A technique based on a determinaiion of the differential counting rate exhibited by the 184-kev gamma radiation associated with the decay of U/sup 235/ was developed for the determination of the U/sup 235/ content in Argonne Low Power Reactor fuel element core blanks. The Argonne Low Power Reactor core blanks were an aluminum-highly enriched uranium alloy containing 17.5 weight per cent uranium (approximately 4 g U/sup 235/) having the following dimensions: length, 6.875 inches, width, 3.31 inches, and thickness, 0.200 inch. The gamma- ray spectrum emitied by uranium is rather complex. Using a scintillation spectrometer and scanning the spectrum, the energy is found to be concentrated primarily in two regions, at 184 and 90 kev. The 184-kev gamma rays result primarily from the decay of U/sup 235/ The gammas in the 90-kev region result from the U/sup 235/ decay and daughter products of U/sup 238/ and U/sup 235/. Using a pulse-height analyzer, it is possibie to select the desired radiation emitted from the source and determine the counting rate for a given source. In this work the 184-kev gamma radiation was counted to determine the amount of U/ sup 235/ present in the individual core blanks. (auth)
Eddy-current and ultrasonic tests on zirconium rod stock and wire, Zircaloy-2 tubing and rod stock, and stainless steel tubing for use in various core compoments are summarized. Eddy-current tests were also performed on the NaK annulus of assembled blanket elements. (D.C.W.)
Date: October 1, 1963
Creator: Selner, R.H.; Renken, C.J.; Perry, R.B. & Balaramamoorthy, K.
The estimate of afterheat in a spallation target of lead (Pb) or tungsten (W), by calorimetry, is the purpose of this experiment in support of the Accelerator Production of Tritium (APT). Such measurements are needed to confirm code calculations, these being the only practical way of gaining this type of information in a form suitable to aid the design of the APT machine. Knowledge of the magnitude and duration of afterheat resulting from decay of activation products produced by proton bombardment of the target is necessary to quantify APT safety assumptions, to design target cooling and safety systems, and to reduce technical risk. Direct calorimetric measurement of the afterheat for the appropriate incident proton energies is more reliable than the available alternative, which is indirect, based on data from gamma-ray spectroscopy measurements. The basic concept, a direct measurement of decay afterheat which bypasses the laborious classical way of determining this quantity, has been demonstrated to work. The gamma-ray energy given off by the decay products produced in the activation of lead or tungsten with high-energy protons apparently does represent a significant fraction of the total decay energy. A calorimeter designed for measurement of isotopes decaying by alpha emission must be modified to reduce energy lost with escaping gamma rays. Replacement of the aluminum liner with a tungsten liner in the SSC measurement chamber resulted in a 270% increase in measured heat, proving that the energy loss in the earlier (1992) measurements was significant. Gamma-ray measurements are needed to confirm the gamma-ray absorption calculations for the calorimeter to determine the correction for loss of heat due to transmission of high-energy gamma rays through the calorimeter walls. The experiments at BLIP have shown that calorimetry can be a useful tool in measuring the afterheat in APT target materials.
This paper is the final report on DOE-OSS Task ANLE88002 Fast Air Chamber Calorimetry.'' The task objective was to design, construct, and test an isothermal air chamber calorimeter for plutonium assay of bulk samples that would meet the following requirements for sample power measurement: average sample measurement time less than 20 minutes. Measurement of samples with power output up to 10 W. Precision of better than 1% RSD for sample power greater than 1 W. Precision better than 0.010 watt SD, for sample power less than 1 W. This report gives a description of the calorimeter hardware and software and discusses the test results. The instrument operating procedure, included as an appendix, gives examples of typical input/output and explains the menu driven software.
Date: October 1990
Creator: Perry, R. B.; Fiarman, Sidney; Jung, Erwin A. & Cremers, Teresa
A nondestructive autoradiographic method is described which can provide a verification that rods in the interior of unirradiated LWR fuel assemblies contain low-enriched uranium. Sufficient absorber must be used to reduce contributions to image density by beta radiation from uranium-238 daughters. When appropriate absorbers are used, the density of the image of a uranium-containing fuel rod is proportional to the uranium-235 enrichment in that rod. Exposure times as short as 1.5 hours can be achieved by using fast film and intensifying screens. Methods are discussed for reducing contributions to the image density of any single rod from radiation produced by all other rods in the assembly. The technique is useful for detecting missing rods, dummy rods, and rods containing depleted uranium. These defects can be detected by visual inspection of the autoradiographs. In its present state of development, the technique is not sensitive enough to reliably detect the difference between the various uranium-235 enrichments encountered in current BWR fuel assemblies. Results are presented for field tests of the technique at BWR and PWR facilities.
