Nuclear Exposure Evaluation.

DOE-STD-3014-96

APPENDIX D

D.1.

Nuclear Exposure Evaluation. The following guidance is intended to assist the analyst

(post-structural) in modeling aircraft crashes in terms of appropriate parameter

assumptions in dispersion modeling and consequence assessment.

D.1.1 Parameter Assumptions. A set of conservative parameter assumptions is made

as follows:

MARi - The material at risk is considered to be the inventory of hazardous

materials for the ith material form, as discussed in Section 7.2.2.

DRij - The damage ratio is generated as follows. With respect to the

phenomenon of crush/impact, the damage ratio is equal to the fraction of

MAR within areas directly impacted by aircraft debris (i.e., all areas in the

path of the penetrators, as established by the structural analysis) and

other areas of the facility determined to collapse as a result of the

penetration (as established by the structural analysis). This damage ratio

may be reduced for material in robust containment for which it can be

established that not all the material will be exposed. For instance, it may

be possible to use geometrical or energy-balance considerations to

estimate a maximum number of cans, pails, or drums with which a given

aircraft fragment might interact during impact.

With respect to the phenomenon of fire, the damage ratio is equal to the

fraction of MAR within areas directly impacted by aircraft debris and, given

the presence of combustible loading to support the propagation of fire, any

adjacent areas within the same fire zone (i.e., up to the next intact fire

boundary). Further, if it is determined that the available combustible

loading will support a fire of a duration in excess of the rating of the next

intact fire boundary, the damage ratio is adjusted to include any MAR in

the adjacent fire zones. Mitigating factors may be evaluated. However,

given the difficulty of demonstrating that any available fire suppression

systems would remain functional following an aircraft impact,

D-1