To determine whether or not the (n,2n) reaction in Be would produce a net increase in fission neutrons in a power plant, the distribution of In resonance neutrons slowed down from fission energies in a graphite block was measured with and without a 2" of Be in front of a U3O8 slab undergoing fission. The thermal neutrons producing the fissions were obtained by slowing down neutrons from a cyclotron source. The observed distribution without Be was well represented by a Gaussian source range 36 cm. (corresponding to an initial fission energy of 3 MeV) and a similar sink of range 7.8 cm. The total In resonance intensity with Be was 5% less than without Be. On the assumption that the effect of the Be is entirely due to its different mean free path and moderating power, the In distribution with Be was calculated. Since the m.f.p. as a function of energy is not known for Be, two separate calculations were made using the highest (2.9 cm.) and the lowest (1.80 cm.) possible values for the effective Be m.f.p. Both calculated curves were found to be higher than the observed Be distribution, indicating that at least 10% of the fission neutrons …

The following document describes the analysis on an attempt at separating mercury isotopes by making their environments as widely different as possible.

The following report was written to replace previous directions submitted in the February 6, 1943 report on the preparation of the solution X(OC₂H₅)₅.

The resonance absorption of uranium for neutrons has been investigated between 20 degree C and 1000 degree C. Experiments were caried out on both UO2, density 4.63, and metal. The resonance activity was measured with respect to that of an iodine monitor at several different temperatures and the ratio of activity at temperature T to that at 20 degree C was determined. The increase in activity is 0.9 per cent per 100 degree C for the oxide and 1.1 percent per 100 degree C for the metal. The period of U239 was found to be 23.54 +- 0.05 min.

Technical report covering (1) analysis of uranium bromide and chloride samples, (2) the ferric-nitrate method of analyzing uranium fluorides for fluorine, (3) spectrographic determination of boron, cadmium and manganese in magnesium metal, (4) service analyses. contributions to other problems, (5) attempted preparation of uranous oxyfluoride, and (6) corrections in previous reports.

Calculations were made to determine the temperature at various points of a thick disc and cap, on the assumptions that the heat production rate is uniform throughout the slug and that the slug is in perfect thermal contact with the cap. Results obtained by different methods of computation are compared with each other and with results obtained by Drew on the Paschkis electrical network computer at Columbia University.

The present report is concerned with the electronic relay which, upon the reaching of a pre-determined value of ionization current in the associated chamber, actuates the safety rod release mechanism. The are here proposed two independent suggestions: (1) An improved trip circuit of such sensitivity and stability as to allow it to be actuated by a signal directly from the chamber without the necessity of interposing intermediate amplifier stages. The value of chamber current at which tripping occurs is stable to +- 0.4%. (2) A triple-wound relay to prevent shut-downs of the pile which would otherwise be caused by development of defects in the safety circuits.

The resonance absorption of a lump is described in terms of three components. Calculations of resonance absorption are carried out using the model for the resonance spectrum of uranium recently derived; calculations are also made with variations of this model which involve local fluctuations in level strengths. For metal and oxide lumps the agreement with observation is satisfactory. For dilute mixtures, whose resonance activation was measured by Mitchell, computed values fall 20% to 30% above measured ones.

The transition region between two parts of a pile which have different compositions is investigated. In the case where the moderator is the same in both parts of the pile, it is found that the diffusion constant times thermal neutron density plus diffusion constant times fast neutron density satisfied the use pile equations everywhere, right to the boundary. More complicated formulae apply in a more general case.

Technical report abstract: Since UNH is a highly dissociated compound which ionizes to NO3 and (UO2), the latter ion being very weakly basic, a solution of pure UNH is quite acid (pH about 3). It is possible to titrate to a phenolphthalein and point with standard caustic solution and obtain a figure which represents the free acid plus the NO3 from the the UNH. However, titration of the free nitric acid alone in such a solution presents quite a problem. By precipitating and removing uranium from solution by means of potassium ferrocyanide, the residual free acid may be titrated directly by means of standard caustic using either methyl red or phenolphthalein indicators, with an error of less than 4%. A method is given to determine formic acid, should that acid be present in the mixture.

