Steam Electric Station Research Articles

Using an Expander-Generator Unit in the Steel Mill CHP Plant for Producing Electricity and Improving the Efficiency of the Compressor Plant

The possibility of energy saving in one of the most energy-consuming compressed air production plants, in which a significant part of the consumed energy gets lost, is considered. The proposed technical solution is based on the joint use of two energy-saving technologies: the first one is the use of a technological pressure drop of the transported natural gas, which is irretrievably lost when it is throttled at gas-pressure regulatory stations, and the second one is the inlet compressor air cooling to reduce the compressor work. An installation circuit design is proposed for a metallurgical enterprise combined steam blower and electric station, in which a two-stage expander-generator unit (EGU) is used to generate electricity and cold in addition to a power turbine producing electricity and heat and a steam-turbine two-stage compressor producing compressed air. The thermodynamics of gas expansion processes is considered, and the choice of a two-stage scheme is justified. The cold produced by the EGU is used to lower the inlet air temperature at the first and second compressor sections, reducing fuel consumption for air compression. Application of the proposed scheme makes it possible to reduce fuel consumption for the compressor drive. It seems reasonable to use the compressed air heat for heating the transported gas at the expander inlet and generating additional electricity. At the same time, the fuel is not consumed to produce electricity, and the heat of the cooling air is not discharged into the environment, i.e., the installation operation is characterized by high environmental performance. The fuel economy calculation procedure for the proposed scheme is presented. The assessment showed that using this scheme allows for a reduction in fuel consumption at the CHP steam blower by 11.2 thousand TOE/year for a gas consumption of about 200 thousand nm3/h, gas pressure at the gas-pressure control station of 0.7 MPa and required air pressure of 0.5 MPa, which is 0.84%. The energy output of the EGU in case will be 5.3 MW.

Physical and chemical characterization of El Kriymat boiler ash to optimize the leachability of some valuable elements

Boiler ash is characterized by the presence of vast aggregates of both economic and strategic elements which reflect the importance for their recovering. A petroleum ash sample was collected from the boiler of El Kriymat steam electric station located in south Cairo, Egypt. Chemical analysis of this petroleum ash sample revealed that V and Ni are present as major elements while the minor elements are represented by Fe and S. Trace elements include Ti, Ca, K, Cl, Si, Ba, Zr, Y, Sr, As, Zn, Cr, Mn, Th and U. The present work aims to investigate the nature of this sample either mineralogically and chemically on the one hand, and the possibilities of extracting such valuable elements on the other.The obtained results revealed the possibility of saving both reagents and time, about 98% leaching efficiency upon the summation valuable metals fractions (0.05–1) amperes (A) by applying the optimum conditions 180 g/l H2SO4 acid, 6% MnO2 (solid/solid ratio) as oxidant agent, 80 °C temperatures, 6 h, 1/10 (S/L) ratio and -200 mesh grain sizes. While, 150 g/l H2SO4 acid at fixed the other parameters (6% of MnO2, 80 °C temperatures, 6 h, 1/10 (S/L) and -200 mesh grain size) upon totality fractions (1–3) amps was sufficient for dissolving more than 98% of the exciting valuable metals.

The Outcomes of the 2-Decade Monthly Monitoring of Fly Ash-Composition in a Lignite-Fired Power Station

In the current study, the evolution of the composition of fly ash (FA), since the beginning of operation of the lignite-fired power station of Amynteon-Filotas [Steam Electric Station (SES) Amynteon-Filotas] in Greece, is presented. The respective evolution of the feedcoal-composition is also showed. This power station began to operate in 1987. Before that, it was predicted that lignite fly ash would turn from strongly calcareous to barely pozzolanic. Moreover, the variation of sulphur (%) (both total and volatile) in feedcoal had revealed that fly ash would not often meat the specifications to be used in the production process of concrete, due to the excessive percentage presence of SO3. These predictions were eventually confirmed in the 23 years of operation of the power station. During these years SO3 (%) kept alternating, rendering—in some cases—fly ash suitable for use in cement industry applications. The periodical changes of the SO3 concentration in fly ash were attributed to the free (volatile) sulphur of feedcoal as well as to the excess of FeS2, which had also a serious effect on the daily power production process (severe erosion of the metallic surfaces of boiler). A number of solutions for tackling this phenomenon are suggested in this study: discard of specific FA grain fractions, intense monitoring of the material and its effective mixture-homogenization and selective mining of lignite.

