Polymers are used for valve diaphragms, gaskets and seals, insulation and sheathing for electric cables, lubricants, greases, pneumatic pipes and adhe­sives. Certain processes are carried out in sealed gloveboxes — the transpar­ent windows are usually polycarbonate, acrylic or PVC, sometimes leaded for extra shielding; seals for the windows can be fluoropolymers or specially formulated nitrile or EPDM seals. The “gloves” themselves are made from chlorosulphonated polyethylene.

Much work has been carried out to characterize polymers for use in radiation areas. Of the common materials polythene, polyamides, poly — imides, fluoroelastomers and, to a lesser extent, PEEK (polyetheretherke — tone) have been used in seals and bearings when radiation levels are low enough. For non-active or low active pipework, the commonest form of gasket is based on PTFE, which has now been used for many years with no difficulties. Unfortunately, PTFE is one of the least radiation-resistant poly­mers and cannot be used in high radiation areas. Indeed, there are no polymers available which will survive high radiation levels for protracted periods and they are usually avoided by the use of metal seals or inorganic materials such as graphite and, to a lesser extent, asbestos.