Research and development on HTGR fuel in the HTTR project

Sawa, Kôichiro; Ueta, Shohei

doi:10.1016/j.nucengdes.2004.08.006

Cited by 67 publications

(38 citation statements)

References 19 publications

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“…In TRISO particles the concentration of ruthenium on the SiC surface is likely to be lower than in this thin film experiment, and consequently the reaction penetration depth into SiC should be lower as well. Experiments have shown that the rate-limiting step in fission product palladium (Pd) attack on SiC depends on the supply of Pd from the kernel and and the rate of diffusion of Pd through the buffer and inner PyC layer [22]. According to Sawa et al [22], studies of interaction of Pd with SiC have shown that the maximum reaction depth will depend on the amount of Pd released from the kernels.…”

Section: Discussionmentioning

confidence: 99%

“…Experiments have shown that the rate-limiting step in fission product palladium (Pd) attack on SiC depends on the supply of Pd from the kernel and and the rate of diffusion of Pd through the buffer and inner PyC layer [22]. According to Sawa et al [22], studies of interaction of Pd with SiC have shown that the maximum reaction depth will depend on the amount of Pd released from the kernels. The penetration depth has been shown to be directly proportional to the cube root of concentration of Pd.…”

Section: Discussionmentioning

confidence: 99%

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Microstructure evolution and diffusion of ruthenium in silicon carbide, and the implications for structural integrity of SiC layer in TRISO coated fuel particles

Munthali

Theron

Auret

et al. 2014

Journal of Nuclear Materials

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A thin film of ruthenium(Ru) was deposited on n-type 4H-SiC and 6H-SiC by electron beam deposition technique so as to study interface reaction of ruthenium with silicon carbide at various annealing temperatures, and in two annealing environments namely vacuum and air. The Ru-4H-SiC and Ru-6H-SiC films were both annealed isochronally in a vacuum furnace at temperatures ranging from 500 -1000 o C, and the second set of samples were also annealed in air for temperatures ranging from 100 o C to 600 o C. After each annealing temperature, the films were analysed by Rutherford Backscattering spectrometry (RBS). Raman analysis and x-ray diffraction analysis were also used to analyse some of the samples. RBS analysis of 4H-SiC annealed in a vacuum showed evidence of formation of ruthenium silicide (Ru 2 Si 3 ) and diffusion of Ru into SiC starting from annealing temperature of 700 o C going upwards. In the case of Ru-6H-SiC annealed in a vacuum, RBS analysis showed formation of Ru 2 Si 3 at 600 o C, in addition to the diffusion of Ru into SiC at 800 o C . Raman analysis of the Ru-4H-SiC and Ru-6H-SiC samples that were annealed in a vacuum at 1000 o C showed clear D and G carbon peaks which was evidence of formation of graphite . As for the samples annealed in air ruthenium oxidation started at a temperature of 400 o C and diffusion of Ru into SiC commenced at temperatures of 500 o C for both Ru-4H-SiC and Ru-6H-SiC. X-ray diffraction analysis of samples annealed in air at 600 o C showed evidence of formation of ruthenium silicide in both 4H and 6H-SiC but this was not corroborated by RBS analysis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Microstructure evolution and diffusion of ruthenium in silicon carbide, and the implications for structural integrity of SiC layer in TRISO coated fuel particles

Munthali

Theron

Auret

et al. 2014

Journal of Nuclear Materials

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“…The outer layer of PyC serves to structurally support the SiC, reduce tensile stress in the SiC after irradiation via layer shrinkage and acts as a final barrier to fission gas products should the SiC fail [46]. Additional details as to TRISO failure mechanisms are not discussed in detail in this manuscript, but can be found in the literature [47,48,46,49,50,51,52,53,54].…”

Section: Triso Fuel For Pebble Bed Systemmentioning

confidence: 99%

Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

Kramer¹

2010

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This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants.The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 µm of tungsten to mitigate x-ray damage. The first wall is cooled by Li 17 Pb 83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li 17 Pb 83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li 17 Pb 83 , separated from the Li 17 Pb 83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF 2 ), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles having a packing fraction of 20% in 2 cm 1 diameter fuel pebbles. The fission blanket is cooled by the same radial flibe flow that travels through perforated ODS walls to the reflector blanket. This reflector blanket is 75 cm thick comprised of 2 cm diameter graphite pebbles cooled by flibe. The flibe extraction plenum surrounds the reflector bed. Detailed neutronics designs studies are performed to arrive at the described design.The LFFH engine thermal power is controlled using a technique of adjusting the 6 Li/ 7 Li enrichment in the primary and secondary coolants. The enrichment adjusts system thermal power in the design by increasing tritium production while reducing fission. To perform the simulations and design of the LFFH engine, a new software program named LFFH Nuclear Control (LNC) was developed in C++ to extend the functionality of existing neutron transport and depletion software programs. Neutron transport calculations are performed with MCNP5. Depletion calculations are performed using Monteburns 2.0, which utilizes ORIGEN 2.0 and MCNP5 to perform a burnup calculation. LNC supports many design parameters and is capable of p...

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“…The result of the measurement determines the disposition of the fuel element, that is, to unload it as spent fuel or return it to the core [6]. If the measured burnup is incorrect, and spent fuel is recycled back into the core, the fuel cladding material can be damaged and increase the risk of radioactive material leakage [7][8][9][10]. In contrast, if the fuel has not yet reached the discharge burnup value, and it is discharged as spent fuel, this leads to increased cost and nuclear fuel waste [11].…”

Section: Introductionmentioning

confidence: 99%

Application of Anticoincidence Technology to Burn-Up Measurement Systems in High-Temperature Gas-Cooled Reactors

2018

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Nuclear energy is the focus of sustainable energy development worldwide. A hightemperature gas-cooled reactor (HTGR) plays a vital role in the development of nuclear energy. In a pebble-bed HTGR, the burn-up measurement system is important for ensuring reactor safety and economy. This study optimized a burn-up measurement system by adding anticoincidence technology with bismuth germanium oxide (BGO) crystals and a plastic scintillator used as anticoincidence detectors. Through Monte Carlo simulation, the detection effects of two different anticoincidence detectors on fuel elements were compared and analyzed. The study focused on varying the wall thickness and top thickness of these detectors to optimize the peak-to-Compton ratio (P/C). The results showed that the size of the BGO detector with the best anticoincidence effect (P/C of 727) consists in a diameter of 140 mm and a length of 210 mm. The best plastic scintillator size (P/C of 180) consists in a diameter of 260 mm and a length of 260 mm. Adding the anticoincidence technology lowered the Compton plateau of the measured gamma spectrum and significantly improved the detection performance of the burn-up measurement system. The new burn-up measurement system has improved detection precision not only for Cs-137 but also for low-activity nuclides.

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Research and development on HTGR fuel in the HTTR project

Cited by 67 publications

References 19 publications

Microstructure evolution and diffusion of ruthenium in silicon carbide, and the implications for structural integrity of SiC layer in TRISO coated fuel particles

Microstructure evolution and diffusion of ruthenium in silicon carbide, and the implications for structural integrity of SiC layer in TRISO coated fuel particles

Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

Application of Anticoincidence Technology to Burn-Up Measurement Systems in High-Temperature Gas-Cooled Reactors

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