Boiling Research Articles

Detection of flow instability in natural circulation boiling water reactors using instantaneous spectral entropy measure

Natural Circulation Boiling Water Reactors (NCBWR) are vulnerable to thermal-hydraulic instabilities in coolant flow under certain operating conditions. Considering the strong coupling between neutronics and thermal hydraulics, monitoring of such instabilities is crucial for safe and reliable operation of NCBWRs. However, wider frequency range, significant non-stationarity and time-varying nature of flow oscillations makes this a challenging task. In this paper, we introduce a novel method using Instantaneous Spectral Entropy (ISE) to detect and evaluate flow instabilities. Key advantage of the method is its ability to clearly differentiate between random noise and oscillations. Comparison between Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT) for calculating entropy revealed that STFT provides superior results. Validation with operational data from a thermal hydraulic facility confirmed the method’s effectiveness in identifying and assessing time-varying flow instabilities.

Factors driving drinking water preferences among atlanta-area pediatric patients

Abstract Background. Global environmental pressures threaten water safety and security. Climate-driven extreme weather stresses water infrastructure and supply, including in US cities. Even when water sources are classified as safe, individuals, including those from historically marginalized communities, may distrust their in-home tap water. Consumption of bottled water further contributes to plastic waste and environmental harm. This pilot study aims to understand the drinking water preferences of patients at a safety net pediatric clinic in Atlanta, Georgia towards informing individual and systems-level water-related climate and health adaptation measures. Methods. Guardians of patients >28 days to <12 years were invited to participate during their child’s well visit. Participants were administered a survey on their family’s drinking water consumption preferences, the reasoning behind these choices, and their access to information on water safety. Descriptive statistics were used to analyze the results. Findings. Of 201 participants, 77% (155) drank only bottled water, 21% (42) drank tap and bottled water, and only 2% (4) drank exclusively tap water. The most selected reasons for exclusive bottled water consumption were: concern that tap is not clean or safe (74%, 114), taste (56%, 86), convenience (26%, 40), and water clarity (13%, 20). Sixty-seven percent of participants did not know how to access emergency alerts like boil water advisories. Conclusion. The overwhelming majority of families who obtain their healthcare at our clinic choose bottled water over tap water, and water safety concerns are the key factor driving this decision. Most patients lack access to real-time basic public health messaging on water advisories. These findings suggest an opportunity for clinicians to provide guidance on drinking-water in clinical encounters and for interdisciplinary partnerships to support clinicians in this climate adaptation measure.

HEAT TRANSFER ANALYSIS AND TURBULENCE MODELS INVESTIGATION OF NUCLEATE BOILING FLOW IN NUCLEAR REACTOR APPLICATION

Boiling water exhibits an exceptionally high heat transfer coefficient, making it a valuable tool across numerous applications. However, once the heat flux surpasses a certain elevated threshold, the heated surface can no longer sustain continuous liquid contact. This is associated with a significant decline in heat transfer efficiency. The result may be a sudden spike in surface temperature within a heat flux-controlled system, or a dramatic decrease in power transferred in a temperature-controlled system. In the present study, the heat flux has been investigated in a circular channel heated by two roads. Parameters with emphasis on water flow velocity correlated with different heat transfer values from the roads. The methodology contains both laboratory experiments and a simulation model. The obtained results indicate that different heating surfaces play an important role in boiling heat transfer. Also, there is a clear relationship between the water flow and surface temperature. The amount of absorbed temperature increases by about 13% in a flow of 0.45 m/s. while in the water flow velocity 0.89 m/s and 1.34 m/s vary to 16.3% and17% respectively. The other impressive result is the phenomenon of alternate water temperature values due to certain regional temperatures. It's observed that there is a difference in heat absorption based on the amount of heat flux from the surface. The general rate of heat flux in the system was 6736.557 W/1°C for each square meter of heat generation. The obtained information is useful in controlling the boiling water reactor from sudden shutdown and also in controlling the boundaries in the design phase.<p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/soc/0789/a.php" alt="Hit counter" /></p>

