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Step 4

Step 4 commenced on 13 February 2020 and is an in-depth assessment of the safety case evidence, security case evidence and the generic site envelope, on a sampling basis.

The aim of this step is to:

  • confirm that the higher-level claims and arguments are properly justified;
  • progress the resolution of issues identified during Step 3;
  • complete sufficient detailed assessment to allow the ONR to decide whether a Design Acceptance Confirmation (DAC) can be issued.

We published the following documents at the start of Step 4:

As part of the ongoing GDA process, GDA assessment work and to provide more up-to-date and comprehensive information to the Environment Agency ahead of their public consultation, we have issued a number of updated documents.  In particular, we have updated the PCER V1 and made some amendments to some PCSR V1 chapters to reflect the additional environmental assessment undertaken since February 2020.

We published the following documents in January 2021:

As part of the GDA, we are required to seek assurance from Low Level Waste Repository Ltd (LLWR) and Radioactive Waste Management Ltd (RWM) that the anticipated radioactive solid waste and spent fuel streams will be acceptable for treatment and/or disposal at the existing waste treatment/disposal facilities and/or at the proposed UK Geological Disposal Facility.

LLWR has assessed all low level waste anticipated to be produced by UK HPR1000 and produced a letter presenting the outcomes of their assessment, which is available below:

RWM has assessed the UK HPR1000 high active waste and spent fuel streams and produced a report detailing their assessment work and associated outcomes, which is available below or on the RWM website:

Some documents may contain commercially sensitive, export-controlled or sensitive nuclear information and so, in line with GDA guidance, we have made judgements on areas to be redacted prior to being made public.

As part of the GDA process, the public is invited to review and comment on the documents, which can be accessed via the links above. The comments process is now closed. A summary of some of the common comment themes we received and our responses can be found on our Common Comment Theme page.

During Step 4, the Environment Agency (EA) also held a public consultation to seek views on its preliminary conclusions of the detailed assessment to date. This consultation ran between 11 January 2021 and 4 April 2021. Information about the consultation is on the EA website.