The Borax-III power system operated for about 1170 hours at 300 psig. The steam generated in the reactor was fed directly to a turbine. Tests were conducted on maintaining the pH and quality of the reactor water. Checks were made on the carryover of activity into portions of the system external to the reactor vessel. Neither of these points appear to be major problems in a direct cycle boiling system. Water decomposition was measured under various water conditions.