Hydraulic Modeling of Air-Entraining Vortex Formation During Flow Withdrawal From Water Storage Tanks

2009 ◽  
Author(s):  
Andrew Johansson ◽  
Mahadevan Padmanabhan ◽  
Stuart Cain ◽  
Bryan Meyer ◽  
David Schowalter
Keyword(s):  
Nuclear Power ◽  
Vortex Formation ◽  
Water Storage ◽  
Air Entrainment ◽  
Hydraulic Modeling ◽  
Water Levels ◽  
Scale Model ◽  
Return Flow ◽  
Storage Tanks ◽  
Water Storage Tank

In response to recent U.S. Nuclear Regulatory Commission (NRC) Component Design Bases Inspection (CBDI) issues, many US nuclear power stations have been required to demonstrate that minimum submergence requirements were properly determined for flow withdrawal from various safety related storage tanks. In many cases, the licensees failed to consider a vortex allowance, or applied an inappropriate vortex methodology. For Duke Energy’s McGuire Station, a Refueling Water Storage Tank (RWST) model was constructed using a geometric scale of 1:4.073. Testing included transient water level conditions simulating the field for selected flows (corresponding to prototype flows of 1,600 to 19,700 gpm) and water levels giving submergences of 1 to 5 ft above the suction nozzle in the model (prototype submergences of 4 to 20.3 ft). Results showed that with no return flow, the submergence at the onset of air entrainment ranged from 0.049 to 0.705 ft prototype for flows ranging from 1,600 to 19,700 gpm prototype, respectively. Based on the test results, it was determined that a vortex suppression device was not required for the McGuire RWST, as the expected water levels during operation would be higher than those indicated for onset of air entrainment for a given flow. The scale model testing showed that the critical submergences for initiation of air-entraining vortices were much lower than those predicted by Hydraulic Institute guidelines.

scholarly journals The effect of household storage tanks/vessels and user practices on the quality of water: a systematic review of literature

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Musa Manga ◽  
Timothy G. Ngobi ◽  
Lawrence Okeny ◽  
Pamela Acheng ◽  
Hidaya Namakula ◽  
...  
Keyword(s):  
Systematic Review ◽  
Water Quality ◽  
Storage Tank ◽  
Grey Literature ◽  
Water Storage ◽  
Storage Tanks ◽  
Water Storage Tank ◽  
Hygiene Practices ◽  
Quality Of Water ◽  
Vessel Material

Abstract Background Household water storage remains a necessity in many communities worldwide, especially in the developing countries. Water storage often using tanks/vessels is envisaged to be a source of water contamination, along with related user practices. Several studies have investigated this phenomenon, albeit in isolation. This study aimed at developing a systematic review, focusing on the impacts of water storage tank/vessel features and user practices on water quality. Methods Database searches for relevant peer-reviewed papers and grey literature were done. A systematic criterion was set for the selection of publications and after scrutinizing 1106 records, 24 were selected. These were further subjected to a quality appraisal, and data was extracted from them to complete the review. Results and discussion Microbiological and physicochemical parameters were the basis for measuring water quality in storage tanks or vessels. Water storage tank/vessel material and retention time had the highest effect on stored water quality along with age, colour, design, and location. Water storage tank/vessel cleaning and hygiene practices like tank/vessel covering were the user practices most investigated by researchers in the literature reviewed and they were seen to have an impact on stored water quality. Conclusions There is evidence in the literature that storage tanks/vessels, and user practices affect water quality. Little is known about the optimal tank/vessel cleaning frequency to ensure safe drinking water quality. More research is required to conclusively determine the best matrix of tank/vessel features and user practices to ensure good water quality.

