scholarly journals Numerical investigation of the large over-reading of Venturi flow rate in ARE of nuclear power plant

2021 ◽  
Vol 53 (1) ◽  
pp. 69-78
Author(s):  
Hong Wang ◽  
Zhimao Zhu ◽  
Miao Zhang ◽  
Jinlong Han
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Numerical Investigation ◽  
Flow Rate ◽  
Nuclear Power

Derivation and Analysis of the Criterion for Onset of Density Wave Oscillation in Tubes and Channels With Riser

2009 ◽  
Author(s):  
Yu. Kornienko
Keyword(s):  
Natural Convection ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Flow Rate ◽  
Nuclear Power ◽  
Density Wave ◽  
Practical Interest ◽  
Analytical Criterion ◽  
Time Density ◽  
Oscillating Processes

In a number of nuclear power plant (NPP) applications questions arise as to appearance and development of oscillations in mass flow rate, enthalpy, coolant density in the channels with riser. Density waves oscillations (DWO) are one of the most common kind of self-oscillating processes in the parallel steam-generating channels system. It concerns inter-channel pulsations as well as oscillations in natural convection loops with a periodical space-time density change propagating together with the flow. That is why obtaining an analytical criterion giving the boundary for onset of DWO is of the notable theoretical and practical interest.

Experimental Research on Steam Jetting and Condensation in Low Sub-Cooled Water

2018 ◽  
Author(s):  
Chunhui Dai ◽  
Mengran Liao ◽  
Qi Xiao ◽  
Jun Wu ◽  
Shaodan Li ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Nuclear Power ◽  
Great Influence ◽  
Low Frequency ◽  
Two Phase ◽  
Noise Characteristics

Steam submerged jetting is an important process in depressurization tank and condenser deaerator tank of nuclear power plant. As the steam contact the liquid water directly, some complicated behaviors such as strong turbulence and phase transition would happens. Especially when the sub-cooling degree is low, the condensation may cause vigorous pressure pulsation and radiation noise, which not only causes noise damage to workers but also affect the safety of the heat exchanger tubes bundle because of vibration transmission. An experiment is proposed to study the complex evolutionary behavior and vibration and noise characteristics of gas-water two-phase flow. The experimental results show that in the case of low subcooling, the mass flow rate of steam has a great influence on gas plume, and, as the mass flow rate increases, the main contribution frequency of noise is gradually increasing from low frequency to high frequency. The researches in this paper can provide the technical basis for the design of the deoxygenation system of condenser in onshore and ship nuclear power plant.

Research on Natural Circulation Flow Characteristics of Floating Nuclear Power Plant in Heaving Motion

2017 ◽  
Author(s):  
Li Ren ◽  
Peng Minjun ◽  
Xia Genglei ◽  
Zhao Yanan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Nuclear Power ◽  
Natural Circulation ◽  
Flow Characteristics ◽  
Circulation Flow ◽  
Drift Flux Model

The FNPP (Floating Nuclear Power Plant) expanded the application field of Integrated Pressurized Water Reactor (IPWR) in the movable marine platform, it is necessary to study the natural circulation flow characteristics in heaving motion on the ocean. From the characteristics of FNPP, by means of THEATRe code which was based on the two-phase drift flux model and was modified by adding module calculating the effect of heaving motion, the simulation model in heaving motion was built. Using the models developed, the natural circulation operating characteristics of natural circulation in heaving motion and the transitions between forced circulation and natural circulation are analyzed. In the case of amplitude limited, the periods of mass flow rate are equal to periods of heaving motion. The oscillation amplitude of mass flow rate increases with the heaving amplitude increase. In the case of period limited, the natural circulation flow rate oscillating amplitude increases with the heaving period increases. The result obtained are not only evaluating FNPP design behavior properly but also pointing out the direction to further optimum design to ensure FNPP operating safety in heaving motion.

