Non-linear vibrations of nuclear fuel rods

Balasubramanian, Prabakaran; Guisquet, Stanislas Le; Piccagli, Lorenzo; Karazis, Kostas; Painter, Brian; Amabili, Marco

doi:10.1016/j.nucengdes.2018.08.013

Cited by 26 publications

(10 citation statements)

References 33 publications

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“…This relative motion origins pellet-pellet friction and pellet-cladding shock in the transverse direction. Due to the recognized difficulty in correctly modeling those phenomena (Ferrari and Balasubramanian, 2018), these mechanisms are usually approximated. Benhamadouche in (Benhamadouche et al, 2009) uses a linear approximation method, by evaluating an equivalent mass density for the rod which takes into account pellet mass density.…”

Section: State Of the Artmentioning

confidence: 99%

Fuel rod nonlinear vibrations to detect and characterize Pellet-Cladding Interaction

d'Ambrosi

Destouches

Ricciardi

et al. 2021

Nuclear Engineering and Design

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Pellet-Cladding Interaction (PCI) in a Light Water Reactor is one of the major concerns to guarantee clad integrity while attempting at increasing the flexibility of PWR nuclear reactor operations to follow power grid demand. In order to forbid operations leading to clad failure, modeling capability to simulate the mechanism has improved through the years. Code development needs detailed and precise experimental data. Those data result from dedicated irradiation programs, named "power ramp tests", carried out in experimental devices in Material Testing Reactors (e.g. in France ISABELLE in OSIRIS in the past (Alberman et al., 1997), the ADELINE loop in the Jules Horowitz Reactor JHR in the next future (Cheymol et al., 2011)). Those irradiation devices are highly instrumented to collect the most relevant information with the highest possible accuracy. In parallel with information gained thanks to post-irradiation examination programs, research is working on innovative methodologies to detect and characterize PCI kinetics during the tests. In this frame, we investigate the technological feasibility to measure the effects of PCI, on the vibrations of a nuclear fuel rod externally submitted to the turbulent axial flow rate excitation. We designed and realized the out-of-pile IMPIGRITIA set-up to reproduce, in controlled laboratory conditions, the mechanical interaction originating in the nuclear reactor. A single PWR rod test section, reproducing the main relevant geometrical and material characteristics of ADELINE experimental system, is submitted to the hydraulic excitation representative of the real case. The local closure of the gap is obtained by means of a remotely controlled expansion system. Measurements of the transverse displacement of the sample rod are collected by Laser Doppler Vibrometry. In this paper we introduce the design of the mock-up and the associated measurement method, then we present the two experimental phases and their results: the first one in air, to show the feasibility of the measurement in air in controlled conditions; the second one under turbulent flow rate to state on the feasibility of the passive detection. At the end, conclusions and perspectives for the work are discussed.

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Section: State Of the Artmentioning

confidence: 99%

Fuel rod nonlinear vibrations to detect and characterize Pellet-Cladding Interaction

d'Ambrosi

Destouches

Ricciardi

et al. 2021

Nuclear Engineering and Design

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“…The presence of pellets inside the clad induces the appearance of non linear mechanical dissipations [6]. Internal attachment between pellets and clad as a consequence of gap closure limits those effects and impacts mode and frequencies of the system.…”

Section: The Measurement Principlementioning

confidence: 99%

“…Few researches have instead been carried out on the effects of non linear mechanisms arising from the presence of pellets within the fuel rod. It is generally argued that modeling those effects is rather difficult [6]. Benhamadouche in [7] proposed to evaluate an equivalent mass density for the rod which accounts for the presence of pellets.…”

mentioning

confidence: 99%

“…The fuel rod vibration is then evaluated, still assuming a linear behaviour. The non linear vibration of fuel rod has been recently studied by Ferrari et al [6]: his study concerned a 900 mm zircaloy clad, clamped at both extremities, eventually fulfilled with cylindrical tungsten carbide pellets modelling uranium fuel pellets in terms of dimensions and density. By comparing the dynamics of empty rod, fulfilled rod freely moving (no spring at one bottom of the fuel column) and fulfilled rod axially constrained in air and in quiescent water, they observed that pellets decrease natural frequencies of the rod and that axial constriction increases natural frequencies and reduced damping with respect to freely moving configuration, both in air and in water.…”

