Status of He-EFIT Design Pierre Richard – J. F Pignatel – G. Rimpault

1. Status of He-EFIT Design • Pierre Richard – J. F Pignatel – G. Rimpault

2. Outline • Recall of the Design Approach • Main Issues Addressed since the February (Bologna) Meeting • Updated Table of He-EFIT Main Characteristics • Presentation of the current core design : Core, Spallation module, Power Conversion Cycle • DHR Approach • Conclusions – Next steps

3. He-EFIT Design Approach 1 – Spallation module design using the outcome of the PDS-XADS Project 2 - Define the Proton Beam Intensity (for a maximum proton energy of 800 MeV), the reactor power and the Keff (assuming the potential reactivity insertions and burn up swing which have to be checked later)  3 - Design the core taking into account the design objectives (MA burning, Keff considerations,…) and the core design constraints (Fuel composition, cladding composition, pressure drops,…)---------------------------------------------------------------------------------- 4 - Define the approach for the DHR and design the DHR main components (blowers, HX,…)  5 - Design the primary system 6 - Design the Balance of Plant and Containment and implementation of the plant (cooling loops, confinment building, …) Steps 2 and 3 require iteration loops with neutronics, T/H and geometry considerations  Required some time

4. Proton beam characteristics : Energy changed from 600 MeV to 800 MeV which is currently considered as an upper limit : over 800 MeV, the radio-toxicity increase rapidly Need for higher proton beam intensity 18-22 mA instead of 10-20 mA Plant Efficiency : First Assessment made at CEA : with Tin/Tout = 400/550 °C AMEC/NNC : incentive to increase the Tcore from 150 °C to 200 °C Decision from the Lyon meeting (03/06) : Tin/Tout = 350/550 °C Plant efficiency increased to 43.3 % Fuel Characteristics : CERCER (MgO matrix) limit temperature at nominal conditions decreased from 1860 °C to 1380 °C CERMET (Mo matrix) considered as back up solution (decision from the Cadarache meeting in June) S/A Characteristics : S/A Outer width over flats reduced from 162 mm to 137 mm : target size corresponding to 19 S/A at the center of the core Evolutions since the Bologna Meeting (1/3)

5. Core Design : Core power decreased to 400 MWth (600 MWth before) 3 zones core with different pin diameters Peaking factors : Total peaking factor changed from 1.61 to 1.839 : iteration with neutronic calculations Adaptation to He-EFIT of the objectives defined by the “Specialist Meetings” (March-June 2006) : 42 Kg MA burnt par TWhth Flat Keff versus BU Reasonably low current requirement < 20 mA Low pressure drop < 1.0 bar Clad temperature limit < 1600°C (transient), < 1200°C (nominal) Coolant speed < 50 m/s Others : Wrapper Thickness, Number of grids, … Evolutions since the Bologna Meeting (2/3)

6. Evolutions since the Bologna Meeting (3/3) • Cross-check with FzK and modifications of the correlations for Heat Exchange Coefficients, Core Pressure Drops and Fuel Conductivities (According to DM3 recommendations) : • Rather good agreement : • Core composition f < 0.05 % • Fuel Max Temperatures T< 20 °C • Cladding Max Temperatures T< 6 °C • Pressure drops : incoherency in the Dh calculationsbut small consequences : (P) < 0.034 bar • Safety : • Pressure drop limited to 1 bar for the core and 1.5 bar for the whole primary circuit  Provisional value to be checked by appropriate transient calculations • DHR strategy - Comparison of different two approaches : “XADS-like” approach / GCFR approach

7. Main Characteristics of the Gas-Cooled EFIT (1/3)

8. Main Characteristics of the Gas-Cooled EFIT (2/3)

9. Main Characteristics of the Gas-Cooled EFIT (3/3)

10. Current Design • A three zone core has been preliminarily studied : • Zone 1 (inner) : 45 MWth, 42 sub-assemblies • Zone 2 (intermediate) : 165 MWth, 156 sub-assemblies • Zone 3 (outer) : 191 MWth, 180 sub-assemblies • The main hypothesis and/or design objectives accounted are the following : • Core heigth : 125 cm • External width over flat : 137 mm • Fuel (fuel+matrix) fraction in the diffrent zones : 11%, 21.5 % and 35 % (for respectively zone 1, 2 and 3) • Matrix volmue fraction in the fuel pellet : 50 % • - The total form factor was assumed to be the same in the three zones (1.839) Remarks : 1 - Core pressure drops are not equilibrated (too many design constraints). They are respectively 0.84, 0.74 and 1 bar in zone 1, 2 and 3  some gagging will be necessary 2- The pellet diameter in zone 1 is rather small (2.3 mm). If this induces some problem, the number of pin rows per S/A can be reduced to 11 row per S/A.

