Radiation Safety

Decay in storage

Solid radioactive waste with half lives less than or equal to 120 days can be disposed as ordinary trash under the following conditions:

  1. The waste must be held in storage until the radiation exposure rate cannot be distinguished from background radiation levels.
  2. The waste must be monitored at the container’s surface and with no interposed shielding.
  3. The waste must be monitored with an appropriate radiation detection instrument set at its most sensitive scale.
  4. The licensee must obliterate or remove all radiation labels.
  5. The Record of Disposal form must be complete and maintained at least 3 years.

As a general rule, the contents of the container should be allowed to decay for at least 10 half-lives of the longest-lived radioisotope in the container. The container should be sealed, properly shielded, and labeled with the date sealed, isotopes present, the date when 10 half-lives have transpired, and the individual who sealed the container.

Page last modified May 19, 2011