Hamid Aït Abderrahim On behalf of the MYRRHA Team SCK CEN Boeretang 200, B-2400 Mol, BELGIUM

1. MYRRHAA Multipurpose European ADS for R&DState-of-the-art at mid.2003International Workshop on New Applications of Nuclear Fission (NANUF03)Bucharest (RO), September 7-12, 2003 Hamid Aït Abderrahim On behalf of the MYRRHA Team SCKCEN Boeretang 200, B-2400 Mol, BELGIUM myrrha@sckcen.be

2. Contents 1.Introduction 2. Applications 3. Accelerator 4. Spallation target module 5. Sub-critical reactor engineering 6. Remote handling & ISIR 7. Conclusions

3. Introduction (2) MYRRHA is intended to be: • A full step ADS demo facility • A P&T testing facility • A flexible irradiation testing facility in replacement of the SCKCEN MTR BR2 (100 MW) • A fast spectrum testing facility in Europe, beyond 2010 complementary to RJH (F) • A testing facility for fusion program • An attractive tool for education and training of young scientists and engineers • A medical radioisotope production facility

4. R&D Applications (1) • ADS full concept demonstration • coupling of the 3 components at reasonable power level (ca 40 MWth), operation feed-back, reactivity effects mitigation scalable to an industrial demonstrator • Safety studies for ADS • beam trips mitigation • sub-criticality monitoring and control • restart procedures after short or long stops • feedback to various reactivity injection • spallation products monitoring and control • … • MA transmutation studies • need for high fast flux level (Φ>0.75MeV = 1015 n/cm².s) • LLFPs transmutation studies • Need for high thermal flux level (Φth > 1015 n/cm².s)

5. R&D Applications (2) • Radioisotopes for medical applications • Need for high thermal flux level (Φth = 2 to 3.1015 n/cm².s) • Material research for PWR and BWR • Need for large irradiation volumes with high constant fast flux level (Φ>1 MeV = 1 ~ 5.1014 n/cm².s) • Material research for Fusion • Need for large irradiation volumes with high constant fast flux level (Φfast = 1 ~ 5.1014 n/cm².s with a ratio appm He/dpa(Fe) = ~15 ) • Fuel research • Need irradiation rigs with adaptable flux spectrum and level (Φtot = 1014 to 1015 n/cm².s)

6. Initial choice “Normal Conducting Cyclotron” was motivated by: start from existing technology the most powerful CW accelerator in the world is the PSI cyclotron : 590 MeV * 1.8 mA IBA technology : Cyclone-80 (80 MeV but tested up to 7 mA) and cyclotron of proton therapy (250 MeV but limited to few µA) Accelerator1) NC Cyclotron

7. 4 sector cyclotron physical magnet diameter of 16 m diameter total weight ~ 5000 t Accelerator2) NC Cyclotron solution

8. Now considering : Supra-conducting magnets cyclotron for reducing the dimensions (factor 2) Even better for the ADS demonstration a LINAC approach is now favoured as a result of the WP3 of FP5 PDS-XADS project, indeed The LINAC, with SCRF (super-conducting radio-frequency) cavities for the high energy part is considered as "the solution of choice" for high-power accelerator applications, that is for a power level which exceeds, say, 2 MW Accelerator3) LINAC

9. WP3 is presently investigating in more detail that : such a LINAC matches perfectly the required energy regime, its inherent modularity allows an easy upgrade to whatever energy finally demanded for industrial transmutation, the projected beam currents of such a LINAC, very safely fulfil the industrial request, two other considerations emerge as being in particular support for a SCRF based LINAC for ADS: reliability, availability, maintainability cost-optimisation of the operation Accelerator4) LINAC

10. Accelerator5) LINAC sketch for ADS

11. Spallation Target:1) Radial Geometrical Constraints Small assembly configuration

12. Spallation Target: 2) Boundary Conditions • 350 MeV, 5 mA proton beam for fast neutron fluxes for transmutation, i.e. 1.75 MW of which 80 % is heat • 130 mm penetration depth for 350 MeV - Bragg peak • 72 mm ID radial extent of the beam tube + 122 mm OD radial extent of the feeder - limited by neutronics • Windowless target due to high beam load - despite vacuum • Pb-Bi because of neutronic and thermal properties • 1.4 MW heat in ~ 0.5 l to be removed while meeting thermal and vacuum requirements

