Operational Controls - STD-1128-98master0231

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

practicable and demisters and/or heaters used to pretreat the air from wet processes prior to

HEPA filtration.

The final consideration in the design of air cleaning systems for plutonium operations is the

probability and consequences of accidents. In general, plutonium air-handling systems are

designed so that all probable accidents, including the failure of a single HEPA filter, do not

have measurable consequences offsite. It will be necessary to design the system for all

probable meteorological conditions, including (for some regions of the country) tornados.

The system must also be designed so that some improbable (but not impossible) events

(accidents) have consequences that are less than catastrophic. For example, the

simultaneous failure of two HEPA filters in series is highly unlikely (without a common

cause such as high differential pressure from an explosion or meteorological event) but

facilities must be designed so that these events are not likely to cause fatalities offsite. The

minimum performance criteria for the air-cleaning systems are dictated by DOE design

criteria. Other design parameters are finalized during the Environmental Impact and Safety

Analysis processes. They will differ from facility to facility.

8.2.2 Operational Controls

Plutonium air-handling systems must be operated within the design safety envelope of the

system, designated by Operational Safety Requirements (OSRs). Beyond that, there are

measures that can further reduce the potential for airborne plutonium, even in glovebox

operations. Even within glove boxes, plutonium should be containerized, preferably doubly

encapsulated whenever possible. Spills should be cleaned up promptly. If rags or tissues

are contaminated, they should be bagged as soon as possible.

8.2.3 Waste Treatments

The principal treatment for cleaning plutonium from air is HEPA filtration. There are other

technologies that can be used for pretreatment, but the most common is filtration.

Electrostatic precipitation, wet scrubbing, demisters to remove moisture, and other

technologies may have specific applications. (Treatment of the HEPA filters, a solid waste,

and the wet scrubber effluent, a liquid waste, are discussed in Sections 8.3 and 8.4,

respectively.)

8.2.4 Sampling and Monitoring

Sampling is the primary method used to achieve a complete and accurate legal record of

releases after they have occurred. The primary requirement for a particulate air sample of

any type is that it be representative of the stream being measured. This translates into

isokinetic sampling in a laminar flow section of the exhaust duct. The parameters needed to

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