국내 5기의 석조문화재에 분포하는 기중조류와 생물학적 등급에 관한 연구

The purpose of research was to find aerial algae and to investigate the change of color in each class of photosynthetic pigments in five stone cultural properties of Korea. It turned out to be a total of 29 taxa, including as 26 species, 1 variety and 2 unidentified species. Among them, Haplaosiphon fontinalis and Stigonema turfaceum were found to be newly recorded species of Korea. The average Chl-a concentration from the change of color in the stone cultural properties increased as its class; however, the class 5 showed lower values than the class 4, which was shown in previous studies. From the studies of algal distribution, chlorophytes appeared earlier than cyanophytes in stone cultural properties of algal infestation. Also, 50% or more of the five stone cultural properties already appeared to have bio-pollution.ഀ䡹摲潢楯汯杩愀5㔀3㌭㐴Ѐㄹ㜷਀ㄹ㜷ⴰ〰琁Ų
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Flemer D. and Sherk Jr. J.A. 1977. The effects of steam electric station operation on entrained phytoplankton. Hydrobiologia 55: 33-44 樃᠀䩏剈䉋弲〰㡟瘲㍮ㅟ㌱弰㐶销䅢畮摡湣敳映慵瑯瑲潰桩挠慮搠桥瑥牯瑲潰桩挠湡湯灬慮歴潮⁡湤⁴桥⁳楺攠摩獴物扵瑩潮映浩捲潢楡氠扩潭慳猠楮⁴桥⁳潵瑨睥獴敲渠乯牴栠卥愠楮⁏捴潢敲‱㤸㘉G敩摥爬⁒᠀䨮⁅硰⸠䵡爮⁂楯氮⁅捯氮〰㈲ⴰ㤸㄃1㈳Ā㈀1㈷ⴱ㐵Ѐㄹ㠸਀ㄹ㠸ⴰ〰⸀桴瑰㨯⽤砮摯椮潲术㄰⸱〱㘯〰㈲ⴰ㤸ㄨ㠸⤹〱㘵ⴷᰀ㄰⸱〱㘯〰㈲ⴰ㤸ㄨ㠸⤹〱㘵ⴷขȌ
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Geider R.J. 1988. A abundance of autotrophic and heterotrophic nanoplankton and the size distribution of microbial biomass in the southwestern North Sea in the October 1986. J. Exp. Mar. Biol. Ecol. 123: 127-145 턁᠀䩏剈䉋弲〰㡟瘲㍮ㅟ㌱弰㐸᠀䨮⁗慴⸠偯汬⸠䍯湴⸠䙥搮Ȁ㔱ㄸㄸⴱ㠲㌄1㤷㤊1㤷㤭〰ⴰ fā搀ĂಈȀĀ挀ǟ㠀ǟ㔀─┃最Ā䜀漀氀搀洀愀₱?ꀈ吀ǟ䴂㜀ȁဉ
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Level 2 analysis to estimate LERF risk from a thermally induced rupture of a steam generator tube defect

This paper outlines the Level 2 portion of a methodology for determining the incremental induced steam generator tube rupture large early release fraction caused by an actual through-wall defect. This defect was responsible for the minor steam generator tube leak that occurred in September 2002 at the Comanche Peak Steam Electric Station Unit 1. In order to quantify the performance of the defect over the operating cycle, a range of defect lengths were input to the PROBFAIL computer code [Kenton, M., 2001. PROBFAIL: A Computer Code for Evaluating the Likelihood of Steam Generator Tube Rupture in Severe Nuclear Power Plant Accidents, CREARE TM-2138], using appropriate boundary conditions derived from MAAP4 [Henry, R., et al., May 1994. MAAP4—Modular Accident Analysis Program for LWR Power Plants, Computer Code Manual, EPRI Research Project 3131-02] runs. From the analysis of the calculated times of burst for each assumed defect length, the minimum through-wall defect length necessary for tube burst to occur prior to hot leg or surge line creep rupture was calculated. The probability that the defect would actually have this length was then estimated by determining the fraction of the cycle for which the defect would be at least that long. The methodology development and implementation relied on MAAP4 runs, which are discussed extensively in connection with their role in: (1) guiding the construction of the accident progression event tree, (2) generating relevant information for probability assignments in the various underlying fault trees and (3) obtaining boundary conditions of pressure and temperature for use in PROBFAIL. The overall increment in LERF due to the existence of the defect was calculated to be approximately 4E−08.

