Hazard Category 3

DOE-STD-1027-92

ATTACHMENT 1

materials are present in these facilities but not in sufficient quantities to represent a

significant off-site impact.

Hazard Category 3

Category 3 is designed to capture facilities which largely include lab operations, low level

waste handling facilities, and research machines which possess less than the Category 2

quantities of material and are considered to represent a low hazard. DOE Order 5480.23

states that facilities should be classified as Level 3 if there is only the potential for

"significant localized consequences." Essentially all industrial facilities have a potential for

significant localized consequences because the potential to injure workers from typical

industrial accidents is always present. However, Category 3 facilities pose additional

hazards due to the presence of radionuclides. To establish a system based on inventories,

DOE has modified the EPA definitions of RQs for radionuclides contained in 40 CFR 302.4,

Appendix B. The values for radionuclides represent levels of material which, if released,

would produce less than 10 rem doses at 30 meters based on 24 hour exposure. Table A.1

provides the Category 3 thresholds for radionuclides.

Results

Categorization of most nuclear hazards present in facilities or facility segments should be

possible from the thresholds listed in Table A.1. Further discussion on the origin of some

thresholds is provided in the following section on "Calculations and Assumptions."

CALCULATIONS AND ASSUMPTIONS

Calculation of Category 2 Radiological Thresholds

The NRC derived 10 CFR 30, Schedule C threshold quantities which could result in a dose

of 1 rem at 100 meters by using standard air dispersion/dose calculations. The basic

calculation stated is as follows:

(1 rem)/(RF*(HI + HG + HCS))

where

Quantity of material used as threshold (grams)

RF =

Release fraction for material of concern (unitless)

HI =

Effective dose equivalent from inhalation (rem/gm)

HG =

Effective dose equivalent from ground contamination (rem/gm)

HCS =

Effective dose equivalent from cloud shine (rem/gm)

A-5