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The effects of neutron and ion irradiations on deuterium (D) retention in tungsten (W) were investigated. Specimens of pure W were irradiated with neutrons to 0.3 dpa at around 323 K and then exposed to high-flux D plasma at 473 and 773 K. The concentration of D significantly increased by neutron irradiation and reached 0.8 at% at 473K and 0.4 at% at 773 K. Annealing tests for the specimens irradiated with 20 MeV W ions showed that the defects which play a dominant role in the trapping at high temperature were stable at least up to 973 K, while the density decreased at temperatures equal to or above 1123 K. These observations of the thermal stability of traps and the activation energy for D detrapping examined in a previous study (≈1.8 eV) indicated that the defects which contribute predominantly to trapping at 773 K were small voids. The higher concentration of trapped D at 473 K was explained by additional contributions of weaker traps. The release of trapped D was clearly enhanced by the exposure to atomic hydrogen at 473 K, though higher temperatures are more effective for using this effect for tritium removal in fusion reactors.2

Retention of D in neutron-irradiated W and desorption were examined after plasma exposure at 773 K. Deuterium was accumulated at a relatively high concentration up to a large depth of 50-100 m due to the trapping effects of defects uniformly induced in the bulk. A

The new diamide compound, N,N 0 -dimethyl-N,N 0 -diphenylpyridine-2,6dicarboxyamide (DMDPhPDA), was synthesized and the distribution ratios of lanthanides from 1 to 5 M nitric acid solutions into DMDPhPDA CHCl 3 solution were determined. The extraction mechanism of lanthanide with DMDPhPDA was discussed based on the slope analysis of acid and ligand concentration dependencies and the variation of distribution ORDER REPRINTS ratio along the lanthanides series. The number of DMDPhPDA molecules in extracted complexes increase from 3 for lighter lanthanides to 4 for heavier lanthanides. From the previous EXAFS study of a complex similar in structure, Ln(III) would form an inner-sphere complex with the two DMDPhPDA molecules and an outer-sphere complex with the third and/or fourth DMDPhPDA molecules in addition to an inner-sphere complex. Nitric acid concentration has more influence on the distribution ratio and the difference of distribution ratio among lanthanides than the ligand concentration.

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