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Through Optimum Use and Innovation of Welding and Joining Technologies
Improving Global Quality of Life
engineering disciplines due to the need for high priced welding and testing equipment and laboratories that
must keep up with industry.
Machine GTAW and Semi-Automatic GMAWwill become important in the coming years and this will require
specially trained Welding Technicians to keep the equipment working properly and dialed in for optimal
performance. These positions require training found in 2 year associate degree programmes.
Certified Senior Welding Inspectors and Non Destructive Testing (NDT) technicians are needed to assure
the necessary examinations are performed to provide evidence that welds meet the requisite high quality
standards. New phased array ultrasonic techniques and radiography using digital media will be employed.
Presently individuals competent in these techniques are as difficult to locate and train as welders. Typically
their training is commensurate with an associate degree in engineering technology. The experience levels
needed to work independently are of the order of several years.
A programmatic method for recording welding data will depend heavily on software designed for the task.
The information gathered will provide the utility operators cradle-to-grave traceability. Such data is a great
asset for plant engineering staff when they find deficiencies or degradation in the plant equipment once it
is placed in operation. The engineering and quality control staff will assure this is accomplished and made
available for owner and regulatory review.
Generally speaking, GTAWcan be applied for the austenitic stainless steel andNi base alloys against corrosion,
heat and extremely low temperature. Since the reactors have the large scale structure, it is necessary to
make progress on the welding process with the higher efficiency, the lower heat distortion and the higher
quality. This will mean adopting much higher efficiency welding with high deposition rates, such as narrow
gap Welding, hot-wire TIG welding, multi-electrode welding and laser-arc hybrid welding at the factory
and the local nuclear reactor site. In the case of an International Thermonuclear Energy Reactor (ITER) with
large structure and large wall thickness, high power laser and laser arc hybrid welding can be applied for
high accuracy and high velocity.
Figure 9.9
shows the trend of welding processes for the application to the
nuclear equipment.
Finally, as there are many light-water reactors operating for over 60 years, there will be the need to start
the decommissioning of the used reactors. The cutting and recycling technologies of the metal, such as RPV
and Core Shroud is utilised for the decrease of the waste volume. Moreover, the waste processing system of
used fuel rods, are in operation, and so the components are added to the systems and repaired by remote
maintenance technologies of laser welding.
Figure 9.9
Trends of welding processes
for nuclear power plant (Reproduced
courtesy: Satoru Asai)
High Quality
High Efficiency
Future
Laser-Arc Hybrid
Super Narrow Gap
Multi-Electrode
Advance MIG
Hot Wire
Narrow Gap GTAW
GTAW
High Power Laser
9
Needs and challenges of major industry sectors for future applications
