10 CFR § 55.4 - Definitions.
---
identifier: "/us/cfr/t10/s55.4"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "10 CFR § 55.4 - Definitions."
title_number: 10
title_name: "Energy"
section_number: "55.4"
section_name: "Definitions."
chapter_name: "NUCLEAR REGULATORY COMMISSION"
part_number: "55"
part_name: "OPERATORS' LICENSES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Atomic Energy Act of 1954, secs. 107, 161, 181, 182, 183, 186, 187, 223, 234 (42 U.S.C. 2137, 2201, 2231, 2232, 2233, 2236, 2237, 2273, 2282); Energy Reorganization Act of 1974, secs. 201, 202 (42 U.S.C. 5841, 5842); Nuclear Waste Policy Act of 1982, sec. 306 (42 U.S.C. 10226); 44 U.S.C. 3504 note."
regulatory_source: "52 FR 9460, Mar. 25, 1987, unless otherwise noted."
cfr_part: "55"
---
# 55.4 Definitions.
As used in this part:
*Act* means the Atomic Energy Act of 1954, including any amendments to the Act.
*Actively performing the functions of an operator or senior operator* means that an individual has a position on the shift crew that requires the individual to be licensed as defined in the facility's technical specifications, and that the individual carries out and is responsible for the duties covered by that position.
*Commission* means the Nuclear Regulatory Commission or its duly authorized representatives.
*Controls* when used with respect to a nuclear reactor means apparatus and mechanisms the manipulation of which directly affects the reactivity or power level of the reactor.
*Facility* means any utilization facility as defined in part 50 of this chapter. In cases for which a license is issued for operation of two or more facilities, *facility* means all facilities identified in the license.
*Facility licensee* means an applicant for or holder of a license for a facility.
*Licensee* means an individual licensed operator or senior operator.
*Operator* means any individual licensed under this part to manipulate a control of a facility.
*Performance testing* means testing conducted to verify a simulation facility's performance as compared to actual or predicted reference plant performance.
*Physician* means an individual licensed by a State or territory of the United States, the District of Columbia or the Commonwealth of Puerto Rico to dispense drugs in the practice of medicine.
*Plant-referenced simulator* means a simulator modeling the systems of the reference plant with which the operator interfaces in the control room, including operating consoles, and which permits use of the reference plant's procedures.
*Reference plant* means the specific nuclear power plant from which a simulation facility's control room configuration, system control arrangement, and design data are derived.
*Senior operator* means any individual licensed under this part to manipulate the controls of a facility and to direct the licensed activities of licensed operators.
*Simulation facility* means one or more of the following components, alone or in combination: used for either the partial conduct of operating tests for operators, senior operators, and license applicants, or to establish on-the-job training and experience prerequisites for operator license eligibility:
(1) A plant-referenced simulator;
(2) A Commission-approved simulator under § 55.46(b); or
(3) Another simulation device, including part-task and limited scope simulation devices, approved under § 55.46(b).
*Systems approach to training* means a training program that includes the following five elements:
(1) Systematic analysis of the jobs to be performed.
(2) Learning objectives derived from the analysis which describe desired performance after training.
(3) Training design and implementation based on the learning objectives.
(4) Evaluation of trainee mastery of the objectives during training.
(5) Evaluation and revision of the training based on the performance of trained personnel in the job setting.
*United States,* when used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
[52 FR 9460, Mar. 25, 1987, as amended at 66 FR 52667, Oct. 17, 2001]