Report regarding ion chamber measurements made of the external environmental radiation in various location in the United States during the summer of 1957.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Will Wilson, regarding a legal question submitted for clarification: Constitutionality and Construction of Portions of the Adult Probation and Parole Law of 1957.

Under the Atoms-For-Peace Plan, the specification that uranium be limited to 20% enrichment in the U/sup 236/ isotope has necessitated development of a highly-concentrated uranium--aluminum alloy as the fuel material in the composite aluminum plates of research reactor fuel elements. Efforts have been directed to determining the suitability of a nominal 48 wt.% U--Al alloy in relation to previously established procedures for manufacturing platetype aluminum fuel elements. Increasing the uranium concentration from 18 wt. % to the 48 wt.% resulted in increased segregation, higher strength, and loss of ductility, creating additional fabrication difficulties. Nonuniform deformation of the alloy during roll bonding into composite plates caused localized thinning of the cladding which may limit the material to specific reactor applications. Substitution of Type 6061 aluminum for Type 1100 alumium as frame and cladding of the fuel plates improves this condition. A fuel element, containing the 48 wt.% U-Al alloy, was irradiated in the active lattice of the MTR to an estimated burnup of 25% of the U/sup 235/ atoms with no observable damage. (auth)

Experiments in the controlled melting of irradiated fuel speciman, particularly of the APPR, STR, and MTR types, have confirmed that prolonged heating in air at temperatures in excess of the melting point results in the release of a large portion of the radioactivity. On the other hand, a moderate amount of heating in air or steam sufficient only to melt a specimen results mainly in the partial volatilization of rare gases, iodine, bromine, cesium, and rubidium. In the presence of air or water vapor, strontium and other fission products are not released. At trace concentration of fission products, slow melting of the APPR plate at 1525 d C in air or steam effected the release of 50% of the rare gases, 33% of the iodine, 9% of ihe cesium, and traces of strontiuun. After 25% burn-up, the cesiuun value increased to about 60%. Aluminum alloy of the MTR type, also at trace concentration, upon melting at 700 d C released up to 2% of the iodine, 10% of the rare gases, and negligible portions of other fission products. Zirconium alloy of the STR type after 15% burn-up, when melted at 1850 d C, released up to 95% of the rare …

A series of two-group calculations has been made on the Oracle for the purpose of obtaining critical-mass and flux distribution data for various ORR core configurations. The 3G3R code of Bate, Einstein, and Kinney was used, together with the RSP code developed by Nelson. This made it possible to obtain results for the three-dimensional case. The results, which are presented graphically, are intended to serve as a guide for the design of experiments until such time as actual measurements are available. The calculations were performed for the "clean cold" case, and it should be realized that the presence in the core of experiments and of fission products built up during operation will materially alter the flux patterns found. It is believed that the critical-mass data are accurate to within 10%. Within the fuel region it is believed that the thermal-flux patterns are the also accurate to this degree. Comparison of the results with MTR critical experiments, however, indicates that the thermal flux in the reflector in the vicinity of the fuel-reflector interface may have been underestimated by a factor of as much as 1.3. It should also be recalled that in a two-group calculation the "fast flux" is often a …

Experiments in the controlled melting of irradiated fuel specimens, particularly of the APPR, STR, and MTR types, have confirmed that prolonged heating in air at temperatures in excess of the melting point results in the release of a large portion of the radioactivity. On the other hand, a moderate amount of heating in air or steam sufficient only to melt a specimen results mainly in the partial volatilization of rare gases, iodine, bromine, cesium, and rubidium. In the presence of air or water vapor, strontium and other fission products are not released. At trace concentration of fission products, slow melting of the APPR plate at 1525 C in air or steam effected the release of 50% of the rare gases, 33% of the iodine, 9% of the cesium, and traces of strontium. After 25% burn-up, the cesium value increased to about 60%. Aluminum alloy of the MTR type, also at trace concentration, upon melting at 700 C released up to 2% of the iodine, 10% of the rare gases, and negligible portions of other fission products. Zirconium alloy of the STR type after 15% burn-up, when melted at 1850 C, released up to 95% of the rare gases, 90% of …