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The Disposal of Radioactive Waste

Reviewed 5/31/16


      The disposal of radioactive waste is governed by state and federal regulations and rules established by the low level radioactive disposal sites.  Unfortunately, the complexity of these regulations requires the waste generator to separate radioactive waste in a very specific manner.  We hope this section of the Radiation Safety Manual will “ease the pain” somewhat and aid you, as a generator of low level radioactive waste, in the proper management of this waste.

Some General Rules

1. Approved radioactive waste containers must be located in the vicinity of work areas.  Each container must be conspicuously marked with approved radioactive warning signs and symbols.  Contact the Radiation Safety Office for supplies, signs, etc.

2. Waste containers must be lined with the required bags to aid in handling, please fill plastic bags only ~ ½ to ¾ full.  Containers and bags are available by calling The Radiation Safety Office at 464-6510

3. Non-radioactive items must not be placed in containers with radioactive material.  It is essential that we keep our volume of radioactive waste as low as possible.

4. Waste containers should be brought to the Waste Room, Room 227, WH after scheduling an appointment with the Radiation Safety Office.  Each container must be accompanied by a completed green (3”x5”) “Record of Carcass and Waste Disposal.”  Supplies of the disposal cards are available by contacting the Radiation Safety Office.  Contact this Office, also, for the Waste Room schedule.

5. Each waste generator is required to keep an accurate record of all radioactive waste in each container brought to the Waste Room for disposal.  The record must indicate: type of radioactive material, the activity in microcuries, date of disposal and name of generator.  It is recommended that tally sheets be maintained for each container.

6. All radioactive waste will be taken to Room 227, Weiskotten Hall for disposal.  Contact the Radiation Safety Office at 4-6510 for a waste pickup.

7. In general, waste will be separated by half-life according to the following schedule:

Radioactive Group I:

Half-life 20 days or less (I-131, P-32, P-33 etc.)

Radioactive Group II:

Half-life greater than 20 days but less than 90 days (Cr-51, Fe-59, S-35 etc.)

Radioactive Group III:

Half-life 90 days or greater (H-3, C-14, Ca-45, etc.)

8. Lead and other hazardous materials, as defined by the U.S. Environmental Protection Agency (EPA) must not be mixed with radioactive waste.  At the present time, “mixed” waste (radioactive and hazardous material) cannot be accepted for disposal at any site in the U.S.  Mixed wastes having short radioactive half-lives may be stored on site for decay and then disposed of as a “simple” hazardous material.  Please inform Radiation Safety (4-6510) and the Environmental Health and Safety (4-5782) offices before generating any mixed hazardous waste.

Dry Waste

 Dry waste will include items such as paper, plastic gloves, etc.  Not included are animals and/or tissue, scintillation vials and liquids.  Sharps (broken glass, needles, etc.) must be collected separately.  Dry waste receptacles must be doubly lined with 4-mil plastic bags.  Waste should be separated by isotope, however, isotopes with similar half-lives may be placed together.

Liquid Waste 

All liquid waste must be segregated into the following categories:

            -  Aqueous Waste

            -  Non-aqueous Waste

      Please indicate, for each, the approximate pH and type of compound.  Do not mix compounds that may create release of gases or become reactive.

      Liquid waste must be stored in sturdy plastic containers only.  Appropriate containers will be supplied by the Radiation Safety Office.  Each container must also be equipped with a leak-proof screw cap.

      Sewer disposal of liquids is not allowed unless written authorization is received from the Radiation Safety Officer.

Sewer Disposal

All releases of liquid radioactive waste to the sanitary sewer must comply with the following requirements:

1. Written permission from the Radiation Safety Officer after submission of a written request by the authorized user.

2. Designation and proper labeling of one disposal sink per authorized user.  Appropriate labels are available at the Radiation Safety Office.

3. All liquid waste must be readily soluble in water.  No exceptions.

4. The total annual release allowed will be set by the Radiation Safety Officer.  Releases into the sewer should be spread evenly over the calendar year.

5. Radioactivity concentrations should be diluted to one microcurie or less per liter at the time of disposal.

6. An accurate log indicating the date, radionuclide, and activity of each disposal must be kept.

Liquid scintillation waste

 This waste should be stored in the scintillation vials.  Please do not combine into larger volumes.  We strongly recommend the use of the newer “Biodegradable” solutions which have a flash point above 180 degrees F.  In preparing liquid scintillation fluids for disposal, please do the following:

1. Separate vials at background or containing 0.05 microcuries or less of Carbon-14 or Hydrogen-3 per milliliter.  This waste is not regulated and can be disposed of with regard only to its chemical composition.

2. Separate the vials into two groups:

Group 1:

Flash point greater than 180 degrees F and activity greater than 0.05 microcuries per milliliter.

Group 2:

Flash point equal to or less than 180 degrees F and activity greater than 0.05 microcurie per milliliter.

3. Place vials in a 4-mil plastic bag.  Fill only ½ to 3/4 full.  Seal bag by twisting top of bag and taping with duct or masking tape.  Repeat with two addition 4-mil bags so that the vials are enclosed with a triple layer of plastic, each with a separate end closure.  Place the radioactive waste tag on the outside of the completed package.

Biomedical Waste

Please follow this guidance:

1. Place larger animals singly into 4-mil plastic bags and seal.  Smaller animals may be grouped together provided they contain the same radioactive materials.

2. Free liquid must be absorbed using paper towels, on absorbent pads or other absorbent material approved by the Radiation Safety Office.  Please do not include any other items with this waste.

3. Whenever possible, separate by similar half-life.

4. Biomedical waste containing known pathogens must be treated by an approved method such that the pathogens are rendered inactive-before delivery for disposal.

5. All non-sterile biomedical waste should be kept frozen in the authorized user’s laboratory and delivered frozen to the Waste Room.  If space becomes a problem, contact the Radiation Safety Office.

6. Animal carcasses containing 0.05 microcuries or less per gram of C14 and/or H3 may be disposed of as non-radioactive.  However, records must be maintained indicating the activity per gram and how this was determined, the method and date of disposal.