Numerical Simulation and Analysis of Temperature Fluctuation in Core Outlet Zone of China Experimental Fast Reactor

2013 ◽  
Author(s):  
Huanjun Zhu ◽  
Yijun Xu
Keyword(s):  
Fast Reactor ◽  
Temperature Fluctuation ◽  
Mechanical Damage ◽  
Low Frequency ◽  
Normal Operation ◽  
Large Temperature ◽  
Control Rod ◽  
Sector Model ◽  
And Control ◽  
China Experimental Fast Reactor

As for the fast reactor, the temperature fluctuation in core outlet zone in normal operation was an important and typical thermal hydraulic phenomenon. In certain conditions, these temperature fluctuations can lead to thermal-mechanical damage to the Upper Core Structures (UCS). In this paper, the temperature fluctuation in Core Outlet Region of China Experimental Fast Reactor (CEFR) was numerically simulated and researched using the CFD software FLUENT. In the simulation process, LES turbulence method was used for the turbulent model selection. For the mesh generation, 1/4 sector model was built considering the layout of the symmetry and very small-size cell was used for satisfied with the Corant number. At the same time the core outlet temperatures and flows of the coolant in each subassembly under reactor rated power was used as the boundary conditions. The simulation shows that the temperature fluctuation was mainly concentrated in the zone between the fuel subassembly and control rod assembly for the large temperature difference of these subassemblies CEFR was operated in normal conditions. The largest fluctuation amplitude was 19°C and the remarkable frequency was below 5Hz. It belongs to typically low frequency fluctuation. The conclusion was useful for further experimental work and reactor operation.

Comparative Study on Neutronics Characteristics of a 1500 MWe Metal Fuel Sodium-Cooled Fast Reactor

2016 ◽  
Author(s):  
Kazuya Ohgama ◽  
Gerardo Aliberti ◽  
Nicolas E. Stauff ◽  
Shigeo Ohki ◽  
Taek K. Kim
Keyword(s):  
Fast Reactor ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Nuclear Data ◽  
Cooperative Effort ◽  
Energy Agency ◽  
Control Rod ◽  
Benchmark Study ◽  
Metal Fuel ◽  
And Control

Under the cooperative effort of the Civil Nuclear Energy R&D Working Group within the framework of the U.S.-Japan bilateral, Argonne National Laboratory (ANL) and Japan Atomic Energy Agency (JAEA) have been performing benchmark study using Japan Sodium-cooled Fast Reactor (JSFR) design with metal fuel. In this benchmark study, core characteristic parameters at the beginning of cycle were evaluated by the best estimate deterministic and stochastic methodologies of ANL and JAEA. The results obtained by both institutions are agreed well with less than 200 pcm of discrepancy on the neutron multiplication factor, and less than 3% of discrepancy on the sodium void reactivity, Doppler reactivity, and control rod worth. The results by the stochastic and deterministic were compared in each party to investigate impacts of the deterministic approximation and to understand potential variations in the results due to different calculation methodologies employed. Impacts of the nuclear data libraries were also investigated using a sensitivity analysis methodology.

A Study on the Influences of Reactivity Feedback Mechanisms in China Experimental Fast Reactor Unprotected Transients

2013 ◽  
Author(s):  
Yuanyu Wu ◽  
Hong Yu ◽  
Lixia Ren ◽  
Wenjun Hu ◽  
Hongtao Qian
Keyword(s):  
Fast Reactor ◽  
Reactor Core ◽  
Coolant Temperature ◽  
Inherent Safety ◽  
Fuel Temperature ◽  
Feedback Mechanisms ◽  
Control Rod ◽  
Severe Accidents ◽  
Proper Design ◽  
China Experimental Fast Reactor

Inherent safety properties of reactor have always played an important role in severe accidents preventing and consequences mitigation. With proper design, reactivity feedback mechanisms can bring benign reactivity feedbacks to the reactor core during unprotected transients, thus contributing to the severe accidents mitigation. In overpower transients, the increasing power causes the fuel temperature to increase, which directly brings fuel Doppler feedback and core axial expansion feedback. In unprotected loss-of-flow accidents, as the flow rate decreases, the mismatch of power and flow causes the increase of coolant temperature, thus directly resulting in the coolant reactivity, core radial expansion as well as the control rod driveline expansion feedbacks. Through the simulation of China Experimental Fast Reactor (CEFR) unprotected transients, the influences of different reactivity feedback mechanisms have been investigated and analyzed. The coolant reactivity exhibits significant negative feedback and makes the dominant contribution in controlling the reactivity in both UTOP and ULOF transients.

