Design Features - doe-std-1128-98

DOE-STD-1128-98

10.2 DESIGN FEATURES

Design of the facility should allow easy D&D of equipment and materials. Details on

designing facilities for ease of decommissioning are discussed in the following sections. 10

CFR 835.1002 and Appendix C of this document provide additional guidance on facility

design.

10.2.1 Building Materials

In general, the design features that aid in contamination control during operation

also facilitate decommissioning. The inclusion of all the building materials

suggested in this section may be cost-prohibitive, but they should be considered if

the budget allows. The maintenance procedures that are used during operation are

also important in controlling the spread of contamination to clean areas and,

therefore, they facilitate decommissioning, too.

Less permeable building materials are more easily decontaminated. Any concrete

with uncoated surfaces that comes in contact with plutonium solutions or

plutonium contaminated air will require surface removal and disposal as

radioactive waste at the end of its life. If there are cracks through which

contaminated solutions have penetrated, the entire structure may need to be

disposed of as radioactive waste.

Metal surfaces may also require decontamination. In general, the more highly

polished the surface, the easier it will be to decontaminate. If feasible, all stainless

steel that will come into contact with plutonium should be electropolished before

being placed into service. If high-efficiency particulate air (HEPA) filtration has

failed at any time during facility operation, roofs may require decontamination.

Metal roofs are easiest to decontaminate, but even these may contribute to the

volume of radioactive waste unless unusual measures are taken to clean them.

Built-up and composition roofs will be difficult to clean to unrestricted release

levels.

Interior surfaces are most easily cleaned if they were completely primed and

painted before the introduction of radioactive materials into the facility. If interior

surfaces are repainted during operation, their disposal as clean waste is likely to

require removal of the paint. However, if the paint has deteriorated, cleaning for

unrestricted use may be as difficult as if the material had never been painted. Wood

will almost certainly become contaminated, as will plasterboard and other such

materials.

Floor surfaces are likely to be a problem. Concrete should be well sealed and

covered with a protective surface. Single sheet, vinyl flooring with heat-sealed

seams is preferable to asphalt or vinyl tile because it is more easily cleaned. If the

floor needs resurfacing, it is preferable to overlay new flooring material rather than

remove the old material and expose the underlying floor.

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