Modeling and Analysis Framework for Core Damage Propagation During Flow-blockage-initiated Accidents in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory

Modeling and Analysis Framework for Core Damage Propagation During Flow-blockage-initiated Accidents in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

Get Book Here

Book Description
This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at the Oak Ridge National Laboratory (ORNL). Damage propagation is postulated to occur from thermal conduction between damaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur because of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A scoping study was conducted to learn what parameters are important for core damage propagation, and to obtain initial estimates of core melt mass for addressing recriticality and steam explosion events. The study included investigating the effects of the plate contact area, the convective heat transfer coefficient, thermal conductivity upon fuel swelling, and the initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects on damage propagation. The results provide useful insights into how various uncertain parameters affect damage propagation.

Modeling and Analysis Framework for Core Damage Propagation During Flow-blockage-initiated Accidents in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory

Modeling and Analysis Framework for Core Damage Propagation During Flow-blockage-initiated Accidents in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

Get Book Here

Book Description
This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at the Oak Ridge National Laboratory (ORNL). Damage propagation is postulated to occur from thermal conduction between damaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur because of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A scoping study was conducted to learn what parameters are important for core damage propagation, and to obtain initial estimates of core melt mass for addressing recriticality and steam explosion events. The study included investigating the effects of the plate contact area, the convective heat transfer coefficient, thermal conductivity upon fuel swelling, and the initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects on damage propagation. The results provide useful insights into how various uncertain parameters affect damage propagation.

Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 888

Get Book Here

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.

Study on Severe Accident Fuel Dispersion Behavior in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory

Study on Severe Accident Fuel Dispersion Behavior in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 18

Get Book Here

Book Description
Core flow blockage events have been identified as a leading contributor to core damage initiation risk in the Advanced Neutron Source (ANS) reactor. During such an accident, insufficient cooling of the fuel in a few adjacent blocked coolant channels out of several hundred channels, could also result in core heatup and melting under full coolant flow condition in other coolant channels. Coolant inertia forces acting on the melt surface would likely break up the melt into small particles. Under thermal-hydraulic conditions of ANS coolant channel, micro-fine melt particles are expected. Heat transfer between melt particle and coolant, which affects the particle breakup characteristics, was studied. The study indicates that the thermal effect on melt fragmentation seems to be negligible because the time corresponding to the breakup due to hydrodynamic forces is much shorter than the time for the melt surface to solidify. The study included modeling and analyses to predict transient behavior and transport of debris particles throughout the coolant system. The transient model accounts for the surface forces acting on the particle that result from the pressure variation on the surface, inertia, virtual mass, viscous force due to the relative motion of the particle in the coolant, gravitation, and resistance due to inhomogeneous coolant velocity radially across piping due to expected turbulent coolant motions. The results indicate that debris particles would reside longest in the heat exchangers because of lower coolant velocity there. Also they are entrained and move together in a cloud.

Government Reports Announcements & Index

Government Reports Announcements & Index PDF Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 710

Get Book Here

Book Description


INIS Atomindex

INIS Atomindex PDF Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 730

Get Book Here

Book Description


Modeling & Analysis of Core Debris Recriticality During Hypothetical Severe Accidents in the Advanced Neutron Source Reactor

Modeling & Analysis of Core Debris Recriticality During Hypothetical Severe Accidents in the Advanced Neutron Source Reactor PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 12

Get Book Here

Book Description
This paper discusses salient aspects of severe-accident-related recriticality modeling and analysis in the Advanced Neutron Source (ANS) reactor. The development of an analytical capability using the KEN05A-SCALE system is described including evaluation of suitable nuclear cross-section sets to account for the effects of system geometry, mixture temperature, material dispersion and other thermal-hydraulic conditions. Benchmarking and validation efforts conducted with KEN05-SCALE and other neutronic codes against critical experiment data are described. Potential deviations and biases resulting from use of the 16-group Hansen-Roach library are shown. A comprehensive test matrix of calculations to evaluate the threat of a criticality event in the ANS is described. Strong dependencies on geometry, material constituents, and thermal-hydraulic conditions are described. The introduction of designed mitigative features are described.