Seismic Response of a Cylindrical Water Storage Tank of Nuclear Power Plant

2018 ◽  
Author(s):  
Shinichi Matsuura ◽  
Ichiro Tamura
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Storage Tank ◽  
Nuclear Power ◽  
Water Storage ◽  
Response Behavior ◽  
Water Storage Tank ◽  
Elastic Plastic ◽  
Seismic Motion ◽  
Side Shell

It is important in the confirmation of the safety of the nuclear power plant to clarify the response behavior of a vertical cylindrical water storage tank under seismic motion. When a vertical cylindrical tank is shaken by a large earthquake, deformation of side shell due to the elephant foot buckling, the oval vibration etc. may occur. The occurrence of those deformations depends on materials, shapes, stored water level and time history of seismic motion. Then, response behavior was obtained for a condensate storage tank (CST) model under large seismic motion such as standard earthquake Ss multiplied by 2 with the elastic-plastic finite element calculation. In this calculation, dynamic water pressure and elastic-plastic characteristics of the material were taken into account. In this case, the elephant foot bulge did not occur but the oval vibration of side shell became dominant. Based on the result, we estimated the structural integrity of the tank.

scholarly journals AP1000 Shield Building Dynamic Response for Different Water Levels of PCCWST Subjected to Seismic Loading considering FSI

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Daogang Lu ◽  
Yu Liu ◽  
Xiaojia Zeng
Keyword(s):  
Storage Tank ◽  
Seismic Analysis ◽  
Cooling System ◽  
Water Storage ◽  
Seismic Loading ◽  
Water Levels ◽  
Von Mises Stress ◽  
Fe Model ◽  
Water Storage Tank ◽  
Von Mises

Huge water storage tank on the top of many buildings may affect the safety of the structure caused by fluid-structure interaction (FSI) under the earthquake. AP1000 passive containment cooling system water storage tank (PCCWST) placed at the top of shield building is a key component to ensure the safety of nuclear facilities. Under seismic loading, water will impact the wall of PCCWST, which may pose a threat to the integrity of the shield building. In the present study, an FE model of AP1000 shield building is built for the modal and transient seismic analysis considering the FSI. Six different water levels in PCCWST were discussed by comparing the modal frequency, seismic acceleration response, and von Mises stress distribution. The results show the maximum von Mises stress emerges at the joint of shield building roof and water around the air inlet. However, the maximum von Mises stress is below the yield strength of reinforced concrete. The results may provide a reference for design of the AP1000 and CAP1400 in the future.

Analysis of Flowing Characteristics in IRWST Under Pressure Relief Condition

2013 ◽  
Author(s):  
Mengchao Zhang ◽  
Xiangbin Li ◽  
Xiaolu Fang ◽  
Yuhao Zhang
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Storage Tank ◽  
Nuclear Power ◽  
Water Storage ◽  
Heat Transfer Mechanism ◽  
Heat Transfer Characteristics ◽  
Pressure Relief ◽  
Water Storage Tank ◽  
Thermal Changes

The presurizer is one of main equipments of PWR Nuclear Power Plant. The heat transfer mechanism will change with temperature’s increasing when the steam with high temperature and high pressure condensates as it sprays into the in-containment refueling water storage tank (IRWST), which will be detrimental to the safety of the reactor. In this study, the flow field and heat transfer characteristics are simulated by means of professional CFD software with k-ε turbulence model and Particle modle when the steam sprays into IRWST through the sprayer. The results show thermal changes of water and steam.

Carbon Fiber Reinforcement of a Water Storage Tank for Beyond Design Basis Loads

2016 ◽  
Author(s):  
Alton Reich ◽  
John Charest
Keyword(s):  
Carbon Fiber ◽  
Storage Tank ◽  
Nuclear Power ◽  
Power Plants ◽  
Water Storage ◽  
Safety Margin ◽  
Repair System ◽  
Buckling Mode ◽  
Water Storage Tank ◽  
Design Basis

The severe damage to the Fukushima nuclear plant occurred as a result of a beyond design basis event. This has prompted a systematic review of safety critical systems at US nuclear power plants to evaluate the existing safety margin based on beyond design basis loads. At one US nuclear power plant it was found that the Refueling Water Storage Tank (RWST) did not have sufficient margin to withstand the defined beyond design basis seismic event. An analysis indicated that the RWST would fail in an elephant foot buckling mode. This paper describes the design and analysis of a Carbon Fiber Reinforced Polymer (CFRP) repair system used to strengthen the RWST to increase the critical buckling stress for the elephant foot buckling mode.

