What is the process to obtain a nuclear operator license?
In depth - March 13, 2023

What is the process to obtain a nuclear operator license?

The control room is the "brain" of a nuclear power plant. This is where all the controls are centralized, equipment is monitored, and where changes, records and protocols take place; and, should it be necessary this is where emergencies are managed. The role of the nuclear operator is key in this setting.

Whata is a nuclear operator?

In the control room there are people performing work of extreme responsibility, a team of professionals trained specifically for their position:

  • A reactor operator operating the nuclear reactor, including its auxiliary and safety systems.
  • A turbine operator operating the turbine and the alternator that produces the electricity
  • A room supervisor coordinating the work of the operators
  • A shift supervisor
  • Several operation assistants supporting the control room from the plant's buildings where the systems and components are.

In the control room there are people performing work of extreme responsibility, a team of professionals trained specifically for their position

The team of operators and their assistants works twenty-four hours a day and seven days a week in rotating shifts, to guarantee physical security, radiological protection and the stability of the reactor. The operators operate the nuclear power plants. They handle the control system, turn equipment on and off, monitor and adjust controls and apply protocols to the data in the corresponding records. Should it be necessary, they apply failure or emergency protocols. They can respond to abnormal situations, determine their cause and carry out recovery actions.

What is the process to obtain a nuclear operator license?
Sala de control de una central nuclear

The nuclear operator license

According to the Spanish Nuclear Society's nuclear dictionary, the nuclear operator license is "an authorization granted to a person by the competent authority, qualifying the recipient to manipulate the control and protection devices according to preestablished procedures and instructions".

The role of nuclear operator at a nuclear power plant is one of great responsibility, and thus requires an important training effort with an academic roadmap that starts years before obtaining the necessary license.

The role of nuclear operator requires an important training effort with an academic roadmap that starts years before

Types of nuclear operator licenses

There are two types of licenses for nuclear operators:

  • Supervisor license

The supervisor leads operations at the plant and supervises any alterations in the reaction core and fuel movement. This license also qualifies its recipient to be shift manager.

If the supervisor considers that safety conditions have been reduced, he or she has the obligation to stop the plant's operation. In the exceptional event of his or her absence, this responsibility goes to the operator.

  • Operator license

The operator operates the control and protection devices at the nuclear power plant from the control room or, if necessary from the auxiliary panels, always under the supervisor's command. After a training period, an operator can also take the necessary test and exams to obtain the supervisor license.

Before obtaining a license, it is necessary to provide academic qualifications oriented to this type of position.

The two types of nuclear operator licenses are operator and supervisor

Academic requirements

To obtain a nuclear operator license you need a University degree in technical engineering: telecommunications, mechanics, electric or any other type of industrial engineering.

To access the specific training as nuclear operator, requirements are as follows:

  • Technical engineering or engineering degree in one of the following fields:


Mines (energy specialty)





  • Successful completion of University studies during the years contemplated in the study programme, with high grades.
  • A postgraduate degree in nuclear energy is positively valued.
  • English level of at least B-2 

To qualify for training as nuclear operator, a technical engineering or engineering degree are required

Specific training as operator and supervisor

Training for operator or supervisor at a nuclear power plant in Spain takes place in Tecnatom, an engineering company that builds control room simulators for nuclear power plants around the world, among other things.

Training as operator (three years)

These are some of the disciplines that an operator must master: scientific and technological fundamentals, physics, fluid mechanics, thermodynamics, thermohydraulics, chemistry, material resistance, electricity, electromagnetism, regulation and control, mechanical, electrical and instrumentation components, nuclear physics, plant design, plant operation under normal conditions, transitory controls and accidents, human factors, radiological protection and regulations.

Additional training as supervisor (two years, after a minimum of three years' experience as operator):

The training includes technical operation specifications, design bases, accident analysis, probabilistic safety analysis, severe accidents, emergency plan, waste, additional regulations and fuel movement.

Training as operator lasts three years, and training as supervisor takes two aditional years plus three years' experience

Tests and exams required to obtain the license

The organization that grants the license of nuclear operator in Spain is the Nuclear Safety Council (CSN).

The exam is divided into three qualifying parts:

  1. Written exam (3 days).
  2. Exam in a full-range simulator (one day): operations, performance problems and accidents
  3. Exam in the plant (one day): oral exam solving situations, and a walk around the plant answering questions.

The minimum passing grade is eight out of ten. 

Each license is specific for each of the country's five nuclear power plants.

Each license is specific for each of the country's five nuclear power plants

What is the process to obtain a nuclear operator license?
Graphic depiction of the stages for training and licensing as reactor/turbine operator at Almaraz Nuclear Power Plant (Source: Psicotec). *** Click on the image to enlarge it**


Training as operator and supervisor is very demanding and hard, and it does not end once the license is obtained.

Throughout their working life, operators and supervisors will also have to do more training and pass more exams to keep their knowledge and skills up to date.

Once work starts, the licensee must perform retraining activities for six weeks every year. These activities include updating knowledge, operational experience, any modification in design and procedures. After each session, there is an exam, including exams in the simulator.

Also every year, holders of operator or supervisor licenses must undergo a medical checkup to verify their suitability for their position. This includes physical health, psychological stability and prevention of ionizing radiations associated with the position.

Every year, licensees must perform retraining activities and undergo a medical checkup

Outside Spain

The training and licensing process for a nuclear operator is very similar in other countries: after obtaining the corresponding qualifications, the candidates must do the tests standardized by their country's regulatory organization.

In the United States, the organization that administers the tests is the Nuclear Regulatory Commission (NRC). Candidates are accepted after graduating from high school, although to be a supervisor it is necessary to acquire a scientific or engineering degree.

In the United Kingdom, the tests are provided by the Nuclear Regulatory Office.

En el Reino Unido, las pruebas las administra la Office for Nuclear Regulation (NRO).

In both cases, candidates must previously complete one or two years of practice. They must also pass a periodical medical examination and renew their license after a certain number of years.


Sources: Tecnatom, SNE, @OperadorNuclear, NRC and NRO

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