To facilitate new wells to a mature North Sea platform, a vertical riser bundle was designed and manufactured and was to be installed in 11 sections. The welding processes were to be carried out on the drill floor. As the material was predominantly super duplex, and the tight schedule did not allow for development of ultrasonic or TOFD techniques, the only realistic method was radiography.

The close proximity of control cabins and other essential personnel allowed a controlled area of only 5 metres. Conventional shielding systems were ruled out as the close proximity of each riser would not allow 100% coverage. SAIS designed a shielding system for Selenium 75 in conjunction with MAZEL® using Radishield custom made shielding and a Radishield guide tube to eliminate the ‘flash’ dose from isotope travel through the delivery tube and brought the safe working distance down to 3 metres whilst maintaining acceptable exposure times.

A full sized mock up was built on shore in safe conditions and the whole system assessed for safety and delivery of high quality radiographs. The project was very successful and Safe.