Spray Ponds Research Articles

THERMOGRAPHIC MONITORING OF NUCLEAR POWER PLANT’S SPRAY PONDS USING INFRA-RED DATA PROCESSING METHODS

This paper outlines an approach to monitor nuclear power plant spray ponds using thermographic monitoring. The approach involves measuring temperatures during summer and winter periods to identify potentially dangerous or fault-prone areas and improve the reliability of technical water supply. The automated machine processing procedure for thermograms was developed based on digital image processing. The results demonstrate that the obtained database can effectively help determine losses resulting from critical situations at nuclear power plants.

The Oriented Spray Cooling System for Heat Rejection and Evaporation

Abstract Spray ponds offer significant advantages over mechanical draft cooling towers (MDCTs) including superior simplicity and operability, lower preferred power requirements, and lower capital and maintenance costs. Unlike a conventional spray pond in which spray nozzles are arranged in a flat bed and water is sprayed upward, the oriented spray cooling system (OSCS) is an evolutionary spray pond design in which nozzles are mounted on spray trees arranged in a circle and are tilted at an angle oriented toward the center of the circle. As a result, each nozzle is exposed to essentially ambient air as water droplets drag air into the spray region while the warm air concentrated in the center of the circle rises. Both of these effects work together to increase air flow through the spray region. Increased air flow reduces the local wet-bulb temperature of the air in the spray pattern, promoting heat transfer and more efficient cooling. The authors have developed analytical models to predict the thermal performance of the OSCS that are based on classical heat and mass transfer and kinetic vector relationships for spherical water droplets that rely only on generic experimental thermal performance data. Therefore, the model is not limited in application with regard to spray pressure or nozzle spacing or orientation and is not limited by droplet size considerations. This paper describes specific details such as nozzle type, orientation, and drop spectrum and details on the analytical model never before published that are used to predict the OSCS performance. The paper compares the predicted performance of the OSCS with the rigorous full-scale field test results that were measured in compliance with Nuclear Regulatory Commission requirements at the Columbia Generating Station where the ultimate heat sink (UHS) is two OSCS.

Conservative Tritium Exposure Assessment in the Atmosphere from the Spray Ponds of the Balakovo NPP

Atmospheric tritium discharges from nuclear power plants (NPPs) may have a significant impact on the population and should be constrained by radiation safety requirements. In this study we show that the spray ponds used for water cooling in some Russian NPPs are liable to state registration and regulation in accordance with national legislation. A comparison of possible conservative approaches to assess the intensity of tritium releases from the spray ponds was carried out using the example of the Balakovo NPP. Estimates of the evaporated water amount varied from 35 000 to 60 000 m3 over the 82-day period of stable snow cover in 2016–2017. These estimates corresponded to the total tritium activity discharged into the atmosphere during the evaporation from all spray ponds in the range from 5.2 × 1011 to 9.7 × 1011 Bq. The power of the source was from 7.4 × 104 to 1.4 × 105 Bq/s according to the thermodynamic and thermophysical approaches, respectively. The results of the investigation confirm the assumption that the spray ponds of the Balakovo NPP are a standardized source of tritium releases and should be constrained by setting airborne discharge limits.

Влияние коэффициента проницаемости решетчатых сопротивлений на формирование аэродинамической тени над брызгальными басейнами

Влияние коэффициента проницаемости решетчатых сопротивлений на формирование аэродинамической тени над брызгальными басейнами

Alternative heat rejection methods for power plants

Process waste heat in large power generation plants is commonly rejected to lakes or rivers, or through the use of cooling towers. Although these waste heat rejection methods are effective, they may not be feasible in every application due to cost considerations or geographic location. Moreover, it is desirable to put some of the waste heat to good use, both from the standpoint of improved plant efficiency as well as reduced environmental impact. An analysis of alternative methods of power plant waste heat rejection is presented here as applied to a coal-fired power generation facility in the Midwestern United States. Five approaches for rejecting or recovering the waste heat are considered: cooling canals, open-water algae bioreactors, wintertime greenhouse heating, spray ponds, and modified solar updraft towers. Each of the five technologies can be sized for the needs and operating conditions of a given power plant. The quantitative analysis tools developed in this work are validated by benchmarking against published results. Three of the alternative methods generate secondary benefits: the algae bioreactor, greenhouse heating, and the modified solar updraft tower produce biodiesel, extended periods for horticulture, and electric power, respectively. The land area required to reject 1.16 GW of heat (the condenser heat rejection from a 500 MW plant operating at 30% thermal efficiency) using each of the alternative technologies is compared. The sensitivity of the sizing of the different technologies to changes in the environmental and geometric parameters is quantified. Finally, the net water use for each technology is estimated and compared against a typical cooling tower solution for the same 500 MW plant.

