Study on the Variation of Core Excess Reactivity and Shutdown Margin with Reactor Power in BTRR.

摘要

Core excess reactivity and shutdown margin are important parameters for safe and reliable operation of a nuclear reactor. In this experiment, core excess reactivity and shutdown margin were determined at different power levels of the BTRR. The results were then checked to ensure that the core excess reactivity and shutdown margin were within safe limits. From 0.144 kW to 2310 kW increase in reactor power, core excess reactivity decreased linearly from $7.53 to $5.36. For the same increase in power, magnitude of shutdown margin increased from $6.34 to $8.52. By extrapolating, it was found that shutdown margin would be $9.21 and core excess reactivity would be $4.67 at maximum reactor power of 3 MW. Core excess reactivity remained lower than $10.27 which is its safety limit, while shutdown margin was greater than $0.5 which is desired.