SECTION 7: Radioactive Waste Disposal

• The Radioactive Waste Management Program
• Mixed Wastes
• Waste Disposal Procedures
  • Liquid Scintillation Counting Wastes
  • Liquid Waste
  • Solid Waste

The Radioactive Waste Management Program (top)

Several factors determine the route by which radioactive wastes are disposed. These factors include: half-life, radionuclide, chemical constituents, physical form (liquid or solid), dose rate, and other physical characteristics (is the source sealed and encapsulated or open?).

• Most solid wastes that contain isotopes with half-lives not exceeding 120 days are handled through the centralized Decay-in-Storage (DIS) Program for ultimate disposal as non-radioactive medical waste. The DIS Program is operated by the Molecular Biology Department with oversight by Environmental Health & Safety (EHS).
• Solid radioactive wastes contaminated with radionuclides with half-lives greater than 120 days are disposed of through a contracted radioactive waste disposal services broker as part of the Off-Site Radioactive Waste Disposal Program managed by EHS.
• Certain liquid wastes are disposed of through the Sanitary Sewer Disposal Program managed by EHS.
• All liquid scintillation wastes are disposed of through a contracted radioactive waste disposal services broker as part of the Off-Site Radioactive Waste Disposal Program managed by EHS.
• Special wastes that include animal or other biological waste, hazardous chemical wastes such as phenol, sealed sources, certain uranium and thorium compounds, radium, or transuranic isotopes are disposed of through special arrangement. Contact EHS to make disposal arrangements.

Mixed Wastes (top)

Mixed wastes are radioactive wastes which also contain hazardous waste components regulated under RCRA (the federal Resource Conservation and Recovery Act) regulations. Currently there are limited options for the disposal of mixed wastes, and the options which do exist are often costly.

In the laboratory setting the type of mixed wastes most likely to be generated include:

• contaminated lead
• certain organic solvents such as chloroform, phenol, toluene and xylene.

EHS is available to help determine whether specific wastes meet the definition of mixed wastes. Whenever feasible, contact EHS before generating mixed wastes to allow time to determine disposal options or to establish procedures which may prevent a mixed waste from being generated. The flow charts at the end of this section will allow a user to determine the basic disposal route for any waste form and will either refer the user to detailed disposal procedures or to EHS for further help.

Waste Disposal Procedures (top)

The flow charts at the end of this section will allow a user to determine the basic disposal route for any waste form and will either refer the user to detailed disposal procedures or to EHS for further help.

Summary of Radioactive Waste Disposal Procedures

Step 1: Is this animal or other biological waste?

• Yes - call EHS for procedures
• No - go to Step 2

Step 2: Is this mixed waste?

• Yes - call EHS for procedures
• No - go to Step 3

Step 3: Is this liquid scintillation counting waste?

• Yes - go to LSC procedures
• No - go to Step 4

Step 4: Is the waste liquid?

• Yes - go to liquid waste disposal chart
• No - go to Step 5

Step 5: Is the waste solid?

• Yes - got to solid waste disposal chart

Liquid Scintillation Counting Wastes (top)

• The use of toluene-, xylene- and pseudocumene-based solutions is prohibited.
  
• LSC solutions must have a flashpoint of 140º F. or greater. Acceptable LSC solutions include:
  
  • BCS
  • CytoScint ES
  • Formula 989
  • BCS-NA
  • Ecolite
  • Scintiverse BD
  • BetaMax ES
  • Ecolume
  • Universol ES
  • Bio-Safe II
  • Econo-Safe
  • Fisher’s ScintiSafe solutions
  • Bio-Safe NA
  • Ecoscint
• All LSC wastes, regardless of the isotope, are disposed of through an off-site disposal program.

LSC Waste Disposal Procedures

1. Obtain a lined 5-gallon pail from the department waste contact or from EHS.
   
2. To minimize costs, certain isotopes should be segregated from other isotopes. EHS will provide separate instructions for segregating LSC wastes.
   
3. Place tightly closed vials in the lined pail.
   
4. Do not place gloves or anything except vials in the pail.
   
5. Make an entry on the waste card each time wastes are placed in the pail.
   
6. When the pail is full, securely twist closed and seal the liner, using tape, string or twist ties.
   
7. Contact the department’s waste contact to take full pails to the department’s waste storage facility.
   
8. Contact the department waste contact or EHS for supplies. Call EHS with any questions.

Liquid Waste Disposal Procedures (top)

Solid Waste Disposal Procedures (top)