The application of electron beam welding technology to the joining of components in civil nuclear assemblies is being explored by a U.K.-based consortium led by Sheffield Forgemaster.

Welding of pressure vessels and other thick section components in the nuclear industry has been conducted with arc-welding techniques. These methods require multiple weld passes with inter stage non-destructive Electron beam welding can provide material improvement and reduced manufacturing time and cost. Source: Sheffield Forgemasterexamination and pre-heating of the component to reduce the risk of hydrogen cracking. Tungsten arc welding is a cost- and time-intensive process that can only penetrate to a certain depth so thick-section welding is executed by filling the weld groove with several passes. Completion can involve up to 100 runs of weld for a typical reactor pressure vessel section of 140 mm or greater.

New developments in electron beam welding technology offer the opportunity to weld these components in a single pass and negates the need for non-destructive testing, resulting in time and cost savings during vessel fabrication.

The consortium, which includes Cambridge Vacuum Engineering, TWI, Arc Energy, NAMRC, the University of Manchester and Cambridge University, will test an electron beam welder capable of welding 3.0 m diameter cylinders under localized vacuum and without traditional welding preparation, offering narrower welds than traditional methods plus the ability to weld as part of the manufacturing process, prior to quality heat treatment.

It will then manufacture a civil nuclear component to demonstrate a full-sized (4.3 m high x by 3.0 m diameter) small modular reactor pressure vessel and also produce several grades of steel alloys suitable for civil fission and fusion nuclear applications within the project’s research element.