CDI: Nuclear Incident Characterization

Iodine is a common fission product resulting from the transmutation of uranium fuel in nuclear power reactors.  The short-lived radioactive isotope, 131I, with a half-life of around eight days, would be a particular health concern if released into the environment. 

Capture materials, such as activated carbon, are used routinely in nuclear power plants and medical isotope production facilities to remove chemical hazards during normal operations reducing emissions to safe levels. 

The chemistry of iodine, unlike other common fission products such as noble gases, is challenging to understand because of the wide range of molecular forms and oxidation states (from +VII in IF7 to -I in iodide) that it displays, which can interconvert both in the gas phase and in the solution phase for example. In the atmosphere, a wide variety of chemical forms are observed due to radical pathways that can be initiated by interaction with light, whereas in the solution phase, iodide (I-), iodate (IO3-) and molecular iodine (I2) are the most common species. 

In the event of a nuclear incident and subsequent release of radioactive iodine, such as during the Fukushima Nuclear Reactor accident, iodine-containing species could potentially interact with a number of surfaces causing further molecular interconversions.  For example, the stainless-steel reactor vessel, soil in the sub-surface, and particulates in the atmosphere.  Consequently, a detailed understanding of these complex chemical networks is required to design an effective emergency response to contain the hazard to human health.

This use case focuses on the development of the foundational science needed as a basis for the understanding of the chemical interconversions of radioactive iodine species when released into the environment during a nuclear incident.

There are several projects which are focused on different aspects of iodine chemistry. These include:

  • studies of the interaction of iodine with the surfaces of metal and alloys
  • the chemistry of alkyl iodides reacting with amines for selective chemisorption
  • work on the interaction of iodine species with particulates
  • modeling studies of the adsorption of molecules on activated carbon and their transmutation
  • the design, construction, and operation of an environmental chamber to study chemical interconversions in the gas phase

These projects are closely integrated with data analysis techniques to provide predictive capabilities incorporating quantified uncertainty focused in particular on chemical databases and kinetics modeling.

Use Case Projects