Industrial water supply for the Kursk TÉTs-1 heating and electric power plant with the ecological safety of the River Seim taken into account

The Kursk TETs-1 heating and electric power plant is discussed as an illustration of preventing thermal contamination of its water supply (River Seim) by circulating water. An effective water supply system is taken to be one for which the overheating of the water at a monitoring site (near the outlet location) does not exceed an approved level for the water use conditions. The required cooling capacity of a spray pond for circulating and flow-through water supplies is determined.

Transport of radioactive droplet moisture from a source in a nuclear power plant spray pond

Transport of radioactive droplet moisture from a source in a nuclear power plant spray pond

Performance Model for Ultimate Heat Spray Ponds

A mathematical model for the performance of spray ponds is developed using a detailed computational approach. The model considers heat transfer and evaporation from individual droplets of sprayed water and the pond surface, and drift loss from the sprays. Modification of the temperature and humidity of the surrounding air is taken into account in calculating heat and mass transport from the sprays. Flow of air through the spray field is considered to be either driven by the ambient wind, or by natural convection. Relationships for heat and mass transfer from the drops are derived from the empirical studies of Ranz and Marshall. Numerical experiments demonstrate that simplified models can still be useful for spray pond performance assessments. The models are validated with data on several industrial and nuclear power plant spray ponds, and with data from an extensively instrumented, experimental spray pond. Results of the validation studies demonstrate generally good agreement. These models are used in a complex methodology for predicting the performance of spray ponds used for nuclear power plant service, although it is not limited to this application. A companion paper describes the overall assessment methodology.

Spray Pond Design for Nuclear Power Plants

This paper presents a complex methodology for assessing the performance of spray ponds in ultimate heat sink service at nuclear power plants. A spray pond performance model, developed in the companion paper, is used in conjunction with on‐site and off‐site meteorological data to predict the highest temperature and greatest 30‐day water loss which can reasonably be expected to occur during the lifetime of the plant. The performance model for heat and mass transfer is used to develop an efficient phenomenological model used to scan the long‐term meteorological records. Refined estimates of temperature or water loss may then be based on more complicated models if necessary. Short‐term onsite data are correlated to the long‐term off‐site data to formulate correction factors for the difference in location. Cumulative distribution functions for temperature and water loss are determined from the longterm meteorological records to predict the occurrence of these quantities which are less severe than the peak. The...

Unit Thermal Performance of Atmospheric Spray Cooling Systems

Thermal performance of an open atmospheric spray pond or canal depends on the direct-contact evaporative cooling of an individual spray unit (spray nozzle or module) and the interference caused by local heating and humidification. Droplet parameters may be combined into a dimensionless group, number of transfer units (NTU) or equivalent, whereas large-scale air-vapor dynamics determine interference through the local wet-bulb temperature. Quantity NTU were implied from field experiments for a floating module used in steam-condenser spray canals. Previous data were available for a fixed-pipe nozzle assembly used in spray ponds. Quantity NTU were also predicted using the Ranz-Marshall correlations with the Sauter-mean diameter used as the characteristic length. Good agreement with experiments was shown for diameters of 1–1.1 cm (module) and 1.9 mm (fixed-pipe nozzle).