A knowledge representation model for the nuclear power generation domain

A knowledge representation model for the nuclear power field is proposed. The model is a generalized production rule function inspired by a neural network approach that enables the representation of physical systems of nuclear power plants. The article discusses some techniques currently used for knowledge representation of physical systems and argues that the proposed approach overcomes some aspects of the deficiencies that exist in these other techniques. An application to the Containment Spray System of the Comanche Peak Steam Electric Station is provided. The algorithm developed worked accurately, managed to handle multiple fault scenarios and gave correct and useful information. Also, none of the other knowledge representation techniques discussed seems to be capable of providing the level of detail and the advantages of the method proposed.

Hydrothermal Modeling Studies of Cooling Tower Alternatives

The Environmental Effects Committee of the ASCE Energy Engineering Division has been developing a report on “Energy Production and Reservoir Water Quality” for publication. The report covers the regulatory framework that dictates much of the procedures for studies related to this topic, the fundamental reservoir hydrodynamics and water quality modeling used in preparing studies, the kinds of studies that can be prepared at different levels of analysis, and a series of applications that illustrate the problems encountered and applications of the various techniques. This study of hydrothermal modeling as applied to examining cooling tower alternatives for an existing steam electric station on a moderately large reservoir is included in this report and is presented here as an illustration of the types of studies included. This particular study subtended the usual steam electric plant cooling water discharge studies that relate to specific regulatory thermal plume size standards, and had to be designed around developing plant and cooling tower operations that would meet specific fisheries requirements for a zone of passage and refuge for fishes throughout the receiving embayment. After being used in developing cooling tower and plant operating details for the designers to work with, it was required that the hydrothermal modeling results be verified under actual tower operating conditions. In addition, it was required that the impact of the combined operations on dissolved oxygen be examined in detail. This paper covers the background to setting up the study, the kinds of statistical comparisons used to verify the hydrothermal studies, and similar studies for the analysis of dissolved oxygen distributions.

Investigation of the uptake ability of fly ashes produced after lignite combustion

Fly ash samples from the five steam electric power stations of the Lignite Center of Western Macedonia were used in this study. They consisted mainly of anhydrite, lime, quartz and amorphous material as well as feldspars, calcite, micas+clays, portlandite and gehlenite which were all present in minor amounts. Anhydrite, lime and portlandite in the fly ash samples diminished upon treatment with ammonium acetate aqueous solution, whereas quartz, feldspars, gehlenite and amorphous material were enriched. The uptake ability of the fly ash samples ranged from 89 to 101 mequ./100 g. The uptake ability of the samples was mainly attributed to the amorphous material and the microporous minerals, micas+clays. The amorphous material content was estimated at between 17 and 20 wt% in the treated fly ashes and may be unburned organic matter and amorphous inorganic material that resulted during the combustion of the lignite. A positive correlation was observed between the uptake ability and the total percentage of amorphous material and micas+clays. The relatively high uptake ability of the fly ash samples could lead to additional industrial and environmental uses of the fly ashes. The environmental advantage of fly ash exploitation will be particularly important for large electric power centers, such as the LCWM.

