核电站近区河流排涝对温排水扩散的影响研究

Study on the influence of river drainage in the vicinity of nuclear power plant on the diffusion of thermal discharge

关键词:  温排水,滨海核电站,近区河流排涝,数值模拟,扩散规律

Key words:  Thermal drainage, coastal nuclear power plants, near river drainage, numerical simulation, diffusion law

摘要:

核电站温排水近区的河流排涝可显著改变温排水的扩散格局，准确界定核电站近区的河流排涝对温排水扩散的影响是十分必要的。本研究通过建立田湾核电站温排水扩散数学模型，在充分校验的基础上，深入探讨滨海核电站温排水近区河流不同排水流量下温排水的扩散范围及其规律。结果表明：研究区域冬季水温平面分布特征呈南北向带状分布，温度梯度约0.9 ℃/km；立面上，在涨急时刻由于水深较浅，垂向掺混作用强烈，垂向温度梯度最大为0.18 /（℃/m）。随着排淡河排水流量增加，4、3 ℃温升面积呈缩小趋势，最大缩小面积分别为19.36、17.37 km2，温升面积缩小率分别从0.05 km2/(m3/s)减小至0.02 km2/(m3/s)和0.03 km2/(m3/s)；2 ℃温升面积则是先增后减，温升面积缩小率为0.03 km2/(m3/s)；2 ℃温升面积则是先增后减；1 ℃温升面积呈波动增大趋势。从空间分布上看，3、2、1 ℃温升区均向北扩展，但4 ℃温升区先北扩后南缩，最大扩展约500 m，临界流量为160 m3/s，约为最大流量的31%。

Abstract:

The river drainage near the thermal discharge area of nuclear power plant can significantly change the diffusion pattern of thermal discharge. It is necessary to accurately define the influence of river drainage near the nuclear power plant on the diffusion of thermal discharge. Through the establishment of the mathematical model of thermal discharge diffusion in Tianwan nuclear power plant, on the basis of full verification, this paper deeply discusses the diffusion range and law of thermal discharge under different drainage flows in the river near the thermal discharge area of coastal nuclear power plant. The results show that the horizontal distribution characteristics of water temperature in winter in the study area are north-south zonal distribution, and the temperature gradient is about 0.9 ℃/km. On the vertical surface, due to the shallow water depth, the vertical mixing effect is strong, and the maximum vertical gradient is about 0.18 ℃/m. With the increase of drainage flow, the temperature rise area at 4 °C and 3 °C decreased, and the maximum reduction area was 19.36 km2 and 17.37 km2, respectively. The reduction rate of temperature rise area decreased from 0.05 km2 / ( m3/s ) to 0.02 km2 / ( m3/s ) and 0.03 km2 / ( m3/s ), respectively. The 2 °C temperature rise area increases first and then decreases, and the temperature rise area reduction rate is 0.03 km2 / ( m3/s ). The temperature rise area at 1 °C showed a fluctuating increasing trend. From the perspective of spatial distribution, the temperature rise areas of 3, 2, 1 ℃ all extend northward, but the temperature rise area of 4 ℃ first expands northward and then shrinks southward. The maximum expansion is about 500 m, and the critical flow rate is 160 m3/s, which is about 31% of the maximum flow rate.