Nuclear Infrastructure Council Technical Meeting - February 10/11, 2016 Prof. Tim Abram Steve Threlfall

2 The Energy Trilemma

U-Battery: Technology and Fuel Reactor Building footprint projected to be equivalent to penalty area on soccer pitch. TRISO fuel was first developed in the UK and has a long and successful history of development and deployment. Discussions have taken place with several international vendors including BWXT. TRISO fuel provides damage resistance to temperatures of 1600˚C – well above worse case scenarios. This fuel type is at a high level of Technology Readiness and underpins our safety case. 3 High Temperature Gas Reactor technology, with each reactor rated at 10MW(th) & 4MW(e). Up to 20% U-235 enriched accident tolerant TRISO fuel, embedded within Prismatic Block type fuel. Helium primary coolant transferring heat via intermediate heat exchanger to a nitrogen Closed Brayton Cycle secondary. Reactor outlet temperature of 750˚C. Cycle efficiency of >40% when producing electricity through gas turbine-alternator.

4 U-Battery: Inherently Safe U-Battery’s HTGR technology was selected based on its ability to deliver inherent safety and high fault tolerance, in line with the NRC’s Final Policy Statement on the Regulation of Advanced Reactors [1]. U-Battery’s safety features follow a tiered approach: 1)High negative temperature coefficient of reactivity, meaning the reactor will naturally shut itself down under even severe beyond-design-basis situations. 2)Retaining the highest risk to safety at its source, keeping fission products within the TRISO fuel due to resilience to beyond 1600˚C (unique to TRISO-fuelled HTGRs). 3)Entirely passive post-trip cooling, independent of coolant availability, even under LOCA conditions (a capability not available to LWRs). 4)Long system response times, simple system design, and a neutronically transparent single-phase coolant, requiring the minimum of operator input during normal and accident conditions. 5)Simple reactor and safety system design, using natural circulation to maintain acceptable temperatures during emergency conditions, through passively safe design. 6)Multiple barriers to radionuclide emission, including the multiple layers of the TRISO fuel, fuel location within a fuel element assembly, the primary circuit boundary, robustly protected reinforced concrete active cells, and the reactor building itself. [1] Nuclear Regulator Commission, 10 CFR Part 50, NRC–2008–0237, Policy Statement on the Regulation of Advanced Reactors

5 U-Battery: Designed Secure U-Battery is designed to be secure, and proliferation resistant, with the intention to have minimal-to- no on-site security requirements. This is based on several security and protection measures: 1)TRISO fuel is particularly proliferation resistant. Per Idaho Nuclear Laboratory: 2)Fuel handling, manipulation and removal is only possible using purpose built fuel handling equipment, none of which is stored permanently on-site. 3)Access to the areas containing used fuel is only possible via technically complex interface with through-pilecap plugs, requiring heavy specialist shielded equipment. 4)Access to the pilecap and active areas will only be possible via multiple physical barriers, with a range of access requirements potentially available, including remote authorisation. 5)No fresh fuel will be stored on site, with delivery occurring via the same secure means as the transport of any enriched nuclear fuels. “Because the fuel is very diluted by the fuel element graphite and because of the technical difficulty to retrieve materials from within the refractory fuel coatings, unirradiated TRISO fuel can provide a significant technical barrier to diversion…. Furthermore… the high burn-up of the TRISO used nuclear fuel make it particularly unsuitable for use in weapons.”

