UK regulator issues new guidance for generic design assessment

12 November 2019

The UK’s Office for Nuclear Regulation (ONR), Environment Agency and Natural Resources Wales (NRW) has published new Generic Design Assessment (GDA) guidance to be used for all future GDA work. 

The ONR said it "reflects the changes seen in the nuclear industry in the decade since GDA was introduced, in particular the Nuclear Sector Deal and the potential for Small Modular Reactor (SMR) designs to enter GDA in the future." The new guidance also incorporates lessons learnt from previous GDAs. “A number of updates have been made to further enhance the effectiveness, efficiency and flexibility of the GDA process, whilst maintaining the high standards of safety, security, environmental protection and waste management it requires. It also maintains robustness and independence in regulatory decision making,” ONR said.

The GDA process, developed in response to the government’s 2006 Energy Review, enables regulators to assess the acceptability of new reactor designs upfront in advance of specific proposed developments or at their early stages. This helps to avoid time and cost risks arising from modifications during construction and improves potential investors’ confidence. 

The first generic design reviews started in 2007. Two designs, the EDF Energy and AREVA UK EPR and the Westinghouse AP1000 designs, completed GDA in 2012 and 2017 respectively. In 2013, the Hitachi-GE UK ABWR entered the GDA process and this was completed in 2017. The current GDA process and existing guidance will remain applicable to the ongoing GDA for the CGN/EDF/GNI UK’s UK HPR1000, which started in 2017. 

The new guidance has been produced for all future GDA activities. In addition to incorporating the latest lessons learned, it considers the changes in the nuclear industry in the decade since GDA was devised, in particular the recent nuclear sector deal and the potential for more mature Advanced Nuclear Technologies (ANTs) to enter GDA in the short term. While large portions of the text within this guidance remain unchanged, a number of improvements have been made to enhance the efficiency and flexibility of the GDA process. The key improvements include:

  • conducting the assessment over three steps, together with amending the emphasis and focus of the assessment during each step;
  • ensuring that greater emphasis is placed on earlier engagement, agreement of scope and of submissions to be submitted throughout the process;
  • enhancing the flexibility in the assessment activities conducted by ONR;
  • introducing additional outputs from the GDA process;
  • making explicit the opportunities to make better informed and more effective use of existing safety and security documentation prepared for overseas regulators, supplemented so as to meet ONR’s regulatory expectations;
  • providing better integration of safety and security requirements;
  • capturing lessons learned at the technical assessment topic level in separate guidance; and
  • simplifying and improving clarity.



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