CNL has several high-temperature loop facilities at its Chalk River Laboratories (CRL) that can be used to investigate chemical processes, which occur in high temperature water-cooled systems. These investigations require that conditions, such as temperature, pressure, flow rate and water chemistry, be precisely controlled, while the reactions of interest such as, corrosion of materials, deposition of impurities and other chemical reactions, are carefully measured often using instrumented test sections.
The H5 Loop is a high-temperature, high-pressure loop designed to perform materials testing under conditions similar to those found in the heat transport systems of many water-cooled nuclear reactors (single-phase aqueous solutions at temperatures of ≤ 305° C and pressures ≤ 12 MPa). The mass flow rate in the loop (0.1-2.0 kg/min) allows the study of flow-assisted degradation processes, without incurring excessive energy costs for loop operation. The H5 Loop is capable of maintaining stringent chemistry control of the aqueous solution during tests. The ability to run unattended for periods of over a week allows for long, uninterrupted experiments. During the decade 2001-2010, the H5 Loop achieved a utilization of over 60 per cent while performing 22 tests with durations of up to 227 days.
The Components Test Loop 1 (CTL-1) facility is a virgin (untritiated) heavy-water loop that provides a testing ground for future improved components to be used in nuclear reactors. Historical use has been for the study of ingress of hydrogen isotopes into full scale CANDU® fuel channel components. The heavy-water coolant is particularly important as it allows for detection of low concentrations of hydrogen isotopes (i.e., deuterium) that enter metals as a byproduct of corrosion reactions. The loop is designed to run continuously for extended periods (e.g., hundreds of days) and operates at conditions akin to the heat transport systems of water-cooled nuclear reactors (up to 14 MPa and 330°C). The CTL-1 consists of a main loop with a bypass circuit. The five experimental test circuits can be operated simultaneously with two at reduced temperature. Four sample stations for exposing small specimens, which can be loaded and unloaded while the loop is operating, are also available.
The H3 Loop is a radioactive, high temperature and high pressure system used primarily to study two phase and single phase water conditions using radiotracing methods. The H3 Loop is the only facility in Canada that is used to measure the rates of deposition and removal of corrosion products in high-temperature flowing water using radiotracers. The use of a radiotracer, such as Iron-59 or Cobalt-60, enables investigators to measure the time dependence of the mass of material that has accumulated on a test section as a function of local operating conditions. The investigators can then determine the effect of changes in local conditions, such as changes in water chemistry or thermalhydraulic conditions, and on the amount of material accumulated on the area of interest. This can be done without shutting down the H3 Loop and doing a destructive analysis of the test section.
The High Temperature Recirculating (HTR) Loop is used to perform a variety of studies under high temperature recirculating water and steam conditions. The HTR Loop is a small scale facility that can be used to simulate a wide range of chemistry and operating conditions. It can be operated at a temperature and a pressure of up to 300°C, 10.3 MPa under either single-phase or two-phase flow conditions and at flow rates from 0.5 to 100 kg/min. The loop can accommodate a wide range of specially-designed test sections which are instrumented according to the requirements of each experiment.
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