bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of 1D-CFD Coupling Method to Unprotected Loss of Heat Sink Event in EBR-II Focusing on Thermal Stratification in Cold Pool
Authors: Yoshimura Kazuo , Doda Norihiro , Fujisaki Tatsuya , Igawa Kennichi , Tanaka Masaaki , Yamano Hidemasa 
Published: December 2022

Abstract
Negative reactivity caused by radial expansion of core is known as one of the inherent safety features in a sodium-cooled fast reactor (SFR). In order to confirm the applicability of the reactivity model, the authors have been conducting the benchmark exercises of the unprotected loss of heat sink event tests in a pool-type experimental SFR EBR-II. In the blind phase in the benchmark analyses using the in-house plant dynamics analysis (1D) code, it was found the increase of the core inlet temperature was evaluated lower than that of the measured data and the feedback reactivity was underestimated. Since the discrepancies might be brought by the ignorance of thermal stratification in the cold pool by means of the perfect mixing model in the 1D code, the detailed model of the cold pool for the computational fluid dynamics (CFD) code was introduced and the 1D-CFD codes coupling method was applied to the benchmark analyses. Then, it was confirmed that both the thermal stratification in the cold pool and the core inlet temperature were successfully reproduced. It could insist that modeling the cold pool including the IHX outlet window in detail was important to simulate the thermal hydraulics behaviors including thermal stratification there.
Numerical Study of Heat Transfer Enhancement in Narrow Rectangular Channel With Rotated Elliptic Dimple With Inclined Slit
Authors: Wang Chuntao , Lu Qi , Qiu Xiang , Liu Yu , Deng Jian , Sun Jie 
Published: December 2022

Abstract
In order to enhance heat transfer performance of the reactor core coolant in the narrow rectangular channel of nuclear power system and ensure the safety of the reactor core without local high temperature as well as not cause excessive pressure loss, three different shapes of protruded elliptic dimple were adopted in the channel for numerical research. Firstly, the angle between long axis of the elliptic dimple and direction of the mainstream was rotated, which was defined as a rotated angle θ ranging from 0° to 90°. Secondly, streamwise (in line with the mainstream) slit was processed on the dimple. The last, inclined slit was processed on the dimple. There were five quantitative and two qualitative indicators to account for comprehensive effects of heat transfer, flow resistance and temperature distribution on the wall of the channel, namely, Nu for heat transfer capacity, f for flow resistance, performance evaluation criteria PEC for combination of heat transfer and flow resistance, Tmax and Tavg for maximum and average temperature on the outer wall respectively, velocity field near the inner wall and temperature distribution on the outer wall to show more detail information of the flow and heat transfer characteristics. The study results showed that with increase of θ, heat transfer efficiency and flow resistance all increased. Dimple with whether streamwise slit or inclined slit helped to reduce flow resistance. The dimple with streamwise slit performed best in flow resistance performance and the dimple with inclined slit performed best in heat transfer performance.
The Optimization Design of Direct Vessel Injection Diversion Structure
Authors: Hou Jianfei , Wang Qingli 
Published: December 2022

Abstract
A nuclear power plant adopts the way of direct vessel injection to inject safety injection water directly into the downcomer of reactor pressure vessel after accident. In order to avoid the splash phenomenon when the high speed safety injection water coming through the direct vessel injection nozzle impacts the core barrel, a diversion structure installed on the barrel is introduced into the reactor pressure vessel to guide the direction of safety injection water from horizontal to downward. As the existence of the gap between the diversion structure and direct vessel injection nozzle, a significant proportion of leakage of safety injection water occurs and it will affect the effectiveness of safety injection. After the analysis of flow field around the gap, a optimization to the diversion structure is taken out to reduce the leakage flow rate by adding different shapes and dimensions of baffles, such as semicircular baffles and inverted U-shaped baffles. Computational fluid dynamics method is adopted to simulate the flow in downcomer of reactor pressure vessel with different diversion structures and the shape of downcomer is simplified into cuboid for the convenience of simulation. Results show that all the optimization schemes can reduce the leakage flow rate in different degrees. The diversion structure with semi-circular plates and rounded transition between top plate and back plate can reduce the leakage most. Current work shows the rationality of the research direction and provides guidance for similar research in the future.
Investigation on the Simulation of Turbulent Heat Transfer of Liquid Metal Flow in a Narrow Rectangular Channel
Authors: Zhang Xue , Yu Hongxing , Deng Jian , Du Sijia , Zhang Xilin , Zou Ziqiang , Feng Wenpei , Zhang Yaoxiang 
Published: December 2022

