A helium coolant side-stream purification system consisting of parallel sections for radioactive and non-radioactive de-contamination was designed for the proposed Pebble Bed Reactor Experiment. Primary equipment components are two gas coolers, gas heater, charcoal delay trap, CuO oxidizer, Molecular Sieve adsorber, and full flow filter. The charcoal delay trap is sized to provide a hold-up of 30 minutes for Kr isotopes, 6hr hold-up for Xe isotopes, and 99.9% retention of iodine isotopes resulting in "de-contamination factors" varying from l for Kr85 to 556 for I131. Non-radioactive de-contamination will result in a steady state concentration of CO2 in the coolant of 20.8ppm or less.

A multiple controller system for a single process is formulated in block diagram form. It is shown that for the general case of n controllers and one type of cross coupling, the system equations can be reduced to the standard forms of servomechanism theory. The effects of failure in individual controllers are examined, and it is demonstrated that the system shows considerable promise for both reliability and maintenance without process interruption.

A cross section tape has been prepared containing data for elements of most interest for aqueous homogeneous reactor multigroup diffusion calculations involving combinations of 150, 200, 240, 260, and 280°C temperatures. This tape permits multigroup analysis of a reactor in which two or more regions are at different temperatures.