Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint A novel mass production method for Li 2 TiO 3 tritium breeder ceramic pebbles using polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) assisted granulation method Hailiang Wang a , Hao Guo a , Ruichong Chen a , Yuanyuan Zeng a , Mao Yang c , Yichao Gong d , Yanli Shi a , Diyin Ye a , Zhijun Liao a , Jianqi Qi a , Qiwu Shi a,b,* , Tiecheng Lu a,** a College of Physics, Sichuan University, Chengdu, 610064, China b College of Materials Science and Engineering, Sichuan University, Chengdu, 610064, China c Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900, China d School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, China ARTICLE INFO Keywords: Lithium titanite Tritium breeder ceramic pebble Mass production PVA and PVP assisted granulation method (APG) ABSTRACT A novel mass production method of lithium titanite (Li 2 TiO 3 ) tritium breeder ceramic pebbles using polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) assisted granulation method (APG) was proposed. A binder solution of polyvinyl alcohol (PVA) was used to modify the Li 2 TiO 3 precursor powder. The powders with ad- hesive properties were prilled to form green pebbles (GPs) by spheronization at a low rotation speed and spraying with polyvinyl pyrrolidone (PVP), in several cycles. Then, the density and the crush load of the GPs were improved by high-speed rolling. Finally, the ceramic pebbles were produced by sintering. The phase, the microstructure, and the crush load of the ceramic pebbles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and with a universal tester, respectively. 1. Introduction Li 2 TiO 3 is one of the most promising solid tritium breeder materials and has many advantages including an excellent chemical stability [1], a good compatibility with structural materials [2], and an excellent tritium release ability [3]. Therefore, China chooses Li 2 TiO 3 as one of the alternative materials for tritium breeding. Li et al. [4] speculated that self-sustained tritium would be one of the key issues in the first phase for the 200 MW Chinese Fusion Engineering Testing Reactor (CFETR). To popularize fusion energy, it is necessary to mass-produce tritium. Large-scale tritium factories will have to be constituted to produce tritium in a self-sufficient manner [5]. Since tritium production consumes a large amount of tritium breeder pebbles, improving the production rate of tritium breeder pebbles is an urgent problem that needs to be solved. Besides, Mandal et al. [6] suggested the burn up of tritium breeder pebbles in the fusion reactor would only be 15–17 atomic percentage. At the end of the life of the pebbles, more than 45% unused 6 Li isotope remained. Therefore, the recovery and recycling of the unused Li from Li 2 TiO 3 pebbles may be an alternative option used to improve service efficiency of tritium breeder. Currently, the main preparation methods of breeder ceramic pebble include melting [7,8], wet processes [9], extrusion-spheroidization [10,11]. The melting method is a simple process and a promising ap- proach for mass-producing tritium-breeding ceramic with a high yield and a high density. Schott in Germany can produce 200–300 kg per year by this method [12]. However, it is difficult to control the size (dia- meter) of the pebbles accurately during the melting spray process [13]. In addition, too high temperature differences lead to large internal stress in the ceramic pebbles prepared since microcracks form and af- fect the mechanical properties. The wet method can be used to prepare pebbles with a high sphericity, a high crush load, and a uniform size. Lee et al. [14] prepared Li 2 TiO 3 ceramic pebbles with a size distribution from 1.2 to 1.5 mm and a crush load as high as 50 N. However, the fluidity of the slurry is a critical factor that seriously restricts the effi- cient production of pellets and the annual output only reaches a few dozen kilograms [15,16]. The extrusion-spheroidization technique is an efficient method for the massive production of Li 2 TiO 3 ceramic pebbles. However, the pebble shape is difficult to control during spheroidization and the fabricated pebbles usually have a wide size distribution [17,18]. To overcome the limitations of the current methods, we https://doi.org/10.1016/j.ceramint.2019.10.134 Received 9 July 2019; Received in revised form 7 October 2019; Accepted 15 October 2019 * Corresponding author. College of Materials Science and Engineering, Sichuan University, Chengdu, 610064, China. ** Corresponding author. E-mail addresses: shiqiwu@scu.edu.cn (Q. Shi), lutiecheng@vip.sina.com (T. Lu). Ceramics International xxx (xxxx) xxx–xxx 0272-8842/ © 2019 Published by Elsevier Ltd. Please cite this article as: Hailiang Wang, et al., Ceramics International, https://doi.org/10.1016/j.ceramint.2019.10.134