Quarterly report describing the progress and development of improved zirconium alloys for service in superheated water and steam. This report covers the period between October 1 to December 31, 1960 and was conducted by the United States and the European Atomic Energy Community (EURATOM).

Neutron activation analysis provides the extremely high sensitivity necessary for the measurement of many trace elements. Activation techniques are presently being used to measure the concentrations of various undesirable parent isotopes in reactor process tubing, slug jackets and their corrosion film, and in process vater and vater treatment chemicals. The interpretation of results from activation analysis are sometimes complicated by the fact that a given radioisotope may be produced by fission neutrons (threshold reactions) from other elements as well as by the more common thermal neutron (n,{gamma}) reactions. Shielding the sample with cadmium prior to irradiation or irradiating in the graphite reflector will minimize the contributions from thermal or fission neutrons, respectively. The purpose of this study has been to measure the ratios and magnitudes of the thermal and fission fluxes in process tubing and to compare these with values at locations where neutron activations can be performed. Also, it was of interest to measure the ratios and magnitudes of the thermal and fission fluxes from a point in the lattice to a point well into the graphite reflector, and to determine if the fission neutron spectrum as measured by two threshold reactions, changes appreciably over this region. These data …

The process criteria proposed use of the existing organic wash column, 10, as a stripping column for the neptunium accumulation and isolation cycles. It is now proposed to employ a new processing concept which will permit the use of the scrub section of the neptunium extraction column, 1S, for neptunium stripping thereby obviating the use of the 10 Column. This proposed new scheme will provide increased neptunium stripping efficiency and greater processing flexibility for the 1S Column. The revision will require four new jumpers, but will permit the deletion of eight jumpers required for the original proposal. This document discusses the technical bases and incentives for the proposed change and presents revised flow diagrams and jumper routings.

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The method of dispersion relations has in recent years found a wide application for the study of elementary particle reactions. Most of the work, however, deals with reactions of the type [formula], while the theory of those with more than two particles in the final state is still in a very preliminary stage. One reason for this is that even with only three particles in the final state the theory is already much more complicated. Nevertheless, a further development of the theory seemed to us very desirable. The theory at present is being developed on various levels simultaneously. Generally speaking, the aim of this paper is to put the theory in a form as closely as possible analogous to Mandelstam's formulation of the theory of reactions of type [formula]. In the later sections we specialize on reactions [formula], but as much as possible the formulation is in more general terms.

Further calculations have been made to determine the desired radial fuel distribution in the HFIR and in the forthcoming HFIR critical experiment. In the process the design of the core was changed to include a 1-cm-thick annular space of water between the two nearly equally thick fuel annuli, a metal-to-water ratio in the fuel annuli of 1.0 (0.050 in. thick plates and coolant channels ) was specified, and the active length of the core was increased from 18 to 20 in. Results of the calculations indicated that the largest ratio of maximum meat thickness to minimum meat thickness occurred in the inner fuel annulus and was equal to 3.6, while the maximum fuel concentration occurred in the outer fuel annulus and was equivalent to about 0.7 g of U-235/cm^3 of meat. The total U-235 loading for this core was 8.01 kg, which results in a core lifetime of about 14 days.

A total of 104 thermal cycles between 250°F and 1350°F were imposed on a 3 1/2-in. and a 4-in. freeze flange to determine their susceptibility to thermal fatigue. The flange clamping arrangement was modified and various gaskets were used during the cycling in an effort to reduce the gas leakage problem.

Results of the examinations of corrosion specimens exposed in the HRT are presented. Specimens examined included (1) core screen samples, (2) core specimen array No. 1, (3) blanket specimen array No. 2, (4) core solution line specimen arrays No. 103 and 103A, (5) blanket solution line specimen array No. 203. Complete information is still not available on all the specimens removed from the reactor, however, those data which have been accumulated are presented. These include corrosion rates, computed from specimen weight-changes, and results of chemical analyses of scales removed from the specimens or specimen holders. Also included in the report is a summary of the HRT operating schedule during exposure of the specimen and of the status of examinations for those specimens removed from the reactor prior to run 20.