6 Technology Readiness Levels System Group Sub-System / Major EquipmentTRL Primary System Reactor Pressure VesselMedium Core Mechanical DesignLow Primary Gas DuctMedium Intermediate Heat ExchangerMedium Primary Gas CirculatorHigh Secondary System RecuperatorHigh Pre-CoolerHigh Power Conversion Systems Gas TurbineMedium Compressor(s)Medium Intercooler(s)High AlternatorHigh Start-Up MotorHigh Tertiary Systems Cooling Tower(s)High Tertiary Coolant PumpsHigh System Group Sub-SystemTRL Auxiliary Systems Ancillary Cooling SystemsMedium Coolant Make-Up SystemsMedium Building ServicesHigh Start-Up and Shutdown-SystemsHigh Fuel Route Systems Dry Store Cell(s)Medium Flasking FacilityMedium Fuelling MachineLow FlasksMedium Reactor and Control Rod Servicing EquipmentLow Control and Safety Systems Electronic Control SystemMedium Control Room and Control EquipmentMedium Fire Detection and Suppression (FDS) SystemsHigh Building Security SystemsHigh

It is anticipated that the tasks required to deliver U-Battery will dominantly involve the development and deployment of existing technologies. HTGRs have a long history, and several current technology demonstrations, and can be considered well-developed and of relatively high maturity. There are areas of low TRL, but overall: – Critical component TRL is strong (TRISO fuel, vessels, turbines). – The focus is on the application of engineering solutions, not original R&D. – Primary areas for development are core design, control systems, and fuel solutions. Currently completing Product Breakdown Structure and refining cost estimate. Establishing commercial off-the-shelf components, developing supply chain, and the critical developmental path. 7 Technology Readiness Levels

Leading Members Project Development Leading MembersSupporting Organisations

Phase to £16M. Basic design. Refinement of cost estimate. Preliminary regulatory submissions. Phases 2 and to £18M design and licensing. £100M hardware. Detailed design. Procurement and manufacture. Licensing application and approval. Construction, installation, testing, commissioning. Operation. 9 Phasing of Project

Work streamLead Partner 1. Security/Non-proliferation assurance.Amec Foster Wheeler 2. Fuel supply.URENCO 3. Fresh and spent fuel cartridge transport licensing.Atkins 4. Reactor design and fuel codes.Amec Foster Wheeler 5. Cost estimate confirmation.Amec Foster Wheeler 6. Spent fuel cartridge handling at installation.Cammell Laird 7. Spent fuel management strategy.NNL 8. Turbine/Generator set.Atkins 9. Gas/Gas heat exchanger.Amec Foster Wheeler 10. Building layout/modularisation/ constructability/integration/programme acceleration. Laing O’Rourke 10 Key Work Designated Leads

11 U-Battery as part of a balanced mix

12 The markets and applications vary by country. In UK and many other countries, the main market is for embedded generation at industrial sites, such as URENCO’s enrichment plant. Many sites can make use of the cogeneration capability. Such deployment avoids grid connection costs. In Canada, there are hundreds of remote communities that are not connected to a national grid where electricity would be produced. This is true, also, for many parts of the developing world where it would obviate the need to build a national grid. Elsewhere the application might be for desalination. In the nuclear industry, U-Batteries could be always on emergency generators for large nuclear power plants Projected Markets

13 U-Battery compares favourably to other low-carbon technologies and is lower than offshore wind in 2020

Potential Locations at Capenhurst

Licensing Design and Construction All small and micro-modular reactor vendors whether LWR or other technologies recognise the need for appropriate licensing. NRC’s progressive approach towards this will encourage vendors development efforts. The areas that U-Battery would benefit from a dialogue with regulators are: – how probabilistic safety targets are to be met. – views on safety and security when applied to micro-modular reactors, particularly around the issue of small staff complements and limited security presence. – Fuel cycle options – such as on-site or away-from-site spent fuel storage - will impact the final layout. – In order to address heat only, electricity only and co-generation options, it will be necessary to vary the secondary and tertiary circuits. It will be important to understand each regulators acceptance of these different configurations. 15

Conclusion Technology is deliverable – Development not Research. The market is there. Financing is simpler than large reactors because capital cost is lower and the construction period is much shorter. However, much of the competition is with diesel or CCGT so we create an organisation that allows customers to buy power. An appropriate licensing regime in individual countries is needed. The dream would be for international collaborative licensing, recognising work done in other jurisdictions with comparable safety standards. 16