Study of Correlation Between Beam Vibration and Oval Vibration on Cylindrical Water Storage Tank

2005 ◽  
Author(s):  
Akira Maekawa ◽  
Yasutaka Shimizu ◽  
Michiaki Suzuki ◽  
Katsuhisa Fujita
Keyword(s):  
Natural Frequency ◽  
Large Amplitude ◽  
Storage Tank ◽  
Excitation Frequency ◽  
Water Storage ◽  
Scale Model ◽  
Vibration Test ◽  
Large Radius ◽  
Water Storage Tank ◽  
Test Tank

A large cylindrical water storage tank, widely used at power stations and chemical plants, typically has a large radius/wall-thickness ratio. The relatively thin sidewall of such a tank can deform easily during an earthquake due to vibrations of the tank structure. In order to improve the seismic-proof design practices for a water storage tank of flexible structure and to develop a new seismic resistance evaluation method to be adopted in future, it is important to understand the dynamic responses of such a tank to seismic motions including the nonlinearity of responses to large amplitude vibrations. This paper reports on the results of vibration test, in which sinusoidal wave excitations with large amplitude were conduced to the scale model tank of a thin-walled cylindrical water storage tank, and the theoretical analysis of the dynamics of the vibratory behaviors that were observed during the vibration test. First, a frequency sweep test was performed over the range that covered the natural frequency. The response of the test tank as a whole to given vibrations remained almost the same over the excitation frequency range. Frequency analysis of the response of the tank failed to locate any resonance points at or around frequencies that had been determined by the basic vibration characteristic test that we had conducted in advance. Next, a large amplitude excitation tests were carried out, in which the test tank was excited intensively by several tens of sinusoidal waves of a fixed frequency that was in the vicinity of the resonant frequency. The response of the tank as a whole in the form of beam vibrations did not intensify in proportion to the input acceleration; it did not go beyond a certain level. Since both of the tests produced significant oval vibrations on the sidewall of tank, the influence of oval vibrations over beam vibrations was analyzed. The analysis concerning the deflection of the sidewall of tank by the additional appearance of oval vibrations in the presence of beam vibrations revealed that a major decrease in the flexural rigidity reduced the response (beam vibrations) of the whole tank. The phenomenon was modeled using a nonlinear equation of motion, assumed that the rigidity depended on the amplitude of oval vibrations. The analysis using this equation explained the results of the above-mentioned tests very well. Thus, it was demonstrated both empirically and analytically that beam vibrations of a cylindrical water storage tank are reduced by the appearance of oval vibrations that have the effect of lowering the natural frequency.

The Effect of Obstacle Geometry and Position on Thermal Stratification in Solar Hot Water Storage Tanks

2008 ◽  
Author(s):  
Necdet Altuntop ◽  
Veysel Ozceyhan ◽  
Yusuf Tekin ◽  
Sibel Gunes
Keyword(s):  
Storage Tank ◽  
Thermal Stratification ◽  
Water Storage ◽  
Hot Water ◽  
Storage Tanks ◽  
Domestic Hot Water ◽  
Water Storage Tank ◽  
Temperature Distributions ◽  
Solar Powered ◽  
Obstacle Geometry

In this study the effect of obstacle geometry and its position on thermal stratification in solar powered domestic hot water storage tanks are numerically investigated. The goal of this study is to obtain higher thermal stratification and supply hot water for usage as long as possible. The temperature distributions are presented for three different obstacle geometries (1, 2 and 3) and six different distances (f = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 mm) from the bottom of the hot water storage tank. The numerical method is validated using both experimental and numerical results available in the literature. It is observed from the results that the thermal stratification increases with the increasing obstacle distance from the bottom of the hot water storage tank for obstacle 1 and 3. The obstacle 2 provides less thermal stratification than the obstacles 1 and 3. As a result, in a duration of 30 minutes, the obstacle 3 provides the best thermal stratification for the distance of f = 0.8 mm from the bottom of the hot water storage tank.

