Nuclear Science and Techniques ›› 2019, Vol. 42 ›› Issue (2): 20601-020601.doi: 10.11889/j.0253-3219.2019.hjs.42.020601

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Analysis of LOCA with different break sizes in PWR

Peiqi LIU1,2,Pengcheng ZHAO1,2,Tao YU1,2(),Jinsen XIE1,2,Zhenping CHEN1,2,Chao XIE1,2,Zijing LIU1,2,Wenjie ZENG1,2   

  1. 1. School of Nuclear Science and Technology, University of South China, Hengyang 421001, China
    2. Nuclear Power and Technology Engineering Virtual Simulation Experiment and Teaching Center, Hengyang 421001, China
  • Received:2018-08-28 Revised:2018-11-29 Online:2019-02-10 Published:2019-02-19
  • Contact: Tao YU E-mail:yutao29@sina.com
  • About author:LIU Peiqi, female, born in 1995, graduated from China Three Gorges University in 2016, master student, focusing on reactor thermal hydraulic design and accident safety analysis|LIU Peiqi, female, born in 1995, graduated from China Three Gorges University in 2016, master student, focusing on reactor thermal hydraulic design and accident safety analysis|YU Tao, E-mail:<email>yutao29@sina.com</email>
  • Supported by:
    Supported by National Defense Technology Industry Nuclear Power Technology Innovation Center Project (No.HDLCXZX-2017-HD-017), Hunan Provincial Innovation Foundation For Postgraduate(No.CX2018B610) & University of South China Innovation Foundation for Postgraduate(No.2018KYZ006)

Abstract: Background

Serious accidents refer to a series of processes in which the nuclear reactor core cooling loss and fuel widespread failure threaten or damage the integrity of the pressure vessel or containment of a nuclear power plant and may cause leakage of radioactive material.

Purpose

This study aims to analyze the influence of break size on the loss of coolant accidents (LOCA) in pressurized-water reactor (PWR).

Methods

A typical million-kilowatt PWR unit model in active serving nuclear power plant (NPP) in China was built based on MAAP4.0.3 (Modular Accident Analysis Program). Comparison with different crevasse size LOCA were performed by MAAP code to analyze the accident process. Besides, LOCA with different time to inject cooling water was also simulated to evaluate the mitigation measures.

Results

Results show that in the process of LOCA without safety injection system, under the same other conditions, the larger the crack is, the faster the pressure vessel will fail and the more hydrogen will be produced. During the serious accidents, high head safe injection has little effect on the primary loop pressure. And input safety injection system manually or automatically can protect the integrity of the reactor vessel and prevent producing hydrogen.

Conclusion

The LOCA case with large crevasse can cause more severe rector core damaged. Meanwhile, it is important to inject water into the reactor core at an appropriate time to prevent the severe accident process effectively.

Key words: MAAP, LOCA, Pressurized-water reactor, Mitigation measures

CLC Number: 

  • TL364.4