"Helium, nitrogen, carbon dioxide, and other gases suitable as reactor coolants were evaluated. It is shown that because of the helium conservation program, recently authorized by legislation, sufficient helium will become available for domestic power plants and for the requirements of the Euratom group. Tables of thermodynamic properties for helium and molecular nitrogen were computed from the Beattie-Bridgman equation of state. Specific enthalpy, specific entropy, isobaric specific heat, specific heat ratio, compressibility factor, specific volume, and acoustic velocity are tabulated over the range helium and molecular nitrogen are given."

"The study of the toxicity of Ra and MsTh(Ra/sup 228/) in humans was continued. Several Thorotrast cases were also examined. Physical and clinical studies were made on 151 persons. In all cases possible gamma ray measurements were made of Ra and MsTh decay products retained in the body, alpha -ray measurements of Rn and Rn/sup 220/ in breath, a complete medical history was taken, a complete x-ray examination was made of the skeleton, and urinalysis, hematological, and blood chemistry studies were made."

"The state-of-the-art of heat exchangers for gas-cooled reactor primary circuits is established by describing steam generators, primary heat exchangers, recuperators, and coolers of a number of gas-cooled nuclear projects, and by listing plant and exchanger main characteristics in three summery tables. Information is based in part on references indicated and in par+ on data from manufacturers. The availability of suitable heat exchangers is represented in the form of 35 Data Sheets submitted by manufacturers in response to our request. A list of manufacturers and their addresses is appended."