Search

A drip casting process initiated to obtain zirconium castings uncontaminated by the melting process and to remove volatile impurities from the zirconium feed rod is described. A feed rod of zirconium is held above the mold, and the bottom of the rod is melted rapidly off into a mold to produce the casting. The melting process is carried out under high vacuum, so that very little atmospheric contamination can result, and some removal of volatile impurities is possible. Since no crucible is used to contain the molten metal, no contamination can result from this source. (auth)

Casting a U shield for a kilocurie Co/sup 60/ source is described. The melting equipment is described, and data on the castings are tabulated. Examination of the casting revealed no large blow holes or cracks, and the method was considered adequate. (J.R.D.)

A helix constructed of plutonium was made to test the Doppler temperature effect in ZPR-III. The helix. 1 in. in diameter and 6 1/4 in. long. contained 240 g of deltaphase plutonium alloy encapsulated in titanium tubing. rour piutonium rods were extruded, joined together, and pushed into a titanium tube. This tube was swaged tightly over the piutonium rod. and the assembly was wound into a coil. Electrical leads to the coil were made by swaging copper tubing over the ends of the coil. The helix was tested by cycling about 500 times between 50 and 190 deg C. The coil was heated with a current of 130 amperes and cooled with a blast of chilled helium. Several helices of uranium were cycled during the same tests. Despite the severity of the thermal cycles. the helices were undamaged. (auth)

A total of 35 specimens of U-Pu-fissium alloy and 2 specimens of U-10 wt% Pu-5 wt% Mo alloy were irradiated as a part of the fue1-alloy development program for fast breeder reactors at Argonne National Laboratory. Total atom burnups ranged from 1.0 to 1.8% at maximum fuel temperatures ranging from 230 to 470 deg C. Emphasis was placed on the EBR-II Core-III reference fuel material, which is an injection-cast, U-20 wt% Pu-10 wt% fissium alloy. lt was found that this material begins to swell catastrophically at irradiation temperatures above 370 deg C. The ability of the fuel to resist swelling did not appear to vary appreciably with minor changes in Zr or fissium content. Decreasing the Pu to 10 wt%, however, significantly improved the swelling behavior of the alloy. Both pourcast and thermally cycled material and pour-cast, extruded, and thermally cycled material appeared to be more stable under irradiation than injection-cast material. Under comparable irradiation conditions, the specimens of U-20 wt% Pu- 5 wt% Mo alloy were less dimensionally stable than the U-Pu-fissium alloys investigated. (auth)