Abstract
Liquid metal has the advantages of high boiling point and strong thermal conductivity and is selected as the coolant for a new generation nuclear system. In addition, the narrow rectangular channel is used in the small reactors or research reactors due to its compact structure and high heat transfer capacity. In order to accurately simulate the turbulent heat transfer of liquid metals in narrow rectangular channels, based on the relevant experimental data, this paper explored suitable numerical simulation methods. First of all, according to the research object, the appropriate experimental data was selected, and the geometric modeling, mesh division, and the mesh independence verification were carried out. It was ensured that the y+ meets the requirements of each turbulence model and wall treatment model. Several typical turbulence models and the wall treatment models were evaluated. For the low Prandtl number fluid such as liquid metal, it is necessary to select a suitable turbulent Prandtl number model in the RANS simulation. The sensitivity of the calculation results to the turbulent Prandtl number was analyzed. Finally, the existing turbulent Prandtl number models were evaluated. The suitable Prt at different Pe was given based on experimental value, so that the turbulent heat transfer of liquid metal in a narrow rectangular channel can be accurately simulated.
Study on Natural Circulation Flow Resistance Characteristics in a Rod Bundle Channel
Authors: Zhu Zhiqiang , Ren Tingting , Li Shuaijun , Tian Chunping , Yan Changqi , Wang Jianjun 
Published: December 2022

Abstract
Using deionized water as the working fluid, an experimental study on the resistance characteristics of single-phase and two-phase flow under natural circulation conditions is carried out in a 3 × 3 rod bundle channel. For the single-phase flow, the flow regime transition of rod bundle channel is not as obvious as that of conventional channels such as a circular tube. The flow regime transition in the channel is judged by the change trend of drag coefficient and the flow regime division is obtained. The transition Reynolds number from laminar flow to turbulent flow is approximately 800, and the correlations of the single-phase frictional resistance coefficient for different flow regimes are given. The natural circulation and forced circulation conditions have no obvious influence on the flow state transition. For the two-phase flow, under vertical conditions, a new two-phase frictional pressure drop correlation is fitted on the basis of the Chisholm correlation based on the experimental results. Moreover, the experiment for two-phase flow resistance under the inclined conditions are carried out, and the variation of the two-phase resistance with the mass quality is given, and the correlations of the two-phase friction pressure drop based on different inclination angles are proposed.
A Study on the Steady-State Flow Behavior of the Boiling-Driven Open Natural Circulation System
Authors: Hou Xiaofan , Wang Qianglong , Jiu Jinrong , Chen Hanying , Yao Shiwei 
Published: December 2022

Abstract
Natural circulation is widely used in the many industries owing to inherent safety. A typical case is Passive Containment Cooling System in the Chinese third-generation nuclear plant HPR1000. It uses an open natural circulation structure and contains an inner-containment heat exchanger, an outer-containment altitude water tank and connecting pipes. The altitude water tank connects with atmosphere, making its operation pressure is atmospheric pressure. For designing such an open natural circulation system, the steady-state flow behavior of of which is an important evaluate indicator, because it can directly reflect the flow capacity and heat transfer capacity of the PCS system. Considering that the long-term stable operating condition of the PCS system is the boiling-driven open natural circulation flow. Therefore, it is of significance to study the steady-state flow characteristics of the boiling-driven open natural circulation system.
In this paper, a theoretical formula to determine the steady-state flow behavior of a open boiling-driven natural circulation. Due to the lack of condensation process of two-phase circulation fluid, the integral result of steady momentum equation is not equal to zero. A special formula processing of accelerated pressure drop integral result is taken in this paper during the formula derivation process. The theoretical analysis results of which were validated by the experimental data. This paper aims at providing technical support for the design of open natural circulation systems.
Effect of Pilot Solenoid Valve Throat Diameter on Dynamic Response Time in Main Steam Valve Set
Authors: Liu Chuang , Zang Jia-lin , Jin Zhi-jiang , Qian Jin-yuan 
Published: December 2022

