Introduction

Hydrogen-3 is a commonly used radionuclide with a half-life of 12.3 years, emitting only beta particles with a maximum energy of 0.019 MeV (Million Electron Volts) and an average energy of 0.0057 MeV. The beta particles from H-3 travel a maximum of 6 mm. in air.

Concerns

The major concern with using H-3 is that it cannot be easily monitored during it's use, therefore, special precautions are needed to keep the work environment clean. The regular use of wipe testing is the only way to ensure that your work space is not contaminated. Contamination on the skin will not likely cause a significant dose to the dead layer of skin, however, it could lead to the internal absorption of H-3. The ingestion annual limit of intake (ALI) is 80 millicuries.

Shielding

Glass and plastic are the best shields for beta particles from H-3, normally no additional shielding is necessary.

Detection

A tiny drop of contamination containing H-3 can be easily detected with a wipe test from a liquid scintillation counter. A Geiger counter will not detect the presence of H-3.

Equipment / Supplies

The following equipment and supplies must be available:

• disposable latex or plastic gloves.
• full-length lab coat.
• containers for radioactive waste.
• pipettes dedicated to the use of H-3.
• absorbent bench covering or tray.

Safety Rules

If the following safety precautions are used, personnel radiation exposure will be as low as reasonably achievable.

1. Designate a specific area of the lab for H-3 handling.
2. Full-length lab coats must be worn by all persons who handle H-3.
3. Protect the skin of your hands from becoming contaminated from spills by wearing two pairs of disposable gloves.
4. Never pipette H-3 or any radionuclide by mouth.
5. Only use pipettes which have been dedicated to your specific use of H-3. Pipettes will easily become contaminated and therefore, should not be shared with others.
6. If you have reason to believe that your gloves are contaminated, immediately dispose of them in the radioactive waste container.

Post-Use Procedures

After handling H-3:

• Conduct monthly (weekly) wipe tests.
• Count weekly wipes in a Liquid Scintillation counter.
• Check all equipment, centrifuges, water baths for contamination.
• If any contamination is found, use warm water and a mild detergent with paper towels to clean up the equipment.
• Place the towels in the radioactive waste receptacle.
• If contamination cannot be removed, place a radiation label on the equipment indicating that it is H-3, maximum cpm found, and the date you measured the level.
• Check the work bench and floor.
• If contamination is found, it can usually be removed easily as described above. If it cannot be removed, contact the RSO to obtain shielding materials.
• Inform your fellow lab workers if any unremovable contamination is found.
• Check the normal trash container to make sure no radioactive waste has been accidentally placed there.
• Store waste temporarily in specially marked containers.
• Call the RSO if you have any questions about where to survey, or how to fill out the form.
• Wash your hands thoroughly.
• Bring the waste to the RSO frequently. Do not let it pile up. The RSO accepts waste by appointment only.

Any questions about these procedures?

Call the Radiation Safety Office: 464-6510