Alloy Design and Thermomechanical Processing of Reduced Activation Steels for Nuclear Reactors

The UKs Sixth Carbon Budget set into law the world's most ambitious climate change target, cutting CO2 emissions by 78% of their 1990 levels by 2035, and bringing the UK towards a net zero carbon emission target by 2050. This ambitious target will be realised using a combination of renewable energy sources with energy from nuclear fusion, which offers the ultimate clean power solution, playing an important role in the transition to the required low carbon future. The Spherical Tokamak for Energy Production (STEP) is a UKAEA programme that will deliver net electricity generation from fusion within a very ambitious time frame, with a targeted completion of 2040. The design of STEP will require components to operate at higher doses and higher temperature than ever experienced in service and of course with long component lifetimes to ensure economic energy production. The current reduced activation ferritic martensitic (RAFM) steels for breeder blanket components of fusion reactors are not good enough to survive these conditions. For example, current RAFM steels, such as F82H and Eurofer97, possess a limited application temperature range of ~330-550oC.

This project will design new advanced RAFM steel compositions that will offer superior creep resistance as well as exhibiting greatly improved impact properties, allowing these steels to operate at higher temperatures (>550oC) and be better able to resist radiation hardening/embrittlement and radiation enhanced creep. This will be achieved using a programme of innovative alloy design and novel thermomechanical processing (TMP).