Discerning the effect of various irradiation modes on the corrosion of Zircaloy-4

Using proton irradiation, this study investigates the individual influence of several factors on the corrosion kinetics of Zircaloy-4 in a hydrogenated water environment simulating a Pressurized Water Reactor (PWR). Using both simultaneous irradiation-corrosion and autoclave corrosion, we separately examine (i) the effect of pre-irradiation on modifying the structure of the material, (ii) the impact of irradiation on creating defects in the growing oxide layer during corrosion, and (iii) the influence of irradiation on increasing the corrosion potential through radiolysis during corrosion. To replicate the neutron-irradiated microstructure, two proton pre-irradiation schedules were employed: Schedule 1 (isothermal irradiation at 350 °C to 5 dpa) to simulate high-temperature PWR conditions, and Schedule 2 (two-step process: irradiation to 2.5 dpa at -10 °C followed by 2.5 dpa at 350 °C) to simulate lower temperature PWR and Boiling Water Reactor (BWR) conditions. Long-term autoclave corrosion testing for 360 days at 320 °C revealed no significant difference between unirradiated samples and those pre-irradiated according to either schedule, with all samples exhibiting sub-cubic kinetics within the pre-transition regime. Pre-irradiated samples underwent Simultaneous Irradiation Corrosion (SIC) tests, corroding in 320 °C water while being irradiated with protons. Corrosion was found to accelerate in all SIC-tested samples relative to autoclave conditions, with the greatest increase observed in non-pre-irradiated regions of the samples. Pre-irradiation with either schedule resulted in a slower corrosion rate compared to non-pre-irradiated regions under SIC conditions. The degree of radiolysis observed in the SIC tests surpassed typical PWR conditions, approaching levels found in BWRs. Radiolysis products were identified as a primary contributors to accelerated corrosion, corroborated by radiolysis bar tests. These findings underscore the intricate interactions between irradiation, corrosion, and water chemistry in determining Zircaloy-4 corrosion kinetics within nuclear reactor environments.

Contribution of transient heat transfer to overpressure protection in a passive Boiling Water Reactor

The BWRX-300 reactor is a small modular reactor with 300 MW nominal electric power output. As the abbreviation indicates, the reactor is a boiling type reactor using water as the coolant. The main operating principle of the reactor model is the use of natural circulation of the coolant for both steady-state operation and emergency cooling of the reactor. Isolation Condenser Systems (ICS) have been used in early BWRs and were reintroduced in the 1990s to implement passive safety.Modern technologies enable effective simulation of objects of various complexity. In this study, the thermal-hydraulic system code TRACE v.5 is used to simulate BWRX-300 reactor plant operation. The software enables calculation of a system consisting of the reactor pressure vessel and ICS in both steady-state and transient operation.The ICS is an emergency cooling system borrowed from the previous generation of GE Hitachi BWRs, the ESBWRs, and it consists of a vertical tube bundle heat exchanger immersed in a water tank. Although this system design remains unchanged, its purpose is different. The BWRX-300 design completely eliminates safety and relief valves. This is why the ICS must perform both overpressure protection and long term heat dissipation functions.Three reactor plant operation states were simulated: normal operation with nominal parameters; reactor isolation; and the transient process into the cooling down mode by reactor shutdown and ICS activation. The results demonstrate that the ICS is capable to mitigate overpressure transients. Upon ICS startup, its metallic structures absorb heat well in excess of its nominal steady-state rating. Initial thermal inertia of the system is important for overpressure mitigation in transients.

Evaluating Boil Water Advisory Policies and Practices: Health Outcomes in Hong Kong

Boiling water (BW) is a common global practice, especially in Asia, for ensuring safe drinking water, though it does not remove chemical contaminants. The World Health Organisation recommends BW as an emergency measure against microbial contamination. In Hong Kong, the Water Supplies Department ensures water quality through strict regulations and extensive monitoring. Comparisons with Norway and Canada reveal effective practices such as water safety planning and risk-based advisories. Norway mandates water safety planning and uses messaging notifications for water advisories, ensuring high compliance, while Canada issues site-specific BW advisories based on risk assessments. Hong Kong faces unique challenges, such as a warm climate and complex building infrastructure, which impact water quality. Many buildings lack proper maintenance, leading to potential health risks and necessitating regular maintenance. Health management, public health education and expert guidance are essential for promoting efficient practices and ensuring safe drinking water.