Experimental Investigation Into Thermal Stratification by Direct Condensation in a Scaled Suppression Pool of Fukushima Daiichi Nuclear Power Plant

2014 ◽  
Author(s):  
Byeongnam Jo ◽  
Shinji Takahashi ◽  
Daehun Song ◽  
Wataru Sagawa ◽  
Nejdet Erkan ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Flow Rate ◽  
Thermal Stratification ◽  
Nuclear Power ◽  
Experimental Results ◽  
Steam Condensation ◽  
Wide Range ◽  
Fukushima Daiichi ◽  
Suppression Pool

Experimental and numerical studies into thermal stratification by direct steam condensation in a torus type suppression pool were carried out to investigate the reactor core isolation cooling in the accidents of Fukushima Daiichi nuclear power plants. The suppression pool was manufactured to be a 1/22 scaled model of a Fukushima Daiichi nuclear power plant. Two different types of spargers were employed to simulate different units of the plants. In a sparger, 132 holes were uniformly drilled on the side of a pipe. However, the other sparger injected steam to the bottom. Flow rate was varied in a wide range to examine the effect on thermal stratification in the suppression pool. The experimental results showed that the sparger type influenced formation of thermal stratification. Moreover, steam flow rate strongly affected the onset time of thermal stratification, and the disappearance of the thermal stratification was affected by subcooling temperature. Computer simulation using a commercial software was conducted and the results show similar temperature profiles to the experimental results. Steam condensation was visualized in a vicinity of the spargers using high speed camera.

The Impacts of Scale Effect on Flow Patterns in a Supersonic Steam Injector

2017 ◽  
Author(s):  
Masaya Fujishiro ◽  
Yutaka Abe ◽  
Akiko Kaneko
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Scale Effect ◽  
Flow Rate ◽  
Test Section ◽  
Nuclear Power ◽  
Flow Patterns ◽  
Water Jet ◽  
Steam Flow ◽  
And Performance

From the viewpoint of an importance of safety, the nuclear power plant should be managed to prepare severe accidents. The performance of safety dropped by an accident is strongly to be minimized during the situation of station blackout. The installation of a steam injector (SI) into the nuclear power plant has long been expected. In the SI, the steam condenses due to the direct contact at the surface of water jet, resulting in the force attracting water. The force drives the circulation of an amount of coolant water. SI also works as a reactor condenser thanks to its high efficient performance during the condensation. Because any external forces to circulate water and steam are not required, SI can be operated without the electric powers. The structure of SI is similar to a convergent-divergent nozzle. After the flow acceleration at a throat, the discharged pressure is expected to exceed the inlet pressure. Owing to its quite simple structure, the reduced cost of installation and maintenance is also expected. The following previous studies for four cases of throat diameter clarified two-phase flow structures and heat transfer characteristics in water jet and performance of SI: (i) Narabayashi et al. (2000) examined for 5.5 and 6.5 mm in diameter; (ii) Osakabe et al. (2004) for 3.4 mm; (iii) Koizumi et al. (2006) for 4 mm; (iv) Abe et al. (2014) for 4, 6.5, and 8 mm. Although these clarified the operative state which formed a water jet, operative condition was not elucidated. Furthermore, the scale effect for various diameters of SI has not been discussed in detail. The aim of this study is to clarify scale effect of a test section on operating criteria and performance. Experiment was performed to clarify the scale effect by using three types of throat diameters: 4, 6.5, and 8 mm. As a result, three formations of a water jet were observed: (i) formation, (ii) incomplete formation, and (iii) no formation. We proposed a classification which enables us to categorize complex flow patterns into five regimes. We clarified the operating criteria of them by comparing water flow rate with steam flow rate. SI did not form a water jet on the condition with low steam flow rate. The suppling water was stopped, and only steam was supplied to the test section for the condition that steam latent heat was larger than subcooled water enthalpy.

Sign in / Sign up

Export Citation Format

Share Document