From American Nuclear Society Meeting, New York, Nov. 1963. The need for control of the flow distribution and/or steam quality in boiling reactors is discussed. A quality control device is being developed which consists of an entrance venturi and an exit venturi for measuring the flow rates into and out of the channel, means for comparing the two flow rate signals, and a value for regulating the flow rate. This device can be used either as a constant quality device or as a controlled-quality device. Results are given of air-water studies of two-phase flow in a vertical venturi.

Introduction. Under AEC contract the Martin Company has followed up the design and construction of the PM-1 and PM-3A nuclear power plants with R&D efforts seeking improved plant efficiency, increased core life and higher operating power. The Advanced PM cores have evolved step by step, with the addition of degrees of freedom to design latitude. A first replacement core, Core 2, has been designed to achieve 50 percent greater life than PM-1 through relatively minor design changes. Core 3 realizes the potential extensive modifications in the fuel element and control element configurations. This paper outlines an analysis effort undertaken to define what may be called a performance profile over a range of configurations of interest for Core 3. It should be emphasized that this is a parametric or concept study and not a final design effort. The results of this study clearly indicate that a lifetime of 100 Mw-yr can be obtained from a 7 ft pressurized water core. If employed as a 10-Mw heat source for present PM equipment, this core has a lifetime approaching that of the plant equipment, 90,000 full-power hours. Core 3 will be suitable for applications demanding up to 40-Mw operating thermal power.

At the Chemonuclear Workshop held at Brookhaven National laboratory in November 1962 it was pointed out that the production of ozone from oxygen by a liquid phase fission fragment chemonuclear process appears to have reasonable economic potential. The maximum theoretical reaction yield for the formation of ozone from oxygen is a "G" value of 68 molecules for 100 ev based on heat of reaction data. The authors felt a "G" value of 15 to be reasonable for this study. the reactor system chosen has liquid oxygen as its moderator and the operating pressure and temperature were selected so as to allow boiling of the oxygen-ozone mixture. The total plant investment cost is estimated to be in the range of $100,000,000. Other system designs will be considered in the future.

The effects of competition between resonances of different isotopes were investigated. Flux and reaction rate calculations on a Pu/sup 239/-- U/sup 238/ system revealed that U/sup 238/ exhibits both self-shielding and interference effects, the latter becoming noticeable at enrichment of a few per cent. Gold activation was also found to be depressed by the presence of U, but was insensitive at low enrichment values, Investigation of the Pu/sup 239/ resonance integral showed an asymmetric effect involving both interference between potential and resonant scattering and interference with resonance absorption in another isotope. The interference scattering arising in each resonance level had a notable effect on the average change in the Doppler coefficient. (D.C.W.)

Abstract: To assess diffusion's importance, the temperature distribution in a cylindrical reactor is derived for a coolant with uniform properties and velocity, taking into account both radial and axial diffusion, for a cosine-J0 power distribution. The fractional temperature rise of the coolant is found to be [chemical formula] where E(z) = [sin(z) + sin(Z)]/2 sin(Z), z= π x/2′, x is the axial distance from the core center, -H and ′ are the core half-height and extrapolated half-height, -H≤x≤H; Fn = 1/J0(Pn)·[(Pn/2.405P)2-10, J1(Pn) = 0, P= R/R′ = core radius/extrapolated radius, ρ = r/R, r = radial distance from axis, 0≤r≤R; an = = βnH/Z, 2 Aβn + 1 =[1 + 4αβ(Pn/R)2]½, A = axial diffusivity /u, B = radial diffusivity /u, u = coolant axial velocity, and [chemical formula]. The expression is evaluated for a variety of values for all the parameters, and the results are discussed analytically and presented in tables and graphs. The effect is dependent upon the relative size of the diffusion eddies in comparison with the dimensions of the reactor. The eddy diffusivity is proportional to the size of the particles in the bed and is about ten times larger axially than radially. A small core …

In fast reactor safety studies, it is imperative to know the effects of temperature excursions on the fuel elements. Previous controlled out-of-pile experiments on the behavior of uranium fuel elements under meltdown or near-meltdown conditions have been performed using direct electrical resistance heating or furnace heating. As a step toward obtaining more complete information on reactivity effects accompanying fuel meltdown, the behavior of irradiated EBR II and Fermi A samples under transient nuclear heating in TREAT has been studied. The experiment results obtained indicate that effects of prior irradiation can produce significant effects upon reactivity changes produced by meltdown of metallic fast reactor fuel pins.

