Modelling of PWR lower head failure under severe accident loading using improved shells of revolution theory

Koundy, V.; Hoang, Nguyen-Hieu

doi:10.1016/j.nucengdes.2008.03.006

Cited by 10 publications

(2 citation statements)

References 9 publications

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“…The tests led to the same conclusions about the material behaviour variability as the LHF-OLHF tests for the French material. Some simplified numerical analysis were made in order to simulate these tests [7][8][9][10]. From this established fact, a lot of tests were carried out in order to characterize the French material behaviour (16MND5) according to its steel grades [11].…”

Section: Pvp2009-77258mentioning

confidence: 99%

Unstable Crack Propagation Under Severe Accident Scenario Conditions in a Pressurized Water Reactor

Tardif

Coret

Combesure

2009

Volume 5: High Pressure Technology; Nondestructive Evaluation Division; Student Paper Competition

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In the case of a severe accident scenario of a pressurized water reactor which includes cracking of the vessel bottom head, it is crucial to predict the leak rate and hence the crack size for the ex-vessel accident management. We present an experimental framework to analyze the crack propagation under such severe conditions for different 16MND5 French nuclear steel grades. An original experimental setup has been designed in order to perform bi-axial tests (tensile load independent of internal pressure) at high temperatures (1180K – 1280K) on tubular test specimens. The temperature loading and the mechanical loading can be set to reproduce the stress distribution of the hemispherical vessel bottom head submitted to an internal pressure. Moreover, the test was designed to be easily transposable to the real structure in terms of crack propagation and depressurization thanks to an energy based scaling methodology. We observed the crack initiation and propagation with two high speed digital cameras. Force, internal pressure, displacement and temperature fields were also measured and synchronized with the optical measurements. The different creep stages are observed and characterized. The crack propagation and opening history have been measured. During crack initiation and propagation stages, the depressurization can be correlated with the crack geometry. Finally, the setup has been designed in order to validate future numerical analysis.

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Section: Pvp2009-77258mentioning

confidence: 99%

Unstable Crack Propagation Under Severe Accident Scenario Conditions in a Pressurized Water Reactor

Tardif

Coret

Combesure

2009

Volume 5: High Pressure Technology; Nondestructive Evaluation Division; Student Paper Competition

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“…The first and second programs were performed at the Sandia National Laboratory (SNL, USA) and the third program was performed at the Royal Institute of Technology (KTH, Sweden). All three programs provided data for model development and validation, and have led to a better understanding of the mechanical behavior of the RPV lower head (Koundy and Hoang, 2008). The numerical analyses revealed that there are still uncertainties and deviations between analytical codes and models (Nicolas et al, 2003;Willschütz et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

A thermal structural analysis tool for RPV lower head behavior during severe accidents with core melt

Madokoro

Miassoedov

Schulenberg

2018

Mechanical Engineering Letters

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The Fukushima Daiichi Nuclear Power Plant accident showed a significant effect on the environment due to the release of a large amount of radioactive material. To prevent the damage of the reactor pressure vessel (RPV), an in-vessel melt retention (IVR) by external reactor vessel cooling is considered to be a key severe accident management strategy. For its success, investigation of the thermal-mechanical behavior of the RPV lower head is of importance. The main objective of this study is the development of a thermal structural calculation tool for simulating the failure process and the visco-plastic behavior of the RPV lower head wall during the late phase of a core-melt severe accident. OpenFOAM, an open-source toolbox for developing numerical solvers, was used for the calculation platform. Thermal behavior of the molten pool in the RPV lower head is simulated by the phasechange effective convectivity model (PECM). One of the LIVE (Late In-Vessel Phase Experiments) experiments was analyzed for an evaluation purpose and reasonable results were obtained. The solver was then extended to couple PECM with a structural analysis model that considers thermal expansion, plasticity, creep and material damage. Two FOREVER (Failure Of Reactor Vessel Retention) tests, each of which uses different type of steel, were analyzed: EC-FOREVER-2 with French RPV steel 16MND5 and EC-FOREVER-4 with American RPV steel SA533B1. The deformation and failure time agreed reasonably well with the measured data. In addition, the failure mode was also well predicted qualitatively. The numerical analysis showed that the developed tool has a capability of simulating the lower head thermal structural behavior.

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Numerical study on ICI nozzle ejection of external vessel cooling reactors under severe accident conditions

Bae

Cho

Bang

2017

Int. J. Precis. Eng. Manuf.

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Modelling of PWR lower head failure under severe accident loading using improved shells of revolution theory

Cited by 10 publications

References 9 publications

Unstable Crack Propagation Under Severe Accident Scenario Conditions in a Pressurized Water Reactor

Unstable Crack Propagation Under Severe Accident Scenario Conditions in a Pressurized Water Reactor

A thermal structural analysis tool for RPV lower head behavior during severe accidents with core melt

Numerical study on ICI nozzle ejection of external vessel cooling reactors under severe accident conditions

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