Confinement - doe-std-1128-98

DOE-STD-1128-98

emergency personnel and equipment in the event of a radiological emergency and

to allow for access by repair/corrective action teams.

Equipment should be available to allow for an early and reliable determination of

the seriousness of an accident or abnormal event. Depending upon the consequence

of potential accidents, consideration should be given to relaying all such equipment

alarms to a central control system or a continuously manned area. Installed on-line

equipment should be protected to the extent necessary to ensure its reliability under

accident conditions. To further enhance equipment reliability, the emergency

equipment should, to the extent practicable, be the same equipment used for routine

operations.

Emergency-power requirements that need to be satisfied and the means to provide

the power should be identified in the design effort.

Emergency radiological equipment should be installed or located in areas that

permit periodic inspection, testing, calibration, and maintenance.

Additional emergency-preparedness guidance is provided in Section 9.0.

C.2.2

Confinement

The confinement system is a series of physical barriers that, together with a

ventilation system, minimizes the potential for release of radioactive material into

work areas and the environment under normal and abnormal conditions. The

primary design objective for the confinement system should be to minimize

exposure of the public and plant personnel to airborne contamination. Plutonium

should be separated from the ambient environment by at least two barriers and

from an operator by at least one barrier.

Primary confinement refers to the barrier that is or can be directly exposed to

plutonium, e.g., sealed process equipment (pipes, tanks, hoppers), glove boxes,

confinement boxes, open-faced hoods, conveyors, caissons, and cells and their

ventilation systems. The primary confinement barrier prevents the dispersion of

plutonium through either sealed construction or atmospheric pressure differential or

a combination of both. For example, process equipment that is not sealed but

contains plutonium material in process should be enclosed in glove boxes or other

confinement barriers. Fuel-rod cladding, bags, and other sealed containers can be

considered primary confinement. The chemical reactivity and the heat generation

effect of the plutonium compound should be considered when selecting primary

confinement material.

The primary confinement barrier protects operators from contamination under

normal operating conditions. This type of barrier is likely to be breached under

accident conditions (e.g., glove rupture, damaged seals, improper bag-out

operations, or leaks of flanged joints).

The primary confinement (with the exceptions of fuel rods, sealed sources, or

sealed cans) should be maintained at a negative air pressure with respect to the

secondary confinement in which it is located, and it should be exhausted through a

ventilation system that uses HEPA filters. The barrier and its accessory equipment

C-5