Tue, 20 September, 2022
TWI has been working with Nagra (The Swiss national cooperative responsible for the disposal of radioactive waste) for the past decade to develop designs for canisters capable of containing both nuclear spent fuel (SF) and high level waste (HLW) in deep geological repositories. The canisters need to be capable of safely containing radionuclides with no breach of containment for over 10,000 years. Several different canister designs were investigated in this work; a forged carbon steel canister is the current reference design.
This work has been summarised in a new study, ‘Closure Lid Design and Structural Integrity Assessment of Swiss Nuclear Waste Canisters,’ which is now available to read in full online in the International Journal of Pressure Vessels and Piping (IJPVP).
TWI experts Michael Roy, Yin Jin Janin and Philippe Bastid, Rachel Lunn, and Longjie Wang co-authored the paper alongside Nikitas Diomidis, the Head of Materials Performance at Nagra.
The study summarises the evaluation and optimisation of available options for the canister designs along with the structural integrity of the electron-beam (EB) closure weld considering long-term disposal.
An analytical study of the lid and closure weld design, as well as for the materials selection, were undertaken. These designs also considered the need to avoid heating the contained nuclear waste above allowable temperatures during post-weld heat treatment (PWHT).
This work combined finite element analysis (FEA) expertise with engineering critical assessment (ECA) as complementary disciplines. ECA calculations, performed in accordance with the British flaw assessment procedure BS 7910, were used to estimate the minimum fracture toughness properties required for the closure weld, taking into account plausible flaws and residual stresses.
Supporting the nuclear industry is a key strategic area for TWI. TWI has over 70 Member companies that operate in the global nuclear industry. Such companies cover the complete spectrum of activities from power utilities, fuel cycle companies, research and development organisations, regulators and a large range of engineering contractors from both the civil and defence sectors. To date, over 800 separate nuclear projects have been completed over a period of some 35 years.
You can read the entire article online now without sign-up, registration or fees by following this link, which will remain active until 3 November 2022.