Radionuclide Fact Sheet

TRITIUM (HYDROGEN - 3)

Symbol: ³H

States/Forms: Soluble, except gaseous

Physical Characteristics

Hazard Category

Radiological Characteristics

0% of beta particle energy transmitted through dead layer of skin.
Critical organ: Body water or tissue.
Routes of intake: Ingestion, inhalation, puncture, wound, skin contamination (absorption).
Internal exposure and contamination: Primary radiological concerns with ³H.
External exposure: External exposure from weak ³H beta particles is not a major radiological concern

Dosimetry

Bioassay Requirements

Routine urinalysis is required after handling 100 microcuries (μCi) or greater of ³H. Spot checks may be necessary following spills or incidents of contamination.

External Radiation Hazards and Shielding

There is minimal external hazard with ³H, i.e. the vial containing the ³H provides sufficient shielding from the beta particles. If the skin is contaminated with ³H, the betas will not be able to penetrate through the dead layer of skin. However, if ³H is absorbed into the body via ingestion or cuts in the skin, it will cause a radiation dose.

Hazards if Internally Deposited

ALI (Annual Limit of Intake)

DAC (Derived Air Concentration)

Survey Instrumentation

Tritium cannot be detected using a Geiger-Muller or NaI survey meter.
Smear surveys, using liquid scintillation counters, are required to detect ³H contamination.

Problems and Precautions

Lab coats and protective gloves should always be worn when working with ³H to keep skin free from contamination, and gloves should be changed often.
All waste in a ³H work area is considered to be contaminated. Work areas should be kept free of unnecessary items.
Wastes should be segregated to those with ³H and ¹⁴C only.