10 CFR § 71.83 - Assumptions as to unknown properties.
---identifier: "/us/cfr/t10/s71.83"source: "ecfr"legal_status: "authoritative_unofficial"title: "10 CFR § 71.83 - Assumptions as to unknown properties."title_number: 10title_name: "Energy"section_number: "71.83"section_name: "Assumptions as to unknown properties."chapter_name: "NUCLEAR REGULATORY COMMISSION"part_number: "71"part_name: "PACKAGING AND TRANSPORTATION OF RADIOACTIVE MATERIAL"positive_law: falsecurrency: "2026-03-24"last_updated: "2026-03-24"format_version: "1.1.0"generator: "[email protected]"authority: "Atomic Energy Act of 1954, secs. 53, 57, 62, 63, 81, 161, 182, 183, 223, 234, 1701 (42 U.S.C. 2073, 2077, 2092, 2093, 2111, 2201, 2232, 2233, 2273, 2282, 2297f); Energy Reorganization Act of 1974, secs. 201, 202, 206, 211 (42 U.S.C. 5841, 5842, 5846, 5851); Nuclear Waste Policy Act of 1982, sec. 180 (42 U.S.C. 10175); 44 U.S.C. 3504 note."regulatory_source: "60 FR 50264, Sept. 28, 1995, unless otherwise noted."cfr_part: "71"---
Identifier
/us/cfr/t10/s71.83
Currency
2026-03-24
Positive Law
No
Updated
2026-03-24
Chapter
Nuclear Regulatory Commission
Authority
Atomic Energy Act of 1954, secs. 53, 57, 62, 63, 81, 161, 182, 183, 223, 234, 1701 (42 U.S.C. 2073, 2077, 2092, 2093, 2111, 2201, 2232, 2233, 2273, 2282, 2297f); Energy Reorganization Act of 1974, sec... Atomic Energy Act of 1954, secs. 53, 57, 62, 63, 81, 161, 182, 183, 223, 234, 1701 (42 U.S.C. 2073, 2077, 2092, 2093, 2111, 2201, 2232, 2233, 2273, 2282, 2297f); Energy Reorganization Act of 1974, secs. 201, 202, 206, 211 (42 U.S.C. 5841, 5842, 5846, 5851); Nuclear Waste Policy Act of 1982, sec. 180 (42 U.S.C. 10175); 44 U.S.C. 3504 note.
# 71.83 Assumptions as to unknown properties.When the isotopic abundance, mass, concentration, degree of irradiation, degree of moderation, or other pertinent property of fissile material in any package is not known, the licensee shall package the fissile material as if the unknown properties have credible values that will cause the maximum neutron multiplication.