热管反应堆用钼铼合金的研究进展

Research Progress of Molybdenum-Rhenium Alloys Used in Heat Pipe Reactor

热管反应堆是一种采用热管将堆芯产生的热量传导至反应堆二回路或热电转换装置的新型固态反应堆,具有设计结构紧凑、固有安全性高、运行特性简单等特点,在星表能源、深海探测和陆基电源等新兴领域具有广阔应用前景,因而成为目前国内外重点研发的新型反应堆之一。钼铼合金是在金属钼中添加元素铼形成的一种二元固溶体合金,铼元素独特的“铼效应”使钼铼合金在兼具钼合金优异高温力学性能的同时,还具备其他钼合金不具有的良好低温加工性能。同时,钼铼合金在高温下与UO_(2)、UN、UC等核燃料以及热管传热工质碱金属Li、Na、K等都具有良好的相容性,并且铼元素还是一种较好的谱移吸收体材料,可有效降低反应堆发生事故时的临界风险,因而成为国内外众多热管反应堆尤其是高温空间热管反应堆堆芯的设计材料。本文对热管反应堆用钼铼合金的研究现状及进展进行了归纳总结与梳理,包括钼铼合金的成分及相结构、钼铼合金的制造加工工艺、钼铼合金的热物理性能和力学性能等堆外性能,并对钼铼合金中子学特性、辐照性能、与燃料及热管传热工质的相容性等堆内应用性能研究现状进行了介绍。最后对钼铼合金未来的研究方向进行了展望,以期为钼铼合金的研发和工程应用提供参考。

Heat pipe reactor(HPR)is a newly designed solid-state nuclear reactor which removes the heat passively from the core to the secondary circuit or thermoelectric conversion device.Because of its simple design,inherent safety,easy operation and other advantages,HPR has attracted considerable interest as power source in exoplanet exploration,deep sea exploration,land-based power supply system and other application scenarios.Molybdenum-rhenium alloys are solid solution alloys derived by adding the element rhenium into pure molybdenum,and,unlike other molybdenum alloys,possess simultaneously excellent mechanical strength at high temperature and good processability at room temperature owing to their unique“rhenium effects”.In addition,molybdenum-rhenium alloys have been considered as the candidate materials for heat pipe reactor cores,especially for the space heat pipe reactor operating at extremely high temperatures,because of their excellent mechanical properties and good compatibilities with nuclear fuels like UO_(2),UN and UC,and alkali metal heat pipe coolants like Li,Na and K at high temperatures.Also,there’s another advantage for molybdenum-rhenium alloys,i.e.,the element rhenium could act as the spectral shift absorber which can improve the reactor’s falling criticality safety.This review summarizes the research progress of molybdenum-rhenium alloys used in heat pipe reactor from the perspectives of chemical compositions and crystal structures,manufacture processes,thermal and physical properties,mechanical properties and other out-pile properties.The neutron irradiation behavior,irradiation properties,compatibilities with nuclear fuels and alkali metal heat pipe coolants and other in-pile application properties of molybdenum-rhenium alloys are introduced in detail as well.The paper ends with a prospective analysis about the challenging issues and the future research directions.