Waste Treatments - doe-std-1128-98

DOE-STD-1128-98

waste. Decontamination with high-pressure water has some similar

advantages, but care must be taken to ensure that used decontamination

solutions do not spread contamination.

8.3.3

Waste Treatments

Available treatments for solid waste include compaction and incineration. In

specific cases, there may be decontamination options available, as well.

Compaction, with pressures in the range of 40,000 to 60,000 psi, is most often used

on paper, fabric, and plastic although it is effective on glass, sheet metal, and some

other materials. With such ordinary materials, one commercial reactor has

approached up to 800 pounds of waste per 55-gallon drum, although an average of

500 pounds per drum is considered very good.

Compaction is done by drum compactor or box compactor. Compacting into a

drum or a 4- by 4- by 8-ft box is normally a labor-intensive operation and often

involves some risk of personnel exposure, even though the better compactors are

equipped with HEPA-filtered ventilation systems. Supercompaction uses

considerably higher pressures than compaction, normally 200,000 psi or greater.

Supercompaction usually involves compacting filled waste drums into a box or

overpack. Supercompaction has been success-fully used on piping and other

materials that are normally considered noncompactable.

It is really a choice of words whether incineration is considered a disposal

technique or a volume-reduction technique. All carbon, oxygen (except for any that

becomes bound in oxide ash), nitrogen, hydrogen, and sulfur present in the

incinerator feed will be converted to gasses and disposed to the atmosphere.

Plutonium and most metals will remain as a solid material. As a volume-reduction

technique, incineration is very successful, with volume-reduction factors up to

200:1 or greater achieved on some waste streams. There have been licensing delays

for some incinerators, and often there are limitations brought about by air quality

restrictions. There is also the possibility that incinerator ash may be a mixed waste

due to the concentration of other impurities such as heavy metals in the waste. If a

facility has an incinerator, a quantity of the feed material can be incinerated to

determine if the waste will have hazardous characteristics before the material is

contaminated. In some cases, it is desirable to size-reduce or repackage in

combustible packaging before incineration.

Decontamination is most successful when the material can be recycled for use in a

nuclear facility since the need to prove releasability (cleanliness) is eliminated.

Nevertheless, cleaning material for unrestricted release is also possible in some

cases. It may also be possible to decontaminate an item enough to change its

classification from TRU waste to LLW, thereby allowing immediate disposal of the

item, while a relatively small quantity of decontamination waste is stored as TRU

waste.

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