At ONS we typically don't require operator action at a frequency of less than an hour or so. Rod control is automatic.

However, we would have turnover during a period of no action required. Or RxE would update the prediction to account for the delay.

Carl

Carl D Fago
Reactor Engineering Supervisor
Oconee Nuclear Station
Duke Energy
864-885-3047

At Turkey Point, we normally schedule downpowers so they don't cross shift turnover. Recently, however, we had an emergent downpower that was in progress at shift turnover. At the time, the reactivity plan called for rod insertion every 15 minutes for axial power distribution control. During shift turnover (about 30 minutes), Ops did not move rods, so the axial shape diverged from predicted. It was still in the target band, but more positive than we wanted. (And it stayed more positive the rest of the way down.) Based on this experience, I wanted to find out how other sites manage Ops shift turnover during power changes. Does your site keep turnover time sacred with no reactivity changes, do you make maintaining the core "on track" a priority, or do you balance the two?

Mark Dicus
PTN Reactor Engineering
mark_dicus@fpl.com
305-246-6185