Full System Decontamination (FSD) Prior to Decommissioning

Decontamination prior to decommissioning and dismantling is an internationally accepted approach. Not only does it provide for minimization of personnel dose exposure but also maximization of the material volume available for free release. Since easier dismantling techniques in lower dose areas can be applied, the licensing process is facilitated and the scheduling and budgeting effort is more reliable. The most internationally accepted approach for decontamination prior to decommissioning projects is the Full System Decontamination (FSD). FSD is defined as the chemical decontamination of the primary cooling circuit, in conjunction with the main auxiliary systems. AREVA has long-term experience with Full System Decontamination for return to service of operating nuclear power plants as well as for decommissioning after shutdown. Since 1976, AREVA has performed over 500 decontamination applications and from 1986 on, decontaminations prior to decommissioning projects which comprise virtually all nuclear power plant (NPP) designs and plant conditions: • NPP designs: HPWR, PWR, and BWR by AREVA, Westinghouse, ABB and GE; • Decontaminations performed shortly after final shutdown or several years later, and even after re-opening safe enclosure; • High alpha inventory and or low gamma/alpha ratio; • Main coolant chemistry (e.g. with and without Zn injection during operation). Fifteen decontaminations prior to decommissioning projects have been performed successfully to date. The lessons learned of each project were consequently implemented for the next project. AREVA NP has developed a fully comprehensive approach for decontamination based on the CORD® (Chemical Oxidation Reduction Decontamination) Family, applied using the in-house designed decontamination equipment AMDA® (Automatic Modular Decontamination Appliance). The Decontamination Concept for Decommissioning (DCD) will be outlined in this paper. Based on highlights of previous FSDs performed prior to decommissioning the AREVA concept for FSD and DCD will be outlined: • Application window; • Decontamination area; • Waste considerations; • Positive results for subsequent decommissioning and dismantling activities.