{"data":{"id":"us/10-cfr-51.4","jurisdiction":"us","citation":"10 CFR 51.4","heading":"Definitions.","body":"As used in this part:\nAct means the Atomic Energy Act of 1954 (Pub. L. 83-703, 68 Stat. 919) including any amendments thereto.\nCommission means the Nuclear Regulatory Commission or its authorized representatives.\nConstruction means:\n(1)(i) For production and utilization facilities licensed under 10 CFR part 50 or 10 CFR part 52, the activities in 10 CFR 50.10(a)(1), and does not mean the activities in 10 CFR 50.10(a)(2).\n(ii) For utilization facilities licensed under 10 CFR part 53, the activities in paragraph (1) of the definition of construction in 10 CFR 53.020, and does not mean the activities in paragraph (2) of the definition of construction in 10 CFR 53.020.\n(2) For materials licenses, the activities in paragraph (2)(i) of this definition, and does not mean the activities in paragraph (2)(ii) of this definition.\n(i) Taking any site-preparation activity at the site of a facility subject to the regulations in 10 CFR parts 30, 36, 40, and 70 that has a reasonable nexus to radiological health and safety or the common defense and security.\n(ii) Construction does not include:\n(A) The activities listed in 10 CFR 50.10(a)(2)(i)-(viii); or\n(B) Taking any other action that has no reasonable nexus to radiological health and safety or the common defense and security.\nPreviously disturbed areas means areas that have been changed by development of the facility and remain altered by human activity such that they do not support important habitat or habitat to important species and no longer have the potential to yield historic and cultural resources. This includes the lateral and vertical extent of alteration from natural cover to a managed state.\nNRC means the Nuclear Regulatory Commission, the agency established by Title II of the Energy Reorganization Act of 1974, as amended.\nNRC staff means any NRC officer or employee or his/her authorized representative, except a Commissioner, a member of a Commissioner's immediate staff, an Atomic Safety and Licensing Board, a presiding officer, an administrative judge, an administrative law judge, or any other officer or employee of the Commission who performs adjudicatory functions.\nNRC staff director means the Executive Director for Operations; the Director, Office of Nuclear Reactor Regulation; the Director, Office of Nuclear Material Safety and Safeguards; the Director, Office of Nuclear Regulatory Research; the Director, Office of Public Affairs; and the designee of any NRC staff director.","path":["Title 10—Energy","CHAPTER I—NUCLEAR REGULATORY COMMISSION","PART 51—ENVIRONMENTAL PROTECTION REGULATIONS FOR DOMESTIC LICENSING AND RELATED REGULATORY FUNCTIONS"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-10.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:09Z","sha256":"daa4c4c450e3317c2c433c4dc112656fd1a4699ce8d01d1b96908d98db1cc763","source_id":"us-cfr","stale":true,"prev":"us/10-cfr-51.3","next":"us/10-cfr-51.5"},"notice":"GroundRules: Original legal text. Not legal advice."}