I work in a BWR-5 plant and this outage we will be swapping 36 control rod blades. We currently restrict access to the upper elevations of the drywell during irradiated hardware and fuel moves because of the potential dose rates if we were to drop something. This has a significant schedule impact because of the work restriction, and also takes quite a bit of dose posting and deposting. Has anyone done a MCNP model of a dropped CRB, which is pretty much the worst case? I'm not even going to investigate dropping irradiated fuel. Has anyone developed a case (for or against) working the upper elevations during irradiated hardware moves? Before I get too much more invested in modeling this thing, just thought I'd ask.