This report presents a brief review of reports concerning radiation hazards in the event of various reactor accidents. Conclusions regarding tolerance distance are reported.

Experiments are described in which the change in thermal conductivity of U-impregnated graphite under neutron irradiation was measured. Thermal resistivities relative to the thermal resistivity of undamaged impregnated graphite are reorted as functions of exposure. From applications of the expermental results to the North American Aviation low-power research reactor the peak tem. of the core is determined for a given reactor power and time of operation.

The Bevatron status is: (1) Physical structure of magnet now assembled and being tested. Initial pulsing to rated field currents indicate that magnet is performing as designed. Currents of the order of 8500 amps peak have already been rendered. (About 15,000 gauss). (2) Pumpdown time to approximately 10{sup -5} mm Hg is of the order of 24 hours at present but is expected to improve to 12-15 hours as the high vapor pressure solvents are removed. Lofgren and Brobeck expect that it will be possible to make interval target, etc., changes between operating shifts without excessive loss of experimental time. (3) Injector and linear accelerator are now operating stably. Injected currents to Linac are approximately 3 x 10{sup -3} peak at 450 kev. Linac output is approximately 5% or 70 x 10{sup -6} amps peak with an angular divergence of 10{sup -3} rad. and a maximum energy spread of less than 0.8% at 9.8 kev. (4) Inflector and induction electrodes are to be installed after December 15, 1953. (5) Complete machine, both mechanical and electrical, will be ready for testing and 'de-bugging' approximately December 15; 1953. Initial operation as a research instrument should begin after the first of the year, …

The intercycle evaporators in the Chemical Processing Plant are controlled by density-measuring instruments. Because of difficulties in controlling these evaporators in a satisfactory manner, a series of investigations was begun to measure the boiling points at the elevation of the CPP, and densities near boiling temperatures of a number of solutions in the uranyl nitrate-nitric acid-water system. From these data it was hoped to evaluate temperature sensitve devices as controllers for the evaporators.

This memorandum discusses procedures to test new methods of bonding boron to aluminum tubing in the fabrication of horizontal control rods.