Abstract: The subject matter of this specification can be embodied in, among other things, a rotary mixer with a housing defining a mixing chamber defining a rotation axis, the housing being rotatable about the rotation axis in a rotation direction and having a longitudinal midpoint, a set of blades within the housing, wherein at least one pair of blades of the set of blades forms an angle with respect to each other, and at least one blade of the set of blades is shorter than another blade of the set of blades in the rotation direction, and a splitter blade located within the housing with respect to the longitudinal midpoint and the angle to divide material in the mixing chamber between the at least one blade of the set of blades and the other blade of the set of blades, as the cylindrical housing is rotated about the rotation axis.

Abstract: Methods and systems are provided to improve PGNAA substance analyzers. In one aspect, an analyzer includes: a source of neutrons; an opening to receive a substance; a gamma ray detector; and computational device(s) configured to receive spectral data of detected gamma rays, perform a regression algorithm on the spectral data using spectral responses for known atomic elements to determine coefficients of spectrum, sum effective weight values (corresponding to the coefficients of spectrum) together to form a total effective weight value for the substance being analyzed, divide effective weight values by the total effective weight value for the substance to generate effective weight-percent values corresponding to two or more respective ones of the atomic elements detected in the spectral data, and generate final weight-percent values based on a correlation of previous effective weight-percent values obtained for known samples with elemental or molecular weight-percent values obtained for the known samples.

Abstract: Methods and systems are provided to improve prompt gamma neutron activation substance analyzers. In one aspect, a detector unit for prompt gamma neutron activation analysis includes: a scintillator configured to fluoresce when impacted by gamma rays generated by absorption of neutrons by a substance to be analyzed; a photosensor configured to receive fluorescence from the scintillator; electronics coupled with the photosensor, the electronics configured to receive and process analog signals from the photosensor and output digital detection signals for the substance; and a housing containing the scintillator, the photosensor, and the electronics; wherein the housing includes interfaces configured to receive cables capable of providing power, temperature control, and digital communication signals.

Abstract: Methods and systems are provided to improve prompt gamma neutron activation substance analyzers. In one aspect, a detector unit for prompt gamma neutron activation analysis includes: a scintillator configured to fluoresce when impacted by gamma rays generated by absorption of neutrons by a substance to be analyzed; a photosensor configured to receive fluorescence from the scintillator; electronics coupled with the photosensor, the electronics configured to receive and process analog signals from the photosensor and output digital detection signals for the substance; and a housing containing the scintillator, the photosensor, and the electronics; wherein the housing includes interfaces configured to receive cables capable of providing power, temperature control, and digital communication signals.

Abstract: Methods and systems are provided to improve prompt gamma neutron activation substance analyzers. In one aspect, a substance analyzer unit includes: a source of neutrons; an opening arranged with respect to the source of neutrons to receive a substance; and a detector housing having (i) a detector configured and arranged to receive gamma rays generated by absorption of neutrons by the substance, and (ii) electronics coupled with the detector within the detector housing, wherein the electronics are configured to receive and process analog signals from the detector and output digital detection signals.

Abstract: Methods and systems are provided to improve prompt gamma neutron activation substance analyzers. In one aspect, a substance analyzer unit includes: a source of neutrons; an opening arranged with respect to the source of neutrons to receive a substance; and a detector housing having (i) a detector configured and arranged to receive gamma rays generated by absorption of neutrons by the substance, and (2) electronics coupled with the detector within the detector housing, wherein the electronics are configured to receive and process analog signals from the detector and output digital detection signals.

Abstract: A metering system is described for metering quantities of particles, such as fissile, fertile and shim particles for nuclear fuel elements. Predetermined volume discharges from three particle reservoirs are collected and two of them are weighed in comparison with a predetermined standard. A small amount of particulate material is added to each of the two weighed containers dependent upon the difference between the weight of the volumetrically dispensed particles therein and the predetermined standard. All three intermediate containers are then discharged into a volumetric chamber which is then brought to a standard volume by the addition of further particles. The resultant charge in the volumetric chamber is comprised of a fixed volume in which the weight of particles from two of the three reservoirs is standardized.