Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2004, Vol. 15 ›› Issue (6): 375

• MISCELLANEOUS • Previous Articles    

Mockup tests for developing the CARR-CNS with a two-phase thermo-siphon loop

DU She-Jiao, BI Qin-Cheng, CHEN Ting-Kuan, FENG Quan-Ke, LI Xiao-Ming   

  1. State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049
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DU She-Jiao, BI Qin-Cheng, CHEN Ting-Kuan, FENG Quan-Ke, LI Xiao-Ming. Mockup tests for developing the CARR-CNS with a two-phase thermo-siphon loop.Nuclear Science and Techniques, 2004, 15(6): 375

Abstract: The cold neutron source (CNS) is a facility to increase cold neutrons by scattering thermal neutrons in liquid hydrogen or deuterium around 20 K. For extracting a stable cold neutron flux from the CNS, the liquid quantity in the moderator cell should be maintained stably against disturbance of nuclear heating. The China Institute of Atomic Energy (CIAE) is now constructing the China Advanced Research Reactor (CARR: 60 MW), and designing the CARR-CNS with a two-phase thermo-siphon loop consisting of a condenser, two moderator transfer tubes and an annular cylindrical moderator cell. The mock-up tests were carried out using a full-scale loop with Freon-113, for validating the self-regulating characteristics of the loop, the void fraction less than 20% in the liquid hydrogen of the moderator cell, and the requirements for establishing the condition under which the inner shell has only vapor. The density ratio of liquid to vapor and the volumetric evaporation rate due to heat load are kept the same as those in normal operation of the CARR-CNS. The results show that the loop has the self-regulating characteristics and the inner shell contains only vapor, while the outer shell liquid. The local void fraction in the liquid increases with increasing of the loop pressure.

Key words: CARR, CNS, Two-phase thermo-siphon, Annular cylindrical moderator cell, Self-regulation, Void fraction