This paper presents recent Canadian advances in nuclear-based production of hydrogen with the thermochemical copper-chlorine (Cu-Cl) cycle. Current collaboration between UOIT, Atomic Energy of Canada Limited, Argonne National Laboratory and partner institutions is focusing on enabling technologies for the Cu-Cl cycle, through the Generation IV International Forum. This paper presents the recent advances in the development of individual reactor designs, thermal efficiency, process developments, corrosion resistant materials and linkage between nuclear and hydrogen plants. The paper provides an overview of latest advances by a Canadian consortium that is collaborating on equipment scale-up for the Cu-Cl cycle.

This paper describes the status of the development effort for the Cu-Cl thermochemical cycle. Most of the recent work has been focused on the hydrolysis reaction, which is challenging because of the need for excess steam to achieve high yields. Two types of spray reactors were tested and the ultrasonic nozzle gave excellent results. The conceptual process design for the overall process now includes a spray reactor. Engineering methods to increase efficiency are proposed. Preliminary values for the efficiency and capital costs for producing hydrogen using the Cu-Cl cycle have been calculated.

The copper-chloride hybrid thermochemical cycle is one of the best potential low temperature thermochemical cycles for the massive production of hydrogen. It could be used with nuclear reactors such as the sodium fast reactor or the supercritical water reactor. Nevertheless, this thermochemical cycle is composed of an electrochemical reaction and two thermal reactions. Its efficiency has to be compared with other hydrogen production processes like alkaline electrolysis for example.

The Cu-Cl thermochemical cycle is among the most attractive technologies proposed for hydrogen production due to moderate temperature requirements and high efficiency. In the present study, one of the main steps of the cycle – H2 gas production via CuCl-HCl electrolysis – was investigated using a newly designed electrolyser system. The electrolysis reaction was performed with the applied voltage from 0.35 to 0.9 V. The current efficiency of the electrolysis system was evaluated based on the observed rate of hydrogen production. The effects of temperature and reagent flow rate on the electrolysis performance were studied. Several types of anion-exchange and cation-exchange membranes were tested in the electrolyser, and their performance was compared with respect to process efficiency and tolerance to copper crossover.

The CuCl cycle is a hybrid thermochemical cycle to produce hydrogen using both electricity and heat to split water into hydrogen and oxygen. Already described in the early 70s, it has recently been revisited because of its low maximal temperature and its high potential efficiency. Furthermore, raw materials are cheap, which allows a drastic diminution of constraints for industrial deployment.

We investigated a novel, continuous hybrid cycle for hydrogen production employing both heat and electricity. Calcium bromide (CaBr2) hydrolysis, which is endothermic, generates hydrogen bromide (HBr), and this is electrolysed to produce hydrogen. CaBr2 hydrolysis at 1 050 K is endothermic with a 181.5 KJ/mol heat of reaction and the free energy change is positive at 99.6 kJ/mol. What makes this hydrolysis reaction attractive is both its rate and the fact that well over half the thermodynamic requirements for water-splitting free energy of ÄGT = 285.8 KJ/mol are supplied at this stage using heat rather than electricity.