Operational Quantities - doe-std-1128-98

DOE-STD-1128-98

Table 6.3. Radiation Dose Limits for DOE and DOE Contractors

Type of Radiation Exposure

Annual Limit

Occupational Exposures

Stochastic Effects

5-rem total effective dose equivalent

from external sources and the CEDE

intakes received during the year

Non-Stochastic Effects

Lens of eye

15-rem dose equivalent

Extremity

50-rem dose equivalent

Skin

50-rem dose equivalent

Individual organ tissue

50-rem dose equivalent

Embryo/fetus of a Declared Pregnant Worker

Gestation period

0.5-rem dose equivalent

Planned Special Exposure

Event plus Annual

5-rem total effective dose equivalent

Occupational exposure

Minors

0.1-rem TEDE

6.1.2

Operational Quantities

Because of the difficulties in determining effective dose equivalent from direct

measurements, the concept of operational quantities has been introduced to be

more closely related to measurable quantities. Operational quantities include

ambient dose equivalent used for area monitoring and personal dose equivalent

used for personnel dosimetry. Operational quantities are designed to be a

conservative estimator of effective dose equivalent, i.e., the values of the

operational quantities will be equal to or higher than the effective dose equivalent

specified for the limiting quantities.

The ambient dose equivalent, H* (d), is the dose equivalent at a depth, d, in a 30-

cm-diameter sphere of tissue, where a) the radiation field has the same fluence

and energy distribution as the point of reference for the measurement and b) the

fluence is unidirectional (i.e., the sphere can be viewed as being in an aligned

radiation field). Most survey instruments are designed to measure ambient dose

equivalent, and international standards are based on the ambient dose equivalent

concept. The depth of interest is 1 cm of soft tissue, as specified in 10 CFR

835.2.

The personal dose equivalent, Hp(d), is the dose equivalent in soft tissue at the

appropriate depth, d, below a specified point on the body. Obviously, personnel

dosimeters should be calibrated in terms of personal dose equivalent.

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