Mechanistic prediction of Westinghouse TRITON11® BWR fuel critical power with MEFISTO-T subchannel analysis code

The TRITON11® fuel design is the latest Boiling Water Reactor (BWR) fuel product developed by Westinghouse, based on an 11 × 11 optimized fuel rod lattice, including mixing vane spacer grids, three large water rods and 18 part-length rods. The design offers larger fuel cycle cost saving, improved fuel reliability and increased thermal margin over previous Westinghouse fuel products. The critical power performances of the TRITON11 fuel design were assessed at the Westinghouse thermal–hydraulic FRIGG loop using a full-scale test bundle covering a wide range of BWR core conditions (covering normal operation and Anticipated Operational Occurrences) with various radial and two axial power distributions. The resulting FRIGG steady state database was simulated with Westinghouse subchannel analysis code MEFISTO-T based on a two-phase three-field approach of annular two-phase flow, accounting for the drop deposition enhancement provided by the spacer grids. A new model of local film entrainment was introduced due to the liquid “scrapping off” effects provided by the frame and side vanes of the spacer grids along the fuel channel and water rods. After spacer grid effect calibration, the steady state critical power is simulated mechanistically by power iterations up to complete local film dryout. The MEFISTO-T code can successfully predict the critical power performance of the Westinghouse TRITON11 BWR fuel design, including on part-length rods, with almost no bias and trend, within a standard deviation of about 5 %.

Applying Gaussian Process Regression for Machine Learning-Assisted Reactor Simulations

Abstract This study explores the integration of machine learning, specifically Gaussian Process Regression (GPR), into traditional reactor core simulations. Building upon previous work on Boiling Water Reactors (BWR), GPR is implemented to predict and correct errors in lower-fidelity simulation outcomes. The findings demonstrate significant improvements in prediction accuracy when GPR is coupled with the diffusion-based core simulator, exhibiting remarkable reductions in both keff and nodal power errors. The comparison reveals that the GPR-enhanced core simulation model significantly outperforms both the standalone simulation and a combination of simulation with Multivariate Linear Regression. It also competes effectively with the performance of a Deep Neural Network-enhanced model. Importantly, this methodology enhances simulation accuracy while maintaining low computational costs. The research emphasizes the vast potential of machine learning, particularly GPR, in progressing nuclear reactor simulations, highlighting the immense value of combining traditional simulation methods with advanced statistical learning techniques.

Euler–Euler modeling of turbulent annular regime

Euler–Euler methods are one of the many approaches available in literature for modeling droplet-laden flows. These models consider both the gas and droplet phases as inter-penetrating continua, thereby separate sets of transport equations are solved for these phases. The current work focuses on modeling of thin liquid films on solid surfaces in the context of the two-fluid approach to multiphase simulation. In majority of the literature, liquid films are modeled using a 2D Laminar approximation with a parabolic profile for the velocity across the film. However, a number of industrial applications demonstrate a turbulent behavior of the film which would affect the effective viscosity and thereby the thickness of the film. In the current work, a turbulent model for liquid films is proposed based on the Universal Velocity Profile. Additional models are employed to capture the deposition of droplets onto solid surface and stripping off of droplets from the film due to surface waves. The liquid film model is validated on experimental data from available literature. Finally, the newly implemented turbulent film model is applied to study the flow over a fuel rod assembly in a Boiling Water Reactor.

