Safety-Class Design Standards and Criteria

DOE-HDBK-6004-99

providing sufficient air exchange rate within the confinement zones. (ASHRAE,

ASHRAE 91, DOE 6430.1A)

b) Monitor the contamination levels in the zones to ensure personnel radiological safety

is maintained. (ASHRAE 91, DOE 5480.11, DOE 6430.1A) In addition, any potential

for airborne toxic and corrosive products in the atmosphere that may compromise

personnel safety or equipment operability should be monitored and controlled.

c) Monitor the radiological releases to the environment to ensure the continued

effectiveness of the confinement system to capture and retain radioactive contaminants

before they are exhausted to the environment. (ASHRAE 91, DOE 5480.11, DOE

6430.1A)

d) Maintain the required temperature and humidity conditions in the zone. (ASHRAE 91)

2. Maintenance:

Provide the necessary ventilation system functional capabilities to allow for any intentional

breaches of the confinement system that are required to perform maintenance on any portion of

the system. (ASHRAE 91)

3. Design Basis Accidents:

a) Prevent and control the spread of gaseous and radioactive contamination during and

following all credible design basis accidents. (ASHRAE, ASHRAE 91, DOE

6430.1A)

b) Monitor the radiological releases to the environment during and following any

credible design basis accident. (ASHRAE 91, DOE 5480.11, DOE 6430.1A)

c) Maintain temperature, pressure and humidity conditions for the equipment required to

operate during and following a DBA. This includes the ability to rapidly remove heat

in worst case loss of coolant accident condition.

Safety-Class Design Standards and Criteria

The safety analysis to determine the safety system classification of the confinement systems and their

associated HVAC systems should be based on the requirements given in DOE-STD-1027-92 or

equivalent. Ventilation systems that are classified as "safety class" should be designed to operate in

conjunction with their associated physical barriers to limit the release of radioactive or other

hazardous material to the environment. In addition they should be subject to appropriately higher

quality design, fabrication and test standards and codes to increase the reliability of the system and

allow credit to be taken for their functional capability in a safety analysis. In addition the safety

analysis should determine the appropriate level of redundancy, diversity, independence and the need

for emergency power to ensure safety system function capability during and following all credible

postulated design basis accidents.