Source of Cobalt in BWR

[robotengineer]

All
I'm looking for ways to determine the source of cobalt in BWR without replacing all the stellite. It seems the plants in the US have a wide range of cobalt values with big differences in personnel exposure as indicated by BRAC.
Does anyone know which LWR's have tracked down cobalt sources using XRF, or sampling with a QA program which positively identified specific sources of cobalt whcih resulted in a difference in BRAC? Has anyone looked for elemental cobalt in condensate demin resins? What is the fate of high stokes value "chunks" of cobalt which are removed from valve guides or seats during normal operation ; do they sit in fluid somewhere and slowly "dissolve" prior to becoming crud residing in the fuel zone? Is it possible that there is some gavamic (anodic depletion) removal of material and combination with some anion to form a component of crud?
EPRI, GE and BWR OG have been little help
Thanks

 

[ccw]

Outside of the elec. utility reactors, the Oak Ridge High Flux Isotope Reactor might be a source of information. The HFIR operators and engineers are very sensitive about their pool chemistry. There was a recent program conducted to remove high gamma dose cobalt loaded junk parts (stellite) from the pool bottom where they had collected for quite some time. The parts were removed from the pool and handled as high gamma, low alpha, solid, stabilized waste, packaged, and shipped to the Nevada Test Site repository.