Fires cont'd - h3010v10321

DOE-HDBK-3010-94

7.0 Application Examples; Solid Waste Example

noncombustible material, such as metal tools, inorganic solids, HEPA filters, glass,

etc. The predominant release mechanism for these materials is heating. The bounding

ARF and RF for these phenomena are significantly below those for combustion, so

accounting for this factor would reduce the overall source term estimate by 25% or

more.

Up to 320 drums containing a maximum of 10,000 g of plutonium can be stored in

the TRU waste annex. Therefore, if all 320 positions are used, the average drum

loading is 31 g, which is essentially the historical average. Other than the material

packaged inside the drums, the combustible loading in the Butler building annex is

very limited. In the absence of a large external source of some kind, a fire involving

all of the drums is not reasonable to postulate. A localized fire would be expected to

be fueled by the same type of bulk combustibles postulated in the drum packaging

room fire. As a result, the fire would not provide the rapid heat generation rate

typical of conditions where drum lids are blown off. The release that would be

estimated is a simple multiple of the average to maximum range (1.5E-2 g to 0.1 g)

for a single drum based on how many drums are postulated to be involved.

The only potential source of a large fire involving all of the drums is an extreme

event such as a jet airplane crash into the annex. The event itself is very unlikely,

and the actual damage that might be inflicted is largely indeterminate and based on

factors such as type of plane, angle of descent, point of ground impact, and skid

distance prior to impacting the structure, etc. The assumptions can always be made

worse by simply assuming the airplane nosedives directly into the center of the

facility, thereby making an improbable scenario more improbable. If that temptation

is resisted, and a type of airplane is specified, then basic modelling such as the

amount and type of debris reaching the facility after the crash, amount of fuel from

the fuel tanks, if any, spilling in direct proximity to the facility or its remains, and the

fraction of drums directly in the flame zone can be attempted. Drums that are largely

intact (i.e., waste still relatively packed in drum, drum shell intact with minor

openings or lid jarred) would use the ARF and RF for packaged waste if they were in

a fire zone, as would undamaged drums outside the intense flame zone. The contents

of drums broken up by missile impact would be considered uncontained waste if they

were in the fire zone. Shock-impact releases would be estimated for these drums as

well and added to the total source term. It can be assumed for drums in the intense

flame zone that a fraction of the drums blow their lids and some fraction of the

combustible waste is ejected to burn as uncontained combustible waste.

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