Factors Affecting the Longevity of Interim ILW Stores, Monitoring Methods and Techniques Supporting Store Life Extension

Life-limiting features of stores (i.e. components of a typical Intermediate Level Waste (ILW) store that are vulnerable to failure) can be separated into those related to store design, the continuing operation of the store and equipment and store management. Environmental factors, including temperature, humidity, atmospheric pollutants and radiation fields also affect the longevity of ILW storage buildings and the integrity of the waste packages within the store. The current condition of the store and the causes and rates of any observed deterioration need to be determined to estimate the current operating life of the store and to analyse the costs and benefits associated with life extension. Suitable monitoring techniques and methods for extending the operating life of stores, either by remediation or replacement of identified life-limiting features, have also been assessed. Techniques including visual inspection (directly or by use of CCTV or inspection cells), corrosion coupons, crane monitoring and a wide range of indirect measurement methods can be used to monitor the condition of life-limiting features and the store environment. Methods for extending store life include the application of paint or coatings to retard degradation, use of electro-chemical treatments and repair of the concrete structure or replacement of components.