Skip navigation
Nuclear Safeguards Education Portal

Nuclear Material Inventory (cont.)

There are several reasons why a facility's inventory might change.  Below is a list of the more common reasons.

  • Increases:
    • import
    • domestic receipt
    • nuclear production
    • accidental gain
    • retransfer from retained waste
    • de-exemption of nuclear material from IAEA safeguards
  • Decreases:
    • export
    • domestic shipment
    • nuclear loss
    • other loss
    • measured discard
    • transfer to retained waste
    • exemption of nuclear material from IAEA safeguards
    • termination of IAEA safeguards on nuclear material transferred to non-nuclear use

The accounting records for each MBA contain all: 1) inventory changes, to permit a determination of the book inventory at any time 2) measurement results that are used for determination of the physical inventory 3) and adjustments and corrections that have been made in respect of inventory changes, book inventories, and physical inventories.

In addition to accounting records, the facility must maintain operating records which contains a set of data on the operation of the facility in connection with the use or handling of nuclear material.  An example of this for a reactor would be the integrated thermal power for a period, power history, and location of each fuel element.

Operating records for a MBA contain:

  • operating data used to establish changes in the quantities and composition of nuclear material
  • data obtained from calibration, sampling, analyses and the procedures to control the quality of measurements and the derived estimates of random and systematic error
  • description of the sequence of the actions for the physical inventory
  • description of the actions taken in order to ascertain the cause and magnitude of any accidental or unmeasured loss that might occur

Page 7 / 17