Radioactive Waste

5-Gallon Radioactive Waste Pail

This section includes information about the disposal of several different types of radioactive waste including solid waste, liquid waste, liquid scintillation counting wastes, mixed waste (waste that is both radioactive and chemically hazardous), and uranium and thorium wastes. 

Click on the links at the bottom of this page to see the specific procedures for each type of waste.

Preparing Waste Pails for Disposal

  1. Pull up the top of the yellow pail liner.  Close the neck of the bag and twist it.  Use the cable tie to close the bag securely.    
  2. Place the lid on the pail and twist the lid securely shut.
  3. Pail must not be overfilled – you must be able to seal the bag and close the pail. 
  4. Complete both halves of the the ID Tag.  Note that the Date on the tag is the date on which you deliver the pail to EHS. For long-lived wastes, you must enter the amount of radioactivity in the pail.  For short-lived waste, it is acceptable to check either the < 1 mCi or> 1 mCi boxes.

Removing Waste from Your Lab

  1. When the radioactive waste pails in your lab are filled or no longer needed, contact one of the waste collection staff listed in the Staff menu.  If your lab is located in Carl Icahn Laboratory, Guyot Hall, Lewis Thomas Laboratory, Moffett Laboratory or Schultz Laboratory, you will make an appointment to bring your waste pails to the Radioactive Waste Facility in Room 066, Moffett Laboratory.  If you work in any other building, you will make an appointment for EHS staff to pick up your waste pails. 
  2. Put your pails on a cart or carry them over.  Wear a lab coat and gloves.

Solid Radioactive Waste

Long-Lived Waste

For wastes with half-lives > 120 days. Example: solid waste contaminated with H-3 or C-14.

Solid wastes containing radioisotopes with half-lives greater than 120 days are collected in white 5-gallon polypropylene pails lined with heavy plastic yellow liners.

White 5-gallon pail for long-lived solid waste

Use this pail for solid wastes with half-lives > 120 days

Short-Lived Solid Waste (Decay-in-Storage Waste)

Solid wastes containing radioisotopes with half-lives of 120 days or less are collected in pails within laboratories and then transferred to a campus storage facility, known as the Decay-in-Storage (DIS) Facility. These wastes are held for a minimum of ten half-lives and then surveyed. If no detectable radioactivity is found, the waste is then disposed of as non-radioactive medical waste.

Decay-In-Storage Waste with Very Short Half-Lives (< 15 days)
Example: P-32

Solid wastes containing radioisotopes with half-lives < 15 days are collected in the lab in gray 5-gallon polypropylene pails lined with heavy plastic yellow liners.

Gray 5-gallon pail for P-32 waste

Use this pail for your P-32 solid waste.

Decay-In-Storage Waste with Moderately Short Half-Lives (between 15 - 120 days)
Example: P-33, S-35, I-125

Solid wastes containing radioisotopes with half-lives between 15 and120 days are collected in the lab in blue 5-gallon polypropylene pails lined with heavy plastic yellow liners.

Blue 5-gallon pail for solid wastes such as P-33, S-35 or I-125

Use this pail for P-33, S-35 and I-125 solid wastes.

Prohibitions

A red sharps box

Put your syringes, razor blades, pasteur pipettes and other sharps into a sharps box and then put the box into the radioactive waste pail!

  • No unprotected sharps
  • No liquids, except for droplet amounts and damp materials
  • No hazardous chemical wastes
  • No animal wastes
  • No contained sources (see the section below about contained source disposal)
  • No lead (such as lead pigs and lead shielding)

Radioactive Gels

Radioactive gels should be disposed of in the solid radioactive waste bins and not down the sink. They do not need to go in a secondary container in the solid waste bins.

