Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (7): 70602-070602.doi: 10.11889/j.0253-3219.2015.hjs.38.070602

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Experimental research on the formation and controlling of molten salt frozen-wall

ZHOU Jinhao1,2 SUN Bo1,2 SHE Changfeng1,2 DOU Qiang1,2 LONG Dewu1,2 LI Qingnuan1,2 WU Guozhong1,2   

  1. 1(Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China) 2(Key Laboratory of Nuclear Radiation and Nuclear Technology, Chinese Academy of Sciences, Shanghai 201800, China)
  • Received:2015-01-16 Revised:2015-03-18 Online:2015-07-10 Published:2015-07-10

Abstract: Background: As corrosion of processing equipment from the high aggressive reagent is a serious problem during the pyroprocessing, the molten salt frozen-wall is proposed as an option for protecting the metallic walls from corrosion by a layer of frozen salt. Purpose: In order to study this means of corrosion protection, the research on the formation and controlling of molten salt frozen-wall was carried out. Methods: Nitrate molten salt (melt point: 142 oC) was used as the research medium and heat transfer oil was adopted as coolant. An experimental platform for the research of molten salt frozen-wall was built, which contains an up-flow tapered test tank covered with heat exchange jacket. The frozen-wall was formed and maintained by controlling the internally heating and the cooling of outer part of the test tank. The thickness of frozen wall was directly measured by caliper and also figured out by the measured temperatures. Results: The operation temperature of molten salt ranges from 150 oC to 250 oC; the maximum flowrate of molten salt is 500 L?h?1; the operation temperature of heat transfer oil ranges from 5 oC to 120 oC; and the flowrate of oil ranges from 1.5 m3?h?1 to 15 m3?h?1. Under the expected operating conditions, a layer of frozen can be easily and predictably deposited and maintained on surfaces contacted by the salt. The molten salt frozen-wall was adherent and stable. The average formation rate ranges from 0.2 mm?min?1 to 0.5 mm?min?1. The heat flow decreases with the thickness increasing during the process of formation, at the same time temperature difference through frozen-wall layer gradually increased, and the change trends are all damped. The frozen-wall could reach static equilibrium by controlling the heat transfer rate. When frozen-wall is in a state of balance, the temperature gradient and the thickness of frozen-wall are constant; the decay heat of fission produces simulated by heating rod is equal to the heat flow through frozen-wall layer, and is also equal to the cooling power of heat transfer oil. We also simulated the real application scenarios to test the operation parameters and get some good results. Conclusion: All the research results would be helpful for the developing of fluoride molten salt frozen-wall technology.

Key words: Molten salt, Reactor, Pyroprocessing, Frozen-wall, Heat transfer