scholarly journals Benchmarking the new ENDF/B-VIII.0 nuclear data library for OECD/NEA medium 1000 MWth sodium-cooled fast reactor

2020 ◽  
Vol 239 ◽  
pp. 22006
Author(s):  
Donny Hartanto ◽  
Bassam Khuwaileh ◽  
Peng Hong Liem
Keyword(s):  
Monte Carlo ◽  
Fast Reactor ◽  
Nuclear Data ◽  
Control Rod ◽  
Continuous Energy ◽  
Nuclear Data Library ◽  
And Control ◽  
Benchmark Evaluation ◽  
Data Library

This paper presents the benchmark evaluation of the new ENDF/B-VIII.0 nuclear library for the OECD/NEA Medium 1000 MWth Sodium-cooled Fast Reactor (SFR). There are 2 SFR cores: metallic fueled (MET-1000) and oxide fueled (MOX-1000). The continuous-energy Monte Carlo Serpent2 code was used as the calculation tool. Various nuclear libraries such as ENDF/B-VII.1 and JENDL-4.0 were included to be compared with the newest ENDF/B-VIII.0. The evaluated parameters are k,βeff, sodium void reactivity (∆ρNa), Doppler constant (∆ρDoppler), and control rod worth (∆ρCR).

scholarly journals MONTE CARLO SIMULATION OF NEUTRONICS START-UP TESTS AT CHINA EXPERIMENTAL FAST REACTOR (CEFR)

2021 ◽  
Vol 247 ◽  
pp. 10008
Author(s):  
Jiwon Choe ◽  
Chirayu Batra ◽  
Vladimir Kriventsev ◽  
Deokjung Lee
Keyword(s):  
Monte Carlo ◽  
Fast Reactor ◽  
Impact Analysis ◽  
Physical Models ◽  
Monte Carlo Code ◽  
Control Rod ◽  
Preliminary Results ◽  
Research Activities ◽  
Start Up ◽  
China Experimental Fast Reactor

China Experimental Fast Reactor (CEFR) is a small size sodium-cooled fast reactor (SFR) with a high neutron leakage core fueled by uranium oxide. The CEFR core with 20 MW(e) power reached its first criticality in July 2010, and several start-up tests were conducted from 2010 to 2011. The China Institute of Atomic Energy (CIAE) proposed to release some of the neutronics start-up test data for the IAEA benchmark within the scope of the IAEA’s coordinated research activities through the coordinated research project (CRP) on “Neutronics Benchmark of CEFR Start-Up Tests”, launched in 2018. This benchmark aims to perform validation and verification of the physical models and the neutronics simulation codes by comparing calculation results against collected experimental data. The six physics start-up tests considered for this CRP include evaluation of the criticality, control rod worth, void reactivity, temperature coefficient, swap reactivity, and foil irradiation. Twenty-nine participating research organizations are performing independent blind calculations during the first phase of the project. As a part of this coordinated research, IAEA performed neutronics calculations using Monte Carlo code SERPENT. Two kinds of 3D core models, homogenous and heterogeneous, were calculated using SERPENT, with ENDF/B-VII.0 continuous energy library. Preliminary results with a reasonably good estimation of criticality, as well as theoretically sound results of other five test cases, are available. The paper will discuss the core modelling assumptions, challenges and key findings of modelling a dense SFR core, preliminary results of the first phase of the CRP, heterogeneity impact analysis between homogenous core models and heterogeneous core models and future work to be performed as a part of this four-year project.

Study on Thermal Striping at UIS of Advanced Loop Type Fast Reactor: Water Experiment Using a 1/3 Scale 60 Degree Sector Model

2009 ◽  
Author(s):  
Jun Kobayashi ◽  
Nobuyuki Kimura ◽  
Akira Tobita ◽  
Hideki Kamide ◽  
Osamu Watanabe ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Thermal Fatigue ◽  
Technology Development ◽  
Development Project ◽  
Control Rod ◽  
Sector Model ◽  
The Core ◽  
Technology Development Project ◽  
Frame Work ◽  
Thermal Striping

An advanced loop type sodium cooled fast reactor, JSFR, has been investigated in the frame work of Fast Reactor Cycle Technology Development Project (FaCT). As the temperatures difference between the control rod channels and the core fuel subassemblies is around 100 °C, temperature fluctuation due to the fluid mixing at the core outlet may cause high cycle thermal fatigue at the bottom of Upper Internal Structure (UIS). Then, a water experiment was conducted using an 1/3 scale 60 degree sector model. Temperature and its fluctuation intensity distributions around the control rod were measured and an effect of the improved structure against the thermal fatigue was examined.

