Power Plants In India Research Articles

Development of In-service Inspection techniques for nuclear power plants in India

Nondestructive Evaluation (NDE) plays a major role in ensuring the safe and reliable operation of Pressurised Heavy Water Reactors (PHWRs) which are the mainstays of the nuclear power programme in India. This paper discusses the significant developments made over the last two decades which have contributed towards establishing novel methodologies and techniques for In-service Inspection (ISI). The techniques covered are broadly divided into two classes viz. (a) magnetic and electromagnetic, (b) acoustic techniques. Techniques discussed under the first category include eddy current testing (along with the various developments linked with it such as the remote field eddy current testing, eddy current imaging and the phased array eddy current testing), Magnetic Barkhausen Noise and Infrared Imaging. Under the second category, the emphasis is on ultrasonics (for defect detection with high sensitivity and for characterisation of microstructures) and acoustic emission techniques. Developments on the software front, including the application of concepts of Artificial Intelligence and knowledge-based systems in the form of validated expert systems for ultrasonic testing and radiography are described. The expert systems would improve interpretations to a large extent leading to reliable inspections.

Acid Deposition in the Vicinity of a Super Thermal Power Plant in India

An Acid deposition study was conducted in the vicinity of a Super Thermal Power Plant at Singrauli, Uttar Pradesh State in India. During the monsoon season of 1992, rain water samples were collected at three sites around the power plant. Measurements of trace gases (SO2, NO2, NH3 and O3) and Total Suspended Particulates (TSP) were also carried out for a period of 10 days during the monsoon season. Rain water samples were analysed for pH and all major inorganic ionic species. The high concentration of TSP (196 μg m^(-3)) observed near the power plant may have been due to fly ash emissions from coal combustion, coal dust from the nearby coal mines and from soil dust. It was found that the rain water which was acidic in the vicinity of the power plant turned to alkaline as the distance increased from the power plant.

Development of in-service inspection techniques for nuclear power plants in India : International Journal of Pressure Vessels and Piping, Vol. 56, No. 2 pp. 183–211 (1993)

Development of in-service inspection techniques for nuclear power plants in India : International Journal of Pressure Vessels and Piping, Vol. 56, No. 2 pp. 183–211 (1993)

Development of in-service inspection techniques for nuclear power plants in India

The present status of in-service inspection (ISI) in the Indian nuclear power plants using non-destructive testing (NDT) techniques such as eddy current testing (ECT), acoustic emission (AE) monitoring, ultrasonic testing (UT) is discussed. Development of digital signal analysis techniques that will lead to better analyses of the NDT data are highlighted. ECT has been successfully developed to locate the garter springs in the calandria/pressure tube assemblies of the pressurized heavy water reactors (PHWR) and the profiling of the gaps between the calandria and pressure tubes. It is now a standard ISI technique. AE has been successfully used to locate leakage paths in the end shields and coolant tubes of PHWRs. Digital signal analysis has been used for enhanced sensitivity and better defect characterization in difficult to inspect austenitic stainless steel weldment by UT. Digital eddy current impedance imaging has been applied to locate weld centreline in austenitic stainless steel weldments towards automated in-service inspection.

Chemical characterisation of fly ash from coal-fired thermal power plants in India

Fly ash samples collected from electrostatic precipitators of coal-fired thermal power plants in India were analysed for major and trace elements using energy dispersive X-ray fluorescence (EDXRF). A few coal samples were also analysed and element concentrations compared with those in fly ash. Concentrations varied widely, but are well within the ranges cited in the literature for various coal types. The samples were classified into six groups according to the ash content of the coals, which varied from 4 (for lignite) to 40%. The concentrations of Zn, Cu, Ni, Cr and V were high in fly ash samples from lignite. Sulphur concentrations were found to be lower than values reported in the literature for other countries. The K/Ca ratios for fly ash from non-lignite coals were found to correlate with their Si and Fe content. Inter-element correlations in the samples showed associations of Si with K; Cu and Zn with Pb; K with Rb; Al and Ca with Sr; and Fe with Ti. The ash/coal ratios for various elements indicate that most of them are enriched, except for S, which is depleted. Copper and Cr show higher enrichment than other elements by a factor of 4. Concentrations of the toxic elements S, Pb, Cr, As and Cu released from a typical thermal power station complex having a total of 1150 MWe installed capacity were estimated from the measured fly ash composition, the total ash content and the partitioning values reported by Page et al., load factor and amount of coal consumed. The concentrations of these elements in air due to their release in the flue gases of the plant do not exceed accepted levels. The enrichment factor of As in fly ash with respect to crustal rock was found to be high and it can be used as a marker element for fly ash samples obtained from an electrostatic precipitator.

Geofabrics improve load bearing characteristics of flyash

Thermal power plants in India are producing millions of tons of flyash annually. The material is non-plastic and mainly comprises of the oxides of aluminium, iron, calcium and magnesium. It is a fine grained material and, as such, its use is not feasible as an engineering material. Since it is rarely being used commercially, its storage and disposal have created enormous problems. Experiments are being carried out to improve the load bearing characteristics of flyash with the help of geofabrics. This reinforced flyash will be specially useful for the construction of road and railway embankments particularly where extensive fillings are needed. After a detailed study of different types of woven and non-woven fabrics, Madura Coats (type 3C) was selected for the experimental studies. Different laboratory tests, including California Bearing Ratio and Triaxial tests, were conducted for unreinforced as well as reinforced and treated flyash to compare the behaviour of load bearing characteristics. The results are promising and it will be possible to ascertain an economical procedure for the use of reinforced and treated flyash in different civil engineering works.

Electric power plant in India: a strategy of self-reliance

Electric power plant in India: a strategy of self-reliance

Electric power plant in India A strategy of self-reliance

This paper examines the development of the Indian power plant sector in relation to the aims of promoting economic growth, import substitution, and international competitiveness. Particular attention is paid to Bharat Heavy Electricals Ltd (BHEL), a public enterprise which was established with extensive foreign assistance. Major difficulties were encountered in assimilating foreign technology, coping with rapid technical change, building up expertise in quality assurance, and research and development, obtaining satisfactory materials and components from Indian firms, and achieving satisfactory capacity utilization. Nevertheless, in production capacity and size of market, BHEL is increasingly comparable to the 10 or so suppliers that dominate the international market as well as their home markets. The main challenge is to achieve higher productivity of the capital employed in this sector by strengthening indigenous technological capabilities in all aspects of power engineering, including in the manufacture of power equipment, and the construction, operation, maintenance and repair of power stations.