Entrainment, impingement and BTA evaluation for an intake located on a cooling water reservoir in the southwest

The Comanche Peak Steam Electric Station (CPSES) is a two-unit, combined 2300 MWe nuclear power station located about 65 miles southwest of Dallas. Unit 1 was approved for commercial operation in August 1990; Unit 2 in August 1993. The NRC’s 1981 Final Environmental Statement discussed entrainment and impingement, expressing some concern over intake approach velocities which were estimated to exceed 0.5 ft/s; the final NPDES Permit required a 316(b) Demonstration once Unit 2 went into commercial operation (which turned out to be autumn 1993). CPSES is a once-through power station that withdraws its cooling water from Squaw Creek Reservoir (SCR), which was built by the company to provide a reliable source of condenser cooling water for a nuclear power plant. A secondary benefit has been the development of a nice sport fishing resource in an area starved for such water bodies. SCR was created by damming Squaw Creek and several minor tributaries to create a 3272 acre impoundment. It was completed in February 1977, and filled in May 1977. The Texas Parks and Wildlife Department has done initial and supplementary stockings of forage and game fish since then, including threadfin shad, largemouth bass, smallmouth bass, white bass, hybrid striped X white bass, and channel catfish. SCR has an average depth of 46 ft; a maximum depth of 135 ft; and a volume of 150,000 acre-ft. It has 70 miles of shoreline and a “Shoreline Development Index” (SDI) of five (a SDI of one would indicate a round configuration, whereas SCR has numerous natural coves formed by flooded tributary mouths and other natural indentations in the original valley). Units 1 and 2 share a common intake structure located flush on the shore of an excavated recess of SCR. This recess is 50 ft deep at the trash racks. Its bottom is exposed bedrock and sand, and its shoreline was cleared and rip-rapped to prevent slumping of riparian vegetation and soils into the intake area (something more important to licensing nuclear power plants than fossil ones). CPSES has a standard shoreline intake with eight circulating cooling water pumps rated at 275,000 gpm each; twelve traveling screens with 12″ mesh that are rotated every 4 h or when pressure differentials dictate more frequent rotation; a common debris trough; and no fish return system. The CPSES intake daily withdraws and recirculates about 6.4% of SCR’s volume at full operating capacity. An entrainment, impingement and waterbody monitoring program was performed according to NPDES specifications. In contrast to what many pundits may have predicted, total annual impingement (including threadfin shad) is very low for a plant of this size, and entrainment is dominated by forage species with high fecundity and pelagic spawning habits. Impingement and entrainment of gamefish is extremely low, and fishing for basses and catfish remains good. This paper describes how the design specifications developed to ensure reliability and safety also helped minimize adverse environmental impact by locating the intake in a zone of “low biological value” relative to alternative areas. There are lessons to be learned as the EPA seeks to define new measures of adverse impact, such as proposed use of the “Rapid Bioassessment Protocols” in the Tier 2 screening stage of the Best Technology Available (BTA) process. For example, creating an intake area less favorable to species diversity, and therefore inviting fewer species and individuals to the intake area, may have set the stage for the CPSES intake to be subjected to increased scrutiny rather than getting credit for the multi-disciplinary BTA which it does, in-fact, represent! This, and other features of reservoirs constructed for cooling water purposes, argues in favor of site-specificity and possibly distinguishing such reservoirs from natural lakes in other parts of the country.

Conceptual containment venting strategy for Susquehanna steam electric station

Abstract To mitigate the consequences of postulated BWR reactor accidents, generic industry guidance for venting the primary has been proposed to prevent catastrophic failure, maintain low pressure vessel injection capability, and/or remove combustible gas which may cause failure if ignited. Detailed analysis of the generic guidance shows that such venting must not be performed irrespective of off-site consequences. The decision to vent must be made with an evaluation of the off-site consequences. The conclusion of this paper is that venting without a source term or with a limited source term is permissible, either to maintain core cooling or to preserve the function for the future. However, with a large potential source term, such as would result from severe core melt and relocation, venting is not an effective risk management policy and maintenance of containment is paramount. This paper reviews the generic venting approach, the reasoning behind the generic approach, and presents a conceptual venting strategy for the Susquehanna Steam Electric Station (SSES) in light of PP and L's (formerly Pennsylvania Power and Light, Co.) own severe accident analysis experience.