An attempt is made to estimate the influence of operation upon the mechanical properties of tubealloy. It is to be emphasized that the work is highly speculative, being base upon a set of judicious assumptions regarding the transport material within the metal and should not be used as a substitute for a set of well-planned experiments. The two principal effects considered are the hardening which results from the atomic displacement produced by the fission fragments and the changes in mechanical properties arising from the presence of the fission products. The principal conclusion to be drawn is that the disruption of the metal which accompanies operation takes place at at sufficiently high rate that it could readily cause serious changes in the mechanical properties of the slups. the reversal of the disruption resulting from thermal effects probably is sufficiently high to prevent serious embrittlement as a consequence of displacement through most of the volume of the slug if not at the surface. On the other hand, the migration of atoms also appears to be sufficiently high that the rare gas products may have time to diffuse to cracks and produce embrittlement.

Abstract. Measurements were made to determine the effect of thermal cycling on heat transfer from slug to jack using a slug with a sand blasted surface. The value of the transfer coefficient h decreased from initial values ranging from 10 to [formula], to values and [formula] after 1700 cycles, and to a range of 0.15 to 0.45 [formula] after 3200 cycles. Comparisons are made with the results found for slugs with different surfaces.

Abstract. In order to anticipate radiation - chemical effects in solutions of active lanthanum, various solutions and suspensions containing lanthanum were irradiated with an electron beam. Separation of lanthanum from barium by the alcoholic HCl method is not rendered less efficient by radiation, although considerable gas evolution occurs. Suspensions of lanthanum as hydroxide and as ferrocyanide are not appreciably solubilized by radiation. Lanthanum oxalate is decomposed by radiation, is partially thrown into solution, and finally dissolves completely when all the excess oxalate ion in the solution has been destroyed.

Abstract. the fluctuation in pile intensity caused by an oscillating point absorber is calculation. It is found that the nature of the response depends on the frequency of the impressed oscillation. If the frequency is high compared to the decay rate of the high harmonics, the response consists of a wave which is propagated away from the oscillator. If the frequency is low, the propagated wave character of the response disappears and the intensity of the whole pile tends to oscillate with the same phase. The amplitude of the response decreases with increasing frequency.

The solubility constants are presented for He , Kr , Xe , O2 , N2 , and air in H20 . Inter-diffusion constants for gases and the diffusion of gases in water are given.

Abstract. Irradiated Whiting graphite possesses a small negative or a positive Hall constant, depending upon the dosage. Annealing at 500 degrees C for 1 hour in helium results in a Hall constant which is large in magnitude and negative in sign. The properties of the annealed graphite are presumably close to those of the original unirradiated material. Unirradiated AGOT-K graphite has a large, negative Hall constant. A mechanism is suggested which accounts for the change in sign of the Hall constant as a result of neutron bombardment.

Abstract: "Tests have been developed for both the qualitative detection and quantitative determination of fluorine in chlorine. The qualitative test is made by passing the gas through manganous chloride. If the pink solid tubes brown there is greater than 0.5 percent of fluorine in the gas. The quantitative test is a modification of the Steiger and Marvin Test with oxidized titanium solution."

The following report discusses ohmic characteristics in resistors, including methods for determining the polarization characteristics of high megohm resistors that may determine the suitability of these resistors for spectrometric measurements.

Abstract: "The possibility of detecting small quantities of uranium with an X-ray spectrometer was investigated. An X-ray spectrograph was modified by substituting a geiger counter for the photographic film. Both primary and secondary methods of excitation were studied. Radiation background of high intensity and variability limits the sensitivity of the present apparatus to 1%. Suggestions are made for increasing the sensitivity of the method."

Abstract: "The definitions of the fundamental measures of calutron operation including enhancement, current ratio, and process efficiency are set forth with derivations of the relationships between them. An analysis of the plant process is carried out for both the tanks limited and the charge limited case. Equations are derived for plant X output and plant X utilization efficiency. Effective production is defined and the value of increment to a mass of product material in terms of effective production is determined. An equation giving the X concentration below which product material should be reprocessed is derived."

This report records analyses on the fluorescence procedure of uranyl salts.

The following report briefly covers broad general features of the chemical studies to be used by the Atomic Energy Commission in considering future work on the chemical studies of phosphate rock and shale.

The following report describes the results from studies based on the toxicity and metabolism of radioactive substances derived from uranium fission. Rats and mice were administered radioactive sodium and reactions and changes were studied.

Introduction: Static, total immersion corrosion tests were carried out at room temperatures with Carboloy grades 44-A, 78, 907, X-3119-A and X-3119-B in Redox process solutions (ANL, June 1, 1949 Flowsheet) 1AX, 1AF, and 1AS.