SUN Xiaohui¹，GU Haifeng²，WANG Hui¹

1.CNNC Key Laboratory on Severe Accidentin Nuclear Power Safety，China Nuclear Power Engineering Co.，Ltd.，Beijing 100840，China；2.Fundamental Science on Nuclear Safety and Simulation Technology Laboratory，Harbin Engineering University， Harbin 150001， China

Abstract

Objective　During a severe accident at a nuclear power plant，the containment，serving as the final barrier to confine radioactive

fission products，plays a crucial role in preventing the spread of radiation.Passive containment cooling systems（PCS）are incorporated  into third-generation reactors，such as AP1000 and Hualong series，to cool and depressurize the containment vessel following a severe

accident，thereby preventing containment failure.During the cooling process in Hualongreactors，temperatureand gas concentration gradien-tsform near the PCS heat transfer tubes.These gradients drive aerosol dynamic phenomena such as diffusiophoresis and thermophoresis in

the PCS，which enhance the removal of aerosols from the containment vessel during severe accidents.However，due to our insufficient unde-rstanding of PCS’s enhanced aerosol removal effect，the effect has not been considered in traditional source term assessments.Therefor-e，research on the enhanced aerosol removal effect of PCS is beneficial for optimizing source term assessments and improving economic

efficiency.

Methods　In this study，the discrete zone method was employed to solve the aerosol transport equation，focusing on the impact of PCS heat transfer tubes on aerosol removal within the containment.The theoretical calculation model was compared and verified through experiments. The calculations considered various processes affecting aerosol particles，including convection，diffusion，coagulation，condensation，

nucleation，and deposition.The deposition process includes four mechanisms：gravitational settling，Brownian diffusion，thermophoresis， and diffusiophoresis.Experiments were conducted in a simulation chamber with a volume of approximately 12 m³，where the parameters of the heat transfer tubes were consistent with those of the prototype PCS in the Hualong pressurized reactor 1000（HPR1000）.Titanium dioxide aerosols were generated using a Palas RBG2000 aerosol generator，and their particle size distribution was measured using a Palas Promo3000HP aerosol spectrometer.To investigate the impact of PCS on aerosol size evolution，experiments were conducted under two conditions：with and without heat transfer tubes.During the experiments，after introducing aerosols into the chamber，they were allowed to mix thoroughly before initiating measurements of their size distribution to establish a baseline.The evolution of aerosol particle sizes within the cha-mber was subsequently tracked over time.

Results and discussion　The process of solving the aerosol transport equation using the discrete zone method is described in the pape-r.The effects of various factors，including heat transfer tube surface area，temperature gradient between the heat transfer tube wall and surrounding atmosphere，and non-uniform aerosoldistribution within the containment，on aerosol removal were studied.The results showed

that：1）the calculated results of the theoretical calculation model in the paper matched well with experimental results，indicating its applicability for analyzing aerosol deposition processes.2）Increasing PCS heat transfer tube surface area and the temperature gradient

near the tube wall could both enhance aerosol removal.Therefore，increasing the surace area of heat transfer tubes can be consideredin

PCS design to optimize the source term.3）When evaluating the enhanced effect of PCS on aerosol removal，non-uniform aerosoldistribution within the containment should be considered，as results based on uniformity assumptions are not conservative.4）In the scaled-down conta-inment model of the HPR1000 studied in the paper，PCS heat transfer tubes increased aerosol deposition efficiency by approximately 12%.

Conclusion　The following conclusions are drawn from the analysis：1）The developed theoretical model can be used for studying aerosol  deposition processes.2）Increasing the surface area of the PCS heat transfer tubes and the temperature gradient near these tubes greatly enhance aerosol removal.3）When evaluating the enhanced effects of PCS heat transfer tubes on aerosol removal within the containment，the non-uniformity of aerosol distribution within the containment must be considered，as evaluations based on uniformity assumptions are not conservative.4）PCS heat transfer tubes can significantly enhance aerosol removal within the containment.

Keywords：aerosol；HPR1000；passive containment cooling system；diffusiophoresis

Get Citation:SUN Xiaohui，GU Haifeng，WANG Hui.Impact of HPR1000 PCS heat transfer tubes on aerosol removal within containment［J］.China Powder Sci-ence and Technology，2025，31（2）：1−12.

Received:2024-06-25，Revised:2024-08-22，Online:2024-11-21.

Funding Project:国家重点研发计划项目，编号：2020YFB1901400。

First Author:孙晓晖（1989—），男，高级工程师，博士，研究方向为严重事故分析。E-mail：sxhmxh333@sina.com。

Corresponding Author:谷海峰（1980—），男，教授，博士生导师，研究方向为核动力装置及反应堆热工水力。E-mail：guhaifeng@hrbeu.edu.cn。

DOI：10.13732/j.issn.1008-5548.2025.02.015

CLC No:TB4；TQ324.8             Type Code:A

Serial No:1008-5548（2025）02-0001-12