TU Electric’s Experiences with the Development and NRC Approval of a Reload Safety Analysis Methodology

TU Electric has developed and obtained U.S. Nuclear Regulatory Commission (NRC) approval of the methodologies required to support core reload safety analyses. The Electric Power Research Institute-sponsored computer codes RETRAN-02 and VIPRE-01 are used in the non-loss-of-coolant-accident thermal-hydraulic analyses. These methods were employed to support the loading of the core of the Comanche Peak Steam Electric Station, Unit 1 (CPSES-1), Cycle 5.An overview of the reload safety analysis development effort is provided, with the focus on the qualification of the system transient analysis methodologies. Interactions with the NRC are described. Included is a discussion of the types of questions asked by the NRC and the corresponding TU Electric responses. Comparisons of calculated results to actual plant data which demonstrate the validity of the CPSES plant model, are provided. The importance of performing “good” benchmark comparisons is addressed as it relates to the demonstration of technical competence in the use and interpretation of RETRAN.The effectiveness of the approach used by TU Electric to obtain NRC approval of the reload safety analysis methodology is examined in retrospect. Finally, an assessment is made of the benefits, tangible and intangible, derived from having an in-house reload safety analysis capability.

Risk Assessment for Spent-Fuel Pool Cooling at Boiling Water Reactors

A risk assessment of potential events at Susquehanna Steam Electric Station (SSES) is described wherein a loss of cooling occurs in a spent-fuel pool (SFP). This evaluation was performed as part of...

Remote cranking of steam electric stations

This paper focuses industry attention on power system restoration. During the initial phase of restoration, black-start combustion turbines are often considered as remote cranking sources for the start-up of steam electric stations. In general, remote cranking operation is carefully planned, simulated and then verified by field tests. This paper describes the planning and simulation used in black-start of two coal-fired generating units utilizing remote combustion turbines. It discusses a number of constraints which have to be considered and simulated in preparation for testing and verification. The paper concludes that, in order to minimize the possibility of damage to equipment during testing or actual restoration, it is necessary to undertake extensive simulation of the procedure. It recommends that the realistic generator reactive capability models be made a part of the network models to allow: optimum selections of tap positions for all the transformers within the remote cranking power system, thus providing adequate lead/lag reactive powers and to maintain acceptable voltage profile while proceeding through various stages of operation.

Silver and Copper Accumulation in Two Estuarine Bivalves, the Eastern Oyster (Crassostrea virginica) and the Hooked Mussel (Ischadium recurvum) in the Patuxent River Estuary, Maryland

In order to assess the source of trace elements and to compare uptake between different bivalve species, oysters and mussels were transplanted to five sites in the upper Patuxent River estuary during 1988. Transplant sites were located above and below the discharge of Chalk Point Steam Electric Station (CPSES)—a historic point source for copper. Organisms were sampled approximately monthly for 1 yr and analyzed for copper and silver. During spring and summer, concentrations of silver and copper increased in oysters at the upstream stations. There was very little change in silver and copper concentrations in the mussels with either time or among stations. Copper concentrations accumulated by oysters approached those found during previous periods when CPSES used Cu−Ni alloy condenser tubes (1966–1987), suggesting that corrosion from the Cu−Ni condenser tubes was only a minor contributor to the copper burdens of oysters in the river nearby. The lack of accumulation by mussels at the same sites suggests that part of the reason for the accumulation by oysters may be a taxonomically specific physiological effect caused by the salinity regime in the upper Patuxent.

Modelling of Off-Site Radiological Dose Consequences from an Accidental Airborne Release at the Susquehanna Steam Electric Station

Modelling of Off-Site Radiological Dose Consequences from an Accidental Airborne Release at the Susquehanna Steam Electric Station

Modelling of Off-Site Radiological Dose Consequences from an Accidental Airborne Release at the Susquehanna Steam Electric Station

Modelling of Off-Site Radiological Dose Consequences from an Accidental Airborne Release at the Susquehanna Steam Electric Station

Survivorship and Predation Changes in Five Populations of Botrychium dissectum in Eastern Pennsylvania

