Confinement/Heating, Ventilating, and Air Conditioning (HVAC) Systems - Continued

DOE-STD-6003-96

Design features for confinement systems and their associated HVAC systems include the

following:

a. Provide barriers against the release or spread of gaseous and particulate contamina-

tion during normal and off-normal conditions. (DOE 1989, ASHRAE 1988, ASHRAE

1991)

b. Provide the necessary ventilation system functional capabilities to control differential

pressures such that air flows from cleaner areas to potentially more contaminated

areas during normal and off-normal conditions. (ASHRAE 1991)

c. Provide filters or other means to remove contaminants before exhausting the

environs.

d. Maintain the required ambient conditions within confinement (e.g., temperature, pres-

sure, humidity, and concentrations of radiological, toxic, corrosive, or explosive

substances), to protect personnel and ensure the capability of personnel or equipment

to perform safety functions. (ASHRAE 1991)

e. Provide the capability to isolate and control tritium or any other contaminant released

within confinement.

Provide instrumentation and/or testing and surveillance to monitor the condition and

capabilities of the confinement system, the ambient conditions within confinement,

and the effluents from confinement to the environs. Applicable items should be moni-

tored during normal and off-normal conditions as required to ensure and verify safety

function. In addition potential airborne contaminants or corrosive agents that may

compromise the ability of personnel or equipment to perform safety functions should

be monitored and controlled. (DOE 1989, ASHRAE 1991, and DOE 1990)

Design-basis loads are derived from the internal and external events identified in the

safety analysis. Loads and the combinations thereof used in the design should

envelop loads considered in structures per ANSI 1993b.

Methods of analysis depend on the performance category and loads being considered

(e.g., ASCE 1980). Elastic system analysis methods may be adequate for lower per-

formance categories, whereas for higher performance categories inelastic analysis

methods may be required. Guidelines to seismic analysis are available in DOE 1994b.

Dynamic seismic structural analysis may be performed for predicted ground motions

based on geotechnical site-specific information including variability using response

spectra or time history. For large embedded structures, soil structure analysis may be

considered.

Capacity calculations, DOE 1994b, depend primarily on the national consensus code,

UBC 1991. For reinforced concrete structures, DOE 1984 and ACI 1989 provide the

criteria for safety-class and other building structures, respectively. For steel structures,