Imperial College London
Supervisor: Professor Mike Lowe
Industry Sponsor: EDF
The exploitation know-how in guided waves for challenging inspections of sections of pipes that are difficult to access would be ideally suited to the academic applicant’s interests. Added to this, this the project has strong relevance to the long history of research by the NDE group at Imperial for the nuclear power industry.
Ferritic steel pipes are commonly used in the tertiary circuit of pressurized water reactors for the transport of raw feedwater. Typical dimensions are 50cm to 60cm diameter and from 6. up to 10mm wall thickness, with an outer coating of resin or paint as corrosion protection. Pipes are joined with butt-welds and may contain helicoidal or longitudinal welds, none of these welds is in general grinded flush.
Assessment of the remaining wall thickness using ultrasound is trivial, except on sections which are covered by the support structure. In these regions, inaccessible for conventional ultrasound, corrosion, cracking or pitting may be cause of failure. Support structures vary widely in size, shape and material; the pictures below show support frames with H or U shape, which cannot be removed prior to inspection.
The objective of this thesis is to study the feasibility of a guided wave assessment of the remaining wall thickness in regions covered by the support structure, and ideally over a wider section of the pipe including covered zones, taking into account a number of constraints, such as the presence of bents and the impossibility to remove layers of paint.