Design of a System for Hydrogen isotopes Injection into Lead-Lithium

Abstract In a fusion reactor based on liquid breeding blankets, tritium is generated due to the neutron irradiation of lithium based alloy, such as eutectic lead-lithium (PbLi). Then, tritium is extracted from the liquid metal by means of technologies that are presently under development such as the vacuum sieve tray, the permeation against vacuum or the gas liquid contactors. Nevertheless, for the experimental validation of these technologies at laboratory scale, hydrogen isotopes cannot be generated in situ in the liquid metal as in the breeding blanket. Hence, a system able to inject the gas in the flowing liquid at desired concentrations is required, avoiding the formation of bubbles as a consequence of the low solubility of hydrogen/deuterium in PbLi. The system should be capable of solubilizing the hydrogen to replicate as close as possible the conditions of a breeding blanket. A design of an injector based on a permeable membrane is here presented, being the driving force the gradient of concentrations existing between the two surfaces of the membrane. A hydrogen transport model for a tube-in-tube injector has been developed, showing that the injected hydrogen flux is proportional to the tube radius. However, the change on this parameter, that affects the velocity of the liquid and thus the mass transport coefficient, has opposite consequences on the rate of injection whose final impact relays on the properties of the employed membrane. An evaluation of the physical and geometrical aspects of a conceptual injector is depicted with the aim of optimizing the design to obtain adequate injection rate depending on the facility where the injector is installed. Finally, a conceptual design of a system to be implemented in an experimental PbLi loop for the validation of the permeation against vacuum technique for tritium extraction from PbLi is presented. The injector is based on a multi-tube component made of niobium able to inject hydrogen at the same rate as it is extracted under relevant conditions for a Dual Coolant Lithium Lead breeding blanket.

[1]  Akira Tahara,et al.  Measurements of Permeation of Hydrogen Isotopes through α-Iron by Pressure Modulation and Ion Bombarding , 1985 .

[2]  G. Gervasini,et al.  The impact of tritium solubility and diffusivity on inventory and permeation in liquid breeder blankets , 1988 .

[3]  Dennis R. Heldman,et al.  Encyclopedia of agricultural, food, and biological engineering , 2014 .

[4]  S. Horn,et al.  Compatibility of refractory metals and beryllium with molten Pb17Li , 1996 .

[5]  Andrea Ciampichetti,et al.  Determination of hydrogen solubility in lead lithium using sole device , 2006 .

[6]  I. Palermo,et al.  Conceptual Design of the EU-DEMO Dual Coolant Lithium Lead Equatorial Module , 2016, IEEE Transactions on Plasma Science.

[7]  H. Neuberger,et al.  Status of the engineering activities carried out on the European DCLL , 2017 .

[8]  Dong Won Lee,et al.  Progress of Tritium Extraction and Measurement Methods Development from Liquid Breeder Blanket in Korea , 2012 .

[9]  Fabio Giannetti,et al.  WCLL breeding blanket design and integration for DEMO 2015: status and perspectives , 2017 .

[10]  S. Tosti,et al.  Behaviour of hydrogenated lead–lithium alloy , 2017 .

[11]  Massimo Zucchetti,et al.  Performance of a hydrogen sensor in Pb–16Li , 2007 .

[12]  F. Reiter,et al.  Solubility and diffusivity of hydrogen isotopes in liquid Pb17Li , 1991 .

[13]  Andrea Ciampichetti,et al.  TRIEX facility: an experimental loop to test tritium extraction systems from lead lithium , 2007 .

[14]  A. Malavasi,et al.  Investigation on efficiency of gas liquid contactor used as tritium extraction unit for HCLL-TBM Pb-16Li loop , 2016 .

[15]  Jean-Charles Jaboulay,et al.  Design of the helium cooled lithium lead breeding blanket in CEA: from TBM to DEMO , 2017 .

[16]  L. Giancarli,et al.  Tritium transfers and main operating parameters impact for demo lithium lead breeding blanket (HCLL) , 2008 .

[17]  Yasushi Yamamoto,et al.  Vacuum sieve tray for tritium extraction from liquid Pb–17Li , 2012 .

[18]  S. Fukada,et al.  Experiment on Recovery of Hydrogen Isotopes from Li17Pb83 Blanket by Liquid-Gas Contact , 2017 .

[19]  N. Alpy,et al.  Hydrogen extraction from Pb–17Li: Tests with a packed column , 1998 .

[20]  J. Sanz,et al.  Design and fabrication of a Permeator Against Vacuum prototype for small scale testing at Lead-Lithium facility , 2017 .

[21]  Development of a hydrogen permeation sensor for future tritium applications , 2014 .

[22]  David Rapisarda,et al.  Design of a permeator against vacuum for tritium extraction from eutectic lithium-lead in a DCLL DEMO , 2017 .

[23]  B. Raj,et al.  Liquid metal corrosion in nuclear reactor and accelerator driven systems , 2012 .

[24]  John Crank,et al.  The Mathematics Of Diffusion , 1956 .

[25]  K. Furukawa,et al.  Hydrogen and Deuterium Transport through Type 304 Stainless Steel at Elevated Temperatures , 1981 .

[26]  Neil B. Morley,et al.  Normal operation and maintenance safety lessons from the ITER US PbLi test blanket module program for a US FNSF and DEMO , 2014 .

[27]  J. Konys,et al.  Corrosion behaviour of Al based tritium permeation barriers in flowing Pb?17Li , 2002 .

[28]  L. V. Boccaccini,et al.  Objectives and status of EUROfusion DEMO blanket studies , 2016 .