Performance and Reliability of Metallic Materials for Nuclear Fission Power Generation

Lead Research Organisation: Imperial College London
Department Name: Materials

Abstract

In this research programme we will address fundamental research challenges for the long-term performance and stability of materials for nuclear fission power plant. The lifetime of power plant components is limited because of limits in their endurance under exposure to high temperatures, high loads, radiation, and the effects of cycling of load and temperature; there are issues related to corrosion that are exacerbated by applied stresses and residual stresses in materials; and the high neutron radiation flux in the core of the reactor generates progressive damage that must be understood if we are to be able to design new materials for future reactor systems with improved lifetimes and efficient use of nuclear fuel. This research programme will underpin the development of the nuclear fission power generation systems of the future.Metallic systems used in nuclear reactors range from pressure vessel steels to fuel cladding tubes to stainless steels used in the heat exchangers. The particular operating conditions for each component are unique and require carefully tailored materials properties. There are significant challenges in enhancing materials performance for operations at higher temperatures for longer lifetimes, and we have to improve our understanding of the fundamental mechanisms by which materials degrade and by which damage develops in nuclear reactors and their associated high-temperature plant.We will address fundamental research problems in improving the long-term performance of materials for nuclear plant exposed to service conditions of high temperatures, high neutron radiation fluences and complex load histories. The critical research challenges that arise for materials performance under these conditions are Materials Stability and Degradation and State Monitoring of Materials . We propose to address them through a broad collaborative programme incorporating the leading UK university groups and our wide network of external partners.The research programme is targeted mainly at the theme of Long term materials behaviour , but with a significant contribution in the area of fuel cladding materials . We have integrated work in these two areas because there is significant commonality in the research methodology (experimental and modelling) required for the study of the different metallic systems and because of our experience of the significant benefits that flow from maintaining close relationships with other nuclear research programmes in partner institutions.From our previous track record, we confidently expect a high degree of gearing as the work of the new consortium will complement and bring together our existing individual programmes, funded by industry and the Research Councils. In addition to delivering new research outputs and a cohort of trained researchers, this will place us in a strong position to respond effectively and in a coordinated manner to future funding opportunities from industry, the EU and the wider international nuclear community.
 
Description A systematic study of many of the important microstructural features associated with SCC as a result of the introduction of cold work were examined and as a result several proposed theories were rejected. The idea that martensite induced by plastic strain was a cause of the decreased SCC resistance was not found and no link could be made due to occurrence of "special" CSL grain boundaries. The big increase in SCC was observed for a narrow window of cold work of 0.5-2%. More than this and the cold work showed a protective nature with no cracks observed at 20% cold work or greater. It was proposed this was due to heterogeneous plasticity effects at low levels of cold work generating micro-level residual stresses
Exploitation Route Research being taken forward by second PhD. We will use EBSD to look for microlevel stresses to test our theory. We will study the effect of weld residual stresses on SCC and the effects of salt level needed for SCC.
Sectors Energy

 
Description As above the results will be reviewed by EDF Energy as part of their safety case proposal for the dry storeat Sizewell and a second paper to be published for which we are collecting additional data on the effects of salt loading on SCC could potentially have a big impact on the safety case.
First Year Of Impact 2016
Sector Aerospace, Defence and Marine,Energy,Government, Democracy and Justice
Impact Types Economic

 
Description Award to extend GG Scatigno's PhD funding period to study the effect of atmospheric SCC on the 316L material that the dry store containers are made from.
Amount £20,000 (GBP)
Organisation EDF Energy 
Sector Private
Country United Kingdom
Start 06/2015 
End 12/2016
 
Description Rolls-Royce plc 
Organisation Rolls Royce Group Plc
Country United Kingdom 
Sector Private 
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