Lead Technology

Task 6.2Materials for mechanical pump

for HLM reactors

M. Tarantino, I. Di Piazza, P. Gaggini

Work Package MeetingKarlsruhe, November 2012

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

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

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

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

HELENA Facility

HELENA Facility

Main FeaturesMain 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)

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/m2

Total power: 230 KW

• Uniform heat flux pin will be adopted

• Pins will have wall-embedded TCs

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APR 11 201211:32:38

AREAS

TYPE NUM

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 m3/h

Lead Flow Rate: 35 kg/s

Lead Temperature: 453°C – 401°C

HELENA Facility

HELENA Facility

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