Hazard Category 1

DOE-STD-1027-92

ATTACHMENT 1

INTERPRETATION: Facilities with quantities of hazardous radioactive materials, which

meet or exceed the Table A.1 values.

CRITERIA:

Quantities of radioactive materials as specified in Table A.1.

CONSIDERATIONS: The definition of the Category 3 threshold is designed to exclude

those facilities which cannot have a significant radiological impact

outside the facility.

DISCUSSION

Hazard Category 1

DOE Order 5480.23 states that Category 1 hazards have the potential for "significant off-

site consequences." Based on total curie content, potential material forms, and maximum

energy for dispersion available, one class of facilities which possess this hazard potential is

the Class A nuclear reactors. In addition, the PSO may designate other facilities as

Category 1 if he feels there exists the potential for significant off-site consequences.

Hazard Category 2

The approach for designating Category 2 hazards was constructed from existing regulations

which define minimum thresholds for many radionuclides and hazardous chemicals on the

basis of consequences from these hazards in the immediate vicinity of a facility. Table A.1

provides the resulting TQs for radioactive materials which define a Category 2 facility.

Such an approach is consistent with the intent of DOE Order 5480.23 to categorize at level

2 those facilities with the potential for "significant on-site consequences."

For radioactive materials, 10 CFR 30 derived quantities above which byproduct material

licensees must provide emergency plans for responding to a release because such a

release could give a dose of 1 rem at 100 meters under very conservative meteorological

conditions (stable air with intermittent breezes, i.e., F at 1 m/sec). Table A.1 includes

thresholds for byproduct material on the basis of this regulatory premise. Differences

between the NRC calculation and the DOE calculation are explained in the Calculations and

Assumptions Section of this Attachment.

The threshold value for fissile material as specified in Table A.1 is the minimum theoretical

mass necessary for a nuclear criticality to occur with moderation and reflection. These

values for aqueous solutions are approximately 450 grams for Pu 239, 500 grams for U 233,

and 700 grams for U235. This stipulation is necessary because the on-site effects of a

criticality are potentially severe within the immediate vicinity of a facility. Category B nuclear

reactors should therefore be classified as Category 2 since critical quantities of fissile

A-4