Where does India find heavy water for Candu reactors?

Abstract Several small modular reactor (SMR) designs are emerging, but only the CANDU Small Modular Reactor and a couple of Indian designs incorporate the familiar features of the larger CANDU-reactors. This paper shows that while the CANDU concept did not seem to receive wider attention among SMR designers, it has influenced a few. The paper discusses how the CANDU operating experience can aid in the construction and operation of some SMRs. For example, the concept of passive reactor shutdown by draining the moderator, which was utilized in the early Pickering A units, is adopted in the Copenhagen Atomics Waste Burner; a molten slat (LiF-ThF$ _4 $) heavy-water moderated reactor. The heavy-water and lithium in this salt produce tritium and can benefit from the CANDU experience in handling tritium. The online refueling of CANDU reactors, their large heat sinks and seamless configuration are also reflected in SMR designs.

Download Full-text

Deuterium Ingress at the Rolled Joints in CANDU Reactors: Where Does it Comefrom and How Can It be Reduced?

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4048313 ◽

2020 ◽

Author(s):

Scott Langille ◽

Christopher Coleman ◽

Glenn McRae

Keyword(s):

Stainless Steel ◽

Heat Transport ◽

Heavy Water ◽

Nuclear Reactors ◽

Hydrogen Isotopes ◽

Operating Principle ◽

Small Scale ◽

Candu Reactors ◽

Pressure Tubes

Abstract Simple, small-scale, experiments demonstrate the high deuterium concentrations found in the zirconium pressure tubes at CANDU rolled joints comes from the initial as-received protium in stainless-steel end fittings exchanging with deuterium before being gettered by the zirconium. We propose to reduce the concentration of hydrogen isotopes at the ends of pressure tubes in heavy-water nuclear reactors with yttrium getters placed in the outer regions of the stainless-steel end fittings away from the heat-transport heavy water. Simple, small-scale, experiments demonstrate the operating principle showing that yttrium can getter hydrogen isotopes from the zirconium through the stainless steel.

Download Full-text

The Feasibility of Multidimensional CFD Applied to Calandria System in the Moderator of CANDU-6 PHWR Using Commercial and Open-Source Codes

Science and Technology of Nuclear Installations ◽

10.1155/2016/3194839 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Hyoung Tae Kim ◽

Se-Myong Chang ◽

Jong-Hyeon Shin ◽

Yong Gwon Kim

Keyword(s):

Open Source ◽

Heavy Water ◽

Numerical Models ◽

Three Dimensional ◽

Hydrothermal Systems ◽

Candu Reactors ◽

Source Codes ◽

Ansys Cfx ◽

Heavy Water Reactor ◽

Water Reactors

The moderator system of CANDU, a prototype of PHWR (pressurized heavy-water reactor), has been modeled in multidimension for the computation based on CFD (computational fluid dynamics) technique. Three CFD codes are tested in modeled hydrothermal systems of heavy-water reactors. Commercial codes, COMSOL Multiphysics and ANSYS-CFX with OpenFOAM, an open-source code, are introduced for the various simplified and practical problems. All the implemented computational codes are tested for a benchmark problem of STERN laboratory experiment with a precise modeling of tubes, compared with each other as well as the measured data and a porous model based on the experimental correlation of pressure drop. Also the effect of turbulence model is discussed for these low Reynolds number flows. As a result, they are shown to be successful for the analysis of three-dimensional numerical models related to the calandria system of CANDU reactors.

Download Full-text