Plutonium Production in Small, Fast Reactors (SMRs) 20.03.2014 www.toshiba.co.jp Friederike Frieß IANUS, TU Darmstadt Overview • Definition of SMR • Proliferation risks and SMRs • Sodium-cooled reactor model based on Toshiba 4S • Plutonium production in the core • Assessment of material attractiveness • Summary IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 2 www.belona.org • Reactors with < 300 MWe, standardized fabrication • Mainly military deployment, „Economy of Scale“ • Exception: Bilibino, R www.porkcoffee.com Small, Modular Reactors IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 3 Renewed Interest • DOE funds of $450 Million in 2012 – Deployable until 2022 – Use of proven technology NuScale B&W mPower • R&D and licencing efforts in several countries (US, CA, IN, CN, JP, …) • Demonstration plants: US, CN, AR, … IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 4 What is Proliferation? • Generally: Spreading of nuclear weapons knowledge, technology or fissile material • Two types: – Vertical proliferation: Actor increases its capabilities – Horizontal proliferation: Actor gains new capabilities • Dual-use problem: Where is the boundary between civil and military use? IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 5 SMRs and Proliferation Risk • High number (several thousands ?) • Widely spread • Increased trafficking of fissile material • Transportation of entire cores • Operating crews • Reprocessing facilities IANUS | TU Darmstadt | Friederike Frieß - for personal use only - Safeguards? Terrorists? Spreading of knowledge/technology 6 Toshiba 4S • Super Safe, Small, and Simple • Demonstration in Canada? • Sodium-cooled fast reactor • 10 MWe power • Underground reactor building • LEU metal alloy fuel • Core exchange every 30 years, no refueling IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 7 Procedure Fuel Composition: Isotopes & Concentration IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 8 Vertical Section of the Reactor Core Vertical Section of the Reactor Core Steel Sodium UZr-alloy Hafnium Helium selfmade MCNPX model IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 9 Cross Section of the Reactor Core Steel selfmade MCNPX model IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 10 Cross Section of one Assembly • U-235: 17% or 19.9% enrichment • U-Zr 10% alloy • 169 fuel pins UZr – 17% Steel UZr – 19% Sodium selfmade MCNPX model IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 11 Burn-up - Model • Reflector starts at 120 cm (keff = 1) • Temperature: 900 Kelvin 250 cm • Five burn-up cell per fuel rod • Duration: 30 years, after 15 years: withdrawal of hafnium absorber IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 12 Questions – Reference Values • How much plutonium is in the core? IAEA: 8 kg is the significant quantity • Is the compostion attractive? Pu-239 > 93% → „weapon grade“ But: all Pu compositions can be used! IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 13 Plutonium in the Core Fast SMR: 16 kg/tHM LWR: 10kg/tHM IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 14 Weight Fraction of Plutonium-239 50 cm Partition of the reactor core: Weapon grade at all times IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 15 Criteria to Assess Material Attractiveness (Bathke) • • • • critical mass heat generation advanced dose rate spontaneous neutron emission Newcomer Definition of Figures of Merit (FOM) FOM <0 0-1 1-2 >2 Weapon Usability Very low low medium preferred IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 16 Classification of Fissile Material Time in years Significant Quantities Pufiss / Putotal Classification Criteria FOM1 FOM2 2 ̴1 0.998 2.8 2.5 30 ̴20 0.993 2.8 2.4 • No change in attractiveness if material is stored for 30 years • Small LWR : – UO2 : FOM1<2.6, FOM2<1.7 – MOX: FOM1<2.0, FOM2<1.1 IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 17 Summary • Rising interest in SMRs in the last decade → Detailed evaluation necessary: proliferation risk? • Plutonium Production: – Several significant quantities – Mainly Pu-239 Fast SMRs produce a high amount of weapon grade plutonium IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 18 Thank you for your attention IANUS | TU Darmstadt | Friederike Frieß - for personal use only - 19
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