Influence of thermal processing on sensory profile of crayfish meat

The present study examined the outcomes of boiling (BO), air frying (AF), and boiling combined with air frying (BO-AF) methods on the appearance, texture, taste, and flavor of crayfish meat through a combination of sensory and instrumental analyses. The Free Choice Profiling and Check-All-That-Apply results showed that the BO-AF group had the highest overall acceptability. The BO-AF group presented an attractive golden color, crispy outside, and tender inside characteristics in appearance and texture. However, there was a loss of umami and sweetness in crayfish meat from the AF and BO-AF groups compared to the control (CK) and BO groups. Crayfish meat was identified as containing 42 volatile compounds. Among them, aldehydes and heterocyclic compounds were the main volatile compounds in the AF and BO-AF groups. In particular, the pyrazine compounds were produced by the thermal decomposition of methionine and cysteine. They gave the crayfish meat of the AF and BO-AF groups their characteristic roasted aroma and good color. However, compared to the AF group, the BO-AF group had the characteristic baking aroma of the AF group, as well as a floral and fruity aroma due to the presence of the boiling treatment.

Effect of cooking methods on flavor profiles of Xuanwei Ham: Analytical insights into aromatic composition and sensory attributes

To examine flavor variations in Xuanwei ham due to different cooking methods, we selected one-year cured Xuanwei ham and applied four techniques: dry frying (DF), baking (BA), steaming (ST), and boiling (BO). Organoleptic evaluation revealed ST received the highest overall sensory score. High-performance liquid chromatography (HPLC) revealed that the total nucleotide content was significantly different (P < 0.05), lactic acid predominated the measured organic acids. Solid-phase microextraction-gas chromatography–mass spectrometry (SPME-GC–MS) and chromatography-electronic nose (GC-E-Nose) data indicated that ST resulting in significantly higher total volatile compounds than the other methods (P < 0.05). SPME-GC–MS detected 55 volatile compounds, and 12 characteristic flavor substances were identified using orthogonal partial least squares discriminant analysis (OPLS-DA) (VIP > 1). This study aimed to support comprehensive research on the flavor characteristics of cooked Xuanwei ham and guide the selection of appropriate processing methods.

GARDENING THERAPY WITH BOILED WATER, ICE CUBES, CHEWING GUM REDUCES THIRST IN CKD PATIENTS: LITERATURE REVIEW

Chronic kidney failure occurs due to a failure in the body's ability to maintain metabolism and fluid and electrolyte balance resulting in uremia or retention of urea and other nitrogenous waste in the blood. The research aims to synthesize literature about gargling therapy with boiled water, ice cube therapy, and chewing gum to reduce thirst in CKD patients. The method used is content analysis with a literature search from 2020 to 2023 using the keywords Ice Cubes, gargling, chewing gum, CKD To reduce thirst by using ice there were 6 journals, 4 journals using chewing gum, and 1 journal using boiled water. All articles show that there is an effect of gargling therapy with boiled water, ice cube therapy, and chewing gum to reduce thirst in CKD patients. The literature study shows that the use of ice cubes has the most effect on reducing thirst in CKD patients, however, gargling therapy with boiled water and chewing gum are other alternatives.

CFD simulation of thermal stratification and mixing in a Nordic BWR pressure suppression pool

Boiling Water Reactor (BWR) employs the Pressure Suppression Pool (PSP) as a heat sink to prevent overpressure of the reactor vessel and containment. Steam can be injected into the PSP through spargers in normal and accident conditions and through blowdown pipes in case of a loss of coolant accident (LOCA). There is a safety limit on the maximum PSP temperature at which such steam injection might cause dynamic loads on the containment structures. The performance of the pool can be affected if thermal stratification is developed when temperature of the hot layer grows rapidly while cold layer remains inactive. Simulation of pool behavior during realistic accident scenarios requires validated models that can sufficiently address the interaction between phenomena, safety systems and operational procedures. Direct modeling of steam injection into a water pool in long-term transients is computationally expensive due to the need to resolve simultaneously the smallest space and time scales of individual steam bubbles and the scales of the whole PSP. To enable PSP analysis for practical purposes, Effective Heat source and Effective Momentum source (EHS/EMS) models have been proposed that avoid the need to resolve steam-water interface. This paper aims to implement mechanistic approaches previously developed by authors for the simulation of transient thermal stratification and mixing phenomena induced by steam injection through spargers in a Nordic BWR PSP. The latest version of the EHS/EMS models using the ‘Unit cell’ approach has been validated against integral effect pool tests and applied to plant simulations. Several scenarios with boundary conditions corresponding to postulated accident sequences were simulated to investigate the possibility of stratification development and the effects of activation of different systems (e.g., blowdown pipes, high momentum nozzle) on the pool behavior.

