Radioactive waste is what is left over from the use of radioactive materials. Radioactive waste that is not high-level waste, or uranium or thorium millings, is classified as low-level radioactive waste. Low-level radioactive waste includes items that have become contaminated with radioactive material. For the purposes of this discussion, radioactive waste will refer to “low-level” radioactive waste.
Scientific research laboratories use radioactive materials for various types of research and development. During research and chemical analysis using radioactive materials, test tubes, bottles, tubing and process equipment come into contact with the radioactive material. This material must be segregated as radioactive waste. Sometimes, laboratory animals are injected with radioactive material for research purposes. The animal carcasses containing the radioactive material become radioactive waste and must be handled appropriately. Other examples of typical waste are contaminated protective clothing and gloves, wiping rags, mops, filters, equipment, and tools. Small quantities of radioactive chemicals which are left over from an experiment, or which are no longer needed can also be classified as radioactive waste.
It is the responsibility of the Permit Holder to manage the procurement and use of radioactive material and to minimize the production of radioactive waste. Permit Holders shall maintain records relating to the transfer, storage, or disposal of all radioactive material in their inventory.
It is the responsibility of the facility‘s Location Radiation Protection Officer (LRPO) to coordinate the collection, storage, and disposal of radioactive waste. The LRPO reviews and compiles records of disposals, or transfers, performed by the Permit Holders and maintains records of all facility releases, disposal, and shipments.
Permit Holders are encouraged to manage their activities so as to limit the amount of radioactive waste they produce. Techniques include avoiding the spread of radioactive contamination, surveying items to ensure that they are radioactive before placing them in a radioactive waste container, using care to avoid mixing contaminated waste with other trash, using radioactive materials whose radioactivity diminishes quickly and limiting radioactive material usage to the minimum necessary to establish the objective.
The danger of exposure to radiation in radioactive waste varies widely according to the types and concentration of radioactive material contained in the waste. Low-level waste containing some radioactive materials used in biochemical research labs, for example, is not particularly hazardous unless inhaled or consumed, and a person can stand near it without shielding. Low-level waste may be stored to allow short half-life isotopes to decay to background levels and to provide safekeeping when access to disposal sites is not available.
Each facility with Permit Holders using unsealed isotopes shall designate a room, area, or building for the storage of radioactive waste, which must be listed on a Permit, usually the LRPO Permit. The entrance to this area shall have a sign saying “caution, radioactive material.” In addition, the entrance should be posted with the name, office location, and phone number of the LRPO and others to be contacted in case of an emergency.
Waste with common properties managed in a similar manner is called a waste stream. Radioactive waste should be segregated into an appropriate waste stream for processing and disposal. Some examples of waste streams are:
When radioactive material is ordered, the receipt information is documented on the Radioactive Material Usage Form that was produced when the material was ordered. The Radioactive Material Usage Form must be used to track the life of the radioactive inventory item, from receipt until it is finally all consumed and transferred to the location waste status. When radioactive material inventory is transferred to waste, its administrative characteristics are no longer tracked (such as purchase order number, or catalog number). Only the physical isotope characteristics are tracked in radioactive waste, as several inventory items may be mixed together. An inventory item transfer to waste must be documented on the Radioactive Material Usage Form (or a similar tracking sheet). Radioactive waste is generated and collected in the laboratory, in a radioactive waste container. When the waste container is full, it is moved to the facility’s designated waste storage room or building. Each container shall list the isotope, activity, and date for each waste item placed in waste.
Dry, solid waste can be stored in metal or plastic containers provided they
Liquid radioactive waste can be stored in containers, provided there is a secondary containment system capable of collecting all of the liquid in case of a spill or breakage, or there is sufficient absorbent material to absorb twice the amount of liquid present in the primary container. The container shall be clearly labeled with a sign saying “caution, radioactive material.”
Liquid Scintillation vials should be collected in trays or racks in the laboratory. Vials should not be stored in the room with the liquid scintillation counter. Liquid scintillation fluid can be collected into bulk containers only in the location’s designated waste room.
Animal carcasses containing quantities of tritium (H-3) or carbon (C-14) can be disposed of as if they were not radioactive provided the activity for either isotope does not exceed 0.05 micro-Curies per gram of tissue. In using this disposal method, an animal carcass cannot be used for food.
Liquid scintillation, counting fluids containing quantities of tritium (H-3) or carbon (C-14) can be disposed of as if they were not radioactive provided the activity for either isotope does not exceed 0.05 micro-Curies per gram of medium.
Records of the isotope and activity disposed of under these exemptions must be maintained.
Waste disposal records must be complete and maintained permanently.
Maintain a separate file of each type of disposal performed at the location, such as decay-in-storage or transfer to a waste broker.
Radioactive isotopes with a half-life of 120 days or less may be disposed of as non-radioactive waste after being held for decay for at least 10 half lives. To do this, the waste shall be placed in containers that will prevent or contain spills. The containers will be labeled to indicate the date sealed, the isotope, activity, and physical form of the material. The waste shall be kept locked in the designated waste storage area. After 10 half-lives have elapsed, each bag or container of waste shall be surveyed in a low background area using a calibrated survey meter. The meter shall be capable of detecting the radiation emitted by the radioactive material. When radiation levels are indistinguishable from background, the waste can be disposed of as non-radioactive, provided all radiation labels are removed or obliterated from the waste bags or containers. Records of decay-in-storage surveys and disposals shall be maintained.
Sanitary sewerage in accordance with § 10 cfr 20.2003
Readily dispersible biological material and aqueous radioactive wastes that are readily soluble in water may be disposed of via the sanitary sewer system. All disposals shall be authorized by the facility’s LRPO. The concentration limits for material disposed of through the sanitary sewer system shall not exceed the limits specified in 10 CFR 20 Appendix B Tables , Table 3 sewer release limits and should not exceed 10 percent of those limits. These limits apply to the monthly average of the concentration at the point where the effluent leaves the control of the facility. These concentrations shall be met at the time of disposal, without regard for the additional dilution by the facility’s water usage. Disposal through septic and lagoon systems is not permitted, except by special permission of the Radiation Safety Division, after careful concentration analysis studies have been completed.
Interim storage is defined as storage of radioactive waste having a half-life greater than 120 days, with no other plans in place for transfer or disposal of the waste. Facilities must maintain detailed records of waste that is maintained as on-site interim storage. The Radiation Safety Division allows short term interim storage measures, but favors disposal rather than storage over the long term.
USDA locations with unsealed isotope Permit Holders will use licensed radioactive waste brokers for transfer of radioactive waste to licensed radioactive waste disposal or treatment facilities. The LRPO will maintain copies of the radioactive waste manifests for radioactive material shipped from their location.
See Radiation Safety Division Technical Guidance on Incineration
Burial of waste on the grounds of any USDA facility is forbidden.