1. Lead Technology Task 6.2 Materials for mechanical pump for HLM reactors M. Tarantino – ENEA Work Package Meeting – ENEA Bologna, November 17th, 2010

2. Overview The erosion of structural materials in fluent lead is considered acceptable if the relative velocity between the lead and the structural surface is kept below 2 m/s. This limit cannot be respected for the mechanical pump where the relative velocity is up to 10 m/s or even higher at local areas. Material capable to operate in fluent lead with relative velocity up to 10 m/s and environment temperature up to 500°C with acceptable performance shall be individuated and qualified.

3. Proposed Material MAXTHAL has been identified as one of the most promising candidate material for the pump impeller MAXTHAL (Ti 3 SiC 2 ) is a ternary compound that can be considered as a nano-laminar composites with a layered microstructure where mono-atomic Si-element sheets are interleaved with Ti 3 C 2 -layers. The main significant aspect of MAXTHAL is that it combines some of the most attractive proprieties of ceramics with those of metals:  machinable  thermally and electrically conductive  resistant to thermal shock  deforms plastically at elevated temperatures  Refractory  oxidation resistant

4. Physical and Electrical Density, gm/cm 3 4 - 5 Electrical Conductivity at RT, ohm -1 m -1 2 - 4.5 x 10 6 Thermal Properties CTE, °C -1 8 - 12 x 10 -6 Thermal Conductivity at RT, W/m.k30 - 45 Thermal Conductivity at °C 1200, W/m.k25 - 35 Service Temperature, Air, °C1000 - 1400 Service Temperature, Inert or Vacuum, °C1400 - 1800 Mechanical Properties Elastic Modulus, GPa270 - 320 Hardness, Vickers400 - 600 Tensile Strength at RT, MPa (brittle)100 - 200 Tensile Strength at, MPa (ductile)20 - 40 Flexure Strength at RT, MPa (brittle)250 - 400 Flexure Strength at, MPa (ductile)50 - 100 Compressive Strength at RT, MPa (brittle)700 - 1100 Compressive Stregth at, MPa (ductile)200 - 500 Fracture Toughness, K IC, MPa  m. 6 - 9 Thermal Shock,  T C (100  m grain size)1200 - 1400  C Thermal Shock,  T C (5  m grain size)500 - 700  C MAXTHAL Properties

5. To evaluate the corrosion performance of the MAXTHAL as pump impeller material, several samples have been realized and tested in the CHEOPE III loop, by the ENEA Brasimone research centre. No oxidation was observed No pure Lead penetration inside the MAXTHAL matrix was observed Operative Parameters Process fluidLead Working temperature500°C Exposure Time2000h Oxygen concentration10-6 wt% Stream velocity1 m/s Background: First Experimental Results Ti3SiC2 as supplied Ti3SiC2 exposed in pure Lead 30  m scale

6. Task 6.2: Proposed activity Specific materials (MAXTHAL) will be tested in representative conditions in the HELENA Lead loop.  Operating Temperature: 400 – 450°C  Relative Velocity: 10 - 20 m/s  Oxygen Content in the melt: 10-6 wt%  Working Time: 1000 – 2000 h (5000 – 8000 h)  HELENA is a Lead loop designed by ENEA, to be installed by the Brasimone Research Centre, funded in the frame of the national program  Conceptual design has been completed on September 2010  Detailed design will be completed by March 2011, and the procurement of main component and facility building-up will start by June 2011  Tests will start from January 2012

7. HELENA Facility  HELENA is a Heavy Liquid Metal Experimental Loop for Advanced Nuclear Applications  The aim of the facility is to:  Investigate the thermal hydraulic behavior of heavy liquid metal coolant (i.e. heat exchange under forced convection)  Characterize structural material when working in lead (i.e. AISI 316L, T91, 15-15 Ti, 14 Cr-ODS, 9 Cr-ODS, coated steels)  Qualify prototypical components (i.e. centrifugal pump with MAXTHAL impeller, prototypical ball valve)  Develop and test suitable instrumentations for HLM applications  Support the CFD and system code validation when employed in lead cooled system  The main component have been designed (circulation pump, heat exchanger, heat section, corrosion test section, qualification valves test section)

8. HELENA Facility  Main Features  Working Fluid: Pure Lead  Design Pressure/Temperature: 10 bar / 550°C  Circulation Pump: Centrifugal with opened impeller in MAXTHAL  Pump Performance (BEP): 35 kg/s, 3.5 bar  Piping Dimension: 2,5” - extrastrong  Piping Material: AISI 316L  Power Heating Section: 100 kW  Main length: 8000 mm  Main height: 4000 mm  Lead Inventory: 1.6 ton  Heat Exchanger: tube in tube doubled wall, counter flow type  Secondary fluid: pressurized water (50 bar)

9. Heat Exchanger Qualification Valve Test Section Corrosion-Erosion Test Section Heating Section Centrifugal Pump HELENA Facility

11. Conclusion and Remarks The tests scheduled on the HELENA loop will allow to characterize the MAXTHAL performance when employed as structural material for lead pump impeller The tests are strictly related to the procurement of the pumps as well as the overall loop. Both these actions are funded in the frame of a national research program The budget available in the frame of the Leader Project (25 k€ as EC contribution) for the task 6.3 does not allow to support the main component procurement, so the scheduled tests could be delayed more if the national program does not start promptly.