Decontamination and Decommissioning Experience

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

operation, the quality assurance plan, and the health physics, fire control, and site emergency

manuals written for the operation.

Discussions of D&D activities at several DOE plutonium facilities are provided by Adkisson

(1987), Bond et al. (1987), and King (1980), as well as by Shoemaker and Graves (1980), Garner

and Davis (1975), Wynveen et al. (1982), Hunt et al. (1990), Freas and Madia (1982), and Garde

et al. (1982a, 1982b). They describe D&D activities that took place in several types of plutonium

facilities, including fabrication facilities, research and development laboratories, and a storage

facility. Plutonium-contaminated glove boxes, hoods, ventilation ductwork, laboratory equipment,

structural components (i.e., walls and floors), and filter banks were decontaminated. Typically,

decontamination methods included wiping with a damp cloth or mop, using strippable coatings,

mechanical spalling of concrete floor surfaces, and fixating contamination on a piece of equipment

(e.g., a hood), followed by disassembling the item inside a contamination control enclosure.

Some lessons learned from past studies include the following:

-- Waste management planning should begin early in the D&D planning stages and consider the

following:

- The possibility exists that there may be more stringent regulations for shipping hazardous or

radioactive wastes than disposing of it and

- Compliance with all applicable waste management requirements may be difficult (e.g., the

Waste Isolation Pilot Project (WIPP) does not accept mixed wastes or TRU waste that

contains plastics or foams).

-- It is difficult to decontaminate some items with inaccessible surfaces to less than the TRU limit

(100 nCi/g) so that they can be disposed of as LLW. In some situations, it may be possible to

decontaminate to <100 nCi/g of TRU, but the decontamination process may generate a large

volume of liquid waste or be time-consuming enough to prohibit its use.

-- Temporary enclosures are effective in controlling contamination when reducing the size of

large equipment such as glove boxes. Any loose contamination on the equipment should be

fixed before placing it in the enclosure.

-- Criticality safety issues regarding the geometry of any waste material containing fissile material

need to be considered.

Adkisson (1987) reported on the decommissioning of a plutonium fuel fabrication plant at the

Sequoyah Fuels Corporation's Cimarron Facility, located in north-central Oklahoma. Process

equipment, glove boxes, tanks, piping, and ventilation ducts required decontamination. Controlling

10-11