1. Lead Technology Task 6.2 Materials for mechanical pump for HLM reactors M. Tarantino, I. Di Piazza, P. Gaggini Work Package Meeting Karlsruhe, November 2012

2.  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. Open Issue

3. Coatings for free-oxygen HLM system Fe-Al coating Successfully tested in Pb but not yet tested in creep rupture test Fe-Al coating Successfully tested in Pb but not yet tested in creep rupture test Ta coating Successfully tested as bulk material in LBE. Successfully tested with plastic deformation in room conditions. Not yet tested in creep-rupture tests. Not suitable for cladding protection due to high neutron capture and transmutation to W Ta coating Successfully tested as bulk material in LBE. Successfully tested with plastic deformation in room conditions. Not yet tested in creep-rupture tests. Not suitable for cladding protection due to high neutron capture and transmutation to W 1850h (same behaviour at 190h) 1µm

4. Proposed activity Pump impeller made in stainless steel and coated by Tantalum will be tested in representative conditions in the HELENA Lead loop.  Operating Temperature: 450 – 480°C  Relative Velocity: 10 - 20 m/s  Oxygen Content in the melt: 10 -7 – 10 -8 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  The conceptual design review has been completed in September 2011  Detailed design has been completed in April 2012, and the procurement of main component and facility building-up started in July 2012  Tests will start from April 2013

5. 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 exchanger under forced convection)  Characterize structural material (coated) when working in lead  Qualify prototypical components (i.e. centrifugal pump 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 facility has been completely designed and the installation started

6. HELENA Facility

7.  Main Features  Working Fluid: Pure Lead  Design Pressure/Temperature: 10 bar / 550°C  Circulation Pump: Centrifugal with opened impeller coated in Ta  Pump Performance (BEP): 35 kg/s, 3.5 bar  Piping Dimension: 2,5” - extrastrong  Piping Material: AISI 316L  Power Heating Section: 250 kW  Main length: 8000 mm  Main height: 4000 mm  Lead Inventory: 1.6 ton  Heat Exchanger: shell and tube doubled wall, counter flow type  Secondary fluid: pressurized water (100 bar)

8. Fuel bundle wire - spaced  19 rods placed on a hexagonal bundle (Wire spaced)  Pin diameter: 6.55 mm  Pitch to diameter ratio: 1.28  Active length: 600 mm  Wall heat flux : 1 MW/m 2  Total power: 230 KW Uniform heat flux pin will be adopted Pins will have wall-embedded TCs

9. Lead Water Heat Exchanger Shell/straight tubes counter-current  Working Fluid: pressurized water  Water Pressure: 100 bar (311°C)  Water Temperature (in): 220-230°C  Water Temperature (out): 230-238 °C  Water Flow Rate: 10 m 3 /h  Lead Flow Rate: 35 kg/s  Lead Temperature: 453°C – 401°C

10. HELENA Facility

12. Conclusion and Remarks The tests scheduled on the HELENA loop will allow to characterize the SS-coated with Ta (CVD) performance when employed as structural material for lead pump impeller. The HELENA loop will be operated adopting a low oxygen approach, allowing to prove techniques and procedure in lead (loop-system) Tests will start on April 2013