Investigations of Capacitor Discharge Welding for the Attachment of Endcaps to Molybdenum‐Based Nuclear Fuel Rod Cladding

This paper firstly gives a brief description about the principle of resistance-butt welding of nuclear fuel rod, and it points out that the power supply is a key technology for welding process. According to the welding process and the welded material properties, capacitor discharge power supply is devised as welding power supply. The design of charging circuit of single-phase bridge rectifier with SCR and control circuit is finished. The process of power discharge is simulated and the parameters (capacitance C, charging voltage uc) are optimized with Matlab. By the welding experiments, it shows that the output current curve is suitable for resistance-butt welding of nuclear fuel rods, and the test results of welding samples entirely consistent with process requirements.

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Interfacial structures of dissimilar materials joined by capacitor-discharge welding

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170402 ◽

1994 ◽

Vol 52 ◽

pp. 534-535

Author(s):

C. P. Doğan ◽

R. D. Wilson ◽

J. A. Hawk

Keyword(s):

Rapid Solidification ◽

Fusion Zone ◽

Dissimilar Materials ◽

Solidification Process ◽

Weld Interface ◽

Capacitor Discharge ◽

Fine Grained ◽

Iron Aluminum ◽

Conductive Ceramics ◽

Capacitor Discharge Welding

Capacitor Discharge Welding is a rapid solidification technique for joining conductive materials that results in a narrow fusion zone and almost no heat affected zone. As a result, the microstructures and properties of the bulk materials are essentially continuous across the weld interface. During the joining process, one of the materials to be joined acts as the anode and the other acts as the cathode. The anode and cathode are brought together with a concomitant discharge of a capacitor bank, creating an arc which melts the materials at the joining surfaces and welds them together (Fig. 1). As the electrodes impact, the arc is extinguished, and the molten interface cools at rates that can exceed 106 K/s. This process results in reduced porosity in the fusion zone, a fine-grained weldment, and a reduced tendency for hot cracking.At the U.S. Bureau of Mines, we are currently examining the possibilities of using capacitor discharge welding to join dissimilar metals, metals to intermetallics, and metals to conductive ceramics. In this particular study, we will examine the microstructural characteristics of iron-aluminum welds in detail, focussing our attention primarily on interfaces produced during the rapid solidification process.

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3D finite element analysis of a nuclear fuel rod with gap elements between the pellet and the cladding

Journal of Nuclear Science and Technology ◽

10.1080/00223131.2015.1037374 ◽

2015 ◽

Vol 53 (2) ◽

pp. 232-239 ◽

Cited By ~ 2

Author(s):

Chang-Hak Kang ◽

Sung-Uk Lee ◽

Dong-Yol Yang ◽

Hyo-Chan Kim ◽

Yong-Sik Yang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Nuclear Fuel ◽

Element Analysis ◽

3D Finite Element ◽

3D Finite Element Analysis ◽

Fuel Rod

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Enhancement of Heat Transfer Performance in Nuclear Fuel Rod Using Nanofluids and Surface Roughness Technique

Volume 8B: Heat Transfer and Thermal Engineering ◽

10.1115/imece2015-51476 ◽

2015 ◽

Cited By ~ 1

Author(s):

Kang Liu ◽

Titan C. Paul ◽

Leo A. Carrilho ◽

Jamil A. Khan

Keyword(s):

Heat Transfer ◽

Surface Roughness ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Nuclear Fuel ◽

Three Dimensional ◽

Pressurized Water ◽

Bulk Fluid ◽

Fuel Rod ◽

Dimensional Surface

The experimental investigations were carried out of a pressurized water nuclear reactor (PWR) with enhanced surface using different concentration (0.5 and 2.0 vol%) of ZnO/DI-water based nanofluids as a coolant. The experimental setup consisted of a flow loop with a nuclear fuel rod section that was heated by electrical current. The fuel rod surfaces were termed as two-dimensional surface roughness (square transverse ribbed surface) and three-dimensional surface roughness (diamond shaped blocks). The variation in temperature of nuclear fuel rod was measured along the length of a specified section. Heat transfer coefficient was calculated by measuring heat flux and temperature differences between surface and bulk fluid. The experimental results of nanofluids were compared with the coolant as a DI-water data. The maximum heat transfer coefficient enhancement was achieved 33% at Re = 1.15 × 105 for fuel rod with three-dimensional surface roughness using 2.0 vol% nanofluids compared to DI-water.