Design of In-Containment Refueling Water Storage Tank of Chinese 3rd Generation Nuclear Power Plant

2017 ◽  
Author(s):  
Liu Yulin ◽  
Sun Xiaoying
Keyword(s):  
Storage Tank ◽  
Nuclear Power ◽  
Power Plants ◽  
Water Storage ◽  
Stability Evaluation ◽  
Water Storage Tank ◽  
Structure Interaction ◽  
Structural Calculation ◽  
Structure Strength ◽  
The Stability

In this paper, the structure configurations of the in-containment refueling water storage tank (IRWST) of Chinese 3rd generation nuclear power plants (NPPs) was described firstly. Then, the general structural calculation for several loads, especially thermal load, were presented, as well as the stability evaluation of IRWST base-slab. The effect from fluid-structure interaction was also considered in the calculation to evaluate the design margin of IRWST. Finally, structure strength evaluation was performed for construction load case.

Decoupling Method of Sloshing Water in PCCWST of Large-Scale Advanced Passive PWR Nuclear Power Plant

2017 ◽  
Author(s):  
Boyu Han ◽  
Fang Yuan ◽  
Zufeng Xia ◽  
Honghui Ge ◽  
Shenghua Liu ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Large Scale ◽  
Seismic Analysis ◽  
Water Storage ◽  
Cooling Water ◽  
Fluid Element ◽  
Decoupling Method ◽  
Simplified Approach ◽  
Water Storage Tank ◽  
The One

Modeling water in passive containment cooling water storage tank (PCCWST) using fluid element will result in large amount of calculation when conducting seismic analysis of shield building or NI. Thus, it is necessary to simplify the modal of water so as to reduce the difficulty of seismic analysis under condition that the error is slight enough to be ignored. By formula deduction and analysis, on the one hand, this paper proofs that modeling “sloshing mass” as fixed mass on structure is unreasonable. On the other hand, this paper proposes that the reasonable simplified approach is to decouple “sloshing mass” totally from the structure system. Furthermore, conditions of utilizing decoupling method are illustrated.

Earthquake Resistance Assessment of Contaminated Water Storage Tank and its Reinforcement Basic Design at Fukushima

2017 ◽  
Author(s):  
Haruo Morishige ◽  
Katsuhisa Fujita ◽  
Yousuke Yamashiki
Keyword(s):  
Water Storage ◽  
Great East Japan Earthquake ◽  
Great Earthquake ◽  
Contaminated Water ◽  
Vertical Acceleration ◽  
Storage Tanks ◽  
Side Plate ◽  
Design Guideline ◽  
Water Storage Tank ◽  
Fukushima Daiichi

The core melt accidents at Fukushima Daiichi Units 1-2-3 have occurred due to the tsunami of the Great East Japan Earthquake at March 11, 2011. Now a coolant of approximately 100t is injected into each Reactor Vessel (RPV) in order to cool the fuel debris, and a part of the coolant leaks out from the water. The contaminated water is collected, and it is stored in the contaminated water storage tanks more than approximately 1,000 and the total amounts of coolant exceeds 1,000,000 t. Although the contaminated water is purified by ALPS, it is still in high nuclear pollution density. According to the homepage of Nuclear Regulation Authority (NRA) in Japan, the storage tanks have been placed on the concrete bed without any anchor. Tokyo Electric Company (TEPCO) reported to NRA in 2015 that the design acceleration used for the overturning evaluation of the tanks have 0.3G. At the Fukushima Daiichi Power Station in the Great East Japan Earthquake, the maximum horizontal acceleration was 0.6G, the maximum vertical acceleration was 0.326 G at the time of the Great East Japan Earthquake. Even if an earthquake that is a fraction of this earthquake comes back, there is a possibility that this tank will fall over. The temporary special design guideline is adopted. These tanks have already stored the contaminated water for 6 years. However, it is thought that the more long term countermeasures is necessary for preventing the contaminated water from flowing out into the Pacific Ocean when another great earthquake will attack this area in future. In this paper, we propose a drastic structure to add a foundation without causing ground to the present tank. In the past, the member fastening the steel plate of the upper structure of the tank and the concrete of the lower structure is a foundation bolt, but this time it is a stud welded to the tank side plate. This made it possible to flexibly design and reinforce the foundation itself even after tank installation.

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