A hot-pressing system was designed and is adaptable for bomb melting experiments up to 2000 deg C. Two devices were constructed for measuring. One was designed to measure Seebeck coefficients, resistivities, and bond resistances of swaged and machined thermoelectric wafers and the other was designed to measure thermoelectric parameters of cylindrical thermoelectric pellets up to 1000 deg C. Design studies on a fission-fired thermoelectric generator were completed. Seebeck coefficient and resistivity were determined for Li/sub .06/Ni/ sub .94/ and p type PbTe as a function of thermal fiux at 400 deg C (average). Designs of prototype thermonuclear fuel elements are presented which include single-leg, double-leg, multi-junction notched-bar, and multi-junction pelletized designs. The effects of heattreatment on the thermoelectric properties of n and p type PbTe were determined at 68 deg F. The compatibility of PbTe and GeTe with cladding materials was investigated at 510, 600, and 650 deg C. The results of life testing a swaged single-leg GeTe element are discussed. The nuclear characteristics of a 500-kw thermoelectric core that employs a rod-type fuel element were calculated. Designs of a thermoelectric reactor system that utilizes thermal circulation are presented. (For preceding period see WCAP- 1545.) (C.J.G.).