Click here for Laboratory Radioactive Waste Disposal Procedures - Solid Waste

Disposing of Contained Sources

Examples of contained sources (plated and sealed sources)

In a contained source, the radioactivity is present in a form that is not easily dispersible due to its design characteristics.  For example, the radioactivity may be encapsulated in a welded capsule, embedded into a matrix or plated onto a surface.  Contact EHS prior to disposing of contained sources.  Special waste packaging and disposal arrangements may be necessary.

Liquid Radioactive Waste

Lab sink posted with Radioactive labeling

Liquid Waste

Liquid radioactive waste generated on campus may be disposed of through laboratory sinks if certain regulatory and University conditions are met. 

  • Sink Location
    You must use the pre-approved Radioactive Disposal sink in your lab.  As shown in the photo above, the sink will be clearly labeled with Radioactive labeling.
  • Solubility and pH
    The compounds you dispose of either be readily dispersible biological materials or must be aqueous or readily soluble in water. Refer to the list of Radioactive Compounds Approved for Drain Disposal.  If any of your compounds do not appear on the list, contact EHS for a solubility determination.  The pH of your waste must be 5-9.
  • Limiting Contamination
    Pour close and into the drain and run water for a minute after the disposal.
  • Recording & Reporting Disposals
    Every time you dispose of radioactive waste to the sink, you must record your disposal on the lab's Sink Disposal Log and estimate the amount of radioactivity released (see the Resource sidebar to download the form).  At the end of each calendar year, EHS will request that your lab report the total amount of radioactivity released per isotope for that calendar year.
  • Estimating the Amount of Radioactivity in Your Disposal
    You may consult with members of your own lab to estimate what percentage of the radioactivity is expected to end up in the liquid waste.  You may also contact EHS to collect samples of your liquid waste.  EHS will perform liquid scintillation counting of your samples and will provide you with radioactivity concentrations.  
  • Radioactive Gels
    Radioactive gels should be disposed of in the solid radioactive waste bins and not down the sink. They do not need to go in a secondary container in the solid waste bins.

Drain Disposal 

EHS maintains a list of radioactive compounds approved for drain disposal. Disposal of any material not on this list must be approved in writing by EHS. Questions: 609-258-5294 or ehs@princeton.edu

Compounds Approved for Drain Disposal PDF »

[Updated 2/19]

Liquid Scintillation Counting Wastes

A 5-gallon red plastic pail for liquid scintillation wastes

Use this red pail for liquid scintillation wastes.

All liquid scintillation vials, regardless of radioisotope, are collected in red 5-gallon polypropylene pails lined with heavy plastic yellow liners.

Restrictions

  • LSC solutions must have a flash point of 140°F or greater.  Most solutions described as eco-friendly or biodegradable are acceptable, but you are expected to read the product literature to verify that the flashpoint is at least 140°F.
  • Do not place any other waste materials (such as gloves, etc.) in the scintillation vial waste pails.
  • Be sure that the vials are tightly closed.

Mixed Wastes

Mixed wastes are radioactive wastes which also contain hazardous waste components regulated under RCRA (the federal Resource Conservation and Recovery Act) regulations.  It may not be easy to dispose of mixed wastes, and often we must establish special collection and storage procedures that are specific to your protocols.  Contact EHS before generating mixed wastes.  

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.

If you are not sure whether your wastes are mixed wastes, i.e., containing both radioactive and hazardous components, contact EHS to make the determination.

Uranium and Thorium Wastes

Do not dispose of any uranium or thorium compounds as regular trash or as hazardous chemical waste. In general, all uranium and thorium wastes, regardless of how the uranium or thorium was purchased, must be disposed of as radioactive waste. Contact the Radiation Safety Officer to discuss disposal options and to make disposal arrangements.

Radioactive Sewer Release Report

Isotope #1
μCi
Isotope #2
μCi
Isotope #3
μCi
Isotope #4
μCi
Isotope #5
μCi
Isotope #6
μCi
Isotope #7
μCi
Isotope #8
μCi
Please send all calendar year sewer release paper copies to EHS at 262 Alexander St.