Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A preliminary set of nine evaluation models (EMs) was added to the FRAPCON-1 computer code, which is used to calculate fuel rod behavior in a nuclear reactor during steady-state operation. The intent was to provide an audit code to be used in the United States Nuclear Regulatory Commission (NRC) licensing activities when calculations of conservative fuel rod temperatures are required. The EMs place conservatisms on the calculation of rod temperature by modifying the calculation of rod power history, fuel and cladding behavior models, and materials properties correlations. Three of the nine EMs provide either input or model specifications, or set the reference temperature for stored energy calculations. The remaining six EMs were intended to add thermal conservatism through model changes. To determine the relative influence of these six EMs upon fuel behavior calculations for commercial power reactors, a sensitivity study was conducted. That study is the subject of this paper.
Influence of FRAPCON-1 Evaluation Models on Fuel Behavior Calculations for Commercial Power Reactors. [PWR ; BWR].
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A preliminary set of nine evaluation models (EMs) was added to the FRAPCON-1 computer code, which is used to calculate fuel rod behavior in a nuclear reactor during steady-state operation. The intent was to provide an audit code to be used in the United States Nuclear Regulatory Commission (NRC) licensing activities when calculations of conservative fuel rod temperatures are required. The EMs place conservatisms on the calculation of rod temperature by modifying the calculation of rod power history, fuel and cladding behavior models, and materials properties correlations. Three of the nine EMs provide either input or model specifications, or set the reference temperature for stored energy calculations. The remaining six EMs were intended to add thermal conservatism through model changes. To determine the relative influence of these six EMs upon fuel behavior calculations for commercial power reactors, a sensitivity study was conducted. That study is the subject of this paper.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A preliminary set of nine evaluation models (EMs) was added to the FRAPCON-1 computer code, which is used to calculate fuel rod behavior in a nuclear reactor during steady-state operation. The intent was to provide an audit code to be used in the United States Nuclear Regulatory Commission (NRC) licensing activities when calculations of conservative fuel rod temperatures are required. The EMs place conservatisms on the calculation of rod temperature by modifying the calculation of rod power history, fuel and cladding behavior models, and materials properties correlations. Three of the nine EMs provide either input or model specifications, or set the reference temperature for stored energy calculations. The remaining six EMs were intended to add thermal conservatism through model changes. To determine the relative influence of these six EMs upon fuel behavior calculations for commercial power reactors, a sensitivity study was conducted. That study is the subject of this paper.
Energy Research Abstracts
Description and Characterization of Evaluation Models in FRAPCON-1
Author: E. Thomas Laats
Publisher:
ISBN:
Category : Nuclear fuel rods
Languages : en
Pages : 52
Book Description
Publisher:
ISBN:
Category : Nuclear fuel rods
Languages : en
Pages : 52
Book Description
FRAPCON-2 Developmental Assessment
Nuclear News
INIS Atomindex
An Improved Structural Mechanics Model for the FRAPCON Nuclear Fuel Performance Code
Author: Alexander James Mieloszyk
Publisher:
ISBN:
Category :
Languages : en
Pages : 163
Book Description
In order to provide improved predictions of Pellet Cladding Mechanical Interaction (PCMI) for the FRAPCON nuclear fuel performance code, a new model, the FRAPCON Radial-Axial Soft Pellet (FRASP) model, was developed. This new model uses 1.5D structural mechanics to represent both the fuel pellet and cladding along with their interaction via interfacial forces. The fuel pellet and cladding are modeled as concentric annular cylinders using similar governing equations with slight differences to allow for cracking of the semi-brittle fuel matrix and plastic behavior in a ductile cladding. By accounting for the structural mechanics of the fuel pellet, FRASP allows for stress-induced deformations which were previously unattainable with the rigid pellet model used by FRAPCON. Because of the significant differences between FRAPCON's previous mechanical model, FRACASI, and FRASP, simply replacing the treatment of PCMI within the code was not a viable option. This led to a complete replacement of FRACAS-I and all associated fuel rod structural calculations. Feedback effects are likely to result from such a major change due to the complexity of nuclear fuel simulation. The potential for these feedback effects dictated a preliminary validation of FRASP against FRACAS-I for typical case. This evaluation was not limited to the investigation of mechanical parameters, but covered a wide variety of predicted parameters by the new and unaltered versions of FRAPCON. The differences which were found in this validation were limited in nature and easily attributable to the differing assumptions of FRASP and FRACAS-I. The newly developed mechanical model was used with the improved fuel behavior models of FRAPCON-EP (Enhanced Performance) to assess the mechanical behavior of fuel rods with a composite silicon carbide (SiC) cladding under Pressurized Water Reactor (PWR) conditions. The fuel rod designs were selected to match previously chosen values for both solid and annular fuel pellets under current and uprated power conditions. Unlike FRACAS-I, which is hindered by the rigid pellet model, FRASP was able to successfully analyze PCMI behavior with the more rigid SiC, even though "hard contact" of the fuel and cladding was encountered. Simulations using the improved models showed that the SiC clad fuel rods may not provide adequate safety margins at the desired burnup, or simply fail to achieve their desired final burnup. Previous analyses which relied on FRAPCON-3.3 may have been overly optimistic in this regard. The new, more conservative predictions are largely due to FRASP's treatment of the inner radius of the annular fuel pellets, which was assumed not to change in previous versions of FRAPCON. These new findings suggest that SiC fuel rod general design and operation require further optimization.