13. Spallation Target: 3) Desired Target Configuration BEAM Fast core Volume-minimized recirculation zone gets lower ‘tailored’ heat input Example of radial tailoring Irradiation samples High-speed flow (2.5 m/s)permits effective heat removal

14. Spallation Target:4) Design and R&D Approach Interaction between: • Experiments with increasing complexity and correspondence to the real situation (H2O–Hg–PbBi) • CFDsimulations to • predict experimental results • optimize nozzles for experiments • simulate heat deposition which can not yet be simulated experimentally

15. 60 16.5° DG16.5 Hg Experiments nominal volume flow 10 l/s Close to desired configuration ! • intermediate lowering of level • some spitting • axial asymmetry

16. DG16.5 H2O Experiments • Similarity check: OK ! nominal volume flow 10 l/s vacuum pressure 22 mbar

17. Pb-Bi Experiments at FZK (KALLA) Similar size as IPUL loop Similar complexity as MYRRHA loop: 2 free surface + mechanical impeller pump fall 2003 Pb-Bi Experiments at ENEA (CHEOPE) Minimum closed loop configuration MHD pump Speed feedback regulation test fall 2003 Spallation Target:5. Future Steps • Proton beam heating • Simulation with CFD code (e.g. FLOW-3D) • Simulated or measured flow field

18. Spallation Loop Technical Lay-Out

19. Sub-Critical Reactor2) Pb-Bi: benefits and drawbacks • Undergoes spallation • Reasonable melting temperature (123 °C) • Water can be used for the secondary cooling • High coolant density (steel and fuel float) • Opaque: blind fuel handling • Possible problems in case of variation of the eutectic composition (deposits of high melting point phases) • Bi activates into Po • The compatibility of Pb-Bi with structural and cladding materials is to be addressed by design

20. Sub-Critical Reactor 3) Engineering • Pool type vessel of  4 m X 7 m height • Standing vessel to alleviate the highest T in case of LOHS at the most stressed line of the hanging vessel • Low high flux exposure => no risk of irrad. embrittlement • Internal interim fuel storage (2 full cores, no coupling) • 4 HX groups (2 HX + 1 PP) => total capacity ~80 MW • Tin = ~200°C, Tout = 350°C, secondary fluid = water • Spallation loop interlinking with the core, cooled via LM/LM HX with the cold Pb-Bi of the core as secondary fluid • Fuel handling from beneath via rotating plug

21. MYRRHA Core

22. Radial Layout

23. Vertical View Proton beam line Spallation loop Fast core Target nozzle Main containment vessel

24. Remote Handling & ISIR • Due to the high activation on the top of the sub-critical reactor due to the neutron leakage through the beam-line, • Due to the a Po contamination when extracting components from the reactor pool, • Due to non-visibility under Pb-Bi, • We decided from the very beginning to consider the operation and maintenance of MYRRHA with remote handling systems and develop appropriate ISIR and visualisation systems

25. Task Requirements • Removal and replacement of plant items • Plant maintenance (e.g Spallation zone replacement) • Decontamination of plant items • Packaging of waste items • Recovery from failure during plant handling (e.g jamming) • Recovery of a failed Ex-vessel Fuel Transfer machine • Recovery of debris from Pb-Bi

26. 7. PLANT LAYOUT AND INFRASTRUCTURE

28. MYRRHA RH in action • Removal of the spallation loop from the reactor and its positioning in the maintenance pit

29. MYRRHA Visualisation in action • Deployment of the In Vessel Inspection Manipulator (IVIM) to inspect the MYRRHA Core internals

30. MYRRHA ISIR system in action • Deployment of the In Vessel Recovery Manipulator (IVRM) : • to recover a miss-placed fuel assembly • To inspect the spallation loop circuit ducts

31. Conclusions • MYRRHA design is progressing continuously towards the detailed engineering design • MYRRHA is developing many innovative feature that can be deployed in any future nuclear facility • MYRRHA is allowing to maintain high skills in the nuclear field • MYRRHA is intended to serve the European ADS programme

32. Conclusions • The best merits of ADS and P&T are: • the rejuvenation of our field of activity and you can see that through the amount of requests for PhDs or trainings from young people in this field, • The renewal of bringing fundamental and applied Physics community together, • The revisiting of reactor physics theory and experimental reactor tools