Metallurgy and corrosion

The performance and longevity of containment vessels (for all levels of waste) is of paramount importance in any nuclear establishment. TWI's Metallurgy and Corrosion group has assisted in assuring the long-term reliability of stainless steels and non-ferrous materials against threats such as welding flaws during fabrication and sealing, and corrosion during service.

In establishing procedures for fabrication and sealing of any waste containment vessels it is essential to consider those metallurgical aspects that can lead to either immediate failure, or reduced life. For example, tendencies towards solidification cracking, microfissuring and liquation should be considered in the specification of the alloys and welding procedures. TWI has over 50 years experience in offering consultancy and trouble-shooting to avoiding metallurgical defects and in mitigating their effects.

The long-term performance of containment vessels is controlled to a great extent by corrosion issues. As with most aspects of performance, the corrosion resistance of any fabrication is largely determined by the susceptibility of the joints to a variety of general and localised mechanisms of attack. TWI has performed extensive corrosion studies to determine the risks of localised attack at joints in a variety of environments, including pitting and crevice attack, stress corrosion cracking, loss of weld metal corrosion resistance due to galvanic action, segregation and loss of weld area corrosion resistance due to the presence of welding oxides. TWI's Metallurgy and Corrosion group have considerable experience in these areas and has the capability to perform a full range of small scale tests and equally valuable experience in correlating short term test data with long term service performance.

For further information, please contact: power@twi.co.uk

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