Neutron activation products

Table II summarizes the parameters which relate to the measurement of each element neutron activation products, half-lives, y-ray energies, lengths of irradiation, decay, and counting. Also listed are the possible interfering radionuclides and interfering reactions producing the same isotopes from another element which were necessarily evaluated. This table is subdivided into three sections representing the elements determined during each of the three counting intervals.

The neutron activation production cycle requires only neutron irradiation without chemical separation. The target and the product are the same chemical element but have different nuclide compositions. The specific radioactivity of the product is a function of the nuclide composition of the target, the neutron flux environment, the irradiation time, and the half-life of the product nuclide, along with the nuclear cross-sections of target and product nuclides. 

Magnox Reactor waste streams include a wide range of materials such as ion exchange (IX) resins, sludge, Magnox fuel element debris (FED), reactor graphite and carbon and stainless steels. Some wastes will exhibit heterogeneity and for many construction materials such as steels there will be radionuclides present which are neutron activation products of trace impurities and were un-quantified at the time of manufacture. 

We will now consider radionuclide techniques utilized in studies of biological uptake and retention within the organism. First, studies will be reviewed that are concerned with the nutritional aspects of essential elements. These will be followed with studies of radionuclides associated with the nuclear age, such as fission and neutron-activation products. 

Many studies have been conducted on the biological uptake and retention of fission and neutron-activation products in organisms, including man and domestic plants and animals. We will consider a limited selection of studies using wild organisms to illustrate this use of tracer technology. 

The major neutron activation product is cobalt-60 with a reasonably long half-life (5.3 years). It emits high-energy beta particles and gamma rays appropriate for radiographic, irradiation, and isotopic power applications. It is an ideal product because naturally occurring cobalt is uniquely mono-isotopic cobalt-59 as well as a relatively stable metal. 

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