Primary Confinement System

DOE-HDBK-1132-99

primary confinement-- established by the cladding or the storage

container (e.g., canning);

secondary confinement-- established by compartments with their

ventilation systems; and

tertiary or final confinement-- established by the building structure and its

ventilation system.

Exhaust ventilation systems are provided with HEPA filtration to minimize the

release of plutonium and other hazardous material through the exhaust path. In

addition, inlet ventilation to the secondary confinement systems should be

provided with either HEPA filtration or fail-safe backflow prevention to minimize

the release of plutonium and other hazardous materials through the inlet path.

Primary Confinement System. Cladding or storage containers typically provide

primary confinement during normal operation and anticipated operational

occurrences, and for accidents. Cladding or storage containers should provide

corrosion-resistant confinement for fuel assemblies and to prevent an

uncontrolled release of radioactive material. Special design features should be

considered to provide safe introduction, removal, and handling of stored

plutonium. These handling systems and equipment should be designed to

protect against the dropping of storage containers, fuel assemblies, and other

items onto the stored plutonium.

Secondary Confinement System. Compartments and their ventilation systems

comprise the secondary confinement system. Secondary confinement barriers

should have positive seals to prevent the migration of contamination. The use

of positive seals should be considered for penetration of enclosures within the

facility building to provide proper ventilation flow paths and to prevent the

migration of contamination within the facility. Ductwork penetrations with fire

dampers need clearance between the structure and the damper sleeve. Boots

may be needed.

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