Experience of on-site disposal of production uranium-graphite nuclear reactor

Pavliuk, A. O.; Kotlyarevskiy, S. G.; Bespala, E. V.; Zakharova, Еlena V.; Ermolaev, V. M.; Volkova, A. G.

doi:10.1016/j.jenvrad.2018.01.005

Cited by 17 publications

(3 citation statements)

References 7 publications

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“…However, nickel, which stabilizes the austenite phase and gives steel its heat resistance, so necessary in high-temperature Gen-IV, experiences problems with induced radioactivity [7,8]. Nickel transition under neutron irradiation from the long-lived radioactive isotope nickel-63 makes reactor core structure disposal very problematic [9]. It is also known that matrix precipitates γ , which gives nickel steels increased strength, are unstable under irradiation [10,11].…”

Section: Introductionmentioning

confidence: 99%

Using the Radial Shear Rolling Method for Fast and Deep Processing Technology of a Steel Ingot Cast Structure

Arbuz,

Kawalek,

Panichkin

et al. 2023

Materials

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In advancing special materials, seamless integration into existing production chains is paramount. Beyond creating improved alloy compositions, precision in processing methods is crucial to preserve desired properties without drawbacks. The synergy between alloy formulation and processing techniques is pivotal for maximizing the benefits of innovative materials. By focusing on advanced deep processing technology for small ingots of modified 12% Cr stainless steel, this paper delves into the transformation of cast ingot steel structures using radial shear rolling (RSR) processing. Through a series of nine passes, rolling ingots from a 32 mm to a 13 mm diameter with a total elongation factor of 6.02, a notable shift occurred. This single-operation process effectuated a substantial change in sample structure, transitioning from a coarse-grained cast structure (0.5–1.5 mm) to an equiaxed fine-grained structure with peripheral grain sizes of 1–4 μm and an elongated rolling texture in the axial part of the bar. The complete transformation of the initial cast dendritic structure validates the implementation of the RSR method for the deep processing of ingots.

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Section: Introductionmentioning

confidence: 99%

Using the Radial Shear Rolling Method for Fast and Deep Processing Technology of a Steel Ingot Cast Structure

Arbuz,

Kawalek,

Panichkin

et al. 2023

Materials

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“…This parameter can be freely chosen to determine the expected value of HTR criticality. Reactor criticality is a variable that express the state of the reactor to get optimum operation [6,7]. Hence, it is important to simulate the reactor state at different variation of kernel radii and UO2 enrichment before conduct the operation in order to produce the expected criticality value [8,9].…”

Section: Introductionmentioning

confidence: 99%

Simulation Of Fuel Ball Dimensional Size And Uranium Enhancement For High Temperature Reactor

et al. 2020

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The purpose of this study was to examine the combined effect of enriching U-235 fuel and fuel fingers (Kernell) to determine its criticality (Keff). In this study, simulation of HTR (High Temperature Reactor) type reactors using MCNPX (Monte Carlo N eXtended Particles). The fuel used is UO2 which has a density of 10.4 gr / cm3, with impurity using 4 ppm Boron atom with Atomic B-10 fraction of 80.1% and B-11 of 19.9%. The variation of enrichment used is 7% to 15% and the fuel radius (Kernell) ranges from 160 µm to 340 µm. From the results, it was obtained that the optimum Keff occurs at 7% enrichment and the radius of the fuel of 310 µm was 1.01236.

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“…Preparation is ongoing at present to decommissioning several already shut down reactors including PUGRs, reactors of the Beloyarsk and Obninsk NPPs. Operations were completed in 2015 in accordance with the project on decommissioning EI-2 PUGR (Pavliuk et al 2018). Service life of the majority of NPP power units including the extension will expire in the nearest future during the period of about 10 -15 years.…”

Section: Introductionmentioning

confidence: 99%

Potential of application of IRT-T research reactor as the solution of the problem of graphite radwaste disposal

Pavliuk¹,

Kotlyarevskiy²,

Bespala³

et al. 2018

NUCET

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Aspects of handling irradiated graphite during decommissioning uranium-graphite reactors (UGR) of different types were investigated. It was demonstrated that handling reactor graphite is complicated by the presence in the composition of graphite of long-lived radionuclides, especially 14C, which may get entrained in biological cycles since carbon constitutes one of the main components of biological chains. Practical implementation of the process of selective separation of 14С can significantly reduce potential danger represented by graphite radioactive wastes due to the reduction of graphite activity as related to the isotope in question, as well as due to the reduction of the leaching rate by separating 14С isotope which is the most weakly bound within the graphite structure. Conclusion was formulated that analytical measurement methodologies and calculation methods allow reliably estimating only the total quantity of 14C accumulated in graphite, the contribution of 14C accumulation channel from 13C(n, γ)14C reaction, as well as the total contribution of 14N(n, p)14C reaction on nitrogen impurities and on nitrogen contained in purge gas. Method was suggested for estimating the values of contributions of different channels of accumulation on nitrogen impurities and nitrogen contained in purge gas using IRT-T research reactor (Tomsk, Tomsk Region). Parallel irradiation of batches of samples of non-irradiated (fresh) reactor-grade graphite contained in different gaseous media constitutes the basis of the study. Algorithm was suggested for calculating contributions of all channels of 14C accumulation according to the results of measurements to be obtained in the proposed studies. Recommendations were formulated on the use of all brands of graphite applied for manufacturing elements of graphite stacks of uranium-graphite reactors designed in Russia for determining selectively separated fraction of 14C for all types of graphite radioactive wastes by the companies in the RF which operated (are operating) the uranium-graphite reactors. Time of exposure of samples of irradiated graphite in the GEK-4 horizontal experimental channel of the IRT-T reactor was calculated and was found to be equal to ~ 10 days. Methodology was suggested for conducting a series of experiments for determining the values of contributions of 14C accumulation channels in the irradiated reactor graphite. The methodology suggested can be applied for determining fraction of selectively separated 14C in irradiated graphite elements of practically all uranium-graphite nuclear reactors, including reactors operated abroad Russia, under the condition of maintaining carbon dioxide gas atmosphere in one of the irradiated containers.

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Experience of on-site disposal of production uranium-graphite nuclear reactor

Cited by 17 publications

References 7 publications

Using the Radial Shear Rolling Method for Fast and Deep Processing Technology of a Steel Ingot Cast Structure

Using the Radial Shear Rolling Method for Fast and Deep Processing Technology of a Steel Ingot Cast Structure

Simulation Of Fuel Ball Dimensional Size And Uranium Enhancement For High Temperature Reactor

Potential of application of IRT-T research reactor as the solution of the problem of graphite radwaste disposal

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