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Rod Bow Ultrasonic Measurements Possibilities

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4041277 ◽

2019 ◽

Vol 5 (3) ◽

Author(s):

Marcin Kopeć ◽

Martina Malá

Keyword(s):

Nuclear Fuel ◽

Nuclear Reactors ◽

Research Centre ◽

Fuel Rods ◽

Fuel Rod ◽

Nuclear Fuel Assembly ◽

Fuel Assemblies ◽

Ultrasonic Measurements ◽

History Of ◽

Fuel Particles

The ultrasonic (UT) measurements have a long history of utilization in the industry, also in the nuclear field. As the UT transducers are developing with the technology in their accuracy and radiation resistance, they could serve as a reliable tool for measurements of small but sensitive changes for the nuclear fuel assembly (FA) internals as the fuel rods are. The fuel rod bow is a phenomenon that may bring advanced problems as neglected or overseen. The quantification of this issue state and its probable progress may help to prevent the safety-related problems of nuclear reactors to occur—the excessive rod bow could, in the worst scenario, result in cladding disruption and then the release of actinides or even fuel particles to the coolant medium. Research Centre Rez has developed a tool, which could serve as a complementary system for standard postirradiation inspection programs for nuclear fuel assemblies. The system works in a contactless mode and reveals a 0.1 mm precision of measurements in both parallel (toward the probe) and perpendicular (sideways against the probe) directions.

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Probabilistic finite element analysis in heat transfer to a nuclear fuel rod bumper support

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406042690425 ◽

2004 ◽

Vol 218 (12) ◽

pp. 1499-1505

Author(s):

Rama Subba Reddy Gorla

Keyword(s):

Heat Transfer ◽

Finite Element ◽

Nuclear Fuel ◽

Cost Effective ◽

Distribution Functions ◽

Cumulative Distribution ◽

Element Analysis ◽

Transfer Rates ◽

Fuel Rod ◽

Design Variables

Heat transfer from a nuclear fuel rod bumper support was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall heat transfer rates due to the thermodynamic random variables. These results can be used to identify quickly the most critical design variables in order to optimize the design and to make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in heat transfer and to the identification of both the most critical measurements and the parameters.

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Identification of Non-Linear Vibration Parameters of a Nuclear Fuel Rod

Volume 8: 30th Conference on Mechanical Vibration and Noise ◽

10.1115/detc2018-86212 ◽

2018 ◽

Author(s):

Marco Amabili ◽

Prabakaran Balasubramanian ◽

Giovanni Ferrari ◽

Stanislas Le Guisquet ◽

Kostas Karazis ◽

...

Keyword(s):

Nuclear Fuel ◽

Harmonic Balance Method ◽

Resonance Phenomenon ◽

Pressurized Water ◽

Fuel Rods ◽

Fuel Rod ◽

Fuel Pellets ◽

Safety Margins ◽

Fuel Assemblies ◽

Non Linear

In Pressurized Water Reactors (PWR), fuel assemblies are composed of fuel rods, long slender tubes filled with uranium pellets, bundled together using spacer grids. These structures are subjected to fluid-structure interactions, due to the flowing coolant surrounding the fuel assemblies inside the core, coupled with large-amplitude vibrations in case of external seismic excitation. Therefore, understanding the non-linear response of the structure and, particularly, its dissipation, is of paramount importance for the choice of safety margins. To model the nonlinear dynamic response of fuel rods, the identification of nonlinear stiffness and damping parameters is required. The case of a single fuel rod with clamped-clamped boundary conditions was investigated by applying harmonic excitation at various force levels. Different configurations were implemented testing the fuel rod in air and in still water; the effect of metal pellets simulating nuclear fuel pellets inside the rods was also recorded. Non-linear parameters were extracted from some of the experimental response curves by means of a numerical tool based on the harmonic balance method. The axisymmetric geometry of fuel rods resulted in the presence of a one-to-one internal resonance phenomenon, which has to be taken into account modifying accordingly the numerical identification tool. The internal motion of fuel pellets is a cause of friction and impacts, complicating further the linear and non-linear dynamic behavior of the system. An increase of the equivalent viscous-based modal damping with excitation amplitude is often shown during geometrically non-linear vibrations, thus confirming previous experimental findings in the literature.

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