scholarly journals Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Xingtuan Yang ◽  
Yanfei Sun ◽  
Huaiming Ju ◽  
Shengyao Jiang
Keyword(s):  
High Temperature ◽  
Heat Shock ◽  
Steam Generator ◽  
Flow Rate ◽  
Heat Removal ◽  
Emergency Shutdown ◽  
Start Up ◽  
Sudden Load ◽  
High Temperature Gas ◽  
Residual Heat

After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was carried out based on a one-dimensional mathematical model for steam generator and steam pipe of start-up loop to achieve safety and reliability. The results show that steam generator should be discharged and precooled; otherwise, boiling will arise and introduce a cold shock to the boiling tubes and tube sheet when coolant began to circulate prior to the helium. Additionally, in avoiding heat shock caused by the sudden load of helium, the helium circulation should be restricted to start with an extreme low flow rate; meanwhile, the coolant of steam generator (water) should have flow rate as large as possible. Finally, a four-step procedure with precooling process of steam generator was recommended; sensitive study for the main parameters was conducted.

Transient Analysis of Active Residual Heat Removal Process for HTR-PM

2013 ◽  
Author(s):  
Hongye Zhu ◽  
Xingtuan Yang ◽  
Huaiming Ju ◽  
Shengyao Jiang
Keyword(s):  
Heat Shock ◽  
Steam Generator ◽  
Flow Rate ◽  
Transient Analysis ◽  
Heat Removal ◽  
Low Flow ◽  
Removal Process ◽  
Start Up ◽  
Sudden Load ◽  
Residual Heat

An active residual heat removal process is required by the gas-cooled reactor pebble-bed module plant being constructed in China, in order to improve the economical performance of the plant by shortening the restart duration. This process makes use of steam generator and start-up loop as heat sink, whose structure may suffer cold/heat shock while the sudden load of coolant or hot helium at the beginning. To achieve safety and reliability, transient analysis was carried out based on a one-dimensional mathematical model for steam generator and steam pipe of start-up loop. The calculation results show that steam generator should be discharged and pre-cooled; otherwise, boiling will arise and introduce a cold shock to the boiling tubes and tube sheet when coolant began to circulate prior to the helium. Additionally, in avoiding heat shock caused by the sudden load of helium, the helium circulation should be restricted to start with an extreme low flow rate; meanwhile, the coolant of steam generator (water) should have flow rate as large as possible. Finally, a four-step procedure with pre-cooling process of steam generator was recommended; sensitive study for the main parameters was conducted.

scholarly journals Experimental Study on the Residual Heat Removal System in HTR-10

2021 ◽  
Vol 2048 (1) ◽  
pp. 012037
Author(s):  
Jing Li ◽  
Liqiang Wei ◽  
Yanhua Zheng ◽  
Tao Ma ◽  
Xiaoming Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Experimental Studies ◽  
Heat Removal ◽  
Operating Characteristics ◽  
Pebble Bed ◽  
Operation Conditions ◽  
Heat Removal System ◽  
High Temperature Gas ◽  
Removal System ◽  
Residual Heat

Abstract The 10MW high temperature gas-cooled reactor (HTR-10) is a modular pebble-bed type reactor, of which the inlet and outlet helium temperature are 250 and 700 °C, respectively. It reached to its first criticality in December, 2000, and operated for nearly twenty years successfully. Currently, HTR-10 is the only pebble-bed type high temperature gas-cooled reactor that can operate in the world. To verify the natural circulation operating characteristics and safety features of the passive residual heat removal system, a series of experimental studies have been performed under different operation conditions of HTR-10, which include the performance tests of the passive residual heat removal system under various reactor operating power, different ambient temperature and single loop run mode. According to the data collation and result analysis, it shows that the performance of the residual heat removal system in HTR-10 meets the design and safety requirements.

scholarly journals Analysis of Precooling Injection Transient of Steam Generator for High Temperature Gas Cooled Reactor

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Yan Wang ◽  
Lei Shi ◽  
Yanhua Zheng
Keyword(s):  
High Temperature ◽  
Mass Flow Rate ◽  
Steam Generator ◽  
Mass Flow ◽  
Flow Rate ◽  
System Analysis ◽  
Water Injection ◽  
Normal Operation ◽  
Coolant Temperature ◽  
High Temperature Gas

After a postulated design basis accident leads high temperature gas cooled reactor to emergency shutdown, steam generator still remains with high temperature level and needs to be cooled down by a precooling before reactor restarts with clearing of fault. For the large difference of coolant temperature between inlet and outlet of steam generator in normal operation, the temperature distribution on the components of steam generator is very complicated. Therefore, the temperature descending rate of the components in steam generator needs to be limited to avoid the potential damage during the precooling stage. In this paper, a pebble-bed high temperature gas cooled reactor is modeled by thermal-hydraulic system analysis code and several postulated precooling injection transients are simulated and compared to evaluate their effects, which will provide support for the precooling design. The analysis results show that enough precooling injection is necessary to satisfy the precooling requirements, and larger mass flow rate of precooling water injection will accelerate the precooling process. The temperature decrease of steam generator is related to the precooling injection scenarios, and the maximal mass flow rate of the precooling injection should be limited to avoid the excessively quick temperature change of the structures in steam generator.

Thermal-Hydraulic Characteristics of the 250MW Pebble-Bed Modular High Temperature Gas-Cooled Reactor in Start-Up and Shutdown Processes

2009 ◽  
Author(s):  
Xunxiang Hu ◽  
Yujie Dong ◽  
Yanhua Zheng ◽  
Yangping Zhou ◽  
Lei Shi
Keyword(s):  
High Temperature ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Reactor Power ◽  
Hydraulic Characteristics ◽  
Pebble Bed ◽  
Start Up ◽  
Computer Codes ◽  
Design And Manufacture ◽  
High Temperature Gas

The start-up and shutdown processes are two important issues of the reactor control and operation for high temperature gas-cooled reactor plants. The analysis of thermal-hydraulic characteristics in these two processes can provide useful reference to the reactor design and manufacture, especially to the final establishment of the operation procedure. In this paper, according to the preliminary design of the 250MW Pebble-bed Modular High Temperature Gas-cooled Reactor (HTR-PM), the start-up and shutdown processes are studied by the help of two computer codes THERMIX and BLAST. The key parameters of these two processes, including the reactor power, the core inlet and outlet helium temperatures, the primary pressure and flow rate, as well as the secondary water flow rate and the outlet steam temperature, are analyzed in detail. Moreover, some uncertainties, such as the adjustment of power and secondary water temperature in the start-up process, the flow rate adjustment between the primary helium and the secondary water in the shutdown process, etc., are analyzed to evaluate the influences on the key parameters. The analysis results indicate that the pre-established start-up and shutdown rules are reasonable.

Experimental study on capability and start-up characteristic of advanced secondary passive residual heat removal system

2021 ◽  
Vol 140 ◽  
pp. 103929
Author(s):  
Qianhua Su ◽  
Haiyan Xu ◽  
Donghua Lu ◽  
Xiaohang Wu ◽  
Xi Yao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Heat Removal ◽  
Start Up ◽  
Heat Removal System ◽  
Removal System ◽  
Residual Heat
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