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WP3: Coolant Chemistry Control

Work package number: 3
Start date or starting event: M1
Work package title: Coolant Chemistry Control
Activity Type: RTD
Participant number: 1 - 2 - 3 - 9
Participant short name: SCK•CEN - ENEA - KIT - INR
Person-months per participant: 37 - 12 - 46 - 10.20

The main objectives of this work package are related to the control of the coolant chemistry and associated with that the filtering and mass transport of impurities. The objectives are summarised as follows:

  • Determination and assessment of corrosion products to be expected in MYRRHA under operation
  • Determination and assessment of spallation products and neutron activation products to be expected in MYRRHA under operation
  • Determination of loop filter efficiency, lifetime and pressure drop for several filter types
  • Determination of feasibility and efficiency of LBE pool type filter
  • Validating an Oxygen Control System (OCS) based on solid oxide particles inside a pool type facility and measurement of PbO formation and dissolution kinetics in LBE
  • Absorption of oxygen from the cover gas under regular operating conditions and acciden-tal ingress of oxygen into the cover gas
  • Entrainment of oxides floating on the liquid-metal surface
  • Oxygen absorption from water vapour introduced below the liquid-metal surface (HEX leak)
  • Mass-transport of dissolved metals, especially nickel

Description of Work (SCK•CEN, ENEA, KIT, INR)
Task 3.1:
Determination of Source Terms (KIT,SCK•CEN)
It is important for normal operating conditions to estimate the amount of oxidation and corrosion products that are formed. This information is needed to design and in a later stage operate the required LBE impurity control units. Oxygen control, impurity control and the cover gas handling are important issues in this field. In addition information about spallation products and neutron activation products in the LBE under operation are required, because they will interfere with the non-active impurity control handling. At KIT the expected formation of corrosion products on materials and components of a MYRRHA reactor under operation conditions will be determined and assessed. At SCK•CEN the formation of spallation products and neutron activation products of a MYRRHA reactor under operation will be evaluated and assessed using MCNPX calculations.

Task 3.2: Filtering Techniques (SCK•CEN, ENEA, INR)
Metallic and non-metallic impurities (oxides) are observed in loops and pool facilities after operation. Such impurities can aggregate and result in blockage of systems. Therefore cleaning and filtering devices are required for operation of LBE cooled systems. In loops some filter-systems were tested in the past but no final judgement could be given so far. In pool type systems different approaches not investigated in detail up to now have to be developed.
At SCK•CEN a loop type filter will be placed in a small delta T loop equipped with sacrificial rods to measure the pressure loss as a function of material loss from these sacrificial rods. Secondly, an overflow pool type filter will be developed and placed in an LBE pool to examine the applicability and efficiency of such filter to trap oxide particles from the LBE surface.
ENEA will adapt and test loop type filters based on adsorption techniques to an LBE pool environment and tested. Furthermore a detailed investigation to understand the formation of solid impurities accompanied by quantitative qualification of filtering performance will be done.
INR is a new partner in the field of heavy liquid metal technology. Their contribution will encompass the exchange of know-how and the acquirement of hands on experience by performing filter tests in the small delta T loop at SCK•CEN.

Task 3.3: Control, Mass Transport and Interaction of Oxygen, Metallic and Non-Metallic Impurities with LBE (SCK•CEN, ENEA, KIT)
Several open questions for LBE impurity control including oxygen will be addressed in this task. The use of oxygen control systems based on solid PbO oxides will be addressed from an engineering and physic-chemical point of view. Mass exchange, entrainment of solid particles (oxides), interaction, adsorption and deposition of impurities will be experimentally and theoretically investigated. Tests of oxygen sensors to be operated in a pool facility are foreseen.
At KIT vessel-type experimental device containing ~200 kg molten LBE will be developed and used for investigating mass transport and interaction phenomena. The design will be supported by CFD calculations to optimize the design and the position of oxygen sensors and cooled probes for deposition of dissolved metals. Quantitative (local oxygen activity, dissolution of metals) and qualitative (dispersion of dissolved metals) measurements of mass-transfer and transport will be done to form the basis for integrating these phenomena in the CFD code. Ultrasonic measurements of the liquid metal flow during the experiments are used for verifying these calculations. Finally a model for the absorption of oxygen from the cover gas and vapour bubbles will be developed.

A compact experiment to determine the solubility limit and the formation and dissolution kinetics of PbO in LBE will be constructed at SCK•CEN. The set-up will comprise of 2 ceramic lined pots connected by a quartz or ceramic coated transfer tube. Both pots have independent temperature and cover gas control. The PbO solubility limit and its formation and dissolution kinetics in LBE, assuming that the liquid metal transfer is not the rate limiting step, will be measured. The temperature and oxygen concentrations while be varied systematically in the closed system at high temperature.
Different oxygen control methods for a pool type facility will be investigated at ENEA. A gas/liquid systems and a solid/liquid systems (based on solid PbO) will be designed, implemented and tested in the CIRCE facility The reliability of Oxygen Sensor technology in a pool test facility (CIRCE) will be tested.

D3.1 Report on formation of spallation products and neutron activation products in a MYRRHA type reactor (SCK•CEN) (M12)
D3.2 Report on expected corrosion products in a MYRRHA type reactor (KIT) (M18)
D3.3 Final report on the filter lifetime and efficiency (SCK•CEN) (M36)
D3.4 Final Report on oxygen control systems for HLM large pool system (ENEA) (M36)
D3.5 Final Report on oxygen adsorption, entrainment of oxides and mass transport (KIT) (M36)

Technical Documents
T3.1 Design of an oxygen control system and filtering devices for HLM pool systems ENEA (M12)