I think the biggest issue is the fighting between Ops, RP and the senior management. Sometimes getting an outage completed "on time" does not work well with what RP wants.
I know my plant has some leakers from what we think are new assemblies installed during our last outage 7 months ago. We now have some limits on how fast we can change reactor power for normal maneuvering. Just hope you don’t get a plant trip from 100% power because those will really get things stirred up.
Wlrun3: Soft Shutdown is a term I learned about just recently. It is basically where you shut down a reactor without just dropping the control rods in the core once you have lowered power. Instead you drive them in with the control rod drive. There are some important tidbits about this.
At the PWR I work at, we have 3 types of control rods. They are; Safety Rods, Regulating (reg) Rods and Axial Power Shaping Rods. Using Control rods and boron allows us to control PWR reactors. The Safety Rods must all be out 100% before you make the reactor critical. There are limits on how high you can make your boron concentration due to reactivity coefficients. The problem with too much boron is that it can make your moderator temperature coefficient positive which is a big NO NO (it can be slightly positive at the beginning of core life for a few hours during zero power physics testing).
A soft shutdown uses both boron control at certain concentrations (Reactor Engineers figure this out) and the Control Rod drive inserting the reg rods to shut the reactor down before you even start to move in your safety rods. Once the reactor is shut down, you can then insert your safety rods. It is a balance between boron and control rod worth depending on the time in the core life.
...it sounds like information available to the reactor engineering department allows them to predict noble gas/iodine air concentrations during outage...
...planned evolutional ventilation line ups must also be available...
...given the current industry learning curve status, with 90% plus availabilty factors, deviations from the plan must be rare...
...recent conspicuous reductions in exposure, industry wide, and increased and ongoing sensitivity to exposure control suggests that noble gas/iodine outage issues will become, as did so many other exposure challenges, a thing of the past...
...this topic...it's beginning to look like this will be driven, as was the notable recent source term reductions, by the operations, chemistry and reactor engineering departments...
...if i'm right, this would allow the radiation protection department, during outages, to avoid the embarrassing experience of being reactive after the fact and, instead, be prepared for well understood and anticipated performance expectations...
...are the outage delays presented by noble gas/iodine issues, in the more conspicuous cases, of such magnitude as to seriously impact outage success...
...or, given the options available to the operations department, is an outage noble gas/iodine issue secondary, understandably, when overall outage success is at stake...