10 CFR 1017.8: Subject areas eligible to be Unclassified Controlled Nuclear Information.

To be eligible for identification as UCNI, information must concern at least one of the following categories:

(a) The design of production or utilization facilities as defined in this part;

(b) Security measures (including security plans, procedures, and equipment) for the physical protection of production or utilization facilities or nuclear material, regardless of its physical state or form, contained in these facilities or in transit; or

(c) The design, manufacture, or utilization of nuclear weapons or components that were once classified as Restricted Data, as defined in section 11y. of the Atomic Energy Act.