A Design of the Liquid-Metal Reactor Having an Almost Constant Reactivity

The objective of this effort is to minimize the excess reactivity of the liquid-metal reactor (LMR) over the core cycle, which will allow control rods to have less worth to control the core. This reduces the potential available transient reactivities and thus improves the LMR’s inherent safety characteristics. The core characteristics are modified to effect a constant k_eff over the cycle. Use of limited moderator and poison islands is incorporated into the core design to optimize the LMR core geometry and to help achieve the design objective. The feasibility of this concept is shown to be valid by an example, and further possible improvements in the method are suggested.