An essential part of establishing the acceptability of warm extruded Zircaloy-4 for the CVTR pressure tube application was the determination of irradiation effects on mechanical properties of the alloy. Representative specimens were irradiated in low temperature process water in the WTR for simulated two, three and five year exposure. The effects of this irradiation were then evaluated in terms of changes in tensile, impact and creep properties. The experiment results concluded that the irradiation-induced changes in mechanical proprieties will not introduce any operational hazard to the CVTR pressure tube under anticipated operating conditions.

Abstract. The determination of the infinite multiplication factor, k∞ , from measurement son a small test sample was investigated by both theoretical and experimental techniques. Theoretical relations were developed to calculate the error in the measurement due to a mismatch between the flux ratios in the critical assembly and those of the test sample. Experiments were carried out at the Hanford Laboratory of the General Electric Company with the PCTR, to obtain values of the multiplication factor for comparison with the theoretical results. Calculations with two-group theory gave results that agreed with the experimental results when the test sample, with natural uranium fuel, was surrounded by a buffer region of the same material. When this buffer region was loaded with highly enriched fuel, the errors in the measured values were not predicted by the two-group theory. Three-group theory relations were derived which gave calculated values in agreement with the experimental values and indicated that a mismatch of the epithermal neutron group leads to the measured differences in the value of k∞ for the two buffer types.

Investigation of whether the multi-thousand psi pressure pulses that occurred in the BORAX-I and SPERT-I destructive power excursion could have been generated by thermal mechanisms in the geometries of unmolten reactor cores. These pressure pulses were "at least as high as 6,000 psi, and probably higher than 10,000 psi " in BORAX I, and "between 3,000 and 4,000 lb/in" in SPERT I. An experimental investigation was undertaken of pressure pulse generation by purely thermal means.

This study is part of a research into trace element physiology of fresh water snails. As an average, biological materials contain [approximately] o.0% (fresh weight) NaCl ; this means [approximately] 3540 mg Na/1 (in snails, 0.4% NaCl [approximately] ms/1). Under these conditions, the application of neutron activation plus gamma spectrum analysis for the study of most trace elements as a routine method, is difficult. We will narrow down the scope some more and consider only the interference between Na24 and Cu64.

Many measurement of neutron spectra have been made in water assemblies. In these system a large part of the spectrum is given by an essentially Maxwellian distribution at the moderator temperature which is insensitive to the scattering model. Hence, the test of the energy exchange scattering kernel is in the difference of the spectrum and the fundamental or Maxwellian component. The figure shows the spectrum for the Nelkin model. Once the fundamental has been subtracted neither theoretical model seems to fit the data extremely well. Below kT the Nelkin model is a closer fit than the gas model but it underestimates the deviation from the Maxwellian whereas in the joining region it overestimates the distortion.

Asymptotic low energy neutron spectra have been measured for two multiplying systems. The reentrant hold spectrum (scalar flux) and the surface leakage spectrum were obtained for both assemblies using the pulsed-source chopper technique at the RPI linear accelerator.

Abstract. Some diffusion parameters of water are computed with various thermal-neutron scattering laws. It is found that the diffusion cooling coefficient, in particular, is reasonably sensitive to the scattering law, but that the diffusion cooling coefficients predicted by the Radkowsky and Nelkin kernels are in fortuitious agreement. The coefficients computed for the Nelkin kernel, when treated in a manner consistent with the way in which experimental data are treated, are in reasonable agreement with the results of a recent experiment.

