Focusing on the fields [water chemistry and ALARA]

Generally, exposures at US light water reactors are continuing to fall. Among the reasons are reduced outage work and reduced human presence in radiation fields. The Electric Power Research Institute's work in radiation field reduction focuses on minimising ''the formation and deposition of Co-60 (and to a lesser extent Zn-65) on components that have to be inspected, repaired, or replaced by plant maintenance personnel''. Among the ways this can be achieved are: reducing the cobalt source term; controlling PWR and BWR primacy chemistry to minimise corrosion product activation; preconditioning of out-of-core surfaces to minimise incorporation and deposition of activated corrosion products; and using chemical decontamination solvents to remove deposited Co-60. (author)