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ONR Presentation to NuLeAF

ONR Presentation to NuLeAF. Tanya MacLeod. Responsibilities. Prime responsibility for the assessment and management of Flood and Coastal Risk on site rests with the ‘duty holder’ – i.e. the Licensee

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ONR Presentation to NuLeAF

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  1. ONR Presentation to NuLeAF Tanya MacLeod

  2. Responsibilities • Prime responsibility for the assessment and management of Flood and Coastal Risk on site rests with the ‘duty holder’ – i.e. the Licensee • ONR is responsible for regulating nuclear safety on nuclear licensed sites, including the safety implications associated with hazards arising from flood and coastal erosion. • The EA is the principal flood risk management authority in England providing a strategic overview relating to all forms of flood risk (SEPA, NRW).

  3. About ONR – the work we do • The Office for Nuclear Regulation's mission is to provide efficient and effective regulation of the nuclear industry, holding it to account on behalf of the public. • ONR regulates 37 nuclear licensed sites across England, Scotland and Wales • ONR is responsible for the regulation of nuclear safety, security, safeguards, transport, and conventional health and safety at licensed sites • Protection from flood hazards is a well established part of ensuring safety at nuclear sites in the UK.

  4. Protecting Nuclear Sites • The Licensee must set out how an acceptable level of safety will be achieved in a safety case. ONR’s expectations as set out in SAPs are: • Risks are As Low as Reasonably Practicable (ALARP) • Design Basis, this is a “1 in 10,000 /yr event” for natural hazards • There should also not be a disproportionate increase in risk for more extreme events • Margin and a defence-in-depth approach to safety are essential to ensuring minimal public and worker risk • Redundancy, Diversity, Segregation, Separation

  5. Tolerability of Risk and ALARP • ALARP = As Low as Reasonably Practicable • “So Far as is Reasonably Practicable” is the primary legal requirement from the Health and Safety at Work Act, translated to ALARP in the SAPs (Safety Assessment Principles) • Key references: Reducing risks protecting people: HSE’s decision making process (R2P2) The tolerability of risks from nuclear power stations (TOR) ONR SAPs (Safety Assessment Principles)

  6. Assessment and Mitigation • The safety case needs to consider still seawater levels, precipitation, storm surge, tides, tsunami, river flows and erosion and some of these will be affected by climate change. Local topography, bathymetry and shoreline management can all influence the nature of the hazard. Hierarchy of safety measures: Passive safety measures Automatically initiated active engineered safety measures. Active engineered safety measures that need to be manually brought into service in response to the fault. Administrative safety measures Mitigation safety measures Typical flood protection includes: Site platform level Sea-walls/sand dunes Site drainage and site topography Local protection such as damboards and building base height Forecasting and advanced warning systems Pumping out buildings in the event of water entry Most preferred Least preferred

  7. Access Roads Access roads may become flooded. This is not considered a major issue because, if flooded by the sea, the tidal cycle over these timescales will typically naturally render the site accessible (although impoundment is possible).  Generally AGR and Magnox sites have a minimum of 24 hours (driving towards 72 hours) before they claim any need for off-site assistance following severe  loss of safety -critical equipment.  Mobile equipment held off-site: e.g. ATV's designed to drive through water, mobile cranes for access and site clearance, etc Shut-down reactors (Oldbury, etc): no immediate or short term actions (i.e. within a few weeks) are necessary to ensure adequate fuel cooling should a flooding event occur

  8. Learning from Experience Post-Fukushima Review Completed Recommendation IR-10: The UK nuclear industry should initiate a review of flooding studies, including from tsunamis, in light of the Japanese experience, to confirm the design basis and margins for flooding at UK nuclear sites, and whether there is a need to improve further site-specific flood risk assessments as part of the periodic safety review programme, and for any new reactors. This should include sea-level protection. Supporting off-site infrastructure is also at risk from natural hazards and nuclear sites need to ensure adequate self sufficiency in the event of loss of off-site services etc (e.g. see IR-8)

  9. New Build Sites 8 proposed nuclear new build sites in the UK to be sited along the coast 5 of these are at least partially in Flood Zone 3 – High Risk* Strategic level assessments carried out by EA suggest that all potential new sites identified in the National Policy Statement for nuclear power plants in England and Wales could potentially be protected from flooding. *Key reference: DECC, National Policy Statement for Nuclear Power Generation EN-6, July 2011

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