Derived Air Concentration

DOE-HDBK-1188-2006

136.

DERIVED AIR CONCENTRATION (DAC). For the radionuclides listed in appendix A of

10 CFR 835, the airborne concentration that equals the ALI divided by the volume of air

breathed by an average worker for a working year of 2000 hours (assuming a breathing volume

of 2400 m3 ). For the radionuclides listed in appendix C of 10 CFR 835, the air immersion

DACs were calculated for a continuous, non-shielded exposure via immersion in a semi-infinite

atmospheric cloud. The value is based upon the derived airborne concentration found in Table 1

of the U.S. Environmental Protection Agency's Federal Guidance Report No. 11, Limiting

Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for

Inhalation, Submersion, and Ingestion, published September 1988. This document is

available from the National Technical Information Service, Springfield, VA. [10 CFR 835.2]

137.

DERIVED CONCENTRATION GUIDE (DCG). The concentration of a radionuclide in air

or water that, under conditions of continuous exposure for one year by one exposure mode

(i.e., ingestion of water, submersion in air, or inhalation) would result in an effective dose

equivalent of 100 mrem or 0.1 rem (1 mSv). DCGs do not consider decay products when the

parent radionuclide is the cause of the exposure (DCG values are presented in Chapter III of

DOE O 5400.5 Chg 2). (1 rem = 0.01 sievert) [DOE O 5400.5 Chg 2]

138.

DESIGN BASIS. The design inputs, the design constraints, and the design analysis and

calculations. It includes topical areas such as seismic qualification, fire protection, and safe

shutdown. It encompasses consideration of such factors as plant availability, plant efficiency,

costs, and maintainability, and that subset that relates to safety and the authorization basis.

[EH62dd1]

139.

DESIGN BASIS. The set of requirements that bound the design of systems, structures, and

components within the facility. These design requirements include consideration of safety, plant

availability, efficiency, reliability, and maintainability. Some aspects of the design basis are

important of safety, although others are not. [DOE O 5480.23]

140.

DESIGN BASIS ACCIDENTS. Those postulated accidents that establish design and

performance requirements for systems, structures, and components important to safety.

[EH62dd1]

141.

DESIGN BASIS ACCIDENTS (DBAs). Accidents that are postulated for the purpose of

establishing functional requirements for safety significant structures, systems, components, and

equipment. [DOE O 5480.23]

142.

DESIGN BASIS EARTHQUAKE (DBE) (equivalent to safe shutdown earthquake). An

earthquake that is the most severe design basis accident of this type and that produces the