scholarly journals Protection and Response of a Tertiary Hospital in Shenzhen, China to the COVID-19 Outbreak—the Practice of the Comprehensive Response Mode

2021 ◽  
pp. 1-17
Author(s):  
Benling Hu ◽  
Le Yang ◽  
Chan Wei ◽  
Min Luo
Keyword(s):  
Prevention And Control ◽  
Tertiary Hospital ◽  
Control Model ◽  
Normal Operation ◽  
Process Reengineering ◽  
Equipment Management ◽  
Hospital Acquired Infection ◽  
Public Health Emergencies ◽  
Hospital Acquired ◽  
And Control

ABSTRACT Objective: To evaluate the management mode for the prevention and control of coronavirus 2019 (COVID-19) transmission utilized at a general hospital in Shenzhen, China, with the aim to maintain the normal operation of the hospital. Methods: From January 2, 2020 to April 23, 2020, Hong Kong–Shenzhen Hospital, a tertiary hospital in Shenzhen, has operated a special response protocol named comprehensive pandemic prevention and control model, which mainly includes six aspects: 1) human resource management; 2) equipment management; 3) logistics management; 4) cleaning, disinfection and process reengineering; 5) environment layout; 6) and training and assessment. The detail of every aspect was described and its efficiency was evaluated. Results: A total of 198,802 patients were received. Of those, 10,821 were hospitalized; 26,767 were received by the emergency department and fever clinics; 288 patients were admitted for observation with fever; and 324 were admitted as suspected cases for isolation. Under the protocol of comprehensive pandemic prevention and control model, no case of hospital-acquired infection with COVID-19 occurred among the inpatients or staff. Conclusion: The present comprehensive response model may be useful in large public health emergencies to ensure appropriate management and protect the health and life of individuals.

scholarly journals Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1216
Author(s):  
Xin Wang ◽  
Bo Li ◽  
Fan Zhao ◽  
Xinyu Luo ◽  
Luxi Huang ◽  
...  
Keyword(s):  
Field Strength ◽  
Solar Eclipse ◽  
Low Frequency ◽  
Signal Propagation ◽  
Normal Operation ◽  
Time Code ◽  
Long Distance ◽  
Time Service ◽  
Annular Solar Eclipse ◽  
Signal Field

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

scholarly journals Large Temperature Fluctuations due to Cold-Air Pool Displacement along the Lee Slope of a Desert Mountain

2017 ◽  
Vol 56 (4) ◽  
pp. 1083-1098 ◽  
Author(s):  
Matthew E. Jeglum ◽  
Sebastian W. Hoch ◽  
Derek D. Jensen ◽  
Reneta Dimitrova ◽  
Zachariah Silver
Keyword(s):  
Low Frequency ◽  
Temperature Fluctuations ◽  
Atmospheric Modeling ◽  
Large Temperature ◽  
Complex Flow ◽  
Near Surface ◽  
Cold Air ◽  
Flow Interactions ◽  
Initial Drop ◽  
Program Temperature

AbstractLarge temperature fluctuations (LTFs), defined as a drop of the near-surface temperature of at least 3°C in less than 30 min followed by a recovery of at least half of the initial drop, were frequently observed during the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. Temperature time series at over 100 surface stations were examined in an automated fashion to identify and characterize LTFs. LTFs occur almost exclusively at night and at locations elevated 50–100 m above the basin floors, such as the east slope of the isolated Granite Mountain (GM). Temperature drops associated with LTFs were as large as 13°C and were typically greatest at heights of 4–10 m AGL. Observations and numerical simulations suggest that LTFs are the result of complex flow interactions of stably stratified flow with a mountain barrier and a leeside cold-air pool (CAP). An orographic wake forms over GM when stably stratified southwesterly nocturnal flow impinges on GM and is blocked at low levels. Warm crest-level air descends in the lee of the barrier, and the generation of baroclinic vorticity leads to periodic development of a vertically oriented vortex. Changes in the strength or location of the wake and vortex cause a displacement of the horizontal temperature gradient along the slope associated with the CAP edge, resulting in LTFs. This mechanism explains the low frequency of LTFs on the west slope of GM as well as the preference for LTFs to occur at higher elevations later at night, as the CAP depth increases.

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