Nuclear Engineering Commons^™

Cfd Simulation Of Hydrodynamics And Scrubbing Behaviour Of Iodine Vapors In A Self-Priming Venturi Scrubber, Paridhi Goel, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

In a severe accident scenario, the inadequate heat removal in a nuclear reactor can lead to over pressurization of the containment thus challenging its integrity. If not controlled, this can lead to release of radionuclides and high pressure steam in the environment. To ensure that the containment building remains intact and the reactor depressurizes, the vent line from the reactor is directed to a scrubber tank consisting of multiple venturi scrubbers, metal fiber filter and demister pad (known as Filtered Containment Venting System (FCVS)). This is a passive safety measure suggested for installation in advanced and existing nuclear reactors post …

Critical Heat Flux And Power Transients At Low-Pressure Low-Flow Conditions In Vertical Flow Boiling, S. R.G. Vadlamudi, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

In the advanced boiling water reactor concepts such as AHWR and ESBWR, the recirculation pumps are eliminated in order to simplify the design. During the start-up of such reactors, to establish the natural circulation, the primary coolant has to be heated up slowly in steady steps; it is quite important to determine the characteristics of boiling and critical heat flux (CHF) values in order to establish operational limits. Flow boiling experiments were conducted in an annular channel at very low flow rates and atmospheric pressure varying the inlet subcooling from 20 to 400 C. CHF occurred during the oscillatory flow …

Experimental Evaluation Of Critical Heat Flux In Downward-Facing Boiling On Flat Plate Relevant To In-Vessel Retention In Indian Phwrs, Sumit V. Prasad, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Retention of corium inside the CV and cool it by calandria vault water is essential to mitigate severe accidents in PHWRs. The thermal failure of CV can be prevented by effective decay heat removal on the outer surface of CV using vault water, which depends on the heat transfer behaviour from the outer surface of CV to the vault water. Determination of limiting heat removal capability of vault water through outer surface of calandria vessel is very important. Since, the calandria vessel has a very large diameter and length, the bottom most part of the calandria vessel almost behaves as …

A Review Of Core Catchers For Advanced Reactors, Samyak Munot, A. K. Nayak

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

In order to address the challenges of severe accident and to ensure safety of people and environment, a core retention device called as “core catcher” has been incorporated in the present and future reactor designs. The concept of core catcher came into existence as early as in early nineties. It is the system which is placed inside the reactor in such a manner that even in the severe accidental scenario, it will retain the corium, quench it and then sustain the coolability of the debris formed due to corium water interactions. From then various approaches to development of core catchers …

Preliminary Assessment Of Steady-State And Transient Reaction-Rate Measurements At The University Of Wisconsin Nuclear Reactor, J. A. Roberts, T. R. Ochs, D. M. Nichols, W. Fu, Y. Cheng, J. C. Boyington, D. S. Mcgregor, P. P.H. Wilson, R. J. Agasie, C. S. Edwards, Y-H. Park

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Recently, a number of reactor-physics experiments were conducted at the University of Wisconsin Nuclear Reactor (UWNR) using a set of 7 micro-pocket fission detector (MPFD) probes and 3 resistance temperature detector (RTD) probes. The UWNR core is a TRIGA-fueled, MTR conversion using 2x2 fuel bundles separated by coolant channels. Each MPFD probe contained 4 detectors, and each RTD probe contained 6 detectors, all arranged uniformly along the active fuel height. These probes were placed in four different configurations to measure fluxes and temperatures in every accessible coolant channel for a variety of steady-state and transient operations. Relative fluxes can be …

Micro Structured Sensors For Neutron Detection, D. S. Mcgregor, S. L. Bellinger, J. C. Boyington, Y. Cheng, R. G. Fronk, W. Fu, L. C. Henson, J. D. Hewitt, C. W. Hilger, R. M. Hutchins, K. E. Kellogg, J. A. Medina, D. M. Nichols, T. R. Ochs, M. A. Reichenberger, J. A. Roberts, S. R. Stevenson, T. M. Swope, T. C. Unruh

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

The shortage of ³He gas, identified as a problem several years ago, initiated research into alternative neutron detectors for various applications. One such technology is the microstructured semiconductor neutron detector (MSND). These compact detectors have microstructures etched deeply into the substrates that are subsequently backfilled with neutron reactive material. Single sided devices typically have thermal neutron detection efficiencies exceeding 30%, while double sided microstructured semiconductor neutron detectors (DS-MSND) have yielded >69% thermal neutron detection efficiency. Both MSNDs and DS-MSNDs have been integrated into compact low-noise and low-power electronics modules. Dosimetry calculations indicate that these detectors can be used as …

Stratification And Mixing In The Hot Plena Of Liquid Metal-Cooled Reactors, Hitesh Bindra, Brendan Ward, Graham Wilson, Abhinav Gairola

Symposium on Advanced Sensors and Modeling Techniques for Nuclear Reactor Safety

Understanding or modeling the role of stratification and mixing in the plena or containments of nuclear reactors is of prime significance to their safety analysis. Particularly, in case of liquid metal-cooled reactors, thermal stratification in the hot pools under off-normal transients is one of the least understood problems that have multi-physics effects on thermo- mechanics and reactor physics. This is primarily due to lack of high fidelity experimental data for validating CFD or system scale models, which are essential for improved understanding. A scaled liquid metal thermal-hydraulic facility with a scaled hot plenum has been developed at Kansas State University …