Abstract
The Main Steam Valve Set (MSVS) is set at the outlet of the steam generator in the secondary circuit of the Nuclear Power Plant, which plays a key role in overpressure protection of the steam generator. In actual working conditions, the response time of the MSVS is generally longer than the specified time due to the substandard flow coefficient of the pilot valve, which is directly connected to the upper chamber of main valve. In this paper, the flow characteristics of solenoid valve under different throat diameters and opening degrees is analyzed by. The result shows that the velocity and pressure of the flow field in the solenoid valve have an obvious change when the opening degree change from 25% to 50%. But after that, they stay unchanged approximately as the opening degree increases. Also, the outlet mass flow increases fast during the first 50% opening degree. The outlet mass flow when ds is 32 mm is higher than that when ds is 28mm. But when ds is 36 mm, the mass flow has no obvious change. Because the mass flow has a direct effect on response time, the research has a reference for the structural design of the solenoid valve in the MSVS, and ensure the safety of Nuclear Power Plants.
Sleeve Spacing Analysis on Flow Characteristics of Double-Layer Sleeve Control Valve
Authors: Nie Jia-xi , Chen Wei-ping , Hou Cong-wei , Lin Zhen-hao , Jin Zhi-jiang , Qian Jin-yuan 
Published: December 2022

Abstract
Sleeve control valves are one of the most main components of a nuclear piping system, and they are used for superheated steam adjustment, including the flow rate, pressure, temperature, etc. The sleeve, as its core component, plays a critical role in the regulation of flow characteristics in the valve. Therefore, it is very important to study the effect of the sleeve structure of valve core on the flow characteristics in the sleeve control valve. In this paper, the steady numerical model of double-layer sleeve control valve based on the compressible superheated steam was established with full opening, and the effects of sleeve spacing on flow characteristics of double-layer sleeve valve were analyzed based on the standard k-ε turbulence model. The flow characteristics of double-layer sleeve control valve including velocity, turbulence intensity, and Mach number was investigated with four kinds of different sleeve spacing. When the spacing of double-layer becomes larger, it will affect the flow characteristic of double-layer sleeve control valve greatly. This work has a certain reference value for the design of the thickness of the sleeve opening of the sleeve control valve.
Application of Boron Feedback From BOA CIPS/CILC Analysis on Neutronic Models
Authors: Fisher Jesse , Mangham Gary , Briggs Christopher , Wang Guoqiang , Zhang Baocheng 
Published: December 2022

Abstract
This paper summarizes the development of a multi-physics code system for evaluation of Crud Induced Power Shift (CIPS) phenomenon experienced in some Pressurized Water Reactors (PWR). CIPS is an unexpected change in reactor core axial power distribution, caused by boron compounds in crud deposited in the high-power fuel assemblies undergoing subcooled boiling. The approach includes a more robust method compared to previous attempts at coupling codes to account for boron deposition at the nodal level within the neutronic model based on the BOA generated CIPS results. This paper describes the updated linkage with a Python script wrapper around the multi-physics code system ANC9/FUELDUTYDRV/VIPRE-W/BOA. The multi-physics code system can then evaluate changes in core power distributions due to boron deposited in the crud for comparison to measured plant cycle flux trace data. The plant flux trace data provides additional wealth of information for reducing BOA conservatism in the CIPS analysis and benchmarking the multi-physics to the plant-specific source term and plant operation. The linkage of the code system along with the application results will be the base for future development to improve CIPS/Crud Induced Localized Corrosion (CILC) risk for a plant, allowing for the potential benefits of more aggressive fuel management via higher duty cores or improved fuel economics.
Rapid Leak Detection on Slurry Lines by Negative Pressure Wave Detection With Distributed Fiber Optic Sensing
Authors: Murray Alasdair , Godfrey Alastair , Minto Chris 
Published: December 2022

