Abstract
Previously, the neutronics design of a small and compact linear breed-and-burn fast reactor (B&BR) was completed. The reactor produces 400 MWth power, and it can operate with excess reactivity of less than 1$ for more than 50 years without refuelling. As the blanket fuel, the spent nuclear fuel (SNF) from existing light water reactors (LWRs) is used to reduce the burden from the problematic long-lived isotopes in SNF. However, by loading massive nuclides at the initial core, the impact of nuclear data uncertainty on the reactivity calculation results of SNF-fuelled B&BR at the beginning of life (BOL) is expected to be significant because these nuclides have different credentials in evaluated nuclear data libraries. In this study, the impact of nuclear library uncertainty from ENDF/B-VII.0 and ENDF/B-VII.1 on reactivity calculation of B&BR is evaluated using the continuous-energy TSUNAMI-3D module in the SCALE6.2 code package. The uncertainty of reactivity calculation results of B&BR caused by the inaccuracy of two libraries is significant (more than 2000 pcm), mainly from the uncertainty of 235,238U and 56Fe cross section. The energy-dependent sensitivity profiles show that they are significant at the fast energy range. The uncertainty of coolant void reactivity (CVR) is about 18%, and that of fuel temperature coefficient (FTC) is about 15% of the reactivity effect. The top five contributions for CVR accounted for elastic scattering of 238U, capture of 235,238U, and elastic scattering of 23Na and 56Fe. Meanwhile, the top contributors for FTC were accounted for elastic scattering of 238U and 56Fe, capture of 235U, and elastic scattering of 94Zr and 57Fe. It is highly recommended to improve the accuracy of those isotopes’ cross sections at the high energy range to provide a more reliable reactivity calculation for the fast system.
Highlights
The neutronics design of a small and compact linear breed-and-burn fast reactor (B&BR) was completed. e reactor produces 400 MWth power, and it can operate with excess reactivity of less than 1$ for more than 50 years without refuelling
The impact of nuclear library uncertainty from ENDF/B-VII.0 and ENDF/B-VII.1 on reactivity calculation of B&BR is evaluated using the continuous-energy TSUNAMI-3D module in the SCALE6.2 code package. e uncertainty of reactivity calculation results of B&BR caused by the inaccuracy of two libraries is significant, mainly from the uncertainty of 235,238U and 56Fe cross section. e energy-dependent sensitivity profiles show that they are significant at the fast energy range. e uncertainty of coolant void reactivity (CVR) is about 18%, and that of fuel temperature coefficient (FTC) is about 15% of the reactivity effect. e top five contributions for CVR accounted for elastic scattering of 238U, capture of 235,238U, and elastic scattering of 23Na and 56Fe
A small and compact linear B&BR has been designed [1,2,3,4,5]. It is considered a linear type because the blanket region is an axial blanket, and the breed-and-burn wave travels linearly from the initial core to the blanket region. e breed-and-burn wave discontinues when it Science and Technology of Nuclear Installations reaches the end of the blanket region. erefore, it can be concluded that, in the linear B&BR, the core lifetime depends on the length of the blanket region. e recently designed reactor is attractive
Summary
The neutronics design of a small and compact linear breed-and-burn fast reactor (B&BR) was completed. e reactor produces 400 MWth power, and it can operate with excess reactivity of less than 1$ for more than 50 years without refuelling. The neutronics design of a small and compact linear breed-and-burn fast reactor (B&BR) was completed. The spent nuclear fuel (SNF) from existing light water reactors (LWRs) is used to reduce the burden from the problematic long-lived isotopes in SNF. A small and compact linear B&BR has been designed [1,2,3,4,5] It is considered a linear type because the blanket region is an axial blanket, and the breed-and-burn wave travels linearly from the initial core to the blanket region. Besides being safer by producing lower power, it uses spent nuclear fuel (SNF) from the existing light water reactors (LWRs) as its blanket fuel to reduce the environmental burden from the problematic long-lived isotopes in the SNF. It is expected that the blanket fuel consists of almost all isotopes available in the nuclear data library
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