DavyMarkham currently undertake work for Sellafield, AWE, Rolls-Royce and Magnox. The work involves EPC, design and build and “build to print” manufacturing. Projects include working directly for AWE on the Teutates Project and a Silo Emptying Project (SEP) for Sellafield. DavyMarkham have been working on the SEP project for around 15 years.
The business is now engaged in the design and manufacturing of ILW and HLW packages and was recently awarded the Fit4Nuclear accreditation.
British Nuclear Fuels Limited
Location: Sellafield, Cumbria, UK
The Flatrol Haulage System is used to transport empty nuclear flasks and is positioned within the building using a standard diesel locomotive.
The flatrol consists of a rigid fabricated chassis mounted on two cast steel bogies equipped with metalastic suspension, capable of running on standard British Rail gauge track and suitable for carrying a 55 tonne BNFL flask. The flatrol incorporates a Single Cylinder Braking System for use whilst being moved on site via standard rolling stock. Draw gear suitable for use with standard rolling stock including buffers are positioned at either end of the vehicle.
Rope Haulage also supplied as part of this contract handled the vehicle within the confines of the building.
CCLRC Rutherford Appleton Laboratory
Location: Didcot, Oxfordshire, United Kingdom
The Fabrication is a large 2m wide x 2.2m high x 5m long steel rectangular box, with a series of ports on each face, the Interaction Chamber was built to extremely close tolerances from 120mm thick, stress-relieved plate; it weighs around 45 tonnes and was welded to specifications equivalent to those in the nuclear processing industry. It is lined on the inside with 20mm of aluminium to reduce radiation from high energy ions and electrons, as well as reducing activation of the chamber walls, it is covered with 150mm of lead to attenuate gamma radiation and neutrons, plus 100mm of high density polyethylene to moderate and absorb neutrons. Thus shielded, it forms the heart of the new Vulcan Petawatt facility, the world’s leading Ultra High Intensity Laser.
The Interaction Chamber is stable enough for precisely focusing the laser beam, and to withstand an external pressure of around 1 tonne/sq ft when evacuated and accommodate sufficient shielding for the large amount of x-rays, gamma rays and other radiation generated. Normally round in shape, a rectangular design was preferred as more space efficient and 120mm thick mild steel (BS EN ISO25 S3 55 J2 G3) was specified for cost and structural reasons.
Nuclear Engineering Services Ltd
Scope: Modifications to Retrieval Housing
The Retrieval Housing is an integral component of a machine that will be used to remove nuclear waste from silos on the Sellafield site. It comprises a steel box, approximately 3 metres cube, weighing 45 tonnes.
In operation, waste is lifted into the housing and sorted before being deposited into flasks. The housing therefore has a number of penetrations and features to enable tooling to be remotely operated and stored inside, as well as a viewing window.
Davy Markham was commissioned to make significant modifications to the Retrieval Housing to accommodate new tools and to enhance the strength and reliability of the machine during its lifetime of operation.
The modifications included the addition of new holes, and reinforcing of the funnel sections at the bottom of the housing using stainless steel. The housing is also lined with stainless steel which was seal-welded where sections were modified.
As required by the nuclear industry, strict quality control procedures were adhered to cover material testing, weld procedures and non-contamination of stainless steel during machining.