ZERO-POWER EXPERIMENTS WITH BOILING CORE B-1, BORAX-V

Results are reported of the zero-power operation of the initial boiling core B-1 from room-temperature, atmosphenlc pressure conditions at 489 deg F and 600 psig. The core characteristics which were measured are critical mass, control rod calibrations, excess reactivity, shutdown reactivity margin, reactivity effects of various core components, reactivity effects of temperature and voids, neutron flux and power distributions, and cadmium ratios. Some development and calibration work was done on a rotating oscillator rod. It was estimated that the rated full power of 20 Mw(th) probably could not be achieved, and therefore core changes were started for core B-2, designed to achieve more available excess reactivity. (D.L.C.