After a reactor shuts down, the concentration of xenon-135 can continue to rise for several hours. This strong neutron absorber changes core reactivity and may temporarily prevent restart. Understanding the xenon pit explains why both the current power level and the operating history matter in reactor operation.
Uranium concentrate must undergo conversion and enrichment before it can be used to make fuel for conventional light water reactors. Part 3 of the From Ore to Energy series explains why uranium is converted to UF₆, how physical separation changes the proportion of uranium-235, and what happens to the enriched and depleted streams.
In the original RBMK design, initial insertion of fully withdrawn control and safety rods could introduce positive reactivity locally. Drawing on INSAG-7, this article examines the physics of positive SCRAM, its relationship to void reactivity, and the design changes after Chernobyl, focusing on the reliability of the shutdown function.
How is uranium ore processed into the concentrate known as yellowcake? Part 2 of From Ore to Energy explores uranium mining, in situ recovery and ore processing. It explains the distinction between concentration and isotopic enrichment, and shows why tailings management, worker protection and site remediation are integral to this process.
