The manufacture of items destined for use in the nuclear sector involves challenging fabrication issues in a wide range of materials. Applications range from the manufacture of the fuel elements and associated equipment to the decommissioning of aged plant and safe disposal of nuclear waste.
In all areas, welding must be of a high standard so as to produce joints that will meet the exacting demands of nuclear service. TWI has experience of working with the nuclear industry to ensure that welds meet the required standards.
However, our work goes beyond welding as, for example, we were awarded a contract by the Nuclear Decommissioning Authority in 2009 to demonstrate the capabilities of lasers for surface removal of contaminated concrete structures and size reduction of vessels and pipe work. The project was completed successfully in March 2010. As a consequence of the interest generated by this work within the nuclear industry, particularly with respect to the cutting results, TWI demonstrated additional capabilities to cut thick section materials and as well as to cut underwater.
Nuclear power plants produce highly radioactive nuclear materials. These nuclear industrial waste streams remain hazardous for thousands of years, meaning that nuclear waste management is important for any nuclear facility. Radioactive materials can be stored away either at nuclear sites or off site using techniques such as geologic repositories and dry casks.
Disposal of spent nuclear fuel and other radioactive waste, particularly if it is high level, requires remote handling and long-term exclusion of the material from the biosphere by encapsulation and shielding. The latter is often achieved by sealing the waste material in metallic (often stainless steel) canisters specially chosen to survive very long-term storage (up to 100,000 years) in a deep geological repository. TWI has unique global experience of the materials, design and fabrication aspects of nuclear waste containers used for this purpose.
Safely disposing of nuclear materials is also an important part of the wider world nuclear decommissioning process. Decommissioning involves the cleaning up of radioactive material and the organised and progressive demolition of a nuclear plant.
The International Atomic Energy Agency defines three options for decommissioning a nuclear installation:
- Immediate Dismantling (Early Site Release/Decon in the United States).
- Safe Enclosure (postponing the final decommissioning)
- Entombment/Entomb (any remaining radioactive material remains on-site indefinitely)
The total cost of decommissioning nuclear power reactors can be high, which has led to international collaboration between bodies such as the United States Department of Energy, the Nuclear Energy Agency and the European Atomic Energy Community to share knowledge, reduce cost and improve safety within the bounds of regulatory control.
As an independent organisation, TWI can assist our Industrial Members with key aspects of nuclear decommissioning and long lived radioactive waste management.
For more information, please email contactus@twi.co.uk.