Design information consists of "information concerning nuclear material subject to safeguards under the agreement and the features of facilities relevant to safeguarding such material" (INFCIRC 153, para. 8* & INFCIRC 66, para. 32).

Design information includes the facility description; the form, quantity, location and flow of nuclear material being used; facility layout and containment features; and procedures for nuclear material accountancy and control. This information is used by the IAEA to design the facility safeguards approach, to determine material balance areas and select key measurement points and other strategic points, to develop the design information verification plan and to establish the essential equipment list.

Design information for existing facilities should be provided by the State during discussion of the Subsidiary Arrangements; in the case of new facilities, such information is to be provided by the State as early as possible before nuclear material is introduced into a new facility. Further, the State is to provide preliminary information on any new nuclear facility as soon as the decision is taken to construct, or to authorize the construction of, the facility, and to provide further information on the safeguards relevant features of facility design early in the stages of project definition, preliminary design, construction and commissioning. Facility design information is to be provided for any safeguards relevant changes in operating conditions throughout the facility life cycle. Under an INFCIRC/66-type safeguards agreement, the State is to provide design information on principal nuclear facilities to enable the IAEA to perform the design review at as early a stage as possible. Design information is submitted to the IAEA by the State using the IAEA design information questionnaire (DIQ).