Deployment of the RASP System for Cutting a Contaminated Power Reactor Turbine Shaft

A need was identified for the in-situ size reduction of large components such as glove boxes, tanks and other components. A development programme resulted in a new cutting method that could be remotely deployed for the in-situ segmentation of large components of this type. RWE NUKEM has selected RASP as acronym for this technology Remotely-Operated Advanced Segmentation Process or RASP. A review of the standard manual cutting methods highlighted a number of significant shortcomings including operative safety; high energy cutting tools generating high temperatures; spread of contamination over wide areas; risk from sharp edges and operative fatigue. The development of new technology was therefore focused on improving safety for operatives and developing an inherently safe and flexible technology, which can be used for in-situ segmentation of any large components of various sizes and configurations. Important criteria included: minimal space requirements; fast set up times for use in confined spaces or high dose areas; the ability to cut in any direction; the ability to cut virtually any material and geometry; the minimization of secondary waste and low cutting temperature so flammable materials can be cut. It was concluded that a dry low energy mechanical cutting principle, which did not require cooling, would meet these criteria. The development program produced a low energy tool that uses the principles of a reciprocating saw together with a novel operating system that applies the principles of fuzzy logic. RASP technology can be used for virtually any cutting task and is among the safest and most versatile segmentation technologies for the in-situ processing of nuclear components. After completing a test programme in which a number of metal artefacts were segmented, RASP was been set up to cut a redundant SGHWR turbine shaft into pieces to facilitate packaging. The complete turbine assembly is a large heavy item with a steel shaft of 430mm diameter. The modular RASP framework was set up to enclose the unit and the system put to work and a hoist was set up to support the cut portion of the shaft on completion of the cut. The work was completed safely and without incident.