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Navy Rating · Engineering

MMN Machinist's Mate, Nuclear Power

Current service use not established

This code is listed in the directory. Inclusion alone does not confirm current service use.

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Overview

A Nuclear Power Machinist's Mate operates and maintains naval nuclear propulsion plants and associated equipment aboard submarines and surface ships. The machinist's mate operates and repairs reactor, propulsion, and auxiliary support systems, tests and inventories oils, fuels, and water, and maintains operational records and reports.

Minimum ASVAB: GS+AR+MK+EI 252 and AR+MK+MC+VE 235, or AR+MK+MC+VE 252 and GS+AR+MK+EI 235

ASVAB policy: Not policy-reviewed · coverage unknown · as of 2026-10-19

Program scope has not been reviewed.

Policy applicability and coverage of the program's score routes have not been reviewed. Shown-route arithmetic is not an eligibility decision.

Source: milpersman-1306-618-rating-list-2026-04 (source date 2026-04). Policy applicability has not been established.

See if you would hit this score: free ASVAB practice test

Core Skills

  • Integrated reactor and steam plant operation
  • Repair of pumps, valves and heat exchangers
  • Freshwater production and auxiliary systems maintenance
  • Lubricating oil, fuel and water testing

Civilian Career Paths

Career associations are editorial assessments of the cited evidence, not an official crosswalk unless the evidence explicitly says so. O*NET supplies civilian occupation information, not proof of a military match. Related experience does not confer civilian qualifications. Tasks and tools below describe civilian work, not military training.

Power Plant Operators

Operating and maintaining naval steam turbines, propulsion plants and auxiliary pumping systems transfers to civilian power plant equipment operation.

How to prepare: Compare a utility operator training program with your documented turbine and auxiliary-system experience to identify gaps in generator controls and electrical output regulation.

What the civilian work involves
  • Control power generating equipment, including boilers, turbines, generators, or reactors, using control boards or semi-automatic equipment.
  • Monitor power plant equipment and indicators to detect evidence of operating problems.
  • Start or stop generators, auxiliary pumping equipment, turbines, or other power plant equipment as necessary.
Civilian tools and software (examples)
  • Computerized maintenance management system CMMS

Stationary Engineers and Boiler Operators

Naval steam plant work and repair of pumps, compressors, air-conditioning equipment and water systems overlap with stationary plant operations.

How to prepare: Ask the licensing authority where you plan to work which stationary engineer license or state certification applies and how your documented naval plant experience counts toward it.

What the civilian work involves
  • Operate or tend stationary engines, boilers, and auxiliary equipment, such as pumps, compressors, or air-conditioning equipment, to supply and maintain steam or heat for buildings, marine vessels, or pneumatic tools.
  • Analyze problems and take appropriate action to ensure continuous and reliable operation of equipment and systems.
  • Observe and interpret readings on gauges, meters, and charts registering various aspects of boiler operation to ensure that boilers are operating properly.
Civilian tools and software (examples)
  • Building management system software

Nuclear Power Reactor Operators

Naval nuclear propulsion plant operation and application of reactor, electrical and mechanical theory provide relevant experience for a commercial reactor operator training pathway.

How to prepare: Request a utility's operator training entry criteria and compare them with your documented naval qualifications. NRC licensing requires the facility licensee to certify that its training and experience requirements are met, and the resulting license is facility-specific.

What the civilian work involves
  • Operate nuclear power reactors in accordance with policies and procedures to protect workers from radiation and to ensure environmental safety.
  • Respond to system or unit abnormalities, diagnosing the cause, and recommending or taking corrective action.
  • Monitor all systems for normal running conditions, performing activities such as checking gauges to assess output or the effects of generator loading on other equipment.

Training & Development

Choose credentials for your target role. COOL funding markers describe program listings, not a guarantee of eligibility or funding.

Career Growth

  • Certified Maintenance and Reliability Professionals (CMRP)

    Provide voluntary evidence of maintenance and reliability knowledge for plant operators seeking greater responsibility for equipment reliability.

    Eligibility and preparation: No education or work-experience minimum; candidates must not have taken the exam within the preceding six months.

    For: Power Plant Operators, Stationary Engineers and Boiler Operators

Notes & Sources

Evidence for this guidance (7 documents)
  1. NAVPERS 18068F Vol I (NEOCS, Jan 2026 edition): MACHINIST’S MATE, NUCLEAR POWER (MMN)

    [1] Rating chapter "SCOPE OF RATING"; cached text line 51198; NAVPERS 18068F Vol I, 2026-01 edition

    Supports: Integrated reactor and steam plant operation, Repair of pumps, valves and heat exchangers, Freshwater production and auxiliary systems maintenance, Lubricating oil, fuel and water testing, Power Plant Operators (O*NET 51-8013.00), Stationary Engineers and Boiler Operators (O*NET 51-8021.00), Nuclear Power Reactor Operators (O*NET 51-8011.00)

  2. O*NET: Power Plant Operators

    [2] O*NET 30.3 occupational data

    Supports: Power Plant Operators (O*NET 51-8013.00)

  3. O*NET: Stationary Engineers and Boiler Operators

    [3] O*NET 30.3 occupational data

    Supports: Stationary Engineers and Boiler Operators (O*NET 51-8021.00)

  4. O*NET: Nuclear Power Reactor Operators

    [4] O*NET 30.3 occupational data

    Supports: Nuclear Power Reactor Operators (O*NET 51-8011.00)

  5. U.S. Nuclear Regulatory Commission: Licensing Process for Operators

    [5] Process for New Operator Licenses; page last reviewed/updated September 15, 2026

    Supports: Nuclear Power Reactor Operators (O*NET 51-8011.00)

  6. COOL credential mapping: Certified Maintenance and Reliability Professionals (CMRP)

    [6] MMN cached COOL credential feed

    Supports: Certified Maintenance and Reliability Professionals (CMRP)

  7. Society for Maintenance and Reliability Professionals: CMRP eligibility

    [7] Eligibility; retrieved 23 September 2026

    Supports: Certified Maintenance and Reliability Professionals (CMRP)

Defense contractor jobs for MMN

Descriptions may be summarized for clarity. Verify all information with your branch career counselor or official military documentation before making career decisions.

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