Provision of Support on Civil Engineering Safety Assessment for Step 3 of the UK ABWR

STATEMENT OF SERVICE REQUIREMENT FOR THE PROVISION OF SUPPORT ON CIVIL ENGINEERING SAFETY ASSESSMENT FOR STEP 3 OF GDA OF THE UK ABWR BACKGROUND TO THE PROJECT 1) In January 2014 ONR formally started Step 2 of the Generic Design Assessment (GDA) of Hitachi General Electric’s (Hitachi-GE) UK Advanced Boiling Water Reactor (UK ABWR). Hitachi-GE is the Requesting Party for the UK ABWR GDA (referred to as “the RP” in this specification). 2) Step 2 of GDA is an overview of the acceptability, in accordance with the regulatory regime of Great Britain, of the design fundamentals, including review of key nuclear safety and nuclear security claims with the aim of identifying any fundamental safety or security shortfalls that could prevent the issue of a Design Acceptance Confirmation (DAC) (see http://www.onr.org.uk/new-reactors/ngn03.pdf for details). 3) During Step 2, ONR has reviewed the key safety claims put forward by RP in the area of Civil Engineering Preliminary Safety Report (PSR).

ONR completed Step 2 at the end of August 2014. ONR’s technical assessment reports covering the assessment work undertaken during Step 2 and key conclusions were also published in August 2014. 4) During Step 3, ONR will assess the “safety arguments” of the Civil Engineering safety case submissions which support the safety claims made. 5) For Civil Engineering “safety argument” is interpreted as the structured robust justification to underpin the claims made by the RP (see also scope of the services required).

The safety arguments should be coherent, sufficient and commensurate with the potential risks. They should provide the entry points and clear links to the safety case documentation as a whole. 6) ONR’s Step 3 assessment plan in the area of Civil Engineering acknowledged that the key claims on Civil Engineering by the RP during Step 2 were incomplete.

As a result, ONR’s Step 3 assessment will also consider whether the key claims relating to Civil Engineering that underpin the safety of the UK ABWR are complete and reasonable. 7) For Civil Engineering “safety claim” is interpreted as being:  Specific and measurable statements that show that Civil Engineering aspects of the UK ABWR meet the relevant Safety Assessment Principles 2014.  A clearly documented basis of design for each structure – to include classification, safety functional requirements, operational requirements, structural form, load paths, loads and combinations, materials and construction/decommissioning sequence. It should be noted that: • Safety claims and supporting documentation must have a clear structure and hierarchy so that the design basis is set out logically. • The UK context should be fully recognised and addressed • Internationally recognised standards and relevant good practice should be adopted • The codes and standards used for each structure should link to the classification of that structure. Internationally used nuclear codes present less of a challenge than