Methodology for Aircraft Crash Release Frequency Evaluation. - Continued

DOE-STD-3014-96

not be allowed for fire suppression systems unless an explicit analysis shows that

they will remain effective.

Is the force of any explosion capable of causing further barriers to be damaged or

destroyed? Can it cause additional fires and/or explosions in the facility? Again,

credit can be taken for the dissipation of explosive energy by existing barriers, if

they have not been damaged by the crash. Credit can also be taken for diversion

of the explosive force through breaches caused by the crash, thus reducing the

shock to intact barriers. The basis for taking credit should be documented. Again,

characterization of the explosive force generated relative to barrier strength and

the force transmitted to collocated explosives is required to justify the credit.

Step 4. Based on the findings of the previous step, determine if a release could occur,

given the scenario as defined. Again, specific guidance cannot be provided, but the

following questions should guide the analyst's thinking:

Could any of the material at risk in the facility be impacted by any release

mechanism (e.g., shock, fire, explosion) as a result of the scenario? The answer

to this question should be "yes" if there is any material that is not separated from

the energy available from the release mechanism by an intact barrier capable of

dissipating that energy.

Could the primary confinement around any of that material be breached as a result

of the scenario? The answer to this question should be "yes" if the structural

integrity of the primary confinement is degraded below that required under accident

conditions and if there is a driving force capable of causing the material to migrate

through the breach.

Could a path to the atmosphere result from the scenario? The answer to this

question should be "yes" if there are no longer any intact barriers between the

material and the atmosphere, assuming that the primary confinement is failed and

that there is a driving force capable of causing the material to migrate along the

path.