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.).

For light-water moderated reactors using thermoelectric direct-conversion nuclear fuel elements, this study demonstrated that: (1) the reactor using PbTe can be made critical with less than 20% U235 enrichment; (2) a prompt negative temperature coefficient of reactivity must be present in the fuel for safe operation; (3) a cylindrical UO2-PbTe element will withstand operating thermal stresses if properly designed; (4) the element can be fabricated, but at considerable cost; (5) the thermal power density must be considerably reduced upon introduction of the thermoelectric between the fuel and coolant; and (6) the most promising thermal cycle is provided by natural circulation. These results do not rule out feasibility. At present efficiencies, however, the utility of this reactor concept must rest primarily on its ability to provide silent mobile power regardless of other performance characteristics.

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.).

Nuclear Fuel Elements: Design, Fabrication and Performance is concerned with the design, fabrication, and performance of nuclear fuel elements, with emphasis on fast reactor fuel elements. Topics range from fuel types and the irradiation behavior of fuels to cladding and duct materials, fuel element design and modeling, fuel element performance testing and qualification, and the performance of water reactor fuels. Fast reactor fuel elements, research and test reactor fuel elements, and unconventional fuel elements are also covered. This volume consists of 12 chapters and begins with an overview of nuclear reactors and fuel elements, as well as fuel element design and development based on the reactor operator's approach, materials scientist's approach, and interdisciplinary approach. The reader is then introduced to different types of nuclear fuels and their irradiation behavior, considerations for using cladding and duct materials in fuel element design and development, and fuel element design and modeling. The chapters that follow focus on the testing of fuel element performance, experimental techniques and equipment for testing fuel element designs, and the performance of fuels for water reactors. Fuel elements for gas-cooled reactors, fast reactors, and research and test reactors are also described. The book concludes with an assessment of unconventional fuel elements. This book will be useful to fuel element technologists as well as materials scientists and engineers.

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.).