Heat pipe failure accident analysis in megawatt heat pipe cooled reactor

Ma, Yugao; Chen, Erhui; Yu, Hongxing; Zhong, Ruicheng; Deng, Jian; Chai, Xiaoming; Huang, Shanfang; Ding, Shuhua; Zhang, Zhuohua

doi:10.1016/j.anucene.2020.107755

Cited by 59 publications

(6 citation statements)

References 20 publications

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“…The point-reactor model is used to calculate the nuclear power variation in reactor core, and the thermal resistance model is used to describe the heat transfer process within gas gap and heat pipe. For the design of power control methods, the spatial distribution of power and temperature within reactor core is not cared about, thus these simplification methods are reasonable in normal case and make the model simpler than the model constructed with RMC and ANSYS in literature [10]. Moreover, it is enough to analyse the dynamic characteristics of heat pipe reactor with varies disturbance, and provide support for the design and verification of power control methods in thermal operation stage.…”

Section: Discussionmentioning

confidence: 99%

Dynamics Model Construction and Characteristic Analysis of Heat Pipe Nuclear Reactor in Thermal State

Yin

Ren

Mao

et al. 2023

J. Phys.: Conf. Ser.

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In order to facilitate the power control method design of heat pipe nuclear reactor and avoid the high complexity of reactor core modelling, the paper adopts the lumped parameter method to build the thermal state dynamic model of heat pipe reactor. Firstly, the equivalence of the core structure and heat transfer process of the “MegaPower” heat pipe nuclear reactor is carried out to describe a single heat pipe in a hexagonal block. The complex heat transfer process in reactor core is simplified into a two-zone heat transfer model with only fuel and monolith. And the equivalent thermal resistance is used to describe the heat conduction process within gas gap and heat pipe. Then, the reactor core nuclear dynamic model is established using the neutron dynamics equation of point-reactor. Based on the principle of heat balance, the thermal dynamics models of fuel, gas gap, monolith and heat pipe are established respectively, so as to form the state equations of heat generation and heat transfer process in reactor core. Finally, the dynamic characteristics of the reactor with the reactivity disturbance without external control are simulated and analysed. The results show that the heat pipe reactor has a certain self-stability with reactivity disturbance, but the stability time is long, and the power fluctuation is large.

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Section: Discussionmentioning

confidence: 99%

Dynamics Model Construction and Characteristic Analysis of Heat Pipe Nuclear Reactor in Thermal State

Yin

Ren

Mao

et al. 2023

J. Phys.: Conf. Ser.

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“…In this work, the effective thermal resistance network model with the solid assumption is applied in the heat transfer model of heat pipes. This effective model is commonly used and validated in many researches (Liu et al, 2020;Ma et al, 2020;Wang et al, 2020;Liu et al, 2022). According to (Zuo and Faghri, 1998), the effective thermal conductivity coefficient of the wick region is written in Eq.…”

Section: Thermal Modelmentioning

confidence: 99%

“…The heat pipe failure accident is also one of the essential basic accidents in HPRs (Ma et al, 2020). In this calculation, the disabled heat pipe adjacent to the hottest fuel rod is removed from the thermal model, and the adiabatic boundary condition is applied to the surface of the heat pipe hole.…”

Section: Heat Pipe Failurementioning

confidence: 99%

Multiphysics analysis of a metal hydride moderated megawatt heat pipe reactor with burnable poisons

Feng,

Hu,

Wang

et al. 2024

Front. Energy Res.

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With the development of nuclear energy, microreactors have received increasing interest among researchers in recent years. In this paper, a megawatt heat pipe reactor with metal hydride moderators and burnable poisons is proposed. The hydrogen stability of the reactor under accident conditions, including reactivity insertion accidents, loss of power conversion unit heat sink accidents, and heat pipe failure accidents are analyzed. In this work, Gd2O3 is introduced as a burnable poison in the form of mixing with the UO2 fuel. According to the results of the burnable poison design, the 0.1% mass fraction of Gd2O3 is selected as the burnable poison loaded in the core. Safety analysis indicates that the introduction of burnable poisons can be beneficial during the positive reactivity insertion accident as it can reduce the excessive reactivity at BOL, thus reducing power peak and preventing hydrogen dissociation in ZrH1.4 rods. However, during the loss of PCU heat sink accident, ZrH1.4 rods will dissociate regardless of the presence of burnable poisons, whereas YH1.7 rods show better hydrogen stability. Moreover, in the event of the heat pipe failure accident, ZrH1.4 rods are more susceptible to dissociation than YH1.7 rods. As a result, the YH1.7+BP core is a better choice compared with other designs proposed in this paper as it provides a relatively high temperature margin.

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“…When analyzing the thermal safety characteristics of MegaPower HPR in references [31,32], the cooling fluid is air. The use of different cooling fluids will change the convective heat transfer conditions on the surface of the condensation section of the heat pipe, but it will not directly affect the heat transfer in the core.…”

Section: Design Of Heat Exchangermentioning

confidence: 99%

Research on the Dynamic Characteristics Analysis and Power Control Method of Heat Pipe Reactors

Yin,

Yu,

Sheng

et al. 2023

Applied Sciences

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A heat pipe reactor (HPR) is a kind of modular small reactor with broad application prospects, and its dynamic characteristics and nuclear power control are essential to the safe and stable operation of nuclear power plants. Taking the MegaPower HPR as an example, the dynamic characteristics of the HPR are analyzed, and its power control method is designed in this paper. Based on the lumped parameter idea, the equivalent processing of the structure of the HPR core is carried out, and the main parameters of the heat pipe heat exchanger are designed at first. A lightweight dynamic model of the HPR is established using a thermal resistance network, and the accuracy of the model is verified using the solution of the model under the steady-state full power condition. Then, the dynamic characteristics of the HPR without a controller are analyzed respectively with the disturbance reactivity and mass flow rate, indicating strong self-stability and self-regulation of the HPR. Finally, a reinforcement learning (RL) controller based on the twin delayed deep deterministic policy gradient (TD3) algorithm is designed for the HPR power control, and it is adjusted through appropriately setting states, network structures, reward functions, etc. To verify the performance of the controller, a step response simulation ranging from 100%FP to 90%FP, a compound conditions simulation, and a large load change simulation are carried out, respectively. The results show that the RL controller can find the optimal control strategy through training. Meanwhile, it significantly improves the dynamic and steady-state performance of nuclear power compared with uncontrolled case and PID controller case, and it has the ability of power control under all operating conditions.

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Heat pipe failure accident analysis in megawatt heat pipe cooled reactor

Cited by 59 publications

References 20 publications

Dynamics Model Construction and Characteristic Analysis of Heat Pipe Nuclear Reactor in Thermal State

Dynamics Model Construction and Characteristic Analysis of Heat Pipe Nuclear Reactor in Thermal State

Multiphysics analysis of a metal hydride moderated megawatt heat pipe reactor with burnable poisons

Research on the Dynamic Characteristics Analysis and Power Control Method of Heat Pipe Reactors

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