Analysis of neutronic performance of VVER 1200 reactor using accident tolerant fuel

Abstract Oxidation of zirconium cladding with high temperature steam releases additional heat and hydrogen which worsen the situations and may jeopardise safety barriers inside the reactor core. This article proposes coating zirconium clad with thin chromium layers or using low oxidation material such as silicon carbide (SiC). The normal UO 2 fuel is also replaced with a high density material such as uranium nitride (UN) or uranium carbide (UC). VVER-1200 core is modeled and the previous scenarios are applied. The results indicated that SiC clad achieves a higher 5 % K eff and cycle length than normal zirconium clad, while chromium coated zirconium reduces K eff and cycle length by 5 %. The new fuel types UN and UC increase the fuel cycle by 40 and 42 % respectively. UN and UC fuel have higher production of plutonium and Neptonium-237 than normal UO 2 case. Optimization of UN fuel performance was analyzed by studying the effect of ratio 14 N/ 15 N on the cycle length. Kinetic parameters and temperature coefficient of reactivity for fuel and moderator are calculated for fuel types under consideration. Neutron flux and power mapping are evaluated and investigated for all fuel types.