Confinement - hdbk1132990156

DOE-HDBK-1132-99

Confinement . The selection of the confinement system to be used during

D&D operations will be dependent on the condition of the existing building and

ventilation system. It is possible that the existing structure and ventilation

system is adequate without change or upgrade. Where existing systems are

judged to be inadequate, the designer should consider enhancing the existing

system with portable ventilation and tents within the building. The tents and

ventilation would provide the active operation zoning function while the existing

structure and ventilation would continue to provide the shutdown condition

confinement for the remainder of the building. Care in the accident analysis

and design is needed to ensure that credible accidents will not propagate

beyond the work zone.

Radiation Shielding . Shielding design in cleanup activities relies on specific

source reduction rather than shielding walls used in process operations.

Design related to portable shielding is limited to the material (high z or low z),

thickness, and features to make the shielding material easy to install, relocate,

decontaminate, and remove so that it can be reused (waste minimization). The

available space and shape of the object generally determines whether to shield

the object or shield the worker (portable shield wall). Shielding design for

buried items may have to be modular and layered because it is not always

possible to determine radiation levels of buried items until they are actually

uncovered.

Structural Integrity . Structures provide confinement, shielding, a stable

anchor for fixed equipment, segregation or isolation, and a controlled

environment (dust, humidity, and temperature control) for equipment important

to safe operation. Portable equipment is generally self-standing and does not

require an anchor for short-duration use. This leaves the functions of

segregation and climate control. Both of these functions can be provided by a

tent or, under more severe cases, sheet metal structures. The choice of

structural material depends on factors such as duration of the activity,

consequences of structural failure, geographical/meteorological conditions

(snow or wind loading), and whether or not an existing structure is involved

(D&D or soil remediation). Consideration should be given to limiting the mass

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