Ho Cheol Shin

Optimal Control Rod for Boron-Free Small Modular PWR

This paper proposes a new control rod material for a boron-free small modular pressurized water reactor (SMPWR) to compensate the loss of the soluble boron. To design control rod for SMPWR is difficult due to the large amount of reactivity control necessity and the multiple roles of control rod, i.e., the excess reactivity control, the coarse/fine power control, and the axial shape control and shutdown. This paper presents a study of various control rod materials: B4C, Ag-In-Cd, and HfB2. The rod worth and the excess reactivity control capability will be assessed for the SMPWR using Studsvik’s reactor core design code system, CASMO-4E/SIMULATE-3.

Cutback sensitivity test for boron-free small modular PWR

A soluble boron-free small modular pressurized water reactor (SMPWR) uses burnable absorbers (BA) instead of soluble boron to reduce excess reactivity. As a consequence, the fuel cycle length can be shortened by the residual penalty of BA. This paper performs cutback sensitivity tests to extend the cycle length. The influence of the height of the cutback, of the 235U enrichment rate, and of the BA material on the power peaking factor (Fq), the axial offset (AO) and the fuel cycle length is analyzed with the reactor core design system, CASMO-4E/SIMULATE-3 code system.