Summation of Radionuclide Threshold Ratios

DOE-STD-1027-92

ATTACHMENT 1

Hazardous materials used in exempted, commercially available products, should not be

considered part of a facility's inventory. These materials are described in 10 CFR 30 Parts

30.1130.19 and include timepieces, illumination devices, thermostats, electron tubes,

microwave receiver tubes, etc.

Additionally, material contained in DOT Type B shipping containers (with or without

overpack) may also be excluded from summation of a facility's radioactive inventory if the

Certificates of Compliance are kept current and the materials stored are authorized by the

Certificate. However, Type B containers without overpack should have heat protection

provided by the facility's fire suppression system.

These exclusions do not apply to fissile material in the determination of Hazard Category 2

status relative to criticality.

Summation of Radionuclide Threshold Ratios

Facilities or facility segments where there are combinations of radioactive materials should

be designated as Category 2 or 3 if the sum of the ratios of the quantity of each material to

the Category 2 or 3 thresholds exceeds one (e.g., [inventory of isotope A/threshold of

isotope A] + [inventory of isotope B/threshold of isotope B] + [inventory of isotope

n/threshold of isotope n] >1).

Part Time Inventory

A facility that is involved with an inventory of hazardous materials that varies with time must

be categorized on the basis of its maximum inventory of hazardous materials.

Hazard Categories

Hazard Category 1

Hazard Analysis shows the potential for significant off-site

DEFINITION:

consequences.

INTERPRETATION: Category A reactors and facilities designated by PSO.

CONSIDERATIONS: Category A reactors are those that have a steady-state power level

greater than 20 MWt.

Hazard Category 2

Hazard Analysis shows the potential for significant on-site

DEFINITION:

consequences.

A-2