Application of Optimal Preview Control to Power Plant Cooling Systems

This paper deals with the application of dynamic control to cooling systems of power plants. The operation of heat dispersal systems with control can result in a saving of power and cooling water. The performance of all cooling systems depends, mainly, upon the ambient conditions and the heat load to be dissipated. Hence, a control scheme that makes use of information obtained by previewing the weather and load conditions, i.e., preview control, is ideally suited for this problem. An iterative procedure is presented for determining the optimal preview control policy for a dynamical system whose dynamics vary depending upon the mode of operation that the controller selects. The algorithm is applied to two types of cooling systems: one consisting of a spray pond and a natural draft wet cooling tower, and the other consisting of a spray pond and a dry cooling tower. The preview control scheme is shown to be a substantial improvement over the uncontrolled case.

Electric Power and Cooling Systems for PETRA

For 19 GeV operation the PETRA storage ring and its experiments need 25 MW of electric power. The different power distribution systems at medium voltage and low voltage level are described. For powering the PETRA magnet system individual high precision dc-power supplies are employed, all centrally located near the PETRA control room. Details will be given about the magnet circuits and the rf-power supplies. Water cooling of the PETRA magnets, vacuum chambers and rf-components is made by 2 systems consisting of pumps, heat exchangers etc and concentrated in 2 cooling centers together with a cooling tower and a cooling spray pond. Cooling equipment for individual experiments is located near the experiments. Utilization of part of the electric energy for heating is provided.

Scaling and Corrosion in an Experimental Geothermal Power Plant

JPT Forum articles are limited to 1,500 words including 250 words for each table and figure, or a maximum of two pages in JPT. A Forum article may present preliminary results or conclusions of an investigation that the present preliminary results or conclusions of an investigation that the author wishes to publish before completing a full study; it may impart general technical information that does not warrant publication as a full-length paper. All Forum articles are subject to approval by an editorial committee. Letters to the editor are published under Dialogue, and may cover technical or nontechnical topics, SPE-AIME reserves the right to edit letters for style and content. Introduction The San Diego Gas and Electric Co./U.S. DOE Geothermal Loop Experiment Facility (GLEF) located near Niland in the Imperial Valley, CA, has operated on a high-salinity (about 200,000 mg/L) geothermal fluid from the Salton Sea Field since May 1976. The conversion process being tested is a four-stage binary system (Fig. 1). The geothermal fluid is flashed at successively lower pressures in open drum-type separators. Generated steam pressures in open drum-type separators. Generated steam passes through a scrubber and into a tube and shell heat passes through a scrubber and into a tube and shell heat exchanger, where the heat is transferred to a secondary, working fluid. Steam condensate can be cascaded and mixed with the brine in the next stage, collected and combined with the cooled brine and reinjected, or used for cooling water make-up. The working fluid is condensed after expansion across a throttling valve that simulates a turbine. Waste heat is removed with a conventional spray pond, With a turbine generator (to be installed later) this facility will become a 10-Mw power plant. Water was used as the working (binary) fluid plant. Water was used as the working (binary) fluid during start-up and initial operation. Isobutane, which is the expected preferred working fluid for a binary power plant, will replace water. plant, will replace water. The GLEF operated for about 3,000 hours with frequent interruptions for inspection and facility modification. During this period, the facility operated on one production well (either Magmamax 1 or Woolsey 1). production well (either Magmamax 1 or Woolsey 1). Flow rates were 400,000 lb/hr, about one-half the GLEF design capacity. The temperature and pressure of the fluid entering the first stage is 370 deg. F and 165 psia. Exit temperature of the brine is 200 deg. F. All unflashed brine is reinjected in the reservoir. Brine Chemistry The geothermal fluid available from this reservoir is a hypersaline brine containing about 200,000 mg/L total dissolved solids (TDS), mostly chlorides (Table 1). These chlorides remain in solution during the heat extraction process and subsequently are injected back in the reservoir. Certain minor species, however, such as silica, lead, and iron have limited solubility and, as the brine is cooled during the heat extraction process, they precipitate from solution and deposit on pipe and vessel precipitate from solution and deposit on pipe and vessel surfaces. The principal noncondensable specie is carbon dioxide. Small amounts (up to 6 mg/L) of hydrogen sulfide also are found in this geothermal brine. Ammonia is also present in the geothermal brine and has a significant present in the geothermal brine and has a significant effect on brine chemistry. The pH of the brine (5.6 to 5.8) is such that a carbonate type of precipitate normally is not observed in spite of the high carbon dioxide level (up to 0.3 wt %). In this process, the available energy in the geothermal brine is extracted as steam. Drum separators and scrubbers can produce high-quality steam with a TDS content of less than 10 mg/L. However, noncondensable gases (carbon dioxide and hydrogen sulfide) also accompany this steam. Part of the ammonia in the geothermal brine also is driven off with the steam. When these noncondensable gases are removed, the pH of the brine increases to about 6.0. JPT P. 1240

