Within the EDF Engineering and Production Branch, created in 2004, a difference is made between the function of operator and that of investing owner. Whereas the owner is responsible for the development and long-term exploitation of its asset as well as for its dismantling once operations are completed, the operator is in charge of the short and medium term performance of the production plants and of safety, radiation protection and environmental issues on daily basis.

The responsibility of operator is assumed by the Nuclear Generating Division (DPN). Day to day operation of the nuclear power plants, including safety, radiation protection and security, along with availability and costs, are its duties. The Director of the DPN has authority over the nuclear power plant directors and also has at his disposal Head Office departments, comprising expert assessment and technical support services responsible for defining DPN policy and participating in the improvement of plant operation.

Within the DPN, the operating plant support centre (CAPE) is required to provide the plants with help in attaining their safety and performance targets and to help the DPN with plant oversight and monitoring implementation of technical decisions. This unit offers expertise in the nuclear energy production trades, including safety, the environment, maintenance, process engineering, risk prevention and radiation protection. The national engineering unit for operating plants (UNIPE) performs national engineering tasks concerning technical and documentary upgrades, reactor fuel management, and the national emergency response procedures. In particular, its duties are to implement modifications to the installations decided on at a national level and to produce generic operating and maintenance documents. For all the plants, the Operational Technical Unit (UTO) works on generic maintenance, subcontracting policy and buying policy. Finally, the IN (Nuclear Inspection) teams, on behalf of the DPN authorities, carry out verification assignments on the entire division.

Within the nuclear power plants, the departments are organised according to professional fields, for performance of safety and radiation protection, production and maintenance functions. Cross-functional project teams are set up for specific activities such as unit outages. The production and maintenance activities can also call on an engineering department.

The roles of owner and designer lie with the Nuclear Engineering Division (DIN). In this respect, the DIN is responsible for the facilities design reference framework. It performs engineering activities about the future issues, in other words, studies, draft projects and long-term upgrade projects for the facilities which go beyond the natural scope of the operator's work. Finally it has oversight for projects designed to maintain the assets, primarily concerning design aspects, in particular the periodic safety reviews.

Among the DIN's engineering centres, the design department for thermal and nuclear projects (SEPTEN) is responsible for upstream studies and draft projects. The National Centre for Nuclear Equipment (CNEN) is more particularly responsible for equipment design and modification in the nuclear island of the N4 plant series and the EPR (European Pressurized water Reactor) project. The Engineering Centre for Operating Plants (CIPN) works on the nuclear islands for the 900 and 1300 MWe plant series. The National Centre for Electricity Production Equipment (CNEPE) deals with the conventional islands of all the plants. The dismantling and waste management activities are handled by the Engineering Centre for Dismantling and Related Environmental Issues (CIDEN). Finally, the Production and Operation appraisal and inspection centre (CEIDRE) is particularly responsible for in-service inspection of equipment and for conducting appraisals.