摘要:

The paper reviews the possible development of gas-cooled graphite-moderated reactors for power production. It is shown that larger reactors of the Calder Hall type will produce electric power at a competitive cost in the United Kingdom.A very promising line of development is towards higher-temperature operation, since this increases both the heat rating of the reactor and the overall efficiency of the plant, although it requires the development of new materials, particularly for cladding the uranium. As higher temperatures are reached, interest is stimulated in the oxide and carbide forms of uranium, and for very high temperatures an all-ceramic reactor core has been suggested.The paper describes the use of recycled plutonium as a fuel, showing that under certain circumstances this is possible with a natural-uranium fuel. Comparison is also made of the relative merits of a number of possible coolant gases.It is concluded that, given research and development effort, the gas-cooled graphite-moderated reactor is capable of considerable development. For the base-load application, cheaper power should be possible, and the range of application may be extended to smaller power units tailored for specific purposes.

DOI:10.1049/pi-a.1957.0074

出版商:IEE    

年代:1957

数据来源: IET

摘要:

The mechanical stresses in power transformers have steadily increased with transformer size and supply-system capacity. Short-circuit currents are generally based on the rupturing capacity of circuit-breakers which has increased in 25 years from 1 500 MVA to 25 000 MVA.The position has been accentuated in recent years by the established practice of auto-reclosing, which makes repeated switching on to possible faults a normal practice, and the introduction of fault throwing for inter-tripping purposes, where dead short-circuits are deliberately created under normally controlled conditions.Using only simple mathematics, it is shown that the mechanical strength of a transformer is not a simple single value as is implied in the short-circuit clauses of standard transformer specifications. Some of the strains are progressive, and some of the stresses cumulative, leading to short-term and long-term characteristics. The resulting categories of mechanical strength are defined as initial, critical and ultimate, the last named being usually the crucial one.It is shown how the performance in service can be predetermined and the expectation of life, in terms of number of short-circuits, predicted for any given operating conditions.Service records of failures on short-circuits are analysed and found to support the predicted values.Methods of improving the expectation of life are considered.

DOI:10.1049/pi-a.1957.0075

出版商:IEE    

年代:1957

数据来源: IET

摘要:

The paper deals with the theory and practice of the method of corrosion mitigation known as cathodic protection. The nature of electrochemical corrosion and the fundamentals of cathodic protection are briefly discussed. This is followed by a survey of the two practical methods of achieving cathodic protection—sacrificial anodes and power-impressed currents. Since the method of measuring potentials is not that of normal electrical practice, the subject is considered in some detail together with the method of measuring soil resistivity. The possibility of adversely affecting other buried services is noted, and current practice in carrying out potential tests with the owners of such services, and of bonding to eliminate adverse effects, is considered. Finally the application of cathodic protection and the general economics affecting its use are discussed.

DOI:10.1049/pi-a.1957.0078

出版商:IEE    

年代:1957

数据来源: IET