Nuclear and fissile materials

Last checked: February 2025

Nuclear and fissile materials

Nuclear materials, including uranium, thorium, and plutonium, are subject to strict controls at the University, with a focus on the use of Source Materials (e.g., uranyl and thorium compounds) rather than Fissile Materials, and any discovery or need for these materials requires consultation with the Chemical and Radiation Specialist due to the University's permit restrictions.

Nuclear material refers to uranium (U), thorium (Th), and plutonium (Pu) in any form. They can exist as:

1. Source Materials: natural or depleted uranium (U-238) or any isotope of thorium (Th) in any form or concentration. In research settings, these Source Materials are usually used in the form of chemicals rather than radioactive materials. Some examples are uranyl acetate, uranyl formate, uranyl nitrate or thorium nitrate.
2. Fissile Materials: U-235 (also called enriched Uranium), U-233 in any form or Pu-239 in any form or concentration.

While the use of Fissile Material is limited at the University, the use of Source Materials is more common. For example: uranyl acetate, uranyl nitrate and uranyl formate are used as stains in electron microscopy, and thorium salts are used as catalysts and reagents for fluoride determination.

What should I do if I need to use one of those Source Materials or Fissile Materials?

The University has a permit that requires strict controls. For this reason, the University has prohibited any new purchase of these chemicals. Refer to the Chemical Management Guidelines for further information and consult with the Chemical and Radiation Specialist.

What should I do if I find any chemical containing uranium or thorium in my laboratory?

You must contact the Chemical and Radiation Specialist immediately. If the chemical is still being used, directions will be given to ensure the storage and use of these chemicals comply with the University’s permit.