金属ウラン燃料の改良, (II)

ウラン押出棒およびウラン合金の熱サイクルならびに腐食試験

抄録

In the previous study, some grain-refined uranium alloys were developed by giving some additives, heat treatments and hot rollings.
In this experiment some uranium alloys were fabricated by coreduction process, and thermal cycling tests were carried out.
Properties of γ extruded uranium rods were tested and their merits were compared with those of alloying specimens.
Corrosion tests of uranium and uranium alloys were undertaken in a temperature range of 300°600°C.
Limitation of corrosion resistivity of uranium alloys were discussed. Main results were summarized as follows:
(1) On γ extruded uranium rods, β oil quenched specimen shows the smallest growth, warp and wrinkle after the thermal cycling tests.
After oil quenching treatment, it is not necessary to be followed by α annealing procedure.
(2) Requirements to reduce thermal cycling growth by heat treatments are different in each specimen, so the appropriate heat treatments should be considered.
(3) Thermal cycling growth is also large in extremely grain-refined specimens.
(4) Weight gain of uranium alloys in oxidation by CO₂ is larger than that of metallic uranium in the temperature range above 550°C.
(5) In standpoints of grain refinement, workability, thermal cycling growth, corrosion resistivity and neutron economics, U-Nb-Mo, U-Cr-Mo and U-Zr-Mo ternary alloys are recommended as the minor additived uranium fuels.