Leak sealing inaccessible accelerator cooling systems

Cooling water systems associated with experimental facilities often suffer from minor leakage in inaccessible areas. Such leaks can interfere with vacua, electronics or reduce cooling efficiency. Replacement of these defective pipes may cause extensive experimental programme downtime and associated financial costs. The paper describes a novel technique to permanently repair such leaks remotely by injecting a water based sealant into the pipe. The sealants used are fully compatible with pipework, valves and instrumentation. The internals of the pipe are not coated in any way; hence the heat transfer properties of the cooling system are unaffected. This technique has been perfected over the past 30 years in the nuclear power industry. The paper describes how this technology has now been successfully applied to cooling systems within experimental facilities, such as at ISIS, Rutherford Appleton Laboratories (Oxford, UK). A variety of components associated with the linac at the Los Alamos Neutron Science Centre (USA) were sealed during a demonstration of the technique.