Defense in Path

DOE-HDBK-XXXX-2005

06/30/2005

or audit, not to meet the quality or reliability requirements appropriate to the use or

specificity of the item or service procured. It also includes misrepresentation of the

specifications or trademarks associated with the parts/service which fail or are otherwise

found to be inadequate because of random failures or errors within the accepted

reliability level. [DOE M 232.1-1A]

129.

DEFENSE IN DEPTH. An approach to facility safety that builds-in layers of defense

against release of hazardous materials so that no one layer by itself, no matter how good,

is completely relied upon. To compensate for potential human and mechanical failures,

defense in depth is based on several layers of protection with successive barriers to

prevent the release of hazardous material to the environment. This approach includes

protection of the barriers to avert damage to the plant and to the barriers themselves. It

includes further measures to protect the public, workers, and the environment from harm

in case these barriers are not fully effective. [DOE G 450.4-1B]

130.

DEFERRED MAINTENANCE. Maintenance that was not performed when it should

have been or was scheduled to be and which, therefore, is put off or delayed for a future

period and reported annually. [DOE G 433.1-1]

131.

DEFICIENCY. Any condition that deviates from the designed-in capacity of structures,

systems, and components and results in a degraded ability to accomplish its intended

function. [DOE G 433.1-1]

DEFICIENCY TAG/STICKER. A small tag or adhesive-backed sticker that is used to

132.

identify a facility material deficiency. The form may be marked with a serialized number

for administrative control, work order identification, and deficiency location by

maintenance personnel. [DOE G 433.1-1]

DEFLAGRATION. A rapid chemical reaction in which the output of heat is sufficient to

133.

enable the reaction to proceed and be accelerated without input of heat from another

source. Deflagration is a surface phenomenon, with the reaction products flowing away

from the unreacted material along the surface at subsonic velocity. The effect of a true

deflagration under confinement is an explosion. Confinement of the reaction increases

pressure, rate of reaction and temperature, and may cause transition into a detonation.

[DOE M 440.1-1]

134.

DEPARTMENT means the United States Department of Energy or any predecessor

agency. [10 CFR 820.2]

135.

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

DRAFT