Reactivity addition events during shutdown for SRS K-production reactor

Safety analyses have been performed to confirm that the Savannah River Site (SRS) K-production reactor will not inadvertently achieve recriticality from a shutdown condition due to positive reactivity additions caused by [sup 135]Xe decay, core component movement, and/or cooldown events. This confirmatory analysis is necessary for the K reactor because, under worst-case bounding conditions, the total negative reactivity inserted in the form of neutron-absorbing rods during an automatic reactor scram that can be taken credit for in the safety analysis report (SAR) Chapter 15 analyses is less than the combined positive reactivity that can be inserted. The analysis examines all reactivity additions that can occur during shutdown that were not covered elsewhere in the non-loss-of-coolant-accident safety analyses performed for Chapter 15 of the K-reactor SAR. The analysis was divided into two types of cases: immediately following a scram and any other shutdown condition.