www.toshiba.co.jp Plutonium Production in Small, Fast Reactors (SMRs) Friederike Frieß IANUS, TU Darmstadt 20.03.2014
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 2
www.belona.org www.porkcoffee.com Small, Modular Reactors Reactors with < 300 MWe, standardized fabrication Mainly military deployment, Economy of Scale Exception: Bilibino, R 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, 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? 5
SMRs and Proliferation Risk High number (several thousands?) Widely spread Safeguards? Increased trafficking of fissile material Transportation of entire cores Terrorists? Operating crews Reprocessing facilities 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 7
Procedure Fuel Composition: Isotopes & Concentration 8
Vertical Section of the Reactor Core Vertical Section of the Reactor Core Steel Sodium UZr-alloy Hafnium Helium selfmade MCNPX model 9
Cross Section of the Reactor Core Steel selfmade MCNPX model 10
Cross Section of one Assembly U-235: 17% or 19.9% enrichment U-Zr 10% alloy 169 fuel pins UZr 17% UZr 19% Steel Sodium selfmade MCNPX model 11
250 cm Burn-up - Model Five burn-up cell per fuel rod Reflector starts at 120 cm (k eff = 1) Temperature: 900 Kelvin Duration: 30 years, after 15 years: withdrawal of hafnium absorber 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! 13
Plutonium in the Core Fast SMR: 16 kg/thm LWR: 10kg/tHM 14
50 cm Weight Fraction of Plutonium-239 Partition of the reactor core: Weapon grade at all times 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 16
Classification of Fissile Material Time in years Significant Quantities Pu fiss / Pu total Classification Criteria FOM 1 FOM 2 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 : UO 2 : FOM 1 <2.6, FOM 2 <1.7 MOX: FOM 1 <2.0, FOM 2 <1.1 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 18
Thank you for your attention 19