Open AccessMechanical Design of Hybrid Densitometer for Laboratory Applications
Author(s) -
G.N. Walton,
P. J. Polk,
S.T. Hsue
Publication year - 1999
Language(s) - English
Resource type - Reports
DOI - 10.2172/3342
Subject(s) - densitometer , plutonium , uranium , americium , nuclear engineering , neptunium , actinide , radiochemistry , collimated light , nuclear fuel cycle , spent nuclear fuel , materials science , optics , chemistry , radioactive waste , nuclear chemistry , physics , engineering , metallurgy , laser
The hybrid K-edge densitometry (KED) and x-ray fluorescence (XRF) densitometer is a unique nondestructive assay (NDA) technique to determine the concentrations of nuclear material (SNM) in solutions. The technique is ideally suited to assay the dissolver solutions as well as the uranium and plutonium product solutions from reprocessing It is an important instrument for safeguarding reprocessing; it is also a useful tool in analytical laboratories because of its capability of analyzing mixed solutions of SNM without chemical separation. Figure 1 shows the hardware of an hybrid system developed at Los Alamos. The hybrid densitometer employs a combination of two complimentary techniques: absorption KED and XRF. The KED technique measures the transmission of a tightly collimated photon beam through the sample; it is therefore quite insensitive to the radiation emitted by the sample material. Fission product level of {approximately}1 Ci/mL can be tolerated. The technique is insensitive to matrix variation. XRF measures the fluorescent x-rays from the same sample and can be used to determine the ratios of SNM. The technique can be applied to thorium, uranium, neptunium, plutonium, and americium concentration determination. The technique can also be applied to mixed solutions found in nuclear fuel cycle without separation: thorium-uranium, uranium-plutoniun neptunium-plutonium-americium. The design of the hybrid densitometer is shown schematically in Figs. 1 and 2; Fig. 1 shows the top view; Fig. 2 shows the side view. The heart of the design is the changer. The sample changer can accommodate a sample tray, which holds up to six samples. The samples can be a 2-cm path length cell, 4-cm path length cell, or a mixture of both sizes. The sample tray is controlled by a "Compumotor" which in turn is controlled by a computer. The absolute position of the sample cell can be reproduced to a standard deviation of 0.02 mm. The sample changer is housed inside square stainless steel tubing which is bolted onto the glove box. The sample cells can be observed during the movement or assay through a leaded glass viewport, as shown in Fig. 3