An apparatus has been developed which controls automatically the acidity of unbuffered solutions in the region from pH 4 to 10. A potentiostat is used to control the potential of an inert electrode on which the hydrogen gas-hydrogen ion reaction occurs in a solution saturated with hydrogen gas. The inert electrode acts as both a sensing element and a regulating electrode for the control of acidity. Current from the potentiostat passes through the inert electrode and an auxiliary polarizing electrode in an external compartment separated from the main cell by a salt bridge or porous plate. Transients which occur during the regulating action are presented and analyzed. The electrochemical pH-stat may be used to measure corrosion rates. Limitations of the device are discussed and a modification is proposed which makes use of a differential amplifier instead of a potentiostat.

Abstract. A brief review of the development of the subject of lattice defects in solids is given. The relation of this problem to field theory methodology is discussed; the defect is regarded as a particle imbedded in the phonon field. One may then discuss scattering states in the field, or “dressed” states of the particle. Specific application is then made to a defect in a simple cubic crystal including interactions between the defect site and its six nearest neighbors. Scattering solutions and scattering cross-sections are calculated and show that vacancies can cause strong resonant scattering, or pseudo-localized modes, at frequencies well below the Debye frequency. Applications to thermal conductivity and other experiments are discussed briefly.

Introduction. Sorption of gases by surfaces is the primary step in many heterogeneous processes. Because sorption processes are in general pressure-dependent, and very fast at normal pressures, low pressure system are mandatory. In gas-metal interaction studies the flash filament technique with ribbons and filaments and Wagener's technique with evaporated films allow observations at the requisite low pressures. However, these method have two major drawbacks: (1) Since the pressure changes during the sorption experiment, pressure-dependent parameters can only be obtained from indirect evidence; (2) The pressure change in the sorption cell during the experiment may cause significant interaction between the sample and the rest of the system and thus experimental data must be corrected for this effect. These drawbacks have been eliminated in a new approach based on a flow system in which the sample is exposed to constant pressure. This new technique has been employed for the study of adsorption and absorption of gases by filaments and evaporated films. This method can also be used for studying gas-metal solution equilibria.

Abstract. By means of the pulse radiolysis technique a short-lived transient species has been observed in irradiated de-aerated ethanol and methanol, exhibiting an optical absorption throughout the visible and near infra-red. This transient is suggested to be the solvated electron on the basis of the nature of the spectrum, the reactivity with hydrogen ion and with various organic electron acceptors, and the formation of mononegative ions of some of these acceptors. The absolute rate constants have been determined for the reactions of the solvated electron with hydrogen ion, oxygen and benzyl chloride in ethanol and methanol. The diphenylide ion was found to be short-lived in ethanol. The absolute rate constant for the first-order decay of the diphenylide ion has been determined.

Abstract. The rate constants for the reaction of the hydrated electron eaq with a number of solutes and with radicals formed in water radiolysis are reported. Hydrated electrons were formed in the electron pulse irradiated solutions at concentrations in the range from 1 to 10 pM. Their reaction was followed by the decay of the optical absorption of eaq at 5780 A. Generally a 04 psec pulse of 15 MeV electrons was used. In the absence of eaq scavengers, second-order kinetics prevailed owing to the dominance of the reactions,eaq+eaq, eaq+H, and eaq+H202 when OH radical scavengers were present in alkaline solution. An analysis of the decay curves leads to values for keaq+eaq and keaq+H of 0.9~ 1010 and 3 x 1010 M-1 sec-1, respectively. With scavenger present in excess over [eaq], pseudo first-order kinetics were found and rate constants for a number of inorganic and organic compounds are reported. The agreement of these and other rate constants with diffusion-controlled reaction theory is discussed.

