Radiochemical laboratory

(chemistry) A specially equipped and shielded chemical laboratory designed for conducting radiochemical studies without danger to the laboratory personnel.

A laboratory or facility used for investigation and handling of radioactive chemicals that provides a safe environment for the worker and the public. Features vary depending on the type of radioactive emissions to be handled, the quantity, the half-life, and the physical form (solid, liquid, gas, or powder). Special measures to minimize spread of contaminated material and to dispose of radioactive waste are required. Working surfaces should be smooth and easily washable to permit effective decontamination if necessary. Good ventilation and detectors for monitoring radiation and contamination on surfaces or people are also typical features.

Investigations utilizing only very small amounts (a few microcuries) of beta or gamma emitters which are not readily dispersed (no powders or volatile liquids) may sometimes be performed without special facilities on the bench top. In this case, precautions such as working on plastic-backed absorbent paper and wearing protective gloves and lab coat may be sufficient. A special bag or can for disposing of the paper and gloves as radioactive waste is required. If the radioactive isotopes are solely alpha-particle emitters, containment and isolation from direct contact are more serious concerns. Due to the limited penetration but high biological toxicity of alpha particles, it is essential to avoid ingestion or inhalation. For very small quantities, work may take place with double rubber gloves in a fume hood with appropriate filter. Generally, an enclosed glove box is used, situated inside a hood and maintained at negative pressure with respect to the face of the hood and the room. Sensors to monitor proper differential pressure and adequate airflow are usually used to assure containment and to generate an alarm if conditions degrade.

For work with pure beta-emitting isotopes, long-handled tongs or other tools are used for higher levels of radioactivity in order to shield the hands. Generally, since most beta emission is also accompanied by penetrating gamma emission, the entire work area must be enclosed in heavily shielded enclosures. See also Radiation chemistry; Radiochemistry.

Hot laboratories contain walled enclosures for remotely handling larger quantities of gamma-emitting isotopes. A small enclosure is usually referred to as a cave, while large ones are called hot cells. Hot cells are usually equipped with remote manipulators and thick windows made from high-density lead glass.