Our History in Civil Nuclear Powerplants in the UK

Teddington Engineered Solutions has had experience in nuclear power plants for as long as nuclear power plants have existed.

Introduction

From the first Magnox nuclear powerplants in the UK to modern PWR plants across the world, Teddington has been depended upon for its long experience in supplying only the highest quality components for essential purposes in some of the most complicated – and important – machines in the world.

(Teddington has supplied nuclear powerplants all across the world but this particularly case study focuses on our history in the British civil nuclear sector.)

A Summary of Nuclear Power

The first nuclear reactor in the UK was built in Sellafield to produce plutonium for nuclear weapons. The inspired idea of utilising the excess heat to produce energy for the power grid followed. There was a redesign to be more economical, which meant less plutonium, but being much more energy efficient.

A fission reactor in a nuclear power plant generates electricity by harnessing the energy released from splitting atomic nuclei, typically uranium-235 or plutonium-239. Inside the reactor core, these fuel atoms undergo a controlled chain reaction, where neutrons collide with the nuclei, causing them to split and release a significant amount of heat. This heat is used to convert water into steam, which drives turbines connected to generators, producing electricity. The reaction is carefully regulated using control rods, which absorb excess neutrons, and the entire process is contained within a robust structure designed to ensure safety and prevent radiation leaks.

This first generation of nuclear powerplants were powered by Magnox reactors, named after the magnesium non-oxidising alloy used for its cladding, of which eleven were built across the 1950s-1970s. The second generation’s design no longer concerned itself with plutonium production (though it is still a byproduct), and thus used enriched uranium rather than raw uranium, making it much more efficient, of which seven were built across the 1960s-1980s. Later came the PWR reactors, which used almost perfectly enriched uranium and is the most efficient to date.

Feature	Magnox Reactors	AGR Reactors	PWR Reactors
Fuel Type	Natural uranium metal	Slightly enriched uranium dioxide	Highly enriched uranium dioxide (3-5% U-235)
Coolant	Carbon dioxide	Carbon dioxide	Water
Moderator	Graphite	Graphite	Water
Cladding	Magnesium-aluminium alloy (Magnox)	Stainless-steel	Zicronium alloy
Temperature	Lower	Intermediate	Higher
Pressure	Lower	Intermediate	Higher
Efficiency	Lower	Intermediate	Higher
Status	Mostly decommissioned	Mostly nearing end of life	Currently operational (e.g. Sizewell B and more)

Teddington in the UK

Teddington in Magnox and AGR Reactors

In Magnox and AGR reactors, carbon dioxide gas was used as a coolant. The gas circulated through the reactor core, absorbing heat generated by the nuclear fission process, and then transferred that heat to a heat exchanger where it was used to produce steam that drove turbines to generate electricity.

Teddington was approached by Magnox to design and manufacture expansion joints in the carbon dioxide pipelines of these reactors. For Calder’s Hall, the very first civil nuclear powerplant in the UK and the world, Teddington initially supplied 42" NB single-hinged units in the recirculation ducts carrying CO2 at 265 PSI and 420ºC.

Teddington supplied units just like these to ten of the eleven (including the first) Magnox reactors and all seven AGR reactors. Teddington was chosen again and again to contribute to an absolutely essential component in the optimal utility, longevity and safety of these world-changing innovations.

Since then, we have supplied a host of different bellows designs and sizes for various applications in and around nuclear power stations and their sites.

Teddington in PWR Reactors

PWR reactors, as of writing this case study, are the most advanced reactor used in the UK. So far, there has been only one reactor constructed at Sizewell B, and two being constructed at Hinkley Point C.

Most recently, Teddington has supplied bellows assemblies for use on hydrogen gas dryers and a range of double bellows assemblies in Incoloy 825 for the discharge piping systems.

Teddington in future reactors

The UK is also exploring even more advanced nuclear technologies, such as Small Modular Reactors (SMRs) and Advanced Modular Reactors (AMRs), which could potentially surpass PWRs in terms of innovation, flexibility, and safety.

Teddington looks forward to participating further in our country’s development into cleaner and more efficient energy options for the future.

Teddington across the world

Teddington does not only supply to British nuclear powerplants. In fact, Teddington has supplied so many different nuclear powerplants across Europe, America and Asia, that we will need a separate case study for them. Stay tuned.