Chemical Exposure Evaluation

DOE-STD-3014-96

APPENDIX D

simple, straight-line Gaussian dispersion modeling. Guidance on the use of this

and other models can be found in the literature (Reference 2). In addition,

computer codes may be used for modeling material transport and assessing

consequences. Where they are used, their appropriateness should be justified

on a case-by-case basis, recognizing that different codes tend to have different

domains of applicability (e.g., puff releases, explosive releases). Examples of

computer codes that may be appropriate under certain analytical conditions

include the MELCOR Accident Consequence Code System (MACCS)

(Reference 3) and the Explosive Release Atmospheric Dispersion Code (ERAD)

(Reference 4).1

Chemical Exposure Evaluation. A wide variety of chemical releases may potentially

D.2.

occur as a result of an aircraft crash. One of the most critical tasks is to select the vapor

dispersion model that is most appropriate for the accident scenario. Guidance for

characterizing many of the most common types of accident scenarios and for performing

the exposure modeling is provided in References 5 and 6.

D.2.1 Definition of Source Terms. The series of flowcharts in Figure D-1 is intended to

help the analyst clearly define the accident scenario to be modeled. Beginning

on page D-7 of Figure D-1, the analyst should identify which case is most

applicable to the accident scenario being investigated. Page D-7 directs the

analyst to go to another page of Figure D-1 and proceed to identify sections of

references (such as References 5 or 6) or seek expert advice. On subsequent

pages of Figure D-1, the scenarios are broken down into more classes, after

which the analyst is directed to other sections of appropriate references, where

he/she will either find advice on how to model the scenario of interest or be

advised to seek expert advice. Clearly, Figure D-1 is a simple, paper-based

expert system. It can readily be modified to include

These computer codes have been listed as examples only. Their identification here does not represent

endorsement of the codes, individually or collectively, nor does it imply blanket acceptance of the codes

that may be used in meeting the requirements of this standard.

D-4