Snaking around in a nuclear jungle

The paper describes a pipe repair conducted in August 2004 using two types of snake‐arm robot. The pipe was located 5 m below the reactor core of Ringhals 1 nuclear reactor.

The two types of robot worked co‐operatively to replace a section of critical pipe. The 23‐degree of freedom arm snaked around obstructing pipes to positions cameras in a humanly unreachable location in order to give the ideal view of the work site. The more substantial second arm used 13 degrees of freedom to deliver fixtures, cutting tools, gas shields, inspection equipment and also conducted both tack welding and continuous welding.

The leaking pipe was repaired manually during the 2004 outage. The robots successfully completed the externally assessed Factory Acceptance Tests which involved copying the complete procedure on a purpose built mock‐up. The robots are now on standby for 2005 and beyond.

The successful completion of this extremely difficult task indicates that snake‐arm robots are now a viable solution to a variety of complex access tasks in all industries including aerospace, pharmaceuticals, the miltary sector and nuclear industries.

The paper describes a procedure that has never been attempted before using two completely new designs of redundant snake‐arm robot.