Air-Vapor Dynamics in Large-Scale Atmospheric Spray Cooling Systems

Atmospheric spray cooling systems are alternatives to cooling towers and cooling ponds. A quantity NTU containing the spray drop-wise parameters allows prediction of cooling range if local wet-bulb temperature is known. The essential problem is predicting local wet-bulb proceeding windward through the spray field. Theory was developed for this purpose involving wind attenuation and turbulent diffusion. Experiments were performed on a large flow-through spray canal involving segments with two types of floating spray modules. Previous experimental data are available for a fixed manifolded spray pond. A comparison of theory and experiments shows reasonable agreement.

Performance of a Spray Pond for Nuclear Power Plant Ultimate Heat Sink

Spray ponds have become an attractive method of providing the “ultimate heat sink”, i.e., the assured means of dissipating heat from a nuclear power plant. Two redundant spray ponds were the choice for this service in the Rancho Seco Nuclear Generating Station owned by Sacramento Municipal Utility District. This paper describes the results of full scale field tests of the Rancho Seco ponds which were conducted to verify the thermal performance, drift loss characteristics, and the capability to sustain the cooling requirements for a period of 30 days following a loss-of-coolant accident (LOCA). Correlations of local and average nozzle efficiency and of the drift loss are presented. A computer code was developed for the transient thermal performance of the pond. After verification the code was used to predict performance following LOCA under adverse meteorological conditions based on weather records.

Cooling Tower Fog: Control and Abatement

Fogs from cooling towers are causing an increasing number of visibility problems in addition to icing of roads, sidewalks, powerlines, etc. during freezing weather. Enforcement of regulations on thermal pollution for water quality control will cause an increase in the number of cooling towers, spray ponds, etc. Violations of visibility obstruction will rise unless the problems associated with winter operation of low-grade waste heat disposal systems are incorporated in design criteria. This paper summarizes a study made to ascertain the best method of fog control or abatement at a refinery in Houston, Texas. The induced draft, counter-flow cooling towers of concern have design capacities of 750 × 106 Btu/hr and 225 × 106 Btu/hr under local climatic conditions. Several methods of alleviating restricted visibility were considered and cost estimates were made for the most promising methods. A summary of these is provided in the text.

Effect of Air Conditioning on Distribution and Pumping Stations

Effect can be measured by comparison of hourly demands 10 yr ago with present demands, of ratios maximum hour to average day, and of cost of improvements with and without nonconserved air conditioning; situation can be controlled by equipping all air conditioning systems with evaporative condensers, cooling towers, spray ponds or other water conserving equipment.

The Cooling of Water for Power-Plant Purposes: Results of an Experimental Investigation and Description of an Adjustable Spray Nozzle

Abstract This paper presents the results of an extended experimental investigation into the conditions governing the cooling of the condensing water of power plants by means of spray ponds. This investigation involves determining the efficiency of the cooling process under varying conditions of pressure at the spray nozzles, the temperature of the water to be cooled, the power required to circulate the water, the height of sprays above the pond surface, the effect of wind velocity on the cooling range, etc., and the work has resulted in a large collection of data, much of which is presented in the text. As a result of his experiments the author has developed a new form of spray head or nozzle which is so adjustable that the film of water discharged may be broken into either a uniformly fine spray, a mist, or a large number of small drops, as desired. This method of spraying is particularly applicable to low-pressure work, a pressure of 10 in. of mercury giving an exceedingly fine spray, and 8 in. usually sufficing. Probably the most completely controlled means for cooling water in large quantities is found in the forced-draft cooling tower. The newly developed spray head, however, provides for control of the system in a manner which, while somewhat less complete than in the case of the cooling tower, yields results comparing very favorably with those for the tower, and can be installed and operated at a much lower cost.