This technical progress letter contains reports from six Technical Department divisions at the Hanford Engineer Works for February 16 through February 22, 1947. The six reporting divisions are: 100 Areas, 300 Area, 200 Areas, Chemical Development, Laboratories, and Statistical Studies. (JL)

Fission product distribution, fission product activities, and decontamination factors are terms of general usage in the Chemical Development Section. Specific values for some of these terms have been based upon data procured several years ago. In many cases more accurate basic numbers are now available. This report sets forth in tabular form detailed information on fission product activities as a function of decay time for certain conditions. It attempts to quality the use of the theoretical curie as a unit of activity to a unit having a more direct practical significance, the ``countable curie.``

Definite identification has been made of an isotope of the element with atomic number 98 through the irradiation of Cm{sup 242} with 35 Mev helium ions in the Berkeley Orocker Laboratory 60-inch cyclotron. The isotope which has been identified has an observed half-life of about 45 minutes and probably has the mass number 244. The observed mode of decay of the 98{sup 244} is through the emission of alpha-particles, with energy about 7.1 Mev, which agrees with predictions, and other considerations involving the systematics of radioactivity in this region indicate that it should also be unstable toward decay by electron-capture. The chemical separation and identification of the new element was accomplished through the use of ion exchange adsorption methods employing the resin Dowex-50. The element 98 isotope appears in the eka-dysprosium position on elution curves containing 4.6-hour Bk{sup 243} (formed by a d,n reaction in the same bombardment) and the bombarded Cm{sup 242} as reference points; that is, it preceded berkelium and curium off the column just as dysprosium precedes terbium and gadolinium. The experiments so far have revealed only the tripositive oxidation state of eka-dysprosium character but practically no attempts at oxidation to possible IV and V states have …

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A considerable volume of work was accomplished during the past three months in the tracer program, experiments being conducted with At{sup 211}, carrier-free Bi{sup 206}, carrier-free Mn{sup 52}, carrier-free Mo{sup 93,99}, Np{sup 237}, Ta{sup 182} of a fair degree of specific activity, carrier-free Sc{sup 46}, and high specific activity Tm{sup 170}.

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Varying amounts of radiation decomposition during storage in the dry form have been found in the cases of C{sup 14}-labeled valine, norvaline, norleucine, choline chloride, calcium glycolate and cholesterol. These data indicate that investigators using labeled organic compounds should make frequent checks of the purity of these compounds in order to exclude the possibility of the presence of decomposition products.

Using the 1.19-Bev/c antiproton beam recently discovered at the Berkeley Bevatron of the University of California, we have measured the attenuation cross section in beryllium and copper. These cross sections are compared to attenuation measurements made with the same geometry using positive protons of the same incident energy (497 MeV).

The existence of antiprotons has recently been demonstrated at the Berkeley Bevatron by a counter experiment. The antiprotons were found among the momentum-analyzed (1190 Mev/c) negative particles emitted by a copper target bombarded by 6.2-Bev protons. Concurrently with the counter experiment, stacks of nuclear emulsions were exposed in the beam adjusted to 1090 Mev/c negative particles in an experiment designed to observe the properties of antiprotons when coming to rest. This required a 132 g/cm2 copper absorber to slow down the antiprotons sufficiently to stop them in the emulsion stack. Only one antiproton was found in stacks in which seven were expected, assuming a geometric interaction cross section for antiprotons in copper. It has now been found that the cross section in copper is about twice geometric, which explains this low yield.

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There is a definite need to determine the time required for the water in a process tube to boil out after loss of inlet flow. This information is required to evaluate the reactivity and power transients following such an occurrence. Such information will also partially determine the incentive for improvements in safety circuits and equipment, accelerated safety rods in particular. A secondary objective is to learn more about the mechanism of the boil-out. Boil-out times have been theoretically predicted in the past with very little experimental data to back them up. A scanning capacitance method is presented for measurement of the water distribution within a process tube under transient boiling conditions. Preliminary results of exploratory runs are included. The runs simulate inlet pigtail failures on process tubes operating at 725 and 1,000 KW. Curves of water distribution over the tube with time and total tube water content are included. Recommendations are made that the tests be continued to provide valid data for assessing the reactor hazards involved in cases of cooling water supply failure.

