氚在锆合金包壳材料中的扩散行为模拟

周小凯; 佟立丽

doi:10.11884/HPLPB202133.200275

氚在锆合金包壳材料中的扩散行为模拟

doi: 10.11884/HPLPB202133.200275

周小凯,
佟立丽^,

上海交通大学机械与动力工程学院，上海 200240

基金项目: 国家科技重大专项（2019ZX06004013）

详细信息

作者简介:
周小凯（1995—），男，硕士研究生，从事反应堆严重事故研究；zhouxiaokai@sjtu.edu.cn

通讯作者:
佟立丽（1975—），女，副研究员，从事核反应堆安全研究；lltong@sjtu.edu.cn

中图分类号: TL929
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- 被引次数: 0
出版历程
- 收稿日期: 2020-09-20
- 修回日期: 2020-11-19
- 网络出版日期: 2021-03-30
- 刊出日期: 2021-03-05

Numerical simulation and experimental verification on the diffusion behavior of tritium in zirconium alloy cladding materials

Zhou Xiaokai,
Tong Lili^,

School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

摘要

摘要: 基于氚扩散基本模型建立了氚扩散行为一维模拟程序，对模拟程序进行了典型实验验证，模拟结果与实验结果符合较好。分析了不同氚浓度、温度分布对锆合金包壳材料中氚的扩散行为的影响。分析结果表明：包壳-芯块间隙内氚浓度的升高会导致进出包壳的氚扩散通量提高，渗透通量增大；由于包壳氧化层相对较低的扩散系数，包壳氧化层的存在对氚渗透有较大的限制作用；温度对氚扩散速率的影响很显著，温度越高，扩散速度越快；锆合金外表面氧化层的相对低温限制了氚渗透出包壳管的速率，温度梯度导致的热致扩散有利于氚向包壳冷测扩散。
- 氚 /
- 锆合金 /
- 扩散行为 /
- 数值模拟
Abstract: The research on the diffusion behavior of tritium in zirconium alloy is a crucial problem for nuclear power plant radiation safety evaluation. Based on the basic model of tritium diffusion, a one-dimensional simulation program for the behavior of tritium diffusion was established in this work. The simulation program was verified by typical experiments, and the simulation results were in good agreement with the experimental results. The effects of different concentration and temperature distribution of tritium on the diffusion behavior of tritium in zirconium alloy cladding materials were analyzed. The results show that the increase of tritium concentration in P-C gap lead to the increase of tritium diffusion flux and permeability flux in and out of cladding. Due to the relatively low diffusion coefficient of the coated oxide layer, the existence of the coated oxide layer limits the tritium permeability greatly. The effect of temperature on the diffusion rate of tritium is exponential. The higher the temperature is, the faster the diffusion rate is. The relative low temperature of the oxide layer on the outer surface of zirconium alloy limits the rate of tritium permeation out of the cladding tube. Thermally induced diffusion due to temperature gradient is beneficial to limit the permeation flux of tritium diffusing out of the zirconium cladding.
- tritium /
- zirconium alloy /
- diffusion /
- numerical simulation

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图 1 网格示意图

Figure 1. Diagram of the grid

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图 2 模拟与实验结果对比

Figure 2. Comparison of calculation and experiment results

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图 3 Surry-2实验氚释放份额随时间变化的模拟结果

Figure 3. Simulation results of tritium release fraction in Surry-2 experiment

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图 4 不同氚分压情况下模拟结果对比

Figure 4. Comparison of calculation results under different tritium partial pressure

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图 5 不同温度分布情况下模拟结果对比

Figure 5. Comparison of calculation results under different temperature

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图 6 锆合金中氚浓度分布

Figure 6. Simulation results of distribution of tritium concentration in zircaloy

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表 1 氘扩散实验参数表

Table 1. Parameters of the deuterium diffusion experiment

case	thickness (outer oxide layer)/μm	thickness (inner oxide layer)/μm	surface area/cm²	diffusion coefficient (in outer oxide layer)/(cm²/s)	diffusion coefficient (in inner oxide layer)/(cm²/s)
GNF-Ziron	0.5	1	4	2.2×10⁻¹³	1.6×10⁻¹⁴
VB	0.68	0.82	4	4.2×10⁻¹⁴	7.4×10⁻¹⁵

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表 2 Surry-2燃料包壳氚释放实验参数

Table 2. Parameters of the tritium diffusion experiment of Surry-2 fuel caldding

parameter	external diameter of cladding/mm	inner diameter of cladding/mm	height/mm	surface area/m²	temperature/K	burnup/ (GWd/MTU)	thickness of dense oxide layer/μm
value	5.359	4.742	5.5	8.72664×10⁻⁵	773	36	2

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