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LRQA RiskSpectrum case study header – Sizewell B Power Station on the Suffolk coast

EDF Energy relies on LRQA RiskSpectrum to monitor operational risk at Sizewell B.

Case Study

The challenge

Finding a modern NPP risk monitor

EDF Energy is the UK's largest producer of low-carbon electricity with eight nuclear power plants (NPPs) in operation. The company has a history of risk management innovation: Heysham 2 was the first NPP to employ a risk monitor in its control room. Since the mid-1990s, its Sizewell B plant had employed a outage risk management software tool for outage planning.

But Sizewell B's risk application had become outdated and ran on platforms incompatible with modern operating systems. Furthermore, it was not directly coupled with the plant's living PSA (Probabilistic Safety Assessment) model or its maintenance planning tool. This increased the need for manual intervention and it was becoming increasingly difficult to keep the two models aligned.

LRQA RiskSpectrum case study header – Sizewell B Power Station reactor dome

Our response

Understand operating risk minute by minute

EDF Energy had already chosen LRQA's RiskSpectrum PSA to build and maintain its living PSA model, so the RiskSpectrum RiskWatcher monitoring software was a natural companion. RiskSpectrum RiskWatcher uses the PSA model to give a complete and consistent picture of a NPP's risk exposure based on current operating status.

With extensive experience of different plant PSA models, LRQA delivered both consultancy expertise and software support. It advised EDF Energy on how to structure the baseline living PSA model for Sizewell B and the best way to fine-tune RiskSpectrum PSA.

That advice resulted in model updates that took only two to three minutes, fast and accurate enough to support real-time risk monitoring. LRQA also helped interface EDF Energy's outage planning tool to RiskSpectrum RiskWatcher to allow the comparison of risk exposures in different maintenance regimes.

The benefits

Assessing nuclear risk accurately

Since 2016, EDF Energy has relied on RiskSpectrum RiskWatcher for risk monitoring at Sizewell B, constantly supported by LR. A fully validated model based on the living PSA model drives risk calculation. EDF Energy can manage risk within the boundaries of the plant’s technical specifications and also factor risk into operations and maintenance planning.


The RiskSpectrum RiskWatcher model is updated each week with future planned maintenance activities, with tasks rescheduled if the risk is judged too high. Since 2016, plant operators have had live access to RiskSpectrum RiskWatcher to assess the impact of emergent work and help prioritise return to service or further planned plant release. Risk information has also informed the development of other improvements that have delivered both commercial and safety benefits.

The risk information gained through RiskWatcher has enabled the development of improvements that have provided both commercial and safety benefits.
EDF Energy Nuclear Generation

Find out more about RiskSpectrum

Our RiskSpectrum page