Physical and Chemical Changes of Seven Selected Herbs Used as Herbal Bath Affected by Different Drying Methods

The effect of oven drying (OD) at 50±5°C, sun drying (SD), and fresh leaves (control) of seven selected herbs used in herbal preparation as herbal baths were evaluated. Herbal baths (HB) involve mixing herbs into water and boiling them or simply immersing them in the mixture during a regular bath. The herbs selected were leaves of torch ginger, greater galangal, pandan, citronella grass, henna, betel leaves, and kaffir lime leaves and fruits. The herbs were planted in a plot at the Institute of Bioscience, Universiti Putra Malaysia, Malaysia. Physical changes such as HB herbs’ colour, aroma, and chemical composition were evaluated. The hydro distillation method was used for the extraction process of HB herbs, where it produced essential oils (EO), essential water (EW), and boiling water (BW), and their chemical composition was determined by gas chromatography-mass spectrometry. As a result, the OD herbs possessed brighter and more attractive colours compared to the SD method, which was dull and pale. The colour of EO was yellow, colourless for EW, and reddish for BW. Additionally, OD herbs possessed 80% and only 50% of the scent strength of the SD herbs from extracting fresh herbs. The fresh and dried HB herbs contained chemical constituents mostly from the terpene group. Herbal preparation developed using all treatments retained an appreciable amount of chemical composition studied, thus having the potential for commercial purposes.

Neutronics–Thermal-Hydraulics–Coupled Transient Analysis for Reactor Power Change in an Inclined Offshore Floating Boiling Water Reactor

An application of the boiling water reactor (BWR) to an offshore floating nuclear power plant (OFNP) in Japan is discussed. The BWR-type OFNP has some challenges for practical use, although it has high economic efficiency because of downsizing and simplification. One challenge is understanding reactor kinetics under conditions specific to the marine environment. This study quantitatively clarifies the total and spatial changes in power when the BWR is inclined during regular operation. Therefore, the TRACE (TRAC/RELAP Advanced Computational Engine) and PARCS (Purdue Advanced Reactor Core Simulator) codes were used to perform a three-dimensional neutronics–thermal-hydraulics–coupled transient analysis. The calculation model is based on Peach Bottom II. This study clarifies the changing trend in total and local BWR power by inclination with simplified modeling and conditions. The reasons for such changes are discussed based on changes in several thermal-hydraulic parameters. The difference in BWR power against the inclinations is small. Thus, it is implied that the BWR-type OFNP is expected to have a stable power supply capability during natural disasters. However, to confirm the power stability of the BWR reactor under a full range of offshore external conditions, further research is required. A description of additional research needs that would further support the safety case for this reactor design are discussed.

Momentum induced by steam injection into a subcooled pool

Boiling Water Reactors (BWR) and Advanced Pressurized Water Reactors (APWR) often use spargers to release steam from the primary coolant system into a pool with subcooled water to prevent containment overpressure. Direct contact Condensation (DCC) creates sources of mass, heat, and momentum determined by the condensation regimes in a subcooled pool. Thermal stratification can develop in the pool if buoyancy forces created by the heat source dominate the momentum source. Only part of the stratified pool volume can be used as the heat sink which is a safety concern. Modeling of steam injection and its effect on a large pool is computationally expensive due to the considerable spatial and temporal scale differences between the steam-water interface dynamics and global pool circulation. To enable the prediction of realistic plant transients, Effective Heat Source (EHS) and Effective Momentum Source (EMS) models were proposed. These models aim to calculate the time-averaged integral effects of the steam injection on the pool without resolving the dynamics of the interface and DCC phenomena.This work aims to develop the empirical correlations that predict the time-averaged effective momentum induced by steam injection into a subcooled pool. The experimental data were collected in a Separate Effect Facility (SEF-POOL) at LUT, Finland. The force acting on the injection pipe was measured in SEF-POOL to estimate the effective momentum rate created by steam injection. The condensation regime coefficient C, defined as the ratio of effective momentum rate to the theoretical momentum rate of injected steam, is presented as a function of Jakob and Mach numbers. We found that the pitch-to-diameter ratios (P/D) had a significant effect on both the effective (time averaged) momentum rate and instantaneous forces measured in the low Jakob number region, which might be attributed to the interactions between neighboring nozzles.

