frequencies. The Planck theory of SL is consistent with historical experimental data that shows MW's concurrent with SL are produced in cavitation. As the bubbles collapse, MW's are absorbed and the Planck energy accumulates through the rotation quantum state of the bubble wall molecules. A MW photoelectric effect for accumulated MW photons is identified as a new SL parameter. During ultrasonic cavitation, cold fusion on average between the D's on colliding D₂O bubble wall molecules does not occur as the Planck energy is limited to about 2 keV, but a limited number of cold fusion events with a Planck energy in excess of 10keV are possible. However, high power microwaves (HPM) pulsed to less than ~1 ns appear to be a far more efficient way of creating cold fusion in D₂O than by ultrasonic cavitation.

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Simultaneous time and space-resolved emission spectrum from a Nd: YAG laser-ablated plasma on a GaAs target has quantitative information on the generation and the propagation of species in the plasma at 1 atm or lower pressures. The experimental results show that the characteristics of the species in plasma are strongly influenced by the ambient pressure. The time-of-flight distributions of Ga atoms exhibit twin-peak structure, which can be explained by recombination process. The mean projected ranges of As⁺ ions in the atmosphere of different densities were calculated according to Ziegler' theory model and the slowing down processes of them were simulated by using a Monte Carlo simulation program TRIM90. The calculated results are consistent with the experimental.

274

N,N,N'N'-tetrabutyladipicamide(TBAA) has been synthesized, and applied to the extraction of U(VI) and Th(IV) from nitric acid solutions in a diluent composed of 0.50 volume fraction 1,2,4-trimethyl benzene(TMB) and 0.50 volume fraction kerosene(OK). The effects of the aqueous nitric acid concentration, extractant concentration, salting-out agent (LiNO₃) and temperature on extraction ability of TBAA for U(VI) and Th(IV) have been studied. Back extraction of U(VI) and Th(IV) from organic phases were performed by dilute nitric acid. The compositions of extracted complexes, equilibrium constants and enthalpies of extraction reactions have also been estimated. The IR spectra of extraction of U(VI) and Th(IV) have been studied.

426

Mutation induction by low energy heavy ions was scored at the hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus using both normal human fibroblasts and the human-hamster hybrid A_L cells. In addition, the mutation yield at a non-essential chromosome was also examined by using the S1 marker gene locating on human chromosome 11 in A_L cells. Mutagenicity induced by low energy heavy ions was dose and LET dependent. The induced mutant fractions at the S1 locus were consistently higher than those for HGPRT. Using a mutation system that can detect multilocus changes, it can be shown by either Southern blotting or multiplex PCR techniques that radiation can induce chromosomal deletions in the millions of basepairs.

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Uniformly ¹⁵N -labelled ryegrass was used to investigateNH4+ -production, microbial transformation and humification of organic N in two types of red soils by incubating the soils amended with labelled material. The results showed that there was little significant difference in biomass N transformation in the tested soils between ¹⁵N tracer method and conventional method, but the amount ofNH4+ -N from ryegrass measured with ¹⁵N method was significantly higher than that measured with conventional method. The results also indicated that there was moreNH4+ -N released from the ryegrass in the clayey soil than in the sandy soil at all sampling time. By 120 d of incubation, humified N was less than 10% of the amount of the applied N in two types of red soils and the amount of residual N in the clayey red soil was obviously higher than that in the sandy red soil.

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The fitted equations to describe the retentions of α radiator ²³⁵U and β¹⁴⁷Pm as well as γ¹³⁴Cs were obtained respectively. The half life component of ²³⁵U is the longest, T_1/2=197d; of ¹⁴⁷Pm is shorter, T_1/2=76 d; and of ¹³⁴Cs is the shortest, T_1/2=5.1 d. For the rates of sperm abnormality induced by 1 cGy cumulative absorption dose the ratio of reproductive toxicity is α:β:γ =28:3:1. For the frequencies of chromosome aberrations in spermatogonia induced by 1 cGy cumulative absorption dose, the ratio of reproductive toxicity is α:β:γ=29:4:1. In the general, reproductive toxicity of α radiator ²³⁵U is the biggest, next β¹⁴⁷Pm, finally γ¹³⁴Cs.

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