Plutonium Production in Small, Fast Reactors (SMRs)

Transcription

1 Plutonium Production in Small, Fast Reactors (SMRs) Friederike Frieß IANUS, TU Darmstadt

2 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

3 Small, Modular Reactors Reactors with < 300 MWe, standardized fabrication Mainly military deployment, Economy of Scale Exception: Bilibino, R 3

4 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

5 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

6 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

7 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

8 Procedure Fuel Composition: Isotopes & Concentration 8

9 Vertical Section of the Reactor Core Vertical Section of the Reactor Core Steel Sodium UZr-alloy Hafnium Helium selfmade MCNPX model 9

10 Cross Section of the Reactor Core Steel selfmade MCNPX model 10

11 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

12 250 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

13 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

14 Plutonium in the Core Fast SMR: 16 kg/thm LWR: 10kg/tHM 14

15 50 cm Weight Fraction of Plutonium-239 Partition of the reactor core: Weapon grade at all times 15

16 Criteria to Assess Material Attractiveness (Bathke) critical mass heat generation advanced dose rate spontaneous neutron emission Newcomer Definition of Figures of Merit (FOM) FOM < > 2 Weapon Usability Very low low medium preferred 16

17 Classification of Fissile Material Time in years Significant Quantities Pu fiss / Pu total Classification Criteria FOM 1 FOM 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

18 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

19 Thank you for your attention 19