Influence of the Boiling Water Extraction Technique on the Chemical, Physical, Thermal, and Mechanical Properties of the Midrib of Cavendish Variety Banana Plant Leaves from Cameroon

Our study described in this paper sought to show that the fibers of the midrib of the leaves of cavendish variety banana plants from Cameroon can be extracted by boiling water and to compare their properties (chemical, physical, thermal, and mechanical) with those obtained by cold water extraction. The standard tests for the various characterizations were respected. This study showed that the fibers extracted with boiling water contained 64.3% cellulose, 18.1% hemicellulose, 4.5% lignin, and 12.9% pectin, while the fibers extracted by the cold water technique contained 65% cellulose, 19% hemicellulose, 5% lignin, and 11% pectin. The extraction of fibers by the boiling water technique gave a 9.35% extraction yield, 0.94 g.cm−3 density, 15.23 tex linear mass, 11.10% water content, 169.78% water absorption degree, and 36.02% humidity at a relative humidity of 75%, while the fibers extracted by the cold water technique had a 12.35% extraction yield, 0.91 g.cm−3 density, 14.23 tex linear mass, 10.73% water content, 102.4% water absorption degree, and 34.45% humidity at a relative humidity of 75%. The boiling water extracted fibers had a thermal stability temperature of 268.5 °C. The student’s t-test showed that the fibers obtained by the boiling water extraction technique and the cold water extraction technique had identical mechanical properties. Thus, we suggest that the fibers of the midrib of the leaves of banana plants can be extracted with boiling water and used in textiles and composite materials.

Flavor Characteristics of Crab Boiled Water Powder with the Addition of Magnesium Oxide (MgO) as an Anti-Caking Agent

Flavor Characteristics of Crab Boiled Water Powder with the Addition of Magnesium Oxide (MgO) as an Anti-Caking Agent

Medicinal and Aromatic Weed Diversity in Botanic Garden and their Sustainable Utilisation for Conservation

Total 81 weeds belonging to 59 genera and 31 families growing in the University botanic garden at Sagar were found medicinally important. Various parts of all the weeds have been analyzed for their medicinal utility. Out of 81 weeds, leaves of 64 plants are found useful for various disorders. This is followed by root of 25 plants which are medicinally important. Disease wise analysis has also been carried out. Analysis reveals that for cut, wounds, boils and burns about 29 weed plants are used, whereas 21 weed species each are used for asthma and skin diseases.

Ethnomedicinal Plants of Betul District, Madhya Pradesh

The paper deals with ethnomedicinal information on 54 plant species (belonging to 33 families) collected from field survey amongst three tribes viz., Gond, Korku and Gaiki of Betul district, Madhya Pradesh. An analysis of data has indicated that eight plant species are employed as antidote to snake bite and scorpion sting, six to treat fever. five for rheumatism, four to treat cold, cough, skin diseases, as anthelmintic and tonic, and three for stomach diseases while two species to treat impotency, cuts, wounds and as diuretic. On the other hand, only single species has been referred for a number of other ailments like eye diseases, spermatorrhoea, spleen enlargement, tuberculosis, mouth sore, boil, asthma, liver disorder, toothache, bone fracture, abortifacient, antifertility, and in veterinary. Further, a comparison with the concerned literature has revealed that 23 ethnomedicinal uses of plants have not been reported earlier.