1. AN ALTERNATIVE PROPOSAL FOR A HIBRID REACTOR (SUB-CRITICAL FACILITY COUPLED WITH AN ACCELERADOR) Sergio A. Pereira and Adimir dos Santos

2. Schematic representation of Rubbia’s Energy Amplifier

3. RUBIA’S PROPOSAL a cyclotron like this is not possible nowadays with one spallation point, the central fuel elements will achieve higher temperature and burn with higher radial power density to start the reactor, the lead must be liquid - aprox. 4 months Pressure vessel - 30m high structural problems during earthquakes the vapor generator and core maintenance is remote and very difficult, due to the liquid lead

4. more than one point of spallation: - reduce the requirement of proton energy and current of the accelerator, - to make a flatter power density distribution. the subcritical core is replaced by a concept of a solid lead calandria with the fuel elements in channels cooled by Helium: - allows on line refueling or shuffling, - utilization of a direct thermodynamic cycle (Brayton), which is more efficient than a vapor cycle the utilization of He as coolant: - more realistic, since the gas cooled reactors technology is well established, - more efficient from the thermodynamic view, allowing simplification and the utilization in high temperature process like hydrogen generation Objectives

6. Calculation LAHET/HETC Heat generated in the spallation region and their products Angular, spatial and energetic distribution of the neutron and photon sources Spallation region dimension MCNP-4C NJOY Cross section and energy deposition KERMA Power, Power distribution, Keff, Energy deposition, etc... TRANSM Methodology to be used on simulations

7. L A Pb First thermal barrier: area- A el temp - T 1 Second thermal barrier: area - A He temp. - T 2 He cooling pipe ( T He ) Fuel Element T el (800-850°C) (radiation) (conduction) (convection)

8. Experimental and calculated results of JEZEBEL experiment Experimental and calculated results of THOR experiment

9. Comparison between proton been results obtained with FLUKA and LAHET Comparison between EA parameters obtained with FLUKA and LCS

10. Cylindrical fuel element representation with a hexagonal fuel rod distribution Alternative concept with 3 spallation regions

11. Radial power density distribution of the 3 spallation sources configuration

12. Final results

13. CONCLUSION the methodology utilized reproduces with good accuracy the benchmark results in order to keep the lead solid, the solution of using pipes with helium between the fuel elements guarantees that the temperature will stay well below the limit (328  C) the proposed conception possesses a gain of 70. For a 1GeV proton the gain is 110 which is closer to Rubia ( 120) using a tree spallation source configuration we achieved a formfactor smaller than 2, when compared with 7, in the case with one central spallation source configuration.

14. FUTURE WORK Fuel burnup Nuclear Data for Th-232 and U-233 Nuclear Data for the Spallation Process Experimental Support. Closest to the Desirable is MYRRHA. Still in the design stage.