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confidence: 99%

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Experimental characterization of PCI impact on vibrating fuel rod under axial turbulent flow representative of JHR irradiation device ADELINE: Set-up conception and measurement method

et al. 2020

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Mechanical loading originating due to Pellet- Cladding Interaction (PCI) in PWR nuclear fuel rod constitutes a first order importance phenomenon when attempting at increasing the flexibility o f n uclear r eactors o peration t o f ollow grid demand. The need to improve the understanding of such complex multi-physics phenomena motivates the realization of particular irradiation sequences carried out in highly instrumented devices located in Material Testing Reactors. Among this kind, ADELINE irradiation device is being developed and will be installed in the future Jules Horowitz Reactor. In the perspective of designing the adapted measurement methodology to detect and characterize PCI phenomenology during irradiation, we present in this paper the experimental bench and its associated measurement program, designed to investigate eventual effects of PCI on the non-linear, flow i nduced v ibrations o fuclear fuel r od. A nalytical and numerical models cannot predictively describe the system due to the complexity of phenomena thus the IMPIGRITIA experimental set-up has been developed to reproduce the mechanical interaction between the pellet and the clad at low pressure, room temperature and out of neutron flux. T he d esigned test bench presents a clamped free single short rod, centred in the test section by mean of four centring elements. Different rod configurations are implemented and localized closure of the gap is remotely realized by means of a dilatation system. Laser Doppler Vibrometry is used to measure the transversal displacement of the sample rod in three different conditions: in air, in stagnant water and under turbulent axial flow r ate. T he experimental program and expected results are presented and discussed

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“…The structural instability that was induced by pressure pulsation and external force in nuclear power reactors, fuel pumps, air conditioning systems, and heat exchanger tubes has received increasing attention in recent years [1][2][3][4][5][6]. Nuclear fuel rod bundles that were exposed to coolant flow should be protected from structural failure [7].…”

Section: Introductionmentioning

confidence: 99%

Flexural Vibration Analysis of Nuclear Fuel Rod Bundles Interacting with Surrounding Fluid Subjected to Pressure Wave

2020

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The structural behavior of the nuclear rod bundles that consisted of cylindrical beams was predicted using the spectral element method (SEM) while considering the interaction with the surrounding fluid. Viscous fluid behavior was utilized in order to calculate the forces acting on the nuclear rod bundles from the incident pressure waves. The added mass and fluid coupling on the nuclear rod bundles were determined for the position patterns and gaps of each of the cylindrical beams. The pressure field from propagating waves in the surrounding fluid was calculated with respect to the boundary conditions of the surface of the vibrating structures. With the increasing number of nuclear rods and decreasing pressure wavelengths, the structural vibration of the nuclear rod bundles that were induced by the propagating forces affected the scattering events of the pressure field. The frequency response of the nuclear rod bundles from the pressure waves in the water exhibited smaller damping, because the incident pressure wave travels without fluid coupling due to the longer wavelength when compared with distance between rods. The proposed numerical method can be utilized for the detailed design for effective parameters of a supporting system to reduce the vibration of nuclear fuel rod bundles for safety control.

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Non-linear vibrations of nuclear fuel rods

Cited by 26 publications

References 33 publications

Fuel rod nonlinear vibrations to detect and characterize Pellet-Cladding Interaction

Fuel rod nonlinear vibrations to detect and characterize Pellet-Cladding Interaction

Experimental characterization of PCI impact on vibrating fuel rod under axial turbulent flow representative of JHR irradiation device ADELINE: Set-up conception and measurement method

Flexural Vibration Analysis of Nuclear Fuel Rod Bundles Interacting with Surrounding Fluid Subjected to Pressure Wave

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