48 CFR · Federal Acquisition Regulation and Defense supplement

FAR and DFARS navigator

The codified text (eCFR, as of 2026-10-02). Under the Revolutionary FAR Overhaul ↗, agencies follow class deviations with new text for many parts while the formal rules go through the Federal Register: check the solicitation and your contract's clauses, which rule.

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2 sections with “radiological source materials”

  • DFARS 204.470-3 Contract clause.
    …ssionable materials (e.g., uranium, plutonium, neptunium, thorium, americium); (b) Other radiological source materials; or (c) Technologies directly related to nuclear power production, including nuclear or radiological waste materials.
  • FAR 2.101 Definitions.
    …n; to facilitate defense against or recovery from cyber, nuclear, biological, chemical or radiological attack; to support a request from the Secretary of State or the Administrator of the United States Agency for International Development t…

FAR (chapter 1)

DFARS (chapter 2, Defense)

Source: eCFR, 48 CFR chapters 1 and 2 (GPO GovInfo bulk data) ↗. Rule changes in progress: FAR, DFARS. Terms: glossary.