Open Access. Powered by Scholars. Published by Universities.^{®}

Articles **1** - **5** of ** 5**

## Full-Text Articles in Nuclear Engineering

Stochastic Memory Process And Its Application To Cumulative Outage Time In Nuclear Power Plants , Mohamad Ali Azarm

#### Stochastic Memory Process And Its Application To Cumulative Outage Time In Nuclear Power Plants , Mohamad Ali Azarm

*Retrospective Theses and Dissertations*

The safety performance of operating nuclear power plants is strongly affected by the unavailability of safety systems that are designed to mitigate accident conditions. The unavailability of these safety systems during plant operation is controlled by the plant's technical specifications which prescribes limits on the downtime duration (outage time) of the individual safety equipment. In this study, risk- and reliability-based methodologies for the determination of allowable cumulative downtime for safety components and safety systems are developed. The limits on the cumulative downtime durations are determined by taking into account the statistical variations expected from a stochastic process which models ...

A Modular Nodal Method For Solving The Neutron Transport Equation Using Spherical Harmonics In Two Dimensions , Feyzi Inanc

#### A Modular Nodal Method For Solving The Neutron Transport Equation Using Spherical Harmonics In Two Dimensions , Feyzi Inanc

*Retrospective Theses and Dissertations*

A modular nodal method is developed for solving the neutron transport equation by using the spherical harmonics approximation in two dimensional Cartesian coordinates. The spherical harmonics approximation is based upon the second order even-parity form of the neutron transport equation. The boundary conditions of the spherical harmonics approximation are manipulated to have the forms analogous to the partial currents in the neutron diffusion equation. The relationships are developed for generating both the second order spherical harmonic equations and the boundary conditions in an automatic manner. The nodal method developed is based upon a least squares minimization technique. In that method ...

Thermal Hydraulic Aspects Of An Unconventional Liquid Metal Reactor , Cemal Niyazi Sökmen

#### Thermal Hydraulic Aspects Of An Unconventional Liquid Metal Reactor , Cemal Niyazi Sökmen

*Retrospective Theses and Dissertations*

The Trench Reactor (TR) is a liquid sodium cooled fast power reactor. The reactor core is fueled with U-Pu-Zr metal fuel and generates 800 MW of thermal power. The core is located in a sodium pool which is contained in a thin and deep rectangular vessel. Also located in the pool are the two intermediate heat exchangers (IHX) and the two primary pumps. The liquid sodium exists the core at 485°C and is pumped through the IHXs where it is cooled to 343°C and enters the core through an inlet plenum. The reactor building atmosphere is nitrogen which ...

The Sk(N) Approximation: A New Method For Solving Integral Transport Equations , Zekeriya Altaç

#### The Sk(N) Approximation: A New Method For Solving Integral Transport Equations , Zekeriya Altaç

*Retrospective Theses and Dissertations*

A high order transport approximation, the SK[subscript]N approximation, a mnemonic for "synthetic kernel", is suggested for solving the integral transport equation. The method relies on approximating the integral transport kernels by a sum of diffusion-like kernels. The integral equation is then reducible to a set of coupled differential equations, and the boundary conditions (black body and reflecting boundary conditions) are established. These equations, the SK[subscript]N equations, are solved for benchmark problems. The benchmark problems include one- and two-dimensional homogeneous and heterogeneous cell configurations found in nuclear reactor applications. The solutions of the benchmark problems are compared ...

Computer Simulation Of Plastic Deformation In Irradiated Metals , Üner Çolak

#### Computer Simulation Of Plastic Deformation In Irradiated Metals , Üner Çolak

*Retrospective Theses and Dissertations*

A computer-based model is developed for the localized plastic deformation in irradiated metals by dislocation channeling, and it is applied to irradiated single crystals of niobium. In the model, the concentrated plastic deformation in the dislocation channels is postulated to occur by virtue of the motion of dislocations in a series of pile-tips on closely spaced parallel slip planes. The dynamics of this dislocation motion is governed by an experimentally determined dependence of dislocation velocity on shear stress. This leads to a set of coupled differential equations for the positions of the individual dislocations in the pile-up as a function ...