Controlling the radiation field build-up in PHT systems of pressurized heavy water reactors by metal ion injection passivation technique

Corrosion of PHT system structural materials, the transport of the corrosio n products thus formed, their activation in the core by neutrons and the re transportation of the activated corrosion products leads to the problem of radiation field build-up in the out-of-core surfaces of PHWRs. Passivating the primary coolant system surfaces can reduce the corrosion of the structu ral materials which in turn is expected to result in reduced radiation fiel ds. Zinc ion passivation (ZIP) technique is being used in some of the Boili ng Water Reactors (BWRs) to control the radiation field in the reactor cool ant system surfaces. Efforts are currently underway to find out alternate m etal ions which may have either similar or better effect in mitigating the radiation problem. In the present work, the role of magnesium ion as a meta l ion passivator for PHWR primary heat transport system surfaces has been i nvestigated and the results of experiments are discussed.