Client: EDF Energy Nuclear Generation Ltd
Application: Risk monitor implementation for Sizewell B
Location: Suffolk, UK
Background to the project
Risk monitors have been in use by EDF Energy for a long time (in fact, the ESSM Risk monitor for Heysham 2 was the first risk monitor in the world employed in the control room of a NPP). Another example is the ORAM risk monitor that has been used for outage planning at Sizewell B since mid-1990s.
These tools are of old design and not updated to the latest development platforms designed for modern operating systems. Furthermore, they are not directly coupled with the living PSA (Probabilistic Safety Assessment) model.
As the risk monitor is used not only by PSA experts but also by staff responsible for maintenance planning, it is important that the risk monitor tool is capable of fulfilling these requirements. The interface with the plant and maintenance planning tool is also key to minimising the need for manual intervention. Without a software package with tools designed to work in combination it was becoming increasingly difficult to keep the models aligned.
As EDF Energy has used RiskSpectrum as their PSA tool, they were interested in the risk monitor tool, RiskSpectrum RiskWatcher.
Outcomes for EDF Energy
EDF Energy has been using RiskWatcher since 2008 for risk monitoring at Sizewell B with a fully validated model which is closely linked to the living full scope PSA model.
4 Key Benefits:
- This enables EDF Energy to be risk-informed in operations and maintenance planning and to manage risk within the boundaries of the technical specifications.
- The RiskWatcher model is updated each week with future planned maintenance activities, which provides a look ahead and enables tasks to be rescheduled if the risk is judged too high.
- Since 2016, RiskWatcher has been used ‘on-line' by Operators to assess the impact of emergent work and help prioritise return to service or further planned plant release.
- The risk information gained through RiskWatcher has also enabled the development of other improvements that have provided both commercial and safety benefits.
Besides being the developer and supplier of the RiskSpectrum software suite, LR also has extensive experience in working with different plant PSA models which means that we can provide both consultancy expertise and software support. LR was therefore able to advise EDF Energy on the structure of the baseline living PSA model for Sizewell B as well as how to best use the available features in RiskSpectrum in order to achieve reasonable run-times (2-3 mins) with credible results that were fit for purpose for risk monitor purposes.
LR has also helped EDF Energy to develop an interface between the plant outage planning tool and the RiskWatcher risk monitor.
About EDF Energy
EDF Energy is the UK's largest producer of low-carbon electricity with 8 nuclear power stations (NPP) in operation, representing around 77% of the electricity produced by EDF Energy in the UK.
For the last decade, Lloyd's Register (LR) has supported EDF Energy in their implementation and development of a risk monitor for Sizewell B NPP in the UK.