Liquid Sampling and Tank Farm Example Assessment cont'd

DOE-HDBK-3010-94

7.0 Application Examples; Liquid Storage and Ion Exchange Examples

uncontrolled release of hazardous material. Accordingly, greater attention to detail and,

potentially, more analytical documentation are warranted.

It is possible that the large release potential from the room fire may have been fully

appreciated before formally estimating the source term. It is at least as likely, however, that

it had not really been considered by the majority of personnel. In this example, the fact that

no tank venting capacity estimate could be produced would tend to indicate the latter. Given

the day-to-day difficulties of operating a facility, it would be understandable to simply think

"there's nothing that burns in there and we have a vent and a relief valve, end of story."

The amount of fuel estimated to be needed to affect large amounts of solution could also be

used to bolster this position. This would be a natural response if the meaning of the source

term was blown out of proportion and potential variability of the source term became the sole

focus of extensive effort. It is important to remember that, even unmitigated, the source

terms calculated do not represent consequence potentials approaching the catastrophic level of

consequences from higher hazard types of operations for a given area. The source term

estimation process has already provided all the useful information it has to offer.

The source term estimation indicates that the conjunction of a large amount of material in a

form uniquely vulnerable to fire release makes fire prevention a particular concern in the

tank farm area. A potentially serious vulnerability has been identified. The potential

downside of poor combustible control in this area is significantly greater than an area such as

the operating side of the residue dissolver, and allocation of limited resources may need to

reflect that fact. If this information was understood during the hazard evaluation process,

several obvious recommendations would be made. The first recommendation is that an

assessment of the particulars of the combustible loading control program be made and any

available analyses as they relate to the tank farm area be reviewed (or performed if

unavailable) to determine: (1) if the potential mechanisms for and quantities of combustible

loading in the tank farm area have been estimated; (2) if this estimation was based on a

reasonable assessment of existing conditions as verified by a walkdown and considered

nonroutine operational configurations, such as maintenance; and (3) if the significance of

minimizing combustibles in the tank farm area is understood in the safety management

programs. "Closing the issue," results in a hazard evaluation process of no value if such

recommendations are not carried out. The issue can be closed on paper while an existing

assessment is based on facility drawings and old documentation only, and the tank farm

enclosures are used as overflow storage capacity for unused resin bead drums because

"nobody spends much time in there and there's nothing else that burns in there."

The second recommendation is that the venting capacity of the tanks be documented by

analysis or testing. It is important to know whether the vessel vent system can adequately

relieve the generated vapor for the largest credible fire based on the realistic assessment

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