Argonne National Laboratory is decommissioning a facility used to fabricate reactor fuel elements. The equipment is contaminated with alpha emitters. The objective of decontamination is to reduce the TRU concentrations below 10 nCi/g of waste. A portable NDA procedure using Na I (TI ) gamma-spectrometric techniques was selected to measure the residual Pu and 2i 1 Am in the glove boxes. Assays were performed at different stages in the decontamination process to estimate the detection system sensitivity and the effectiveness of the cleaning efforts.
Date: July 1979
Creator: Argonne National Laboratory. Special Materials Division. Nondestructive Assay Section.
A nondestructive autoradiographic technique is described which can provide a verification of the piece count and the plutonium content of plutonium-containing fuel elements. This technique uses the spontaneously emitted gamma rays from plutonium to form images of fuel elements on photographic film. Autoradiography has the advantage of providing an inventory verification without the opening of containers or the handling of fuel elements. Missing fuel elements, substitution of nonradioactive material, and substitution of elements of different size are detectable. Results are presented for fuel elements in various storage configurations and for fuel elements contained in a fast critical assembly.
Calorimetric assay provides a precise, nondestructive method to determine sample plutonium content based on the heat emitted by decaying radionuclides. This measurement, in combination with a gamma-spectrometer analysis of sample isotopic content, yields the total sample plutonium mass. The technique is applicable to sealed containers and is essentially independent of sample matrix configuration and elemental composition. Conventional calorimeter designs employ large water-bath heat sinks and lack the portability needed by inspection personnel. The ANL air-chamber isothermal calorimeters are low-thermal-capacitance devices which eliminate the need for large constant-temperature heat sinks. These instruments are designed to use a feedback system that applies power to maintain the sample chamber at a constant electrical resistance and, therefore, at a constant temperature. The applied-power difference between a plutonium-containing sample and a blank determines the radioactive-decay power. The operating characteristics of a calorimeter designed for assaying mixed-oxide powders, fuel pellets, and plutonium-containing solutions are discussed. This device consists of the calorimeter, sample pre-heater, and a microprocessor-controlled data-acquisition system. The small-sample device weighs 18 kg and has a measurement cycle of 20 min, with a precision of 0.1% at 10 mW. A 100-min gamma-ray measurement gives the specific power with a precision of better than 1% for samples containing 1 to 2 g of plutonium.
Creator: Roche, C. T.; Perry, R. B.; Lewis, R. N.; Jung, E. A. & Haumann, J. R.
The calorimetric instrumentation developed at Argonne National Laboratory (ANL) for making nondestructive measurements of the plutonium content of fuel rods is discussed. Measurements with these instruments are relatively fast (i.e., 15 to 20 minutes) when compared to the several hours usually required with more conventional calorimeters and for this reason are called ''fast-response.'' Most of the discussion concerns the One-Meter and the Four-Meter Fuel-Rod Calorimeters and the Analytical Small-Sample Calorimeter. However, to provide some background and continuity where needed, a small amount of discussion is devoted to the three earlier calorimeters which have been described previously in the literature. A brief review is presented of the literature on plutonium holdup measurements. The use of gamma-ray techniques for holdup measurements is discussed and results are given for the determination of sample thickness using the ratio of intensities of high- and low-energy gamma rays. The measurements cover the plutonium metal thickness range from 0.001 to 0.120 inches. The design of a gamma-ray collimator with 37 parallel holes is also discussed. Neutron-counting experiments using BF3 proportional counters embedded in two polyethylene slabs are described. This detector configuration is characterized for its sensitivity to sample and background plutonium, counting both coincidence (fission) and total neutrons. In addition, the use of infrared imaging devices to measure small temperature differences is considered for locating large amounts of plutonium holdup and also for performing fast attribute checks for fabricated fuel elements.
Date: February 1977
Creator: Brumbach, S. B.; Finkbeiner, A. M.; Lewis, R. N. & Perry, R. B.
This dialog allows you to filter your current search.
Each of the Years listed note their name and the number of records that will be limited down to if you choose that option.
The list can be sorted by name or the count.
This dialog allows you to filter your current search.
Each of the Months listed note their name and the number of records that will be limited down to if you choose that option.
The list can be sorted by name or the count.