This study of five populations of Botrychium dissectum was initiated in 1977 as part of a general environmental monitoring program at the Susquehanna Steam Electric Station. The Botrychium populations were discovered in the course of general flora surveys. Plants of this species were remarkably common in old fields and second growth woodlands on the site; therefore, I decided to monitor these populations in several successional habitats and their fate over several years. Part of the rationale of this study was simply that populations of Botrychium dissectum were observed in several plant communities that I could reasonably expect to remain undisturbed at a protected site. The study area is located in the Susquehanna River valley, 8 km north of Berwick, Salem Township, Luzerne County, in east-central Pennsylvania. Botrychium dissectum produces a single leaf each year from a short underground rhizome. This leaf emerges in mid to late summer, unfolds, and, if a fertile segment is present, spores are shed in early autumn. The fertile segment then withers, but the vegetative blade remains throughout the winter and following spring, senescing as the new leaf emerges. It should be emphasized that if this leaf is damaged or lost, the plant has no photosynthetic organ until the next summer. If the first leaf is damaged as soon as it emerges, occasionally plants will produce a small second leaf. Although this study was initiated with the idea of following the fate (longevity) and production of fertile fronds of plants in several populations, the study has been sidetracked by the discovery that many of the plants were eaten in the autumn soon after the leaf emerged and expanded. The plants have high survival under these conditions; this will be the chief topic of this paper.

Gas-bubble disease in three fish species inhabiting the heated discharge of a steam-electric station using hypolimnetic cooling water

White bass (Morone chrysops), bluegill (Lepomis macrochirus), and largemouth bass (Micropterus salmoides) inhabiting the heated discharge canal of Duke Power Company's Marshall Steam Station, Lake Norman, North Carolina, were examined for signs of gas-bubble disease (GBD) during the winters of 1982–1983 and 1983–1984. Peak percentages of these fish species with GBD occurred between late February and early May each year, corresponding with peaks in total gas saturation in the discharge water. Cooling and warming water temperatures, and thermal stratification of Lake Norman influenced saturation of dissolved gases in the hypolimnetic intake water of Marshall Steam Station, and directly affected the variability in total gas saturation in the discharge canal. Temperature change in the condenser cooling water and electricity output were unrelated to the within-year variability in total gas saturation and GBD. The use of hypolimnetic water for cooling at this station restricts the time to a few months that levels of total gas saturation are sufficient to induce GBD, but probably led to higher peaks in GBD than if epilimnetic water was used. Among years, levels of GBD in white bass, bluegill, and largemouth bass were higher when electrical demand and mean temperature changes of the condenser cooling water at Marshall Steam Station were higher. Higher incidences in GBD in these fishes also occurred during winters when intake water temperatures were coldest.

Simulating the indirect effects of power plant entrainment losses on an estuarine ecosystem

Entrainment caused by the operation of the Chalk Point Steam Electric Station has been shown to be a major source of mortality to the early life stages of forage fish populations in the Patuxent River, MD, USA. While direct losses to these populations are important as a source of reduction for population abundance, these losses also represent decreases in estuarine forage supplies and potential reductions in the abundances of estuarine predators. A simple estuarine trophic dynamics model was constructed to determine the magnitude of the potential losses to major estuarine consumers in the Patuxent River ecosystem due to the power plant-related losses of forage fish. Simulations were completed using two sets of feeding assumptions: feeding proportional to forage abundance, and feeding based on dietary preferences. The model demonstrates that striped bass, bluefish, and weakfish could experience significant losses (> 25%) to overall population production levels if they prefer to prey upon bay anchovy and silversides and entrainment losses to these forage populations is ≥ 70% of juvenile recruitment. The model also shows that indirect predator losses would be expected to be low (< 5%) if the majority of their diets consisted of forage other than bay anchovy and silversides.

Increased-Discharge-Burnup Method for Multicycle Reload Design

A new concept for the fuel cycle analysis of a multicycle design is introduced. This new concept has been applied to the boiling water reactor of the Susquehanna Steam Electric Station. A linear programming method is used to determine the optimum reload pattern for a given set of reload fuel assemblies for each cycle. The optimum reload pattern maximizes the cycle length and provides a target core pattern. Sensitivity functions are computed using the HUDDLE code, which depletes the core using the Haling power distribution. The linear programming convergence characteristics are greatly enhanced by incorporating total programming.