Service and Utility Systems

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

C.4.4.4 Mechanical Equipment

Where possible, mechanical equipment (e.g., motors, pumps, and valves that may

be a source of radioactive contamination) should be located in the process area.

Enclosures that will contain the contamination should be placed around the

equipment. Such enclosures should be easy to decontaminate.

C.5 SERVICE AND UTILITY SYSTEMS

Utility services should be designed to provide reliability that is consistent with 1) the operational

requirements for the control and confinement of radioactive materials and 2) the potential hazards

under all probable conditions. The services and utilities that are important to the continuity of

essential plant functions should be designed to the same integrity level as the function they serve.

Some service or utility systems are connected to other systems or structures that are essential to

prevent the release of radioactive materials. Such service or utility systems must be designed so

that if they fail, connecting systems will remain functional.

C.5.1 Ventilation Systems

Ventilation systems include the supply and exhaust systems and the associated ductwork,

fans, air cleaning, tempering, or humidity control devices, and associated monitoring

instrumentation and controls required to confine radioactive materials within the ventilation

system. The design of ventilation system components does not include process vessels,

primary confinement or containment housing, or the building structure.

C.5.1.1 Design Objectives

The ventilation system should be designed to confine dispersible radioactive

material within prescribed areas of the facility. It should also be designed to limit

airborne concentrations of radioactive material in occupied areas of the facility and

in effluents to levels that are less than the applicable concentration guides and

ALARA.

The ventilation system, which serves as an engineered safety and control system,

should be designed to remain operational or fail safely under all operational and

credible accident conditions. The failure of any single component should not

compromise the ability of the system to maintain confinement of radioactive

materials or control their release to the environment. Specific response

requirements of the system and its components should be identified through a

safety analysis.

C.5.1.2 Air Flow and Balance

The design of ventilation systems should ensure that, under all normal conditions,

the air flows toward areas of progressively higher radioactive material inventory.

Air-handling equipment should be sized conservatively enough that minor

fluctuations in air flow balance (e.g., improper use of an air lock, or occurrence of a

credible breach in a confinement barrier) do not result in air flowing from higher to

lower radioactive material inventory areas. To prevent the movement of

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