105 CMR 120.543
Decay-in-storage
(A) A licensee may hold radioactive material with a physical half-life of less than 120 days (or
longer, if the Agency has approved it) for decay-in-storage before disposal without regard to its
radioactivity if the licensee:
(1) Monitors radioactive material at the surface and determines that its radioactivity cannot
be distinguished from the background radiation level with an appropriate radiation detection
survey instrument set on its most sensitive scale and with no interposed shielding;
(2) Removes or obliterates all radiation labels except for radiation labels on materials that
are within containers and that will be managed as biomedical waste after they have been
released from the licensee; and
(3) Separates and monitors each generator column individually with all radiation shielding
removed to ensure that its contents have decayed to background radiation level before
disposal.
(B) For radioactive material disposed in accordance with 105 CMR 120.543(A), the licensee
shall retain a record of each disposal in accordance with 105 CMR 120.590(M).
SPECIFIC REQUIREMENTS FOR THE USE OF RADIOACTIVE MATERIAL FOR
UPTAKE, DILUTION, OR EXCRETION STUDIES