Calcination and Hydrofluorination Example Assessment

DOE-HDBK-3010-94

7.0 Application Examples; Dry Processing Line Example

fires is warranted. An additional obvious conclusion is that the current practices for storing

plutonium in the calcining glovebox need to be reexamined.

The appropriateness of those practices is particularly questionable when the overall

operational environment is considered. Although well-insulated, there are vessels operating

at very high internal temperatures in both gloveboxes. The calcining glovebox contains a

pressurized oil that is combustible even if the likelihood of ignition is very small. Likewise,

even though it has been painted with a fire-retardant paint, there is a large amount of

combustible shielding surrounding the hydrofluorination glovebox. There is a much greater

standing combustible loading in this process room than any of the other example rooms

considered. Although not considered highly likely, an objective assessment will conclude

there is a greater chance of a large fire in this process room than any others. Given the

existence of combustible loading that does not have to be theoretically assumed, this

operation may be an appropriate worst-case upon which to estimate temperature conditions

that the ventilation filtration system may be exposed to.

As previously noted, potential considerations raised by this example begin with altering

storage practices in the calcining glovebox. Potential improvements could include items such

as limiting material storage quantities at any one time, reconfiguring the geometry of the

storage rack vis-a-vis the containers, or even using different types of containers. It is

undesirable to use metal containers for storing the peroxide precipitate, but the use of Pyrex

or Pyrex-lined containers may be feasible. Other potential considerations include use of a

noncombustible hydraulic fluid in the calciner hydraulic system, ultimate replacement of the

hydraulic sheath rotating unit with an all-electric unit like that installed in the

hydrofluorinator, and reexamination of man-rem vis-a-vis appropriate shielding for the

hydrofluorinator.

A large fire in this room, while unlikely, is probably the most severe, potentially feasible

release examined as a result of internal initiators. As such, it would also be a good

measuring point for judging how responsive integrated safety management is at the facility.

For example, while not based on DOE experience, a worst-case facility walk-through and

subsequent hazard analysis might find the following, based on similar large fire concerns at

an actual industrial facility:

1. The storage rack in the calcining glovebox is made of a combustible material such

as Benelex. Operators state that, in audits and inspections, they have requested it be

replaced on multiple occasions.

2. The hydraulic rotating unit on the calciner leaks fairly regularly. Operators state

that a standing collection of both clean and oily cleaning wipes is kept in the glovebox

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