Publisher:
ISBN:
Category :
Languages : en
Pages : 163
Book Description
In order to provide improved predictions of Pellet Cladding Mechanical Interaction (PCMI) for the FRAPCON nuclear fuel performance code, a new model, the FRAPCON Radial-Axial Soft Pellet (FRASP) model, was developed. This new model uses 1.5D structural mechanics to represent both the fuel pellet and cladding along with their interaction via interfacial forces. The fuel pellet and cladding are modeled as concentric annular cylinders using similar governing equations with slight differences to allow for cracking of the semi-brittle fuel matrix and plastic behavior in a ductile cladding. By accounting for the structural mechanics of the fuel pellet, FRASP allows for stress-induced deformations which were previously unattainable with the rigid pellet model used by FRAPCON. Because of the significant differences between FRAPCON's previous mechanical model, FRACASI, and FRASP, simply replacing the treatment of PCMI within the code was not a viable option. This led to a complete replacement of FRACAS-I and all associated fuel rod structural calculations. Feedback effects are likely to result from such a major change due to the complexity of nuclear fuel simulation. The potential for these feedback effects dictated a preliminary validation of FRASP against FRACAS-I for typical case. This evaluation was not limited to the investigation of mechanical parameters, but covered a wide variety of predicted parameters by the new and unaltered versions of FRAPCON. The differences which were found in this validation were limited in nature and easily attributable to the differing assumptions of FRASP and FRACAS-I. The newly developed mechanical model was used with the improved fuel behavior models of FRAPCON-EP (Enhanced Performance) to assess the mechanical behavior of fuel rods with a composite silicon carbide (SiC) cladding under Pressurized Water Reactor (PWR) conditions. The fuel rod designs were selected to match previously chosen values for both solid and annular fuel pellets under current and uprated power conditions. Unlike FRACAS-I, which is hindered by the rigid pellet model, FRASP was able to successfully analyze PCMI behavior with the more rigid SiC, even though "hard contact" of the fuel and cladding was encountered. Simulations using the improved models showed that the SiC clad fuel rods may not provide adequate safety margins at the desired burnup, or simply fail to achieve their desired final burnup. Previous analyses which relied on FRAPCON-3.3 may have been overly optimistic in this regard. The new, more conservative predictions are largely due to FRASP's treatment of the inner radius of the annular fuel pellets, which was assumed not to change in previous versions of FRAPCON. These new findings suggest that SiC fuel rod general design and operation require further optimization.
Evaluation of Power Reactor Fuel Rod Analysis Capabilities: Code evaluation
Author: Dennis R. Coleman
Publisher:
ISBN:
Category : Fuel burnup (Nuclear engineering)
Languages : en
Pages : 104
Book Description
Publisher:
ISBN:
Category : Fuel burnup (Nuclear engineering)
Languages : en
Pages : 104
Book Description
Government Reports Announcements & Index
FRAPCON-1
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
FRAPCON is a FORTRAN IV computer code which predicts the steady state long-term burnup response of a light water reactor fuel rod. The coupled effects of fuel and cladding deformation, temperature, and internal gas pressure on the behavior of the fuel rod are considered in determining fuel rod response. The cladding deformation model includes multi-axial, elasto-plastic analysis and considers both primary and secondary creep. The fuel temperature model considers the effects of fuel cracking and relocation in determining the fuel temperature distribution. Burnup dependent fission gas generation and release is included in calculating fuel rod internal pressure. An integral fuel rod failure subcode determines failure and failure modes based on the operating conditions at each timestep. The material property subcode, MATPRO, provides gas, fuel and cladding properties to the computational subcodes in FRAPCON. No material properties need to be supplied by the code user. FRAPCON is a completely modular code with each major computational subcode isolated within the code and coupled to the main code by subroutine calls and data transfer through argument lists. FRAPCON is soft-coupled to the transient fuel rod code, FRAP-T, to provide initial conditions to initiate analysis of such off-normal transients as a loss-of-coolant accident. The code is presently programmed and running on a CDC 7600 computer.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
FRAPCON is a FORTRAN IV computer code which predicts the steady state long-term burnup response of a light water reactor fuel rod. The coupled effects of fuel and cladding deformation, temperature, and internal gas pressure on the behavior of the fuel rod are considered in determining fuel rod response. The cladding deformation model includes multi-axial, elasto-plastic analysis and considers both primary and secondary creep. The fuel temperature model considers the effects of fuel cracking and relocation in determining the fuel temperature distribution. Burnup dependent fission gas generation and release is included in calculating fuel rod internal pressure. An integral fuel rod failure subcode determines failure and failure modes based on the operating conditions at each timestep. The material property subcode, MATPRO, provides gas, fuel and cladding properties to the computational subcodes in FRAPCON. No material properties need to be supplied by the code user. FRAPCON is a completely modular code with each major computational subcode isolated within the code and coupled to the main code by subroutine calls and data transfer through argument lists. FRAPCON is soft-coupled to the transient fuel rod code, FRAP-T, to provide initial conditions to initiate analysis of such off-normal transients as a loss-of-coolant accident. The code is presently programmed and running on a CDC 7600 computer.