Technical report surveying radio-chemical analyses by ORNL's Analytical Chemistry Division and Health-Physics Division of large volumes of rainwater for plutonium, uranium, and fission products. Overall, carrying efficiencies for Al(OH)3 scavenging of rainwater were determined for these elements, as well as for Pu and U. [From Abstract, Introduction]

The development of ionic methods for the determination of corrosive products in the highly radioactive Homogeneous Reactor (HR) fuels has been of major interest in the work of the Ionic Analyses Laboratory. Methods for the spectrophotometric determination of aluminum and for the polarographic determination of iron in HR fuels have been developed. The polarographic determination of molybdenum in uranyl sulfate solutions was studied. A polarographic method for the determination of zinc was developed. A fluorometric method for the determination of microgram amounts of fluoride was studied. Three organic reagents were investigated as precipitants for microgram quantities of zirconium in HR fuel. The automatic photometric titration technique was applied to the determination of thorium and of sulfate. A method was developed for the ion-exchange separation and potentiometric titration of cobalt. The ultraviolet absorption spectra of technetium and rhenium were studied.

An evaluation of the relative health hazards of radioisotopes produced in nuclear reactors is reported. The most important hazards were indicated to be I131, the Sr90 - Y90 chain, the Ce144 -Pr144 chain, Sr 89, the Ba140-La40 chain, Y91, the Zr95-Nb95 chain, Pr143, La140 , and Pa233. The most critical body organs affected by air-borne contamination are the thyroid gland, the bone marrow, the lungs, and the gastrointestinal tract. Where possible, continuous daily removal of gaseous and solid fission products from the reactor environment can be shown to permit very significant reductions in the total hazards. Homogeneous reactors, such as the Thermal Breeder Reactor and the Homogeneous Plutonium Producer Reactor, specifically studied in this report, are designed with daily removal cycles and may be considered potentially safer than heterogeneous reactors.

Results of tracer studies suggest that, in tributyl phosphate extraction processes designed to recover and purify fissionable material, minimum ruthenium extraction should be obtained from feeds at least 2 M in nitric acid or at least 1 M acid-deficient. Ruthenium decontamination was decreased by preheating the feed and increased by pretreatment with reducing agents. A pretreatment using 0.06 M ferrous ion and 0.5 M urea with 1 hr simmering at 85°C should increase ruthenium decontamination about 10-fold in the 25 process. If other process considerations dictate the use of a low-acid feed, decontamination from ruthenium may be improved by using 3 M nitric acid as the scrubbing solution. Apparently, the scrubbing process is quite time-dependent; a solvent holdup time of about 15 min may be needed in the scrub section for maximum decontamination.

Report describing the progress made in the Clinch River Study for the period May to October 1961. This report is based off of multiple reports of water sampling conducted across six stations in order to evaluate the safety and radioactive content of the Clinch River.

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.

Experience in handling and purifying rubidium metal, prior to high-temperature corrosion testing, has been obtained. Some of the physical and chemical properties of this metal are listed. Distillation and filtration experiences are described, and the analysis of samples following such purification procedures are given. Stripping procedures following corrosion testing are discussed briefly. Results of preliminary corrosion experiments indicate that Inconel in a satisfactory container material for boiling rubidium at temperatures up to 1520°F.

Calculated data and graphs describing the effects of batch thermal-neutron irradiation of thorium, the usual method of operation of heterogeneous reactors, are presented. The buildup and decay of U233, Pa233, other heavy isotopes, and fission products are considered on the basis of best available cross-section and fission-yield data. The effects of these irradiation products on the Thorex chemical separation process are indicated briefly.

A chemical flowsheet is proposed for recovery of strontium and rare earths from Purex wastes. The iron in the waste is first complexed with tartrate and the pH is adjusted with caustic. Strontium and rare earths are extracted by a solvent comprised of di(2-ethylhexyl)phosphoric--sodium di (2-ethylhexyl) phosphate--tributyl phosphate -- Amsco 125-82. and are stripped with nitric acid. Processing the strip product through additional solvent extraction cycles yields isolated, concentrated strontium and rare earth fractions.

Four naturally occurring materials, namely, vermiculite, variscite, Tennessee rock phosphate, and Florida pebble phosphate, were studied to determine the feasibility of their use in columns for the sorption of strontium from high pH, intermediate-level wastes produced at ORNL. Excepting vermiculite, all materials were found to be effective in strontium removal.

An estimate was made of the beam hole currents to be expected from both the radial and tangential beam holes in the present HFIR design. The angular fluxes required for these calculation were determined by an 18-group, S8 transport calculation (SNG reactor code). Both type beam holes produced thermal neutron currents of 7.5 x 10^10 neutrons/cm^2 sec. at a power level of 100 Mw. The nonthermal component of the beam current was 7.0 x 10^10 and 4.5 x 10^10 neutrons/cm^2 -sec for the radial and tangential holes, respectively.

The hardness of several materials that have been considered for use as valve scats and bearings in thorium oxide slurry systems were measured and are reported for comparison with thorium oxide.

