Year
1990
Abstract
As a precise and non-destructive technique calorimetry is an appropriate method for the measurement of plutonium bearing samples. The sample thermal power measured by the calorimeter, when combined with isotopic ratio data obtained from mass or gamma-ray spectroscopy, provides a measurement result in terms of plutonium mass. The transportable calorimeter described in this paper is of improved design and it is intended for use in the assay of low power (1 to 10 Watts) plutonium bearing samples. The samples, which are in sealed containers, have compositions which range from metal to oxide and metal-salt mixtures. The thermal and electrical characteristics of the calorimeter have been optimized in order to enhance measurement performance. Measurement chamber temperature stability is improved over earlier calorimeters of a similar design and heat-transfer modelling has been employed in the design to reduce measurement times. The device may be used with a preheater and the normal measurement process includes equilibrium sample power prediction. A 'friendly' softwareuser interface is employed so the instrument may be operated by semi-skilled staff. Comprehensive diagnostic and test software is also implemented on the system. Preliminary measurements are reported on a series of plutonium metal billets and smaller plutonium metal samples.