News: Atkins Rotherham aid Forgemasters with nuclear manufacturing

Design experts at Atkins Rotherham have helped Sheffield Forgemasters International Limited (SFIL) in the manufacture of large nuclear reactor parts.

SFIL required a 5.5m diameter rotating table under their largest press, (10,000 tons) so that parts of up to 300 tons can be rotated beneath the press enabling ingots to be forged into the desired shape.

SFIL is the only UK company carrying ASME certification to manufacture civil nuclear castings and forgings and has a long established history of manufacturing for nuclear power production including power generation systems, nuclear fuel transportation and storage and partnerships in the Westinghouse supply chain.

Experts at Atkins had to design a solution that could endure the temperature of the work piece direct from the furnace at 1,250 degrees C and could withstand the maximum forging load even at the edge of the turntable.

The rotating top surface of the table was designed using segments to allow thermal expansion and movement. Beneath these segments, a thicker circular plate transmits the press loads into the base. It is contained in an insulation layer to reduce the heat transfer.

12 hydraulic cylinders are used to lift the circular top plate and the work piece which can have a maximum combined weight of 400 tons. Four more hydraulic motors can then rotate them on a large slew bearing.

The cylinders continue to lower which disconnects the slew bearing from the top plate preventing any of the 10,000 ton press load being transmitted into the slew ring or the hydraulic cylinders.

The table also includes a large central hydraulic cylinder which provides the capability to lift the forged component off the table surface to allow lifting equipment to be secured and lift the forging away.

With the table in place, the forging operation can take place three times a minute with a maximum of a 90 degree table rotation between each forging. The whole forging process lasts for at most one hour.

Atkins, Europe's largest design and engineering consultancy, strengthened its position in the nuclear sector with the acquisition of Rotherham's MG Bennett & Associates in 2008.

They have been involved in the nuclear industry for over 20 years and their mechanical engineering designers have worked on systems for the Sizewell B nuclear power station, lifting frames for nuclear submarines and the design and analysis of nuclear shield doors and restraints.

Atkins Rotherham website
Sheffield Forgemasters website

Images: bennettmg.co.uk / sheffieldforgemasters.com