Stable solutions of basic beryllium nitrate can be formed with beryllium concentrations up to 9M, and an NO3/Be mole ratio as low as 1:1. The efficiency of basic beryllium nitrate as an agent for salting out uranium into a tributylphosphate/kerosene solvent has been compared with that of other salts. It appears possible to separate uranium and thorium from beryllium and fission products using a modified Thorex process in which beryllium nitrate replaces aluminum nitrate.

A method for comparison and evaluation of thermoelastic stresses is given for a range of fuel element shapes based on parameters available from the initial study of a reactor system. The shapes studied, in descending order of stress level are circular rods, concentric tubes, flat plates, and a matrix of circular holes.

This manual gives a description, operating instructions, circuit diagram and parts list of Transistorised Temperature Controller type 30 designed in the laboratories of the Australian Atomic Energy Commission.

The matrix of a dilute homogeneous H.T.G.C. reactor fuel employing metallic beryllium as a moderator can be selectively dissolved by a caustic soda solution containing salicylate ion. At least 99 percent of the uranium and thorium can be recovered as insoluble solids, but in the case of irradiated material the uranium loss might be higher. Some decontamination of the resulting beryllium solution from fission products and Pa233 can also be obtained. A tentative chemical flowsheet is proposed on the basis of the results obtained.

As part of a general study of the co-ordination chemistry of beryllium, the beryllium salicylate complexes have been investigated by ion exchange procedures. The evidence indicates that a neutral 1 : 1 and an anionic 1 : 2 chelate exist in solution under appropriate conditions, and their stability constants have been determined by ion-exchange methos. The values of the stability constants were found to be [beta]1 = 4.97 x 10 (12), and [beta]2 = 2.63 x 10(22).

A summary of the available literature on the development of the various processes for the separation of uranium and thorium from aqueous nitrate solutions is presented. Flowsheets are given corresponding to the various stages in the development of the Thorex processes.

Modifications to the A.A.E.C.'s Siemens Diffractometer are described which enable precision lattice parameter determinations on single crystals. Analysis of the errors and consideration of results suggest that accuracies of about 1--2 parts in 10/sup 5/ are obtained on small beryllium oxide crystals. Details of alignment and measurement procedure are included.

The results of unclassified experiments on the irradiation behaviour of BeO fueled with UO2 and (U,Th)O2 are summarized and discussed. The overall picture is still somewhat confused owing to the different experimental conditions used by different workers. A serious deficiency in most of the work is the failure to quote the energies of the irradiation neutrons and it is not clear whether the observed changes are due to fission fragment or fast neutron bombardment. The irradiation behaviour, in general, appears to be good up to fission doses of at least 5 x 10(20) fissions cm-3 of dispersion.