Radiochemical laboratory

The apphcations described here illustrate the wide range of uses for robotic systems. This chapter is not intended to he exhaustive there are many other examples of successful applications, some of which are referenced below. For instance, Brodach et al. [34] have described the use of a single robot to automate the production of several positron-emitting radiopharmaceuticals and TTiompson et al. [3S] have reported on a robotic sampler in operation in a radiochemical laboratory. Both of these apphcations have safety imphcations. CHnical apphcations are also important, and Castellani et al. [36] have described the use of robotic sample preparation for the immunochemical determination of cardiac isoenzymes. Lochmuller et al. [37], on the other hand, have used a robotic system to study reaction kinetics of esterification. 

The radiation shielding windows are made from high density lead glasses. They are used as viewing windows placed in thick lead and concrete walls for nuclear and radiochemical laboratories. In addition, cerium stabilized borosilicate cover plates are used on the hot side. 

Table 2.5 summarizes the developments at the four major stages of the PUREX process. The success of the process is measured by the quantitative recovery (>99.9%) of U and Pu with high DFs (DF > 106) from the fission products and structural materials. There is also growing concern about the volumes of radioactive waste generated during fuel reprocessing. There have been continuous R D efforts in radiochemical laboratories toward these ends. 

Sherwood Stevens (1965) examined glass-fibre filters from personal air samplers worn by workers in the Radiochemical Laboratories at Harwell. The filters were mounted in an Araldite mixture which rendered them transparent and were covered by autoradiographic stripping film. After exposure and development, the samples were viewed with a high-power optical microscope. Particles were sized, and their activity determined from the number of alpha tracks coming from them. An extremely wide range of particle sizes, 0.2 to 90 m, was found. The smaller particles were plutonium compounds or alloys, and the larger were inert particles with one or more small Pu particles attached to them. An example of the latter is shown in Fig. 5.3. 

Sherwood, R.J. Stevens, D.C. (1965) Some observations on the nature and particle size of airborne plutonium in the radiochemical laboratories. Annals of Occupational Hygiene, 8, 93-108. 

With minor exceptions, the samples handled in a radiochemical laboratory are eventually measured with radiation detection instruments. The types of counting equipment in the counting room depend primarily on the scope and purpose of the radioanalytical chemistry laboratory mission. Common detectors of this type are listed in Table 2.1. 

The RIA-gnost Ferritin kit (no more commercially available) from formerly Behringwerke AG, Radiochemical Laboratory described below uses the principle of an immunoradiometric assay (IRMA). It is a two-site solid phase assay of the sandwich type, based on a plastic bead as solid phase to which the antiferritin antibody adheres. The antibody-solid phase is incubated with standards or serum samples containing ferritin and in this process the ferritin in the solution is bound quantitatively to the solid phase via the antibody. The amount of ferritin bound to the solid phase is then determined by a reaction with 125I-labeled anti-ferritin antibody. An antibody-ferritin-125I-antibody complex is thus formed. 

For the supeiwision of the persons working in radiochemical laboratories, pocket dosimeters (generally ionization dosimeters) and film dosimeters are used. The lower detection limits of these dosimeters vary between about 1 and 40 mR. Furthermore, hand foot monitors are installed near the exit of the laboratories, by which external contamination can be detected. In the case of suspected internal contamination, the person is checked by means of a whole-body counter which allows detection of y-ray emitters with high sensitivity. The presence of natural contributes essentially to... 

Waste water from radiochemical laboratories which may contain radioactive substances, e.g. by mistake, must be checked for radioactivity. If the condition is such that the activity should not be higher than the acceptable limit for drinking water (e.g. 1 Bq/1), very sensitive methods are necessary to detect these low concentrations. For comparison, 1 Bq/1 is the activity of 20 mg of natural K per litre, river water contains about 1 Bq/1, water from natural springs up to several kBq/1, and rainwater sampled after test explosions of nuclear weapons also contained up to 1 kBq/1. The safest method for determination of concentrations of the order of 1 Bq/1 is evaporation of about 11 and measurement of the residue by means of a large-area flow counter. This method makes it possible to detect several mBq of a or emitters. 

In the off-gas system of radiochemical laboratories, filters are installed which retain aerosols and vapours. These filters have to be checked regularly for radio-... 

Activation analysis has the advantage over other methods of trace element determination, in that after irradiation it is insensitive to contamination by inactive material. However, where nuclides of long, or moderately long, half-life are estimated in a radiochemical laboratory precautions must be taken to prevent contamination with residual activity from previous analyses ... 

Urey Radiochemical Laboratory, University of Auckland, Private Bag, Auckland (New Zealand)... 

A detailed discussion of the rules for working in radiochemical laboratories and of radiation protection measures falls outside the scope of this chapter a good summary and references for further reading are given elsewhere (Lieser, 1986). When experiments are judiciously planned, hazards of handling reactor- irradiated biological samples are seldom more important than those encountered in other work involving the use of radionuclides. 

To prepare the compounds RbioTe68i4, CsioTe68i4, RbioRe68i4, and CsioReeSn, a mixture of the alkali carbonate and rhenium or technetium in 5 1 molar ratio was in each case converted at 800 °C in a stream of hydrogen doped with sulfur. The duration of these reactions was between 10 and 16 h. The preparation of the technetium compoimds was performed in a radiochemical laboratory of the For-schungszentrum Julich. The Tc isotope used decomposes by emission. The compounds were obtained as black, lustrous crystals embedded in the partially solidified melt (Fig. 2). All four sulfides are unstable in air. 

Three basic principles are recommended for keeping radiation exposure to a minimum shielding, control, and distance. If a radiochemical laboratory is designed properly and the work performed in such a manner that the g eral background contamination is suffici tly low to do valid low level tracer experiments, then the health aspects of radiation control are satisfied. We indicate the main principles for work with radioactive substances, but in each notion, special rules may apply. 

To apply CPAA one needs access to a cyclotron, a radiochemical laboratory, and y-spectrometry and jS" "-counting equipment. The time needed for one analysis is determined by the half-life of the radionuclide induced and whether a radiochemical separation is necessary or not. The inherent complexity and costs are the major drawbacks of CPAA. 

Protective devices and clothing. In most high-level radiochemical laboratories, special clothing is part of the laboratory practice. The availability of respirators to prevent inhalation of airborne radioactivity in the event of a spill is essential. 

Low activity can, of course, be handled in an ordinary radiochemical laboratory. The limit beyond which total containment becomes a necessity is not very well defined. The concentration of the alpha-active material, as well as the nature of the operation and the skill and care of the operator, are factors which must be considered. At the level of one microcurie, ordinary laboratory procedures can be done if reasonable care is taken, while at higher levels the operations become more and more limited. At the millicurie level total containment becomes necessary for any chemical operation. In any case, proper monitoring of the activity is essential. 

Neutron activation analysis 60-100 multi-element method additional costs for neutrons and radiochemical laboratory no routine method... 

SAL Safeguards Analytical Laboratoy. A particular radiochemical laboratory at IAEA Vienna. 

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