Author: James Yu-Chen Yaung
Publisher:
ISBN:
Category : Nuclear fuel claddings
Languages : en
Pages : 280

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Book Description

Author: Nathan Allen Capps
Publisher:
ISBN:
Category : Boiling water reactors
Languages : en
Pages : 111

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Book Description
In the late 1970s PCI related failures caused the implementation of startup ramp restrictions. These ramp restrictions where intended to reduce the stresses caused by pellet cladding contact. These ramp restrictions had a significant impact on Westinghouse fueled PWRs, reducing PCI related failure until 2003. Through investigation into these fuel rod failures lead to the conclusion that missing pellet surfaces (MPS) were the root cause of the failures. MPS are local geometric defects in nuclear fuel pellets that result from pellet mishandling or the manufacturing process. The presence of MPS defects can cause stress concentrations in the clad of sufficient magnitude to produce through-wall cladding failure for certain combinations of fuel burnup, and reactor power level or power change. Consequently, the impact of potential MPS defects has significant ly limited the rate of power increase, or ramp rate, in both pressurized and boiling water reactors (PWRs and BWRs, respectively). Improved three-dimensional (3-D) fuel performance models of MPS defect geometry can provide better understanding of the probability for pellet clad mechanical interaction (PCMI), and correspondingly the available margin against cladding failure by stress corrosion cracking (SCC). The Bison fuel performance code has been developed within the Consortium of Advanced Simulations of Light Water Reactors (CASL) to consider the inherently multi-physics and multi-dimensional mechanisms that control fuel behavior, including cladding stress concentrations resulting from MPS defects. Bison is built upon the Multi-physics Object-Oriented Simulation Environment (MOOSE) developed at Idaho National Laboratory (INL). MOOSE is a massively parallel finite element computational system that uses a Jacobian-free, Newton-Krylov (JFNK) method to solve coupled systems of non-linear partial differential equations. In addition, the MOOSE framework provides the ability to effectively use massively parallel computational capabilities needed to create high fidelity 3-D models of a fuel rod, as well as full-length R-Z rods, and R-Theta geometric representation. This PhD dissertation documents my contributions to the development of Bison, specifically focused on verification and validation of a 2-D, axi-symmetric version of Bison through benchmarking comparisons to Falcon model predictions and Halden Instrumented Fuel Assembly (IFA) experiments of both thermal and mechanical behavior. Initial benchmark comparisons indicate that Bison predictions agree quite well with 2-D Falcon predictions and Halden experimental data on fuel centerline temperature but that further developments are necessary for some models, including fission gas release and gaseous swelling. The mechanical behavior benchmarking study has compared predictions of clad deformation to dilatational measurements, and the results show promising agreement. Subsequently, this dissertation documents my evaluation of the cladding hoop stress distributions as a function of MPS defect geometry and the presence of discrete pellet cracks for a set of typical operating conditions in a PWR fuel rod, as a function of reactor operating history. These results provide a first step in a probabilistic approach to assess cladding failure during power maneuvers. My research provides insight into how varying pellet defect geometries affect the distribution of the cladding stress, as well as the temperature distributions within the fuel and clad; and are used to develop stress concentration factors for comparing 2-D and 3-D models. Finally, the objective of this dissertation is to develop a methodology to determine rod failure, and then to utilize the resulting failure criteria to evaluate specific historical MPS and PCI failures.

Author: Bernardo N. Nobrega
Publisher:
ISBN:
Category : Nuclear fuel claddings
Languages : en
Pages : 270

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Book Description

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The Zircaloy cladding of water reactor fuel rods is susceptible to local breach-type failure, commonly known as pellet-cladding interaction (PCI) failure, during operational and off-normal power transients after the fuel has achieved a sufficiently high burnup. An optimization of power ramp procedures or fuel rod fabrication to minimize the cladding failure would result in a significant decrease in radiation exposure of plant personnel due to background and airborne radioactivity as well as an extension of core life in terms of allowable off-gas radioactivity. As part of a program to provide a better understanding of the fuel rod faiure phenomenon and to facilitate the formulation of a better failure criterion, a mechanistic study of the deformation and fracture behavior of high-burnup spent-fuel cladding is in progress under simulated PCI conditions.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
In a program sponsored by the Fuel Systems Research Branch of the US Nuclear Regulatory Commission, a series of six electrically heated fuel rod simulation tests were conducted at Pacific Northwest Laboratory. The primary objective of these tests was to determine the susceptibility of irradiated pressurized-water reactor (PWR) Zircaloy-4 cladding to failures caused by pellet-cladding mechanical interaction (PCMI). A secondary objective was to acquire kinetic data (e.g., ridge growth or relaxation rates) that might be helpful in the interpretation of in-reactor performance results and/or the modeling of PCMI. No cladding failures attributable to PCMI occurred during the six tests. This report describes the testing methods, testing apparatus, fuel rod diametral strain-measuring device, and test matrix. Test results are presented and discussed.

Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 762

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Book Description
Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Author: OECD Nuclear Energy Agency
Publisher: OECD Publishing
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 74

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Book Description
Presents brief descriptions of 20 fuel-related safety criteria along with both the rationale for having such criteria and possible new design and operational issues which could have an effect on them.

Author: D. Cubicciotti
Publisher:
ISBN:
Category : Fission-product iodine
Languages : en
Pages : 21

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Book Description
A model for pellet-cladding interaction (PCI) fracture of light-water reactor (LWR) fuel rods is presented, the basis of which is that Zircaloy cladding fails by iodine stress corrosion cracking (SCC). Laboratory data on iodine SCC of irradiated Zircaloy provide the primary input to the model, but unirradiated Zircaloy SCC data and theoretical analyses are utilized to broaden the regime of validity to encompass the various power reactor observations.

Author:
Publisher: OECD Publishing
ISBN:
Category : Business & Economics
Languages : en
Pages : 562

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Book Description
This publication sets out the findings of an international seminar, held in Aix-en-Provence, France in March 2004, which considered recent progress in the field of pellet-clad interaction in light water reactor fuels. It also reviews current understanding of relevant phenomena and their impact on the nuclear fuel rod under the widest possible conditions, and about both uranium-oxide and mixed-oxide fuels.

Author: International Atomic Energy Agency
Publisher:
ISBN: 9789201043191
Category : Business & Economics
Languages : en
Pages : 65

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Book Description
This updated version of Nuclear Energy Series NF-T-2.1 provides information on all aspects of fuel failures in current nuclear power plant operations.