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Application of genetic algorithms in optimization of SFR nuclear reactor design

Żurkowski Wojciech, Sawicki Piotr, Kubiński Wojciech, Darnowski Piotr

Nukleonika

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2021

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Vol. 66, No. 4

139--145

EN

This work presents a demonstrational application of genetic algorithms (GAs) to solve sample optimization problems in the generation IV nuclear reactor core design. The new software was developed implementing novel GAs, and it was applied to show their capabilities by presenting an example solution of two selected problems to check whether GAs can be used successfully in reactor engineering as an optimization tool. The 3600 MWth oxide core, which was based on the OECD/NEA sodium-cooled fast reactor (SFR) benchmark, was used a reference design [1]. The first problem was the optimization of the fuel isotopic inventory in terms of minimizing the volume share of long-lived actinides, while maximizing the effective neutron multiplication factor. The second task was the optimization of the boron shield distribution around the reactor core to minimize the sodium void reactivity effect (SVRE). Neutron transport and fuel depletion simulations were performed using Monte Carlo neutron transport code SERPENT2. The simulation resulted in an optimized fuel mixture composition for the selected parameters, which demonstrates the functionality of the algorithm. The results show the efficiency and universality of GAs in multidimensional optimization problems in nuclear engineering.

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Microstructural Characterization of U-10wt.%Zr Fuel Slugs Containing Rare-Earth Elements Prepared by Modified Injection Casting

Lee Sang-Hun, Kim Ki-Hwan, Kuk Seoung-Woo, Park Jeong-Yong, Choi Ji-Hoon

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

953--957

EN

U-10wt.%Zr metallic fuel slugs containing rare-earth (RE: a rare-earth alloy comprising 53% Nd, 25% Ce, 16% Pr and 6% La) elements for a sodium-cooled fast reactor were fabricated by modified injection casting as an alternative method. The distribution, size and composition of the RE inclusions in the metallic fuel slugs were investigated according to the content of the RE inclusions. There were no observed casting defects, such as shrunk pipes, micro-shrinkage or hot tears formed during solidification, in the metallic fuel slugs fabricated by modified injection casting. Scanning electron micrographs and energy-dispersive X-ray spectroscopy (SEM-EDS) showed that the Zr and RE inclusions were uniformly distributed in the matrix and the composition of the RE inclusions was similar to that of a charged RE element. The content and the size of the RE inclusions increased slightly according to the charge content of the RE elements. RE inclusions in U-Zr alloys will have a positive effect on fuel performance due to their micro-size and high degree of distribution.

3

Surface Characterization of Metallic Fuel Slugs Prepared by Modified Injection Casting

Mun S.-U., Kim K.-H., Oh S.-J., Park J.-Y., Hong S.-I.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

1049--1053

EN

Metallic fuel slugs containing rare-earth (RE) elements have high reactivity with quartz (SiO2) molds, and a reaction layer with a considerable thickness is formed at the surface of metallic fuel slugs. The surface characterization of metallic fuel slugs is essential for safety while operating a fast reactor at elevated temperature. Hence, it is necessary to evaluate the surface characteristics of the fuel slugs so that chemical interaction between fuel slug and cladding can be minimized in the reactor. When the Si element causes a eutectic reaction with the cladding, it deteriorates the metallic fuel slugs. Thus, it is necessary to examine the characteristics of the surface reaction layer to prevent the reaction of the metallic fuel slugs. In this study, we investigated the metallurgical characteristics of the surface reaction layer of fabricated U-10wt.%Zr-Xwt.%RE (X = 0, 5, 10) fuel slugs using injection casting. The results showed that the thickness of the surface reaction layer increased as the RE content of the metallic fuel slugs increased. The surface reaction layer of the metallic fuel slug was mainly formed by RE, Zr and the Si, which diffused in the quartz mold.

4

Minor actinides impact on basic safety parameters of medium-sized sodium-cooled fast reactor

Darnowski P., Uzunow N.

Nukleonika

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2015

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Vol. 60, No. 1

171--179

EN

An analysis of the infl uence of addition of minor actinides (MA) to the fast reactor fuel on the most important safety characteristics was performed. A special emphasis was given to the total control rods worth in order to describe qualitatively and quantitatively its change with MA content. All computations were performed with a homogeneous assembly model of modifi ed BN-600 sodium-cooled fast reactor core with 0, 3 and 6% of MA. A model was prepared for the Monte Carlo neutron transport code MCNP5 for fresh fuel in the beginning-oflife (BOL) state. Additionally, some other parameters, such as Doppler constant, sodium void reactivity, delayed neutron fraction, neutron fl uxes and neutron spectra distribution, were computed and their change with MA content was investigated. Study indicates that the total control rods worth (CRW) decreases with increasing MA inventory in the fuel and confi rms that the addition of MA has a negative effect on the delayed neutron fraction.