Analysis of Containment Performance and Radiological Consequences Under Severe Accident Conditions for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory

Analysis of Containment Performance and Radiological Consequences Under Severe Accident Conditions for the Advanced Neutron Source Reactor at the Oak Ridge National Laboratory PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 252

Get Book Here

Book Description
A severe accident study was conducted to evaluate conservatively scoped source terms and radiological consequences to support the Advanced Neutron Source (ANS) Conceptual Safety Analysis Report (CSAR). Three different types of severe accident scenarios were postulated with a view of evaluating conservatively scoped source terms. The first scenario evaluates maximum possible steaming loads and associated radionuclide transport, whereas the next scenario is geared towards evaluating conservative containment loads from releases of radionuclide vapors and aerosols with associated generation of combustible gases. The third scenario follows the prescriptions given by the 10 CFR 100 guidelines. It was included in the CSAR for demonstrating site-suitability characteristics of the ANS. Various containment configurations are considered for the study of thermal-hydraulic and radiological behaviors of the ANS containment. Severe accident mitigative design features such as the use of rupture disks were accounted for. This report describes the postulated severe accident scenarios, methodology for analysis, modeling assumptions, modeling of several severe accident phenomena, and evaluation of the resulting source term and radiological consequences.

Modeling and Analysis of Core Debris Recriticality During Hypothetical Severe Accidents in the Advanced Neutron Source Reactor

Modeling and Analysis of Core Debris Recriticality During Hypothetical Severe Accidents in the Advanced Neutron Source Reactor PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 29

Get Book Here

Book Description
This paper discusses salient aspects of severe-accident-related recriticality modeling and analysis in the Advanced Neutron Source (ANS) reactor. The development of an analytical capability using the KENO V.A-SCALE system is described including evaluation of suitable nuclear cross-section sets to account for the effects of system geometry, mixture temperature, material dispersion and other thermal-hydraulic conditions. Benchmarking and validation efforts conducted with KENO V.A-SCALE and other neutronic codes against critical experiment data are described. Potential deviations and biases resulting from use of the 16-group Hansen-Roach library are shown. A comprehensive test matrix of calculations to evaluate the threat of a recriticality event in the ANS is described. Strong dependencies on geometry, material constituents, and thermal-hydraulic conditions are described. The introduction of designed mitigative features is described.

Modeling & Analysis of Criticality-induced Severe Accidents During Refueling for the Advanced Neutron Source Reactor

Modeling & Analysis of Criticality-induced Severe Accidents During Refueling for the Advanced Neutron Source Reactor PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 16

Get Book Here

Book Description
This paper describes work done at the Oak Ridge National Laboratory (ORNL) for evaluating the potential and resulting consequences of a hypothetical criticality accident during refueling of the 330-MW Advanced Neutron Source (ANS) research reactor. The development of an analytical capability is described. Modeling and problem formulation were conducted using concepts of reactor neutronic theory for determining power level escalation, coupled with ORIGEN and MELCOR code simulations for radionuclide buildup and containment transport Gaussian plume transport modeling was done for determining off-site radiological consequences. Nuances associated with modeling this blast-type scenario are described. Analysis results for ANS containment response under a variety of postulated scenarios and containment failure modes are presented. It is demonstrated that individuals at the reactor site boundary will not receive doses beyond regulatory limits for any of the containment configurations studied.

Loss-of-coolant Accident Mitigation for the Advanced Neutron Source Reactor

Loss-of-coolant Accident Mitigation for the Advanced Neutron Source Reactor PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 15

Get Book Here

Book Description
A RELAP5 Advanced Neutron Source Reactor system model has been developed for the conceptual design safety analysis. Three major regions modeled are the core, the heat exchanger loops, and letdown/pressurizing system. The model has been used to examine design alternatives for mitigation of loss-of-coolant accident (LOCA) transients. The safety margins to the flow excursion limit and critical heat flux are presented. The results show that the core can survive an instantaneous double-ended guillotine of the core outlet piping break (610 mm-diameter) provided a cavitating venturi is employed. RELAP5 calculations were also used to determine the effects of using a non-instantaneous break opening times. Both break opening time and break formation characteristics were included in these parametric calculations. Accumulator optimization studies were also performed which suggest that an optimum accumulator bubble size exists which improves system performance under some break scenarios.