Every AGR fuel element contains its own unique alphanumeric identification number which defines the design characteristics and manufacturing detail of both the element and its fuel pins. The actual number is marked in 12.7 mm high characters on the outside surface of the outer sleeve of the element, at its upper end. A typical identification code oc­cupies up to 13 characters and would take the form; GADXX200034AB

The first letter defines the power station for which the fuel was made, ‘G’ in this case means Hinkley Point В fuel. A combination of the second and third letters together (‘AD’ above) defines the fuel element ‘TYPE’ number and also the ‘MARK’ number of the fuel pins. The ‘TYPE’ number identifies the fuel element assembly including the fuel pin array, but pays no regard to individual pin detail. For example, Type 6 and Type 6A elements differ only in the supplier of the graphite used during manufacture. The ‘MARK’ number identifies the fuel pin only and refers to vari­ous features of pin design such as ASG array, pellet type, can manufacturing history and so on. Fuel en­richment is denoted by the next two letters (‘XX’ in the example) and the following six digits represent the element’s own unique serial number. The final two letters, which are optional and usually unused, are suffixes to identify special or experimental fuel. An additional letter (not shown), appearing above the first few letters of the fuel element code, and therefore displaced from the 13-character field, relates to special manufacturing tests performed on the element prior to delivery. Each fuel pin also contains identification markings on both its top and bottom end caps. Two identical letters are used on the top end cap to denote isotopic enrichment — these letters will correspond to the enrichment markings contained within the element identification. The lower end cap contains two capitals which are used to define can and pin manufacturing detail as well as the pin ‘MARK’ number.