Swing Reactivity Calculation of Accelerator Driven System Subcritical Reactor 100 MWth

Abstract

Accelerator driven system (ADS) applied subcritical reactor which can effectively transmute plutonium, minor actinide, and thorium as nuclear waste. In order to lower the amount of nuclear wastes sent to the geological repository, an optimized scattered reloading scheme for ADS is proposed to maximize the discharge burnup and lower the burnup reactivity loss. Accelerator Driven System ( ADS) system lead store duce of the amount of the Pu and Th, so it’s not only can create the addition of energy source, but also high safety reactor. The fuel used in this reactor is obtained from LWR’s spent fuel and thorium - based fuel. The use of thorium-based fuel can lower k-eff of the core and generates U-233, which is a nuclear fuel for critical reactor. Neutron obtained from spallation reaction of Pb-Bi target is placed in the center of the core. This ADS design produces subcritical k-eff during the operation of the reactor and can decrease the amount of fission products of LWR’s spent fuel and produce U-233. The objective of the calculation are criticality as a function of burn up (swing reactivity) in the subcritical assembly fuel. this ADS fuel is originated from UO2 PWR spent fuel with enrichment of 3,4 % and burn up level 64 GWD or 100 MWt for 1825 days calculation of accelerator driven system subcritical reactor 100MWth has been performed. This research d one by using Origen2.1, SRAC2006 and MCNP6 Code. Based on the results swing reactivity of the calculation by using Origen2.1 Code, indicates that Kinf whose value be low subcritical condition (k-eff<1) is Kinf resulted fromTh-232 with percentage from 10% to 5%(as U-238 substitution).the calculation by using SRAC2006 Code indicates that at the beginning of life (BOL), the k-eff of ADS design with 50 cm thickness is 0.9821491 and at the end of life (EOL) k-eff is 0.9396284 and the calculation by using MCNP6 Code. At beginning of life (BOL), the k-eff of ADS design is 0.9847 and the end of life (EOL) is 0.9823.The presence of plutonium and mayor actinides makes k-eff get slightly lower. Arrangement at this ADS model is performed to produce subcritical condition, in which an increase in fuel volume cause k-eff>I.