Abstract. the direct and inert-gas radiolysis, as well as the vacuum ultra-violet photolysis of CD3CH2CD3, CH3CD2CH3 and C3H2+C3D3 mixtures have been investigated in the presence of radical scavengers. The major conclusions are : (a) at atmospheric pressures, neutral propane decomposition contributes to the observed products although to a lesser extent than parent ion decompositions ; (b) a variation in pressure has a pronounced effect on the fragmentation of the parent ion ; (c) the hydrogen atoms in the ethyl ion are randomized in the direct as well as in the inert-gas sensitized radiolysis ; (d) rearrangement in the parent ion is of minor importance in the radiolysis ; (e) although the formation of propylene is related to the propyl ion, it is not necessarily produced by the neutralization of this ion.

Abstract. A review has been made of the effects of fluoride ions on the corrosion behavior of zirconium alloys in high-temperature water. Corrosion was found to occur as the result of contamination of the water or the zirconium surface. A major source of fluorides is undue delay in rinsing the HF-HNO3 pickling solution during surface preparation. The oxide on corrosion-resistant material has been found to contain up to 7600 ppm fluoride from this source. The threshold concentration of fluoride in the oxide film which produces poor corrosion resistance ranges from 8500 to 17,000 ppm. Accelerated corrosion from fluorides in water at 300 to 360 C occurs at about 100 ppm, although increased corrosion has been reported at 10 ppm fluoride in water at 300 C. Fluorocarbon plastics degrade and contribute fluorides to the high-temperature water or to the alloy surface when in direct contact with zirconium. Chlorides (1 to 10,000 ppm) and iodides (1270 ppm) do not adversely affect the corrosion behavior of zirconium alloys in water at 360 C. The mechanism of corrosion is not well understood but apparently is related to the formation of insoluble zirconium oxyfluorides during pickling and during exposure to fluoride-contaminated water.

From American Nuclear Society Meeting, New York, Nov. 1963. In computer-coupled automated activation analysis such as in the Mark II system, conventional methods of data readout impose a serious restriction on the minimum handling time per sample. A data coupler for operating between the data accumulation system and the computer tape unit was developed which contributes nothing to the handling time per sample, does not distort the data, and prepares the data for direct computer entry. In addition to activation analysis, the coupler may be used to obtain successive spectra separated in time by 0.16 sec in the study of short-lived isotopes.

Abstract: This report is concerned with the application of an electronic data processing system to the unique combination of scientific and commercial data processing requirement of nuclear materials management. The organization and flow of data from the plant through the data processing equipment to the final report is the principle topic of the report. Included in the discussion, however, are topics concerned with the impact of conversion to electronic data processing on personnel, materials management costs, and on other plant organizations. Portions of the report are devoted to programming systems and decision-making abilities of data processing equipment which make these systems readily adaptable to nuclear materials management.

Summary: The use of dimensionless-parameter frequency response diagrams to determine accuracies of lumped-parameter approximations is demonstrated by two examples: calculation of the heat flux at the surface of a semi-infinite solid due to temperature fluctuations of an adjacent fluid; and the response of a counterflow heat exchanger to inlet fluid temperature perturbations. Dimensionless system parameters make it possible to use general-purpose plots to find the error in particular approximations as a function of the frequency of perturbation. Such plots are directly applicable to control-system stability problems, where the highest frequency of interest is usually apparent.

Technical report discussing a new high-speed electron multiplier using a planar dynode configuration. This multiplier has a total transit time significantly shorter than available in conventional structures of equivalent gain. It also features rise-times generally less than three nanoseconds while providing the large sensitive area of an unfocused configuration. Two basic types of planar dynodes are employed: transmission secondary emission thin films as the early multiplier stages and silver-magnesium modified mesh multipliers as the high current output stages.The relevant gain and pulse-response data for these two types of dynodes are presented. The structure is quite flexible and permits the number and types of dynodes to be easily tailored to a specific application. In particular it will be shown how the number of mesh-type dynodes may be altered to effect a trade-off between current handling capabilities and rise-time characteristics. Several possible combinations of these planar dynods have been incorporated in photomultipliers whose gain, dark current, pulse response, and operating life are discussed.