Guidance Info
H3 Reference Sheet
Handling Precautions: Tritium
Long Lived Radionuclide
- Half-life: 12.32 years
- Type of Emitter: Beta
- Beta Energy: 0.0186 MeV
- Travel Distance in Air: 0.61 cm : 0.24 inches
- Travel Distance in Tissue: Insignificant
Annual Intake Limits
- Inhalation: 80,000 µCi
- Ingestion: 80,000 µCi
Concerns
The major concern with using 3H is internal exposure. 3H cannot be readily monitored during it's use, as with a survey meter, therefore, special precautions are needed to keep the work environment clean. Many tritium compounds readily migrate through gloves and skin because of the chemical compound. Exposure may occur if an individual contaminates their skin, accidentally ingests the material, or breathes in a gas or vapor. Simply put, 3H is not hazardous if external to the body.
None required.
Detection
Removable contamination is detected by a wipe survey (bench tops, floors, refrigerator handles, phone, etc.) and counting the wipes in a Liquid Scintillation Counter.
Safety Rules for 3H
Follow General Safety Precautions for all isotopes.
Specific Recommendations: While Working
- Many tritiated compounds can readily penetrate gloves and skin. Wear two pairs of gloves and change the outer pair every fifteen to twenty minutes to reduce cross contamination (spreading contaminant to other surfaces and areas) and skin absorption.
- Some forms of tritium, such as 3H gas and 3H2O, are volatile. Suitable traps may be necessary to reduce releases.
- Routinely wipe surfaces to monitor for tritium contamination. Portable survey meters (Geiger Counters) are NOT sensitive to tritium.
- Submit a urine sample for bioassay if requested by the Radiation Protection Office or if an intake is suspected.
Specific Recommendations: Post Use
- Conduct a wipe test of work areas and equipment surfaces and count them in a Liquid Scintillation Counter.
- Dispose 3H waste according to the waste disposal guidelines. If by sink disposal, ensure that it is soluble in water and does not exceed the posted limit (1000 µCi daily, if only one radionuclide is being disposed of). Do not exceed this limit , unless otherwise authorized the Radiation Safety Committee in the permit.
- 3H and 14C waste may be combined but must be segregated from short-lived waste.
Email radiation_protection at harvard dot edu to send comments and suggestions to the Radiation Protection Office
