Nuclear Hydrogen Production

1. Nuclear Hydrogen Production Dr Bruce Ewan, Dr Rachael Elder, Prof Ray Allen 17th July 2008 KNOO Annual Meeting

3. Nuclear Hydrogen Production What type of reactor? How to produce hydrogen? How to couple the two? Exploring coupling a reactor to a hydrogen production plant What reactor? How produce H2? Why produce H2? Exploring coupling a reactor to a hydrogen production plant What reactor? How produce H2? Why produce H2?

4. Report:Coupling a Very High/High Temperature Reactor to a Hydrogen Production Plant Copies available to take away on disc Information obtained from literature and directly from: PBMR - Westinghouse General Atomics - HYTECH (mainly CEA and EA) Over 150 references in report and over 500 in database! Part 1 of a trilogy? Nuclear Heat for Hydrogen Production I: Coupling HTGRs to Hydrogen Production Plant Nuclear Heat for Hydrogen Production II: The Sulphur Iodine Cycle Nuclear Heat for Hydrogen Production III: The Hybrid Sulphur Cycle Send to journal � Progress in Nuclear Energy? Questions addressed in reportQuestions addressed in report

5. The Hydrogen Economy: Assumption The Hydrogen Economy will happen For a good discussion of whether, how and when see �A Review of Hydrogen Futures Literature for the UK-SHEC�, McDowall & Eames, Policy Studies Institute, October 2004

6. Nuclear Powered Cars

7. Hydrogen Production Hydrogen does not exist naturally � must be manufactured Many possible manufacturing processes Requires feedstock and energy input Main feedstocks: Fossil Fuels Biomass Waste Water

8. Hydrogen from Water Carbon neutral Two main options under consideration: Thermochemical Cycles Sulphur Iodine (SI) Hybrid Sulphur (HyS) High Temperature Electrolysis (HTE) All require a high temperature heat source >800oC Can only be provided by nuclear or solar

9. Coupling a HTGR to a Hydrogen Production Plant HTGR is a suitable nuclear reactor to reach high temperature required Four main components: HTGR Hydrogen production plant: SI cycle, HyS cycle or HTE Power conversion System: Brayton or Rankine cycle Intermediate heat exchanger (IHX) Coupling very important in terms of safety, efficiency and economics Several coupling configurations possible

10. HTGRs

11. Power Conversion Systems Rankine Cycle Water/steam High efficiencies as liquid when pumped Indirect Brayton Cycle Helium Not yet proven in combination with nuclear Direct or Indirect

12. Combined Cycle Topping Brayton Cycle and Bottoming Rankine Cycle

13. Nuclear Hydrogen Programmes 4 main programmes in world Different PCS Different HPP Different IHX4 main programmes in world Different PCS Different HPP Different IHX

14. Government Funded Nuclear Hydrogen Projects Europe HYTHEC: SI and HyS cycles and coupling RAPHAEL: HTGR and coupling USA Nuclear Hydrogen Initiative (NHI): SI, HyS and HTE and coupling Next Generation Nuclear Plant (NGNP): HTGR technology

15. Coupling Example � Japanese GTHTR300C

16. Coupling Example � US HTE-based H2-MHR

17. Coupling Example - HYTHEC

18. Intermediate Heat Exchanger (IHX) All flowsheets indirectly couple HPP to reactor Primarily due to control and safety constraints Heat transfer fluid helium, inlet temperature on primary loop 950oC Engineering challenge due to high temperature, large heat transfer area required and small space available Different configurations employed Helical shell and tube Printed circuit Plate fin

19. Safety Complicated and very important due to combination of VHTR and HPP VHTR safety Chemical plant safety Explosion risk (hydrogen) Tritium and hydrogen migration Isolation valves

20. Summary Nuclear hydrogen production has potential to provide carbon neutral energy solution Several nuclear hydrogen programmes in place around world Development of HPP, coupling and IHX required Predicted process efficiencies and plant costs at preliminary stage. Cost of hydrogen using nuclear technologies around �1/kg H2 Technological feasibility and testing of key components one of determining factors in plant viability