11. Current Design – 50 MW/m3 (1/2)

12. Current Design – 50 MW/m3 (2/2)

13. “Cold” Window Concept (1/2)

14. Target central part made of a bundle of horizontal W-rods (see detail A) Dext = 266 mm Proton Beam Radial pitch He flow Target lower peripheral ring also in W (assume a porosity of 50% for He flow)) Helium Axial pitch “Cold” Window Concept (2/2)

15. Assumptions : Keeping the indirect Supercritical CO2 cycle with re-compression CO2 remains super-critical : CO2 characteristics above the Critical Point (74 bar/32 °C). This avoids the presence of water in the compressors (badly known behaviour of the components) CEA Low Heat sink Temperature considered too restrictive : 16 °C  21 °C Parametric study on the core inlet temperature : +/- 50 °C Power Conversion Cycle – AMEC-NNC Assessment

16. Power Conversion Cycle Main Compressor Auxiliary Compressor Turbine  43.3 %

17. Goal : Compare different strategies : Active/Passive Guard Containement/No guard Containment Background : GCFR Approach PDS-XADS (He-cooled XADS) Decay Heat Removal - Approach

18. Schematic of DHR system (CEA initial proposal) pool Exchanger #2 Secondary loop H2 Exchanger #1 dedicated DHR loops • 3 loops of DHR • 3 pools • 1 guard containment H1 Guard containment core

19. DHR (CEA studies)

20. GFR STRATEGY (CEA Approach) • For the GFR 2400MWth • -The high back-up pressure strategy (25Bar) is not kept • -for GFR the intermediate back-up pressure strategy (~5 Bar) is studied • -Back Up solution :The full depressurisation (1Bar) (still not studied)

21. PDS-XADS Basic Reactor options: • Reactor power : 80MWth • First core: classical FBR fuel U-PuO2 (35% Pu max) • Accelerator: designed for 600MeV/6mA but can be upgraded to 800MeV/10mA • Core and Target Unit designed for 600MeV/6mA • Separated target: liquid • Primary circuit: He DHR Strategy : • No Guard Containment • Full depressurization 1 Bar • Integrated SCS (but only 2 MWth to be removed by each SCS)

22. PDS-XADS SCS Design • Integrated SCS (Electric Power 55kW)

23. DHR for EFIT • For He-EFIT: • The PDS-XADS solution seems better • Proton beam complexity  Guard containment not keep • If the full depressurization is chosen, a strategy must bedefined : • The blowers must work 1 to 70 Bars : Requires High Power and a complex Blower Design (or 2 systems : 1-10 bars and 10/70 bars? ) OR • Blowers can work only at low pressure :  Acton for fast depressurization System systematically used (safety)  SIMPLIFICATION of procedures • System implementation : • 3 DHR loops designed for 100 % • 2 Solutions : Loops integrated on the vessel/Ex-vessel loops

24. Conclusions (1/2) Current Design : • A three zone core has been preliminarily studied : • Zone 1 (inner) : 45 MWth, 42 sub-assemblies • Zone 2 (intermediate) : 165 MWth, 156 sub-assemblies • Zone 3 (outer) : 191 MWth, 180 sub-assemblies • The main hypothesis and/or design objectives accounted are the following : • Core height : 125 cm • External width over flat : 137 mm • Fuel (fuel+matrix) fraction in the different zones : 11%, 21.5 % and 35 % (for respectively zone 1, 2 and 3) • Matrix volume fraction in the fuel pellet : 50 % • - The total form factor was assumed to be the same in the three zones (1.839) • DHR Approach under discussion

25. Conclusions (2/2) Next steps : • Detailed neutronic calculations : • Neutron source behaviour by the mean of MCNPX Calculations • Core neutronics by the means of MCNPX and ERANOS calculations. • Even if the current core design is not fully defined, He-EFIT main characteristics (core power, main core dimensions)are sufficiently defined to go ahead with : • Safety Approach/DHR strategy : • Pre-sizing of the DHR loop components (AREVA ??) • CATHARE/SIM-ADS modelling (CEA/FzK ???) • Remontage (AREVA)  Dissemination of the main He-EFIT design characteristics – Iteration with the partners