Controlling Uranium Inventories

DOE-HDBK-1113-98

Module 105 Criticality Safety

Lesson Plan

Instructor's Notes

- using materials known as poisons to absorb

neutrons and prevent them from being

absorbed by the uranium atoms,

- controlling material that surrounds containers

or systems containing uranium, and

- controlling uranium inventories.

Controlling Uranium Inventories

One method to prevent a criticality is controlling

uranium inventories. Inventory control involves

knowing where the uranium is at the facility and

the level of enrichment of the uranium. Uranium

enriched in 235U or the presence of 233U is of

concern for criticality; therefore, these are materials

of concern for inventory control. Criticality is a

concern for 238U if fast neutrons are present.

Loss of control of fissile material presents a threat

to criticality safety at the facility and, in a worst

case scenario, to national security. It is no secret

that groups throughout the world are striving to

become nuclear powers. Even the appearance of a

loss of inventory control must be avoided to keep

the public trust and assure continued operations of

DOE programs. For these reasons, inventories of

fissile material are closely monitored.