Abstract
Slurry pipelines can be used to move ore or waste material across large distances. The nature of slurry means that conventional mass-flow and statistical based leak detection systems are poorly suited to leak detection.
External Leak Detection Systems (LDS) based on Distributed Fiber Optic Sensing (DFOS) offer the potential to significantly reduce the overall amount of spilled product before a leak is detected and localized. Such a system has been installed on a slurry pipeline for the past 3 years and since installation there have been three unique leak events identified by the operator using the DFOS system. Two of these events are estimated to have involved leak flow rates of less than 50 LPM. Notably, in one of the incidents the operator indicated that there was no surface expression of the leak when they went to inspect the location. The incidents disclosed in this paper are done so anonymously.
Each of the leak events shared a common characteristic: the recurrent generation of localized NPW signals. This characteristic is suggested to result from the blocking and unblocking of the leak orifice by the solid material.
Centerline Segregation Rating and Its Implications on Mechanical Properties and Weldability of Line-Pipe Steels
Authors: Konar Bikram , Mohammadijoo Mohsen , Dunnett Kendal , Rashid Muhammad 
Published: December 2022

Abstract
In continuously cast line-pipe steel, solute elements segregate near the centerline of the slab. The extent of centerline segregation is compared with reference Mannesmann images either by visual or computer-aided techniques and provided a Mannesmann rating (MR). Originally MR was devised to gauge the casting performance, however, recently it is used as a reliability/performance metric for line-pipe qualification. Centerline segregation phenomenon in the slabs is expected to translate to through-thickness microstructural heterogeneity and precipitate formation in rolled products affecting mechanical properties. Furthermore, weldability of line-pipe steels is impacted by the interplay of heterogeneous centerline microstructure, precipitates, and the utilized welding process parameters and consumable package. In this study, X70 grade steel slabs rated with MR of 2 (MR2) and 3 (MR3) were rolled and submerged-arc welded to form pipes. Microstructural analysis, and mechanical property and hardness measurements as per ASTM standards were performed on these pipes. Despite some microstructural indication, no substantial difference was observed in the mechanical properties of the manufactured MR 2 and MR3 pipes.
WIC (Welding Institute of Canada) and pipe through-thickness weldability testing using cellulosic E8010 electrodes showed no substantial influence of MR on weldability or hydrogen-assisted crack formation. This study highlights MR of slabs is not a good reliability/performance metric for the pipelines, and it is rather important to understand the effects of other downstream processes to establish a quality control criteria.
Stress Analysis of Crossing Highway Pipe Sections Under Vehicle Load Based on the Experiment of Real-Size Pipes
Authors: He Guoxi , Xia Guoqiang , Liao Kexi , He Tengjiao , Tang Xin , Tian Zhiyuan 
Published: December 2022

Abstract
For long-distance natural gas pipes crossing highway, the changing load of vehicles is the most important and frequently acting-live load on buried pipes, which poses a serious threat to the integrity of the pipe. This study has designed and built a buried pipe stress test experimental system. The experimental system is mainly composed of a sealed pipe, an air compressor, and a stress-strain testing system. In this study, a total of 24 sets of stress test experiments are carried out. The research conclusions are as follows. The maximum stress of the pipe occurs at the 12 o’clock position of the pipe when the vehicle load is rolled at the middle. The increase in vehicle load results in an increasing pipe stress value. Both of the vehicle speed and the internal pressure play a certain role in protecting the pipe. After carrying out a real experimental case via Sinopec’s natural gas pipe crossing the highway, we have found that it can withstand the rolling load of a heavy vehicle of 78t, when the L325 steel pipe section that crossing the Grade-4 highway has a buried depth of 0.8m, a diameter of 355.6 × 5.6mm, and a internal pressure of 1.03MPa.
Development of a Pressure Equipment Integrity Management Program in a Multi-Jurisdictional Liquids Pipeline Environment
Authors: Sohail Touqeer , Bohaichuk Katarina 
Published: December 2022

