Safety of Light Water Reactor Fuel with Silicon Carbide Cladding PDF Download

Author: Youho Lee
Publisher:
ISBN:
Category :
Languages : en
Pages : 319

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Book Description
Structural aspects of the performance of light water reactor (LWR) fuel rod with triplex silicon carbide (SiC) cladding - an emerging option to replace the zirconium alloy cladding - are assessed. Its behavior under accident conditions is examined with an integrated approach of experiments, modeling, and simulation. High temperature (1100°C~1500°C) steam oxidation experiments demonstrated that the oxidation of monolithic SiC is about three orders of magnitude slower than that of zirconium alloys, and with a weaker impact on mechanical strength. This, along with the presence of the environmental barrier coating around the load carrying intermediate layer of SiC fiber composite, diminishes the importance of oxidation for cladding failure mechanisms. Thermal shock experiments showed strength retention for both [alpha]-SiC and [beta]-SiC, as well as A12O3 samples quenched from temperatures up to 1260°C in saturated water. The initial heat transfer upon the solid - fluid contact in the quenching transient is found to be a controlling factor in the potential for brittle fracture. This implies that SiC would not fail by thermal shock induced fracture during the reflood phase of a loss of coolant accident, which includes fuel-cladding quenching by emergency coolant at saturation conditions. A thermo-mechanical model for stress distribution and Weibull statistical fracture of laminated SiC cladding during normal and accident conditions is developed. It is coupled to fuel rod performance code FRAPCON-3.4 (modified here for SiC) and RELAP-5 (to determine coolant conditions). It is concluded that a PWR fuel rod with SiC cladding can extend the fuel residence time in the core, while keeping the internal pressure level within the safety assurance limit during steady-state and loss of coolant accidents. Peak burnup of 93 MWD/kgU (10% central void in fuel pellets) at 74 months of in-core residence time is found achievable with conventional PWR fuel rod design, but with an extended plenum length (70 cm). An easier to manufacture, 30% larger SiC cladding thickness requires an improved thermal conductivity of the composite layer to reduce thermal stress levels under steady-state operation to avoid failure at the same burnup. A larger Weibull modulus of the SiC cladding improves chances of avoiding brittle failure.

Author: Raul B. Rebak
Publisher: Elsevier
ISBN: 0128175044
Category : Technology & Engineering
Languages : en
Pages : 237

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Book Description
Accident Tolerant Materials for Light Water Reactor Fuels provides a description of what an accident tolerant fuel is and the benefits and detriments of each concept. The book begins with an introduction to nuclear power as a renewable energy source and the current materials being utilized in light water reactors. It then moves on to discuss the recent advancements being made in accident tolerant fuels, reviewing the specific materials, their fabrication and implementation, environmental resistance, irradiation behavior, and licensing requirements. The book concludes with a look to the future of new power generation technologies. It is written for scientists and engineers working in the nuclear power industry and is the first comprehensive work on this topic. Introduces the fundamental description of accident tolerant fuel, including fabrication and implementation Describes both the benefits and detriments of the various Accident Tolerant Fuel concepts Includes information on the process of materials selection with a discussion of how and why specific materials were chosen, as well as why others failed

Author: David Allan Bloore
Publisher:
ISBN:
Category :
Languages : en
Pages : 101

