Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding
Improving Accident Tolerance of Nuclear Fuel with Coated Mo-alloy Cladding
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DOI：
10.1016/j.net.2015.12.003
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发表时间：
2016-02-01
影响因子：
2.7
通讯作者：
Chou, Peter
中科院分区：
文献类型：
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作者：
Cheng, Bo;Kim, Young-Jin;Chou, Peter
在严重冷却剂损失事故（LOCA）中，类似于在福岛第一核电站和三里岛1号机组经历的那些，锆合金燃料包壳材料由于核衰变加热和锆与蒸汽的快速放热氧化而快速加热。这种加热导致包壳迅速与蒸汽反应，失去强度，破裂或坍塌，并产生大量氢气。尽管维持堆芯冷却仍然是事故管理中的最高优先级，但事故容限燃料（ATF）设计可延长操作员的应对和恢复时间，以恢复应急电源和冷却，并实现安全停堆。ATF需要具有高的抗蒸汽氧化性以减少氢的产生，并具有足够的机械强度以保持燃料棒的完整性和堆芯的冷却性。电力研究所（EPRI）的倡议是证明开发ATF包层的可行性，该包层能够在1，200 - 1，500摄氏度的蒸汽中保持其完整性至少24小时。这种ATF覆层采用了涂有抗氧化表面层的薄壁钼合金。其基本设计由一个薄壁钼合金结构管和一个抗氧化的防腐蚀外层组成。正在研究两种选择：具有优异高温抗氧化性的市售铁、铬和铝合金，以及具有经证实的耐腐蚀性的Zr合金。由于这些复合材料包层将不包含Zr或包含薄的Zr外层，因此在严重LOCA条件下的氢生成将大大减少。钼合金燃料包壳特有的关键技术挑战和不确定性包括：经济的堆芯设计、工业规模的可制造性、辐射脆化以及正常运行、瞬态和严重事故期间的耐腐蚀和抗氧化性。在每个方面都取得了进展，本文件讨论了主要成果。除了帮助工厂应对轻水反应堆（LWR）的挑战外，事故耐受性钼基包壳技术预计将适用于高温氦和熔盐反应堆设计以及非核高温应用。版权所有（C）2015，由Elsevier Korea LLC代表韩国核学会发布。
In severe loss of coolant accidents (LOCA), similar to those experienced at Fukushima Daiichi and Three Mile Island Unit 1, the zirconium alloy fuel cladding materials are rapidly heated due to nuclear decay heating and rapid exothermic oxidation of zirconium with steam. This heating causes the cladding to rapidly react with steam, lose strength, burst or collapse, and generate large quantities of hydrogen gas. Although maintaining core cooling remains the highest priority in accident management, an accident tolerant fuel (ATF) design may extend coping and recovery time for operators to restore emergency power, and cooling, and achieve safe shutdown. An ATF is required to possess high resistance to steam oxidation to reduce hydrogen generation and sufficient mechanical strength to maintain fuel rod integrity and core coolability. The initiative undertaken by Electric Power Research Institute (EPRI) is to demonstrate the feasibility of developing an ATF cladding with capability to maintain its integrity in 1,200-1,500 degrees C steam for at least 24 hours. This ATF cladding utilizes thin-walled Mo-alloys coated with oxidation-resistant surface layers. The basic design consists of a thin-walled Mo alloy structural tube with a metallurgically bonded, oxidation-resistant outer layer. Two options are being investigated: a commercially available iron, chromium, and aluminum alloy with excellent high temperature oxidation resistance, and a Zr alloy with demonstrated corrosion resistance. As these composite claddings will incorporate either no Zr, or thin Zr outer layers, hydrogen generation under severe LOCA conditions will be greatly reduced. Key technical challenges and uncertainties specific to Mo alloy fuel cladding include: economic core design, industrial scale fabricability, radiation embrittlement, and corrosion and oxidation resistance during normal operation, transients, and severe accidents. Progress in each aspect has been made and key results are discussed in this document. In addition to assisting plants in meeting Light Water Reactor (LWR) challenges, accident-tolerant Mo-based cladding technologies are expected to be applicable for use in high-temperature helium and molten salt reactor designs, as well as nonnuclear high temperature applications. Copyright (C) 2015, Published by Elsevier Korea LLC on behalf of Korean Nuclear Society.