Abstract
Demonstrated public safety and environmental responsibility is key to the reputation and success of pipeline companies. This sentiment extends not only to pipelines themselves, but to all facility equipment as well. That is why Enbridge Liquid Pipelines (Enbridge) developed a Pressure Equipment Integrity Management Program that is designed to ensure the safety, integrity, compliance, and operational reliability of all pressure vessels and boilers in Enbridge’s liquid pipeline facilities.
A unique aspect of Enbridge’s Pressure Equipment Integrity Management Program is how it must identify and comply with regulatory requirements in a multitude of both federal and provincial/state jurisdictions in Canada and the United States. Depending on the type of pressure equipment and its location, it may be federally regulated, locally regulated, or potentially both if there is no clear delineation between regulatory authorities. These different requirements can be complex and difficult to follow for personnel tasked with maintaining pressure equipment integrity across the entire pipeline system.
This paper will describe how a liquids pipeline company can structure a successful Pressure Equipment Integrity Management Program that is entrenched in the overall company Integrity Management System. The program must utilize clear, effective, and action-based processes and procedures that identify and comply with multi-jurisdictional requirements and are based on industry best practices. Stakeholder responsibilities shall be clearly outlined as well as process steps and required actions to be taken to effectively manage hazards and risks and maintain compliance.
Improved Fracture Toughness Test Method for Single Edge Notched Tension Specimens in Clamped-End Conditions
Authors: Zhu Xian-Kui 
Published: December 2022

Abstract
The oil and gas industry has favored to use fracture toughness measured using single edge-notched tension (SENT) specimen in the clamped-end conditions for the strain-based design or fitness for service analysis of pipelines. Different SENT fracture test methods have been developed, including DNV, CANMET and ExxonMobil procedures in terms of the J-integral or crack tip opening displacement (CTOD). These efforts led to the first SENT test standard BS 8571 published.
However, these SENT methods may determine inconsistent test results on fracture toughness for the same specimen because no consensus is reached for any of the methods, and different estimate equations are used for an experimental evaluation. This paper aims to develop an improved SENT fracture toughness test method after a comparative study on the primary SENT fracture test methods. Comparisons are performed on available solutions of the stress intensity factor K, the geometrical eta factor, the elastic compliance inverse equation, and the m factor for converting the J-integral to CTOD that all were obtained for the clamped SENT specimens. Through comparisons, this work identified a set of more accurate solutions for the K factor, the eta factor, the compliance equation, the m factor, and those used for weld testing. The difference between the J-converted CTOD and double clip gage measured CTOD is also discussed. On these bases, an improved SENT test method is proposed for determining more reliable fracture toughness or resistance curves for ductile pipeline steels.
Integrity Management Considerations for Pipes in Peat Muskeg and Organic Rich Soils
Authors: Thurairajah Aran , Saad Bassam , Williams Randy , Fernando Viji , Seid-Karbasi Mahmood 
Published: December 2022

Abstract
Gas and oil transmission pipes unavoidably traverse areas with potentially compressible soils such as Peat or Muskeg. These soils are prone to excessive displacements as a result of natural hazards or man-made activities such as excavation, fill placement or equipment crossings. Excessive soil disturbance in areas with potentially unstable soil could result in compromising the integrity of the pipes.
This paper discusses the challenges related to design, construction, and operation of pipes in potentially compressible soils such as peat and organic soils in British Columbia. It provides mitigation measures to manage the pipe concerns related to these soils. Among the design challenges discussed are geotechnical characterization of potentially unstable soil sites and special pipe trench design and foundation alternatives to minimize pipe settlement and localized stresses. To demonstrate the impact of adjacent soil fill or embankment loading on pipe integrity, soil deformation finite element analyses are carried out for various scenarios representing different unstable soil profiles, surface loading configurations, and offsets from the pipe alignment. The paper also provides integrity management measures for managing potential concerns for pipe operating in organic soil and peat environment.