Factors contributing to the economic worth of CEGB magnox plant

The lives of CEGB Magnox stations were considered to have two components when they were first built. The engineering of the structures was conceived to provide substantial margins within the plant for the proposed duty. These structures were believed to be capable of at least 20 years continuous operation and good chances of even 40 years for certain parts of the structures. For financial planning purposes, the initial authorization of the costs of building and operation were to be spread over 20 years. After 10 years of operation a planned lifetime of 25 years, for each Magnox plant with a steel pressure vessel, was declared by the CEGB. More recently a review in 1984 led to extending their lives further. The paper to be presented reviews the factors used by the CEGB to derive the economic worth of these stations in terms of the marginal savings that could arise from extending the operation of the plants. These factors and the model incorporating them form the basis of the decisions taken by management on lifetime issues