Oak Ridge National Laboratory Molten Salt Reactor Workshop 2017— Key Technology and Safety Issues for MSRs Overview of the IAEA activities on Advanced Reactor Technology and those related to MSRs Frederik Reitsma Nuclear Power Technology Development Department of Nuclear Energy Project lead for High Temperature Gas-cooled Reactors October 2017
Overview • The IAEA at a glance • Main activities supporting advanced reactor technology development • … few words on safety design requirements • Activities on Molten Salt Reactors and the potential future role for the agency • Concluding remarks 2
IAEA is an independent intergovernmental, science and technology-based UN organization that serves as the global focal point for nuclear cooperation
Established by the United Nations as an independent organization in 1957, the IAEA serves 168 Member States. “Atoms for Peace” speech presented by US President Eisenhower to the United Nations General Assembly in 1953
The IAEA works to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world, ….. supporting the UN sustainability development goals … while verifying its peaceful use
The Secretariat — the international body of staff tasked with running the IAEA — is made up of a team of 2300 multidisciplinary professional and support staff from more than 100 countries.
Nuclear & SDGs
IAEA Departments Member States Needs Management Technical Cooperation Leading Technical Departments Safeguards Nuclear Safety Nuclear Science Nuclear Energy & Security & Applications
Nuclear Energy Nuclear power, fuel cycle and waste management The Department fosters the efficient and safe use of nuclear power by supporting existing and new nuclear programmes around the world, catalysing innovation and building indigenous capability in energy planning, analysis, and nuclear information and knowledge.
Main activities supporting advanced reactor technology development … also support new-comer member states with the focus on near-term deployment options
Advanced Reactors Technology Development PUBLICATIONS TOOLS MEETINGS CRPs TC Information Modelling and Development of Safety Exchange Simulations Methodologies Technology Education and Knowledge Support Training Preservation Assist MSs with national nuclear programmes; Support innovations in nuclear power deployment; Facilitate and assist international R&D collaborations 11
Nuclear Power Technology Development WCR GCR S + M Technology MSR Development R for Advanced Reactor Lines Fast Reactors NEApp 12
IAEA Technology Assessment • Nuclear Reactor Technology Assessment for Near Term Deployment IAEA NE-Series Document # NP-T-1.10 • Formalized process • Owner exercise • ARIS database provides technical Design Descriptions of advanced NPPs A dvanced R eactors I nformation S ystem
HTGR focus areas : Support to MS • CRPs Information Exchange: Further development - TWG-GCR of HTGR training and • HTGR Reactor Physics, Thermal-Hydraulics - Nuclear Graphite educational simulator and Depletion Uncertainty Analysis Knowledge Base specification • Modular High Temperature Gas Cooled - Technology Needs for - Training workshop Reactor Safety Design Increased Operating and - Draft specification • HTGR Application for Sustainable Extraction Accident and Mineral Product development Processes (unfunded) Temperatures – with NEFW-NFCM Technology Development for HTGRs • Example of Planned Publications • TECDOC: Improving the Understanding of Irradiation-Creep Behaviour in Nuclear TC support: Portals / DB: Graphite Part 1: Models and Mechanisms - Indonesia experimental Support to ARIS, • TECDOC: Graphite Oxidation in Modular power reactor HTGR knowledgebase HTGR (BATAN and BABETEN) and Nuclear Graphite • TECDOC: Performance of German mixed - KA CARE (Saudi Arabia) Knowledge Base Th-U and UO TRISO Fuels on HTGR Technology 14
CRP: HTRs applications for energy neutral sustainable comprehensive extraction and mineral products development CRPs Overall Objective: Study the use of process heat for mineral extraction (with U recovery) Specific Objectives: Advocate total extraction of minerals (also § from low grade ores) with thermal process Recover U/Th by-products to fuel the HTR § Ensure clearer products and reduced NORM in § waste streams Ø 16 member states Ex. Phosphate rock, REE, Tin slag, Copper etc. § Ø 2014- 2018 Ø with NEFW division Increased sustainability of ores and extraction processes while cleaning products and waste
Safety design requirements … a different safety approach warrants different safety requirements
Why the need to be different • Advanced reactors often claim to have enhanced safety characteristics compared to the current fleet of nuclear power plants • …and therefore also claim that a simplified safety evaluation and licensing process should be applied. • High temperature gas cooled reactors are one of these that indeed possess many salient and inherent safety characteristics • Supporters of the technology have for a long time been advocates that a different licensing approach and therefore also a different set of safety requirements should be developed and applied. 17
Modular HTGR safety “No fuel failure for loss of coolant flow and coolant accidents, or for all foreseeable reactivity events, even with no corrective actions” Syd Ball (ORNL) 18
How is the safety approach different … • HTGRs have favorable inherent safety characteristics: – High quality ceramic coated particle fuel – Single phase helium as coolant – Strong negative reactivity coefficients – Slow transients due to large mass of graphite in the core • modular HTGR designs that are based on design principles that ensure: – no significant radionuclide release are conceivable even if all coolant are lost / no active forced convection systems. – The residual heat removal is ensured solely through physical processes (thermal conduction, radiation, convection). • To achieve this we typically need a design with: – Low power density – Long slender core and/or annular design – Reactor Cavity Cooling System external from the reactor to remove the decay heat 19
No early or large FP release Ceramic fuel retains radioactive materials Heat removed passively without primary coolant – all natural means up to and above 1800˚C Fuel temperatures remain below design Coated particles stable to beyond limits during loss-of-cooling events maximum accident temperatures 20
No early or large FP release Ceramic fuel retains radioactive materials Heat removed passively without primary coolant – all natural means up to and above 1800˚C Fuel temperatures remain below design Coated particles stable to beyond limits during loss-of-cooling events maximum accident temperatures 21
CRP: Modular High Temperature Gas- cooled Reactor Safety Design CRPs Overall Objective: Propose safety design criteria based on the useful suitable unique safety features of HTGRs Specific Objectives: § Harmonize designers approach to modular HTGR to the safety design appropriate point Clarify LWR specific concepts such as design § extension conditions (with core melting) Include multiple reactor modules and co- § germane relevant generation considerations Safety analysis and Licensing is often singled Ø 10 member states out as one of the main challenges to the Ø 2013- 2017 deployment of new advanced reactors. 22
Two-Approaches: Past Work: IAEA and other Safety Design Approach Past Work: IAEA and other standards standards Top Down Functional Analysis to defined Defense in Safety Functions Depth Safety Design Approach Retain Radionuclides System Design Choices Control Heat - Key Systems Control Reactivity Control Chem. Attack Defense in Depth Considerations Event Selection Process Evaluate Establish Safety event Safety Design Criteria: Design/Licensing Basis Events sequence Qualitative Functional Requirements frequency PRA and Safety Analysis Safety Design Criteria: Qualitative Functional Requirements Approach 2 Approach 1 “Top-down” approach: Review IAEA SSR-2/1 “Bottom-Up” approach: 23
Revised requirements example • design extension conditions “with core melting” • Fuel handling …. designed to be dropped … more robust 24
Revised requirements example • Containment function approach – with a non-condensable gas • the focus of the requirements on the containment function and structures needs to stress the dominant role played by the coated particle fuel as the most important barrier to fission product release. • No “cascading cliff edge effects” • the requirements of multiple barriers and the implementation of defense in depth should be considered carefully, but also clearly differently. 25
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