EXTERNAL RADIATION HAZARDS AND SHIELDING:

Surface beta dose rate is 111 mrad/hr

Maximum range of beta radiation: glass 0.25 inches

plastic 0.4 inches (1 cm)

There also is some gamma radiation associated with Uranium, but, if chemical purification has removed the radium, the exposure rate will be quite low.

HAZARDS IF INTERNALLY DEPOSITED:

In general, uranyl nitrate or uranyl acetate are considered to be more chemically toxic as a heavy metal (like lead or bismuth) than as a radiotoxic element and care should be taken to prevent ingestion by following goo hygiene: wearing disposable gloves (this will also minimize beta exposure) and washing up after use.

Dusty, or vapor or aerosol-producing operations must be contained in fume hoods or glove boxes since deposition in the lungs is more hazardous.

The Stanford ALARA Annual Limit of Intake (amount which will deliver 10% of the legal limit, i.e. 5 rem to the bone surfaces) is 1 microcurie (oral) or 0.1 microcurie (inhaled).

DOSIMETRY AND BIOASSAY REQUIREMENTS:

Generally dosimeters are not required unless one is handling, i.e. in contact with, uranium samples for more than one hour/week without any absorber between one’s skin and the samples. Usually, it is only appropriate to measure finger doses using TLDs.

SPECIAL PROBLEMS AND PRECAUTIONS:

1. Always wear protective gloves to keep contamination from skin. Change gloves often.
2. G.M. survey meters are efficient for measuring uranium contamination. Smear surveys required for unrestricted areas, e.g. floors.
3. Survey waste in a uranium work area to assess contamination. Please call Health Physics (4-1408) for information on waste disposal.
4. Limit of soluble waste to sewer to 1 microcuries (1.48 g)/day per lab.