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Book Description
High temperature tolerance, chemical stability and low neutron affinity make silicon carbide (SiC) a potential fuel cladding material that may improve the economics and safety of light water reactors (LWRs). "Thick" SiC cladding (0.089 cm) is easier (and thus more economical) to manufacture than SiC of conventional Zircaloy (Zr) cladding thickness (0.057 cm). Five fuel and clad combinations are analyzed: Zr with solid U0 2 pellets, reduced fuel fraction "thick" SiC (Thick SiC) with annular U0 2 pellets, Thick SiC with solid U0 2/BeO pellets, reduced coolant fraction annular fuel with "thick" SiC (Thick SiC RCF), and Thick SiC with solid PuO2/ThO2 pellets. CASMO-4E and SIMULATE-3 have been utilized to model the above in a 193 assembly, 4-loop Westinghouse pressurized water reactor (PWR). A new program, CSpy, has been written to use CASMO/SIMULATE to conduct optimization searches of burnable poison layouts and core reload patterns. All fuel/clad combinations have been modeled using 84 assembly reloads, and Thick SiC clad annular U0 2 has been modeled using both 84 and 64 assembly reloads. Dual Binary Swap (DBS) optimization via three Objective Functions (OFs) has been applied to each clad/fuel/reload # case to produce a single reload enrichment equilibrium core reload map. The OFs have the goals of: minimal peaking, balancing lower peaking with longer cycle length, or maximal cycle length. Results display the tradeoff between minimized peaking and maximized cycle length for each clad/fuel/reload # case. The presented Zr reference cases and Thick SiC RCF cases operate for an 18 month cycle at 3587 MWth using 4.3% and 4.8% enrichment, respectively. A 90% capacity factor was applied to all SiC cladding cases to reflect the challenge to introduction of a new fuel. The Thick SiC clad annular U0 2 (84 reload cores) and Thick SiC U0 2/BeO exhibit similar reactor physics performance but require higher enrichments than 5%. The Thick SiC RCF annular U0 2 fuel cases provide the required cycle length with less than 5% enrichment. The Thick SiC clad PuO2/ThO 2 cores can operate with a Pu% of heavy metal of about 12%, however they may have unacceptable shutdown margins without altering the control rod materials.

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

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A significant effort is being placed on silicon carbide ceramic matrix composite (SiC CMC) nuclear fuel cladding by Light Water Reactor Sustainability (LWRS) Advanced Light Water Reactor Nuclear Fuels Pathway. The intent of this work is to invest in a high-risk, high-reward technology that can be introduced in a relatively short time. The LWRS goal is to demonstrate successful advanced fuels technology that suitable for commercial development to support nuclear relicensing. Ceramic matrix composites are an established non-nuclear technology that utilizes ceramic fibers embedded in a ceramic matrix. A thin interfacial layer between the fibers and the matrix allows for ductile behavior. The SiC CMC has relatively high strength at high reactor accident temperatures when compared to metallic cladding. SiC also has a very low chemical reactivity and doesn't react exothermically with the reactor cooling water. The radiation behavior of SiC has also been studied extensively as structural fusion system components. The SiC CMC technology is in the early stages of development and will need to mature before confidence in the developed designs can created. The advanced SiC CMC materials do offer the potential for greatly improved safety because of their high temperature strength, chemical stability and reduced hydrogen generation.

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

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Book Description
The U.S. Department of Energy Office of Nuclear Energy (DOE NE) established the Light Water Reactor Sustainability (LWRS) program to develop technologies and other solutions to improve the reliability, sustain the safety, and extend the life of current reactors. The Advanced LWR Nuclear Fuel Development Pathway in the LWRS program encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. Recent investigations of potential options for "accident tolerant" nuclear fuel systems point to the potential benefits of silicon carbide (SiC) cladding. One of the proposed SiC-based fuel cladding designs being investigated incorporates a SiC ceramic matrix composite (CMC) as a structural material supplementing an internal Zircaloy-4 (Zr-4) liner tube, referred to as the hybrid clad design. Characterization of the advanced cladding designs will include a number of out-of-pile (nonnuclear) tests, followed by in-pile irradiation testing of the most promising designs. One of the out-of-pile characterization tests provides measurement of the mechanical properties of the cladding tube using four point bend testing. Although the material properties of the different subsystems (materials) will be determined separately, in this paper we present results of 4-point bending tests performed on fully assembled hybrid cladding tube mock-ups, an assembled Zr-4 cladding tube mock-up as a standard and initial testing results on bare SiC-CMC sleeves to assist in defining design parameters. The hybrid mock-up samples incorporated SiC-CMC sleeves fabricated with 7 polymer impregnation and pyrolysis (PIP) cycles. To provide comparative information; both 1- and 2-ply braided SiC-CMC sleeves were used in this development study. Preliminary stress simulations were performed using the BISON nuclear fuel performance code to show the stress distribution differences for varying lengths between loading points and clad configurations. The 2-ply sleeve samples show a higher bend momentum compared to those of the 1-ply sleeve samples. This is applicable to both the hybrid mock-up and bare SiC-CMC sleeve samples. Comparatively both the 1- and 2-ply hybrid mock-up samples showed a higher bend stiffness and strength compared with the standard Zr-4 mock-up sample. The characterization of the hybrid mock-up samples showed signs of distress and preliminary signs of fraying at the protective Zr-4 sleeve areas for the 1-ply SiC-CMC sleeve. In addition, the microstructure of the SiC matrix near the cracks at the region of highest compressive bending strain shows significant cracking and flaking. The 2-ply SiC-CMC sleeve samples showed a more bonded, cohesive SiC matrix structure. This cracking and fraying causes concern for increased fretting during the actual use of the design. Tomography was proven as a successful tool to identify open porosity during pre-test characterization. Although there is currently insufficient data to make conclusive statements regarding the overall merit of the hybrid cladding design, preliminary characterization of this novel design has been demonstrated.

