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About nuclear technology / The operation of NEK
The operation of NEK
From nuclear energy to electricity.


NEK functions in a similar way to a conventional fossil fuel power plant, except that heat is not produced by burning coal, oil or gas. Instead, it makes use of the heat released during the fission of uranium nuclei in a reactor. The reactor consists of a reactor vessel with fuel assemblies which create the core. Ordinary purified water and chemically treated water circulate through the reactor under pressure and carry the released heat into the steam generator, where it is turned into steam. The steam drives a turbine which in turn drives the electrical generator. All the equipment of the reactor and the primary coolant loop is housed in the reactor building, which in view of its function is also known as the containment building.

The reactor vessel containing the fuel assemblies and primary coolant loops are sealed during operation. For scheduled refuelling, the power plant needs to be shut down. The period between two refuellings is known as the fuel cycle. At NEK, the fuel cycle lasts 18 months. At the end of every fuel cycle, the spent fuel elements are replaced with fresh ones.

NEK operating diagram

The NEK operating diagram has been simplified and only the main components are shown.