The energy distribution of ions and electrons in DCX are being studied by means of the Fokker-Planck approximation to the Boltzmann equation. An IBM- 704 code, called FOPP, was constructed to solve simultaneously the coupled Fokker-Planck equations for each of the two species of particles. This report discusses the difference scheme employed and derives the boundary conditions necessary in order that this difference scheme conserve energy and particles in the absence of sources and sinks. In particular, detailed discussion is given of problems arising from the use of two grid sizes, which proved advantageous on account of the great difference in the mass of ions and electrons. (auth)

A fuel-cycle economic study was made for a 315-Mw(e) graphite-moderated U/sup 235/-Th-fueled fused-salt reactor. Fuel cycle costs of approximately 1.3 mills/kwh may be possible for such reactors when reprocessed for U/sup 233/ and U/ sup 235/ recover y at the end of a 9-year cycle. Continuous removal of fission products during the reactor cycle does not appear to offer any great economic advantage for the converter reactor considered. (auth)

To determine the safety of the array in the storage vault for the SM-2 experimental fuel plates, two criticality criteria were applied. A maximum of 18 fuel plates was stored in sthainless steel tubes and the tubes belted to a frame on the wall to prevent movement. No tube could go critical by itseIf. The vauit was then assumed completely flooded by water. In the first calculation, the fuel array was assumed to be distributed uniformly over the wall forming a large slab. This method indicated the array might be critical if the steel tube and cadmium lining were neglected. In the second method, a conservative calculation, wnich included the steel tube and cadmium lining was made. This method indicataed the array was subcritical. Calculations were then made of the criticalty of the SM-2 vault without the steel--cadmium tubes and wcoden blocks. The multiplication factor of the vault was also calculated. In order to determine the accuracy of these calculations, an ORNL critical experimental array was calculated applying the same analytical techniques. (M.C.G.)

The rate of oxidation of chromium(III) to chromium(VI), catalyzed by ruthenium, was determined at various temperatures and oxygen concentrations. The rate at 300 deg C was too rapid for measurement by aliquot sampling. In the temperature range of 225 to 275 deg C, oxidation was rapid and the rate increased with oxygen concentration. A linear dependence of initial oxidation rate on the reciprocal of chromium(VI) concentration suggested that a rate-controlling step in the reaction mechanism may be desorption of chromium(VI) from the ruthenium catalyst. The activation energy calculated for the reaction is 19 kcal/mole. (auth)

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In a prevlous paper, some inequalities occurring in the one-veloclty theory of neutron transport with lsotropic scattering were derived. Some of the previous results are generalized to the case of linearly anisotropic scattering. (auth)

The differential cross sections for elastic scattering of 14-Mev neutrons from nitrogen and oxygen were measured in the angular range from 17 to 140 deg , using liquid targets and annular ring geometry. Inelastic scattering to the 2.31 and 3.95-Mev levels in N/sup 14/ and to the levels near 6 and 7 Mev in O/sup 16/ was investigated over a more restricted angular range. The 2.31-Mev level in N/sup 14/ was not excited appreciably, in disagreement with previously reported results. For both elements, the elastic scattering cross sections (determined to an accuracy of 10%) were found to be appreciably higher than the optical model predictions by Rjorklund and Fernbach for scatterirg angles larger than 70 deg . The inelastic cross sections measured are, within experimental accuracy, the same as the corresponding (p,p') cross sections. (auth)

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Reference (2) requested that we review the possibilities that classified information might be revealed by isotopic composition of fission products, and suggest methods of making any such compositions. These questions have been reviewed thoroughly by Hanford Laboratories experts; their analysis confirms earlier conclusions (Reference 1). Based on current classification guides, isotopic compositions of cesium, promethium, and probably other rate earths could reveal secret information. Unless classification rules are changed, we see no way to declassify these fission products except by blending them with unclassified products from other sources.

Approximately 285 ribbed aluminum process tubes will have been installed in the central zone of each K reactor on completion of the zirconium tube replacement program. This report recommends the use of mixer fuel elements in the ribbed tube and discusses the basis for the recommendation. The recommendation is complicated by the fact that two tube designs having different dimensions will be used and the optimum mixer location for the two tube designs is different also.