Safeguard and protection requirements for Gen-IV reactor systems

Transcription

1 Matthew Gill 25/03/13 Safeguard and protection requirements for Gen-IV reactor systems 1

2 Content 1. Gen-IV reactors Concepts and Advantages TRL and contribution to world energy 2. Proliferation and Fuel cycles Non-State actors and Physical Protection State actors and Proliferation Resistance 3. Conclusion

3 Gen-IV Systems Very High Temperature reactor (VHTR} Supercritical Water-cooled Reactor (SCWR) Sodium-cooled Fast Reactor (SFR) Lead-cooled Fast Reactor (LFR) Gas-cooled Fast Reactor (GFR) Molten Salt Reactor (MSR) Thermal Fast Special

4 Gen-IV: Thermal reactors SCWR Greater thermal efficiency Extension of PWRs VHTR Outlet temperature > 1000oC Robust fuel, high burnup

5 Gen-IV: Fast Reactors Sustainable use of fissile resource Minimising burden on repository and intergenerational waste Require a closed fuel cycle (Proliferation concern) SFR: Near-term design, well understood. LFR: Regional deployment, coolant does not react with water GFR: High outlet temperature, very hard spectrum. 5

6 Gen-IV: Thorium-MSR Thorium fuel cycle Liquid fuel Fast or thermal reactor High outlet temperature One fluid/two fluid Requires a closed fuel cycle: Online-reprocessing Batch-reprocessing Removal of protactinium

7 Regional deployment: VHTR + LFR + MSR TRL and purpose TRL Definition & Description 1 Basic principles 2 Application and concept 3 Demonstration of Basic components 4 Integration of Components into basic system 5 Demonstration of a basic system 6 Prototype construction 7 Prototype demonstration 8 Actual systems constructed and commissioned 9 Successful operation of actual system 10 Widespread, Reliable, Long Term Operation of Many Actual Systems GFR, SCWR LFR, MSR SFR HTR Sustainability: Fast reactors + MSR Minimise Waste: Fast reactors + MSR Process Heat: VHTR + GFR + MSR

8 Proliferation PWR (53 GWd/ton) PWR (MOX) PWR (33 GWd/ton) Magnox (5 GWd/ton) Magnox (3 GWd/ton) 40% 50% 60% 70% 80% 90% 93% MSR VHTR Ratio Pu-239/Pu-total Fast Reactors Requires very pure U-233 U-232 in small amounts causes Poisoning effect (α,n). Thermal degradation of explosives. Refueling is done at an interval of 185 effective full power days Günther Kessler, Proliferation-proof uranium/plutonium fuel cycles : Safeguards and non-proliferation, KIT Scientific Publishing,

9 Fuel Cycle - Diversion Uranium-Plutonium: 2.4 Days Need fuel with high Pu-239% and extract the plutonium Thorium-Uranium: 27.4 Days Need to extract the protactinium Thermal reactors: No reprocessing Do not contain weapons useable material No real problems!

10 Fuel Cycle - PP Physical protection Intrinsic Barriers. Fast reactors: Fuels that are harder to reprocess/separate in a back alley Heterogeneous reprocessing adding minor actinides into fuel. (Self protection, no separated Pu in facilities) Do not use radial breeder blankets, higher residence time (Make material less weapons useable) Minimise transport of materials and stored materials. MSR: Do not isolate protactinium H.F. Bauman, W.R. Grimes and J.R. Engel, MOLTEN-SALT REACTOR CONCEPTS WITH REDUCED POTENTIAL FOR PROLIFERATION OF SPECIAL NUCLEAR MATERIALS

11 Fuel Cycle - PP Non-state actors would need to be very sophisticated Gun-type device: Materials would not be effective. Implosion-type device: Very sophisticated to develop, a device would have to be acquired by other means. Risk: Fast Reactors > MSR > Thermal Reactors Barriers to developing a weapon 1. Acquire blanket fuel 1. Acquire fuel 2. Separate plutonium from blanket fuel 2. Separate protactinium 3. Develop implosion device

12 Regional reactors > Fast Reactors > MSR > Thermal Reactors Fuel Cycle - PR Proliferation resistance - State actor Extrinsic Barriers: Materials measurement Focussing on non-destructive and in-situ Passive detection Detect the removal of material Surveillance Inspection Intrinsic barriers: Assuming a sophisticated state intrinsic barriers can only slow down the process. Increase material required, time to divert it, processes to make it useable. More useful in MSRs

13 Summary Physical Protection (PP) does not appear to be a big issue. Non-state actors would struggle to gain capabilities to utilise material Proliferation Resistance (PR) more dependant on extrinsic factors. Intrinsic factors can make diversion more difficult but not prevent it. Extrinsic factors are needed to detect diversion. Inspection is very big requirement. Large deployment of regional reactors puts a bigger burden on inspection. Enrichment is more of a concern. Molten salt reactors and the thorium fuel cycle is NOT proliferation proof! They are intrinsically better than fast reactor fuel cycles Thank you, questions??