核电厂安全壳内13N输运和浓度分布特性模拟

Simulation of 13N Transport and Concentration Distribution in Containment of Nuclear Power Plant

安全壳内13N气体浓度的精确测量是核电厂一回路压力边界泄漏监测的关键问题,利用计算流体力学软件FLUENT,初步研究了一回路中子活化产物13N泄漏后在安全壳内的输运过程,获得安全壳内不同区域的浓度大小。计算结果表明:在13N气体泄漏700 s后,各代表区域浓度以700-750 s时间段平均浓度值为基准在1.70%范围内保持稳定,不同区域13N气体具体浓度有助于13N辐射监测仪器获取准确度更高的一冋路泄漏量。

Accurate measurement of 13 N gas concentration in containment is a key issue in nuclear power plant primary loop pressure boundary leakage monitoring. The transport process of the first-loop neutron activation product 13N in the containment was investigated by using the computational fluid dynamics software FLUENT, and the concentration of different regions in the containment was obtained. The calculation results show that after the l3N gas leaks for 700 s, the concentration of each representative region is stable within the range of 1.70% with the average concentration of 700 - 750 s. The specific concentration of 13N gas in different regions helps the 13N radiation monitoring instrument to obtain a more accurate primary circuit leakage.