核电安全壳中主要有机化学品挥发特性影响因素研究

The Factors Affecting Volatilization Characteristics of Main Organic Chemicals in Nuclear Power Containment

针对核电安全壳检修期间挥发性有机化学品的挥发动力学特性影响因素不明确,导致难以在确保无因挥发性有机物积累所导致的火灾风险的前提下进一步优化打压前的通风时间的问题,通过模拟核电安全壳通风状态,使用质量损失法测试了不同温度和空间气体速度下主要挥发性有机化学品的挥发特性及挥发时间。在温度分别为30、35和40℃,空间气体速度分别为1.0、2.0和3.3 h^-1的条件下,在模拟通风系统中分别测试了使用量最大、挥发速率较低的威第尔清洗剂(达赛特)和螺栓清洗剂,以及挥发速率较高的NEOLUBE No.2核级润滑剂的挥发特性及挥发时间。研究结果表明:3种物质的挥发特性均符合C m-history模型,在较高温度下(40℃),空间气体速度对挥发速率的影响较小,而较低温度下(≤35℃),空间气体速度对挥发速率的影响较大;以厚度0.50 mm的液膜为例,螺栓清洗剂挥发时间最长,达到134.56 h(30℃,空间气体速度为1.0 h^-1),显著小于常规的10 d通风时间。将检修时间安排在气温较高的时段,可显著缩短通风时间,进一步提高核电运行时效。

Due to the uncertainty of volatilization characteristics of the organic chemicals used during maintenance in nuclear power containment,it is difficult to optimize the ventilation time before pressurization in the condition of ensuring safety without fire disaster risk.To resolve this issue,the volatilization characteristics of the main volatile organic chemicals used during maintenance are tested in a system with simulated ventilation states.The most abundant chemicals with relatively low evaporation rates,including Weidil cleaner and screw cleaner,and the chemicals with relatively high evaporation rate,NEOLUBE No.2 nuclear grade lubricant,are tested to obtain the volatilization curves and volatilization time at the temperature of 30,35 and 40℃,with the airspeed at 1.0,2.0 and 3.3 h^-1,respectively.The results suggest that the volatilization curves of the three chemicals coincide well with the C m-history model.At relatively high temperature(≥40℃),the airspeed affects the volatilization rate slightly,but the effect of airspeed on the volatilization rate is clear at low temperature(≤35℃).Taking a 0.50 mm liquid membrane for instance,the volatilization time of screw cleaner is the longest(134.56 h at airspeed of 1.0 h^-1),and is clearly shorter than the normally required 10 d of ventilation time before pressurization.The ventilation time can be shortened to increase the running efficiency of the nuclear power plant by scheduling the maintenance in the season with relatively higher temperature.