Author: Raul B. Rebak
Publisher:
ISBN: 0128175036
Category : Technology & Engineering
Languages : en
Pages : 236

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Book Description
Accident Tolerant Materials for Light Water Reactor Fuels provides a description of what an accident tolerant fuel is and the benefits and detriments of each concept. The book begins with an introduction to nuclear power as a renewable energy source and the current materials being utilized in light water reactors. It then moves on to discuss the recent advancements being made in accident tolerant fuels, reviewing the specific materials, their fabrication and implementation, environmental resistance, irradiation behavior, and licensing requirements. The book concludes with a look to the future of new power generation technologies. It is written for scientists and engineers working in the nuclear power industry and is the first comprehensive work on this topic. Introduces the fundamental description of accident tolerant fuel, including fabrication and implementation Describes both the benefits and detriments of the various Accident Tolerant Fuel concepts Includes information on the process of materials selection with a discussion of how and why specific materials were chosen, as well as why others failed

Author: P. B. Abramson
Publisher: CRC Press
ISBN: 9780891162629
Category : Technology & Engineering
Languages : en
Pages : 418

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Book Description
The Guidebook to Light Water Reactor Safety Analysis brings together government and expert researchers entrusted with maintaining the safety of reactors, preventing incidents, and for creating the guidelines for responding appropriately to emergency situations. It includes an overview presented by the U.S. Nuclear Regulatory Commission. One of the most relevant compendiums of its time, it's a volume of both historical and scientific significance and well worth the consideration of those currently involved with maintaining reactor safety..

Author: J. N. Lillington
Publisher: Elsevier Science & Technology
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 384

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Book Description
A summary of the main activities that have been carried out towards the development of advanced mechanistic models and computer codes for light water reactor safety (LWR) analysis. The principal features of the two main types of western LWRs are given.

Author: M. Gavrilas
Publisher: CRC Press
ISBN: 1351084968
Category : Nature
Languages : en
Pages : 312

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Book Description
This text arose from a study originally undertaken for the Department of Energy to characterize the principal safety features of light water reactors of western design. This text should be of use to professional engineers interested in safety assessment of operating light water reactors, students interested in the principal safety features of LWRs, and others interested in tracing the design evolution of light water reactors. However, while ambitious in its scope, this text should not be viewed as presenting the levels of reactor safety of the various families of western reactor designs.

Author: David Michael Carpenter
Publisher:
ISBN:
Category :
Languages : en
Pages : 189

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Book Description
(cont.) Because of the fuel geometry, the average fuel temperature is significantly lower, and the stiffness of the SiC cladding helps to maintain the geometry of the annulus during extended irradiation. Experimental projects have been undertaken to study the performance of both the annular fuel rods and silicon carbide duplex cladding. A post-irradiation examination of prototype annular fuel rods with VIPAC fuel, irradiated in the MIT reactor, has been designed and executed. Through this non-destructive examination, the disposition of the fuel grains is examined, and fuel burnup and fission gas release is estimated. These experimental results correlate well with computer calculations. A new irradiation facility was also planned and constructed that consists of a closed loop, operated at pressurized water reactor pressure, temperature, and chemistry conditions. This facility contains silicon carbide duplex cladding samples of various constructions, and it will be irradiated in the core of the MIT reactor for several months.