A generalization of Wigner's simple model for the distribution of nuclear level spacings is studied. It is based on a stochastic process which reproduces the correct joing probability distribution of N enerfy levels for small spacings. The case N=3, which includes the effect of the correlation between adjacent spacings, is discussed in detail. The resulting distribution and the correlation coefficient are compared with experimental data. No definite conclusion can be drawn except to say that the effect of the correlations on the spacing distributions on the spacing distribution is very small.

Five irradiated and five unirradiated wafers were analyzed. Each wafer was analyzed for samarium by emission spectrography. The unirradiated wafers were analyzed for uranium by coulometric and potentiometric methods and for uranium isotopes by mass spectrometry. The irradiated wafers were analyzed for uranium and plutonium by coulometric methods, for plutonium isotopes by the 256-channel alpha pulse analyzer, and for the isotopes of uranium and of plutonium by mass spectrometry. The methods of preparing wafers for analysis are discussed; the data are tabulated.

These specifications for the fuel assemblies for Core I of the Experimental Gas-Cooled Reactor (EGCR) have been developed for use in procuring the first core loading. A fuel assembly for EGCR consists of a cluster of seven cylindrical fuel elements spaced and supported within a graphite sleeve. Each fuel element consists of a stainless steel tube containing a column of hollow UO2 pellets and having a spacer brazed at the midsection to control the spacing between fuel elements in a cluster. A master specification for the fuel assembly, a supplementary specification for each of the components, and a specification on record keeping during manufacture are included.

A helium coolant purification system was designed for the proposed 800 MWT Pebble Bed Reactor. The purification system will operate on a coolant side stream with a flow rate 1% of the total coolant flow and there are provisions for radioactive and non-radioactive contamination removal.

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.

The ORNL analog computer was used to examine one aspect of a safety system for the EGCR. The thermal behavior of the fuel as a result of increases in reactivity at various power levels and gas flows was examined. Safety actions initiated by wither a flux-minus-flow signal or a reactor outlet gas temperature signal were included in simulation.

The steady-state radial and axial temperature profiles of an E. G. C. R. 5 1/2" O. D. through tube are determined for the test condition of an attemperated fuel assembly operating at 1500 KW in the loop. The profiles are determined for the case of the central control rod fully inserted and bank insertion to 62 inches (Δk = 0.025). The data are presented in the form of tables and curves.

The thermal-neutron flux prevailing near the upper hole in the HRE-2 core wall was determined from measurements of the induced activity in a specimen cut from the edge of the hole. The specimen was removed following run 21 and was thus exposed to reactor neutrons during runs 13, 14, 16,17, 18. 19, 20, and 21. The neutron flux, calculated for an average core power level of 2 Mw, was 2.8 x10^13 neutrons/cm^2 sec. the core wall area from which the specimen was removed was located approximately 16-in. from the core center.

Multigroup one-dimensional calculations were done recently to obtain estimates of critical masses, power density distributions and fissioning spectra for some homogeneous molten salt reactors having outer reflectors and central "islands," placed inside the currently proposed MSRE vessel. For a 5-inch-thick outer reflector and 1-ft-diamter island, both beryllium, the calculated critical mass is 108 kg; 40 percent of the fissions occur at thermal, and the maximum power density of 3.9 times the core mean power density occurs at the island-salt interface. If the reflector thickness is increased to 10 inches, the critical mass is reduced to 34 kg; 67 percent of the fissions occur at thermal, and the peak power density of twice the core mean again occurs at the core island-salt interface.

The pneumatic temperature probe (PIM) is a device for measuring gas temperatures by utilizing the dependency of the flow of gases through a restriction on the temperature and pressure conditions. The determination is made by measuring critical mass flow across a restrictive element such as a nozzle and by knowing the upstream pressure and other variables pertinent to the critical flow equation, computing the temperature at the entrance to the restrictive element. In practice it has been found useful to use two critical flow nozzles in series and measure the ratio of the pressures at the nozzle inlets, together with the temperature at the downstream nozzle. The limitations of present thermocouple materials for long term use at elevated temperatures makes resort to this device attractive on many installations.

After shutdown heating rates have been calculated for the target, control plates, and the beryllium reflector of the HFIR. Hilvety previously calculated the after shutdown heating rates in the element and his results are reported in ORNL CP-60-4-110. Decay times of 1.0 10, 10^2, 10^3, 10^4, and 10^5 seconds have been considered, and heat fluxes have been computed for all of the mentioned components. The greatest heat fluxes were found to be at the surfaces of the control plates and the permanent beryllium reflector.

The feasibility of improving the mechanical properties at 1700-1800°F of oxidation-resistant Fe-Al-Cr alloys by means of a refractory dispersion has been explored. A literature search was conducted, preliminary experimental determinations of properties of the alloy and its oxides were carried out, and certain mathematical relations between dispersion characteristics and metallurgical variables were derived. The results indicate that the alloys can be strengthened sufficiently by using a dispersion with an interparticle spacing of about 2-3 µ. High-temperature native oxides of the Fe-Al-Cr alloy consist largely of Al2O3 and in theory would serve as a satisfactory second phase.