Confirmation of On-Line NobleChem™ (OLNC) Mitigation Effectiveness in Operating Boiling Water Reactors (BWRs)

Abstract

The development and implementation of On-Line NobleChem^TM (OLNC) has now occurred for many years with almost the entire US BWR fleet, including Mexico, and some European BWRs using this process to achieve mitigation of IGSCC. The data confirming the effectiveness of OLNC has indirectly shown significant reductions in incidences of crack initiation as well as the suppression of growth of any previously existing cracks. However, the robustness of the process and its ability to protect all core and lower plenum regions requires on-going confirmation of the presence of nanometer sized platinum particles as well as verifying the adequacy of the coverage on surfaces of the core structural materials. Efforts by GE Hitachi Nuclear Energy (GEH) have continued in cooperation with the BWR utilities to both properly inject the platinum solution into the coolant as well as to monitor the surface characteristics of actual core components. This paper will show the results of on-going efforts to confirm platinum coverage of stainless steel surfaces using Field Emission Scanning Electron Microscopy (FE-SEM) methods. Additional efforts to tie all the process methods together to establish and confirm OLNC performance will also be presented. Finally, the paper will review continuing plans moving forward to validate OLNC performance across the BWR fleet.