Routine Worker Exposure

DOE-STD-6003-96

The Environmental Protection Agency (EPA) has set limits on the emissions of beryllium

into the environment from industries that process beryllium ores, metal, oxide, alloys, or waste.

40 CFR 61 limits the amount of beryllium emitted to 10 g in a 24-h period or to an amount that

would result in atmospheric levels of 0.01-g beryllium/m 3 of air, averaged over a 30-day

period. EPA's Office of Water Regulations and Standards limits the concentration of beryllium in

water to between 0.68 and 68 ng beryllium/L for protection of human health.

2.3 Routine Worker Exposure

2.3.1 Radiation

In a fusion facility, occupational exposure to radiation can result from gamma radiation,

neutron fluxes, tritium ingestion or inhalation, and the mobilization of activation products. The

exposures from all these sources are combined into an effective dose (ED) that accounts for the

energy, half-life, and biological mobility of each of the radionuclides.

Under 10 CFR 20 and 10 CFR 835, the radiological workers at commercial and DOE

facilities are limited to an annual ED (internal and external) exposure of 50 mSv (5 rem). Expo-

sures to organs, tissues, or extremities are limited to 500 mSv (50 rem). Lower limits apply to

declared pregnant women, minors (less than 18 years old) and students, visitors, and the public.

Under DOE requirements, permission of the Cognizant Secretarial Officer is required for all

occupational doses in excess of 2 rem. Higher exposures are tolerated for emergency

situations, such as saving a human life, recovering a deceased victim, and protecting health and

property.

The goal for doses due to normal and anticipated operational occurrences is 10 mSv/yr

(1 rem/yr). In all cases the dose to workers must be as low as reasonably achievable. This value

is based on ICRP 26 and NCRP 116 recommendations.

Doses should be kept "as low as reasonably achievable" (ALARA). In the design of facili-

ties the design objective for controlling personnel exposure from external sources of radiation in

areas of continuous occupational occupancy (2000 hours per year) shall be to maintain expo-

sure level below an average of 0.5 mrem (5 microsieverts) per hour and as far below this aver-

age as is reasonably achievable. The design objectives for exposure rates for potential expo-

sure to a radiological worker where occupancy differs from the above shall be ALARA and shall

not exceed 20 percent of the applicable standards of 10 CFR 835.202 (10 CFR 835).

2.3.2 Hazardous Materials

There may be a number of hazardous materials in a fusion facility such as metallic dust,

diborane, inert gases, and organic compounds. Other regulations are concerned with exposures

to these hazardous materials and other industrial hazards. In this guidance emphasis is given to

beryllium and vanadium because these materials are more relevant to fusion facilities. Exposure

limits should be taken from National Institute of Occupational Safety and Health (NIOSH) recom-

mendations (NIOSH 1994), Occupational Safety and Health Act (OSHA) regulations

(29 CFR 1910), and industrial standards.