Changes made in the Thorex process flowsheet were a decrease in the extraction column acidity to decrease thorium losses and the addition of a second thorium solvent-extraction cycle to provide the increased decontamination required when thorium irradiated to 2000-4000 g of U233 per ton is processed. Bonded slugs could not be dissolved by the Thorex flowsheet procedure. Various laboratory scale studies on feed preparation, first-cycle variables, and radiation damage to the solvent are reported.

This quarterly progress report of the Aircraft Nuclear Propulsion Project at ORNL records the technical progress of the research on circulating-fuel reactors and other ANP research at the Laboratory under its Contract W-7405-eng-26. The report is divided into three major parts: I. Reactor Theory, Component Development, and Construction, II. Materials Research, and III. Shielding Research. The ANP Project is comprised of about 530 technical and scientific personnel engaged in many phases of research directed forward the achievement of nuclear propulsion of aircraft. A considerable portion of this research is performed in support of the work of other organizations participating in the national ANP effort. However, the bulk of the ANP research at ORNL is directed toward the development of a circulating-fuel type of reactor. The design, construction, and operation of the Aircraft Reactor Test (ART), with the cooperation of the Pratt & Whitney Aircraft Division, are the specific objectives of the project. The ART is to be a power plant system that will include a 60-Mv circulating-fuel reflector-moderated reactor and adequate means for heat disposal. Operation of the system will be for the purpose of determining the feasibility, and the problems associated with the design, construction, and operation, of a …

In scouting tests, a number of metals used in nuclear reactor fuel elements were dissolved by 44.5-48.5-7.0 mole % ZrF4-KF-NaF fused salt at 675°C through which HF was being passed. These included type 304 stainless steel at 4 mils/hr; type 347Nb stainless steel at 7 mils/hr; thorium at 14 mils/hr; nonirradiated uranium at 17 mils/hr; zirconium at 22-35 mils/hr; titanium at 31 mils/hr; and Zircaloy-2 at 22-46 mils/hr. Only small amounts of volatile fission products formed when irradiated uranium was dissolved. Variables that appear to affect the dissolution rate are the composition of the fused fluoride, the fused fluoride temperature, the HF flow rate, the metallurgical characteristics of the material being dissolved, and the presence of other metals. The low dissolution rate of 0.001 mil/hr observed for nickel suggests that it may be suitable as a material of construction for reaction vessels.

Progress report of the Oak Ridge National Laboratory Biology Division providing updates on various projects, experiments, and other work. This report includes a summary of scholarly output from the division and departmental activities in: cytology and genetics, microbial protection and recovery, mammalian recovery, mammalian genetics and development, pathology and physiology, microbiology, biochemistry, enzymology and photosynthesis, plant biochemistry, general physiology, and biophysics.

This semiannual progress report and future reports will be published as two documents to permit a wider distribution of the unclassified material. The report numbers are assigned in sequence so that the two reports will fall together when filed by report number.

The use of a scalloped cross-sectional coolant channel has been suggested as possible solution of the fuel-element bowing problem inherent in the septafoil type of geometry. Using simplified assumptions, a method has been developed for calculating the rod spacing and scallop size necessary to produce equal average fuel-element surface temperatures in the central and peripheral regions of the coolant flow channel at the mid-section of each fuel-rod cluster under a given set of reactor flow conditions. Since the extent of row-bowing is related to the surface temperature distribution, this requirement should minimize fuel-element deflection.

Standard water treatment practices have proven adequate for scale and corrosion control on the secondary side of the ORR pool-cooling heat exchanger. Corrosion rates measured on specimens exposed to secondary water showed maximum corrosion rates of approximately 1 mpy during the first exposure period and these rates decreased during subsequent exposure.

Lewis in 1929 determined the thermal conductivity of beryllium metal for the first time. The next measurement reported in the open literature on the thermal conductivity of beryllium was by Powell in 1953. Measurements were also made by Grenell, Linebrink, and Johnson at Battelle Memorial Institute in 1947. Their values are in good agreement with those of Powell.

On 3/14/60 the Applied Physics Corporation was awarded a subcontract for the design and development of a high-temperature high-pressure spectrophotometer system based on the Cary Model 14pm Spectrophotometer insofar as possible, and consistent with our specifications, No. CTD-2, December 16, 1959.

Calculations are presented of the fast neutron dose rate, the gamma-ray dose rate, and the thermal neutron flux along the source plate axis in the Lid Tank with the tank filled entirely with water. These calculations are compared with experimental measurements. The calculations are absolute and are compared with absolute measurements.

In the Communications of the ACM of April, 1960, p. 240, there appeared two Algol algorithms for the computation of In, the modified Bessel function of the first kind. One of these algorithms uses a convergent series and the other an asymptotic series. Their author, Dorothea S. Clarke, did not give any information with regard to which algorithm is more appropriate in a given situation (a given situation meaning the computation of In (x) for a definite pair of numbers n and x). Such information is necessary, however, if the algorithms are to be useful, particularly since the asymptotic series is in many cases not valid.