Publication: Diverse approaches to manage early excess reactivity of VVER 1200 reactor
Дата
2025
Авторы
Afroza Shelley
Md. Abidur Rahman Ishraq
Journal Title
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Издатель
НИЯУ МИФИ
Аннотация
The objective of this study is to manage the initial excess reactivity of the VVER-1200 reactor through different approaches, including the use of burnable absorbers and control rods in fuel assemblies with varying enrichments (from 4.95 wt.% to 2.0 wt.%) by using the Monte Carlo code Serpent. It is found that 30 integrated burnable absorbers (IBAs) rods are required to reduce the infinite multiplication factor (kinf) from 1.32408 to 1.06983 in assemblies containing 4.95 wt.% enriched fuel. On the other hand, assemblies with enrichment below 2.5 wt.% do not require any IBA rods. Control rods (CRs) can also effectively reduce excess reactivity at the beginning of life (BOL), provided they are inserted more than 80% of the assembly’s height. When fully inserted, the CRs provide a reactivity worth of 85.5 pcm/cm in 4.95 wt.% enriched assemblies at BOL. Fuel enrichment has a significant impact on delayed neutron fraction as well as the FTC, and MTC. While the effect of IBA rods on these parameters is found to be insignificant; however they do harden the neutron spectrum at the BOL due to the thermal neutron absorption by isotopes 155Gd and 157Gd.
Описание
Ключевые слова
MTC , FTC , Delayed Neutron , Enrichment , Control Rod , IBA Rod , Burnable absorbers , Excess Reactivity , VVER-1200
Цитирование
Shelley A, Ishraq MdAR (2025) Diverse approaches to manage early excess reactivity of VVER 1200 reactor. Nuclear Energy and Technology 11(2): 145-154. https://doi.org/10.3897/nucet.11.151728