Radiation Transport In Stochastic Media, Corey Skinner

Shared Knowledge Conference

The need to investigate numerical methods for the transport of radiation (thermal photons, light, neutrons, gammas) in random mixtures of immiscible materials arises in numerous applications, including inertial confinement fusion, turbid media (e.g., skin tissue), stellar atmospheres, clouds, and pebble bed nuclear reactors. Stochastic geometry techniques enable rendering of realizations of such random media and deterministic finite difference/finite element as well as Monte Carlo techniques are used to numerically simulate radiation transport on a large ensemble of realizations. The results are then averaged to obtain statistical moments of the radiation intensity, in particular the mean and variance, to assess the …

Comparison Of Steady And Transient Flow Boiling Critical Heat Flux (Chf) For Fecral Accident Tolerant Fuel Cladding Alloy, Zircaloy, And Inconel, Soon Kyu Lee

Shared Knowledge Conference

The nuclear reactor design focuses on building a system that is robust and reliable, is efficient and economical, and do not run into undesirable transient accident scenarios. The nuclear reactor safety focuses on ensuring the system operation under the safety margins and requirements provided by the regulatory agencies. Following the Fukushima nuclear reactor accident, the US Department of Energy Office of Nuclear Energy (DOE-NE) Advanced Fuels Campaign (AFC) is working to develop fuel and cladding candidates with potentially enhanced accident tolerance: ‘Advanced Tolerant Fuel’ (ATF). As a part of the AFC, this research focuses on gaining mechanistic understanding of the …

Use Of High Fidelity Fission Models In Criticality Calculations, Daniel H. Timmons

Shared Knowledge Conference

The use of Monte Carlo, random number sampling, for neutron transport has been used for about half a century. There are many benchmarks that have been used to validate neutronics codes, mostly for critical systems. Critical systems are systems where the neutron population from one generation to the next is the same. Subcriticality is when there are less neutrons in the next generation and supercriticality is when there are more neutrons in the next generation than there were in the previous. To calculate criticality, a set number of neutrons are started in a system. Those neutrons interact and the number …

Incorporating Collisions And Resistance Into The Transition From Field Emission To The Space Charge Regime, Samuel D. Dynako, Adam M. Darr, Allen L. Garner

The Summer Undergraduate Research Fellowship (SURF) Symposium

Advancements in microelectromechanical systems (MEMS) and microplasmas, particularly with respect to applications in combustion and biotechnology, motivate studies into microscale gas breakdown to enable safe system design and implementation. Breakdown at microscale deviates from that predicted by Paschen’s law due to field emission—the stripping of electrons from the cathode in the presence of strong surface field—and follows the Fowler-Nordheim (FN) law. As injected current increases at this length scale, electrons accumulate in the gap and FN electron emission becomes space charge limited, leading to the Child-Langmuir (CL) law at vacuum and the Mott-Gurney (MG) law at high pressure. While theoretical …

A Security Approach For The Example Sodium Fast Reactor, Christian X. Young, Robert S. Bean

The Summer Undergraduate Research Fellowship (SURF) Symposium

Increases in the spread of nuclear technology and the rise of non-state terrorism in the modern era has proved the need for effective security approaches to new nuclear facilities. Many documents about security approaches for nuclear plants are non-public material, however, making it difficult to teach others about the basics of security design. To alleviate this issue, we used available texts in the security realm to design a security approach for the Generation IV International Forum’s Example Sodium Fast Reactor. Our approach utilized infrared, microwave, fiber optic, and other advanced technologies to provide security for the special nuclear material present. …

Molecular Dynamics Simulations Of Hydrogen Diffusion And Retention Behavior Near Sub-Surface Defects In Tungsten: Towards Predicting Tritium Retention In The Iter Divertor, Emily Nicole Hutchins

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

Molecular Dynamics Simulations of hydrogen diffusion and retention behavior near subsurface defects in tungsten: Towards predicting tritium retention in the ITER divertor

Plasma-facing components within fusion reactors will be exposed to massive particle and thermal loads, which will pose serious material challenges. The plasma-facing component of interest in this project is the divertor, a device that allows for the online removal of the helium reaction product from the deuterium – tritium plasma. The ITER divertor will be constructed from tungsten, which is also a prime candidate for use in future demonstration fusion reactors, because of its superior mechanical properties and …

X-Means Clustering Implementing The Gap Statistic For Multiple Positron Emission Particle Tracking, Matthew Herald

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

The most efficient and accurate method for clustering Coincidence Lines (CL) for Positron Emission Particle Tracking (PEPT) is undetermined. A number of methods have been created to perform this task. A novel clustering method featuring x-means is presented using an automated k-value estimator for k-means clustering. Gap statistic is used to select the best k-value. Geant4 Application for Tomographic Emission is used to simulate particles of 50 µCi and the detection and electronic chain associated with the Siemens Inveon Pre-Clinical Scanner. The simulation produces an array of coincident lines (CL) in a format consistent with scanner output. The CL are …

Temporal Resolution Of Cell Death Signaling Events Induced By Cold Atmospheric Plasma And Electroporation In Human Cancer Cells, Danielle M. Krug, Prasoon K. Diwakar, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cancer treatment resistance and their invasive and expensive nature is propelling research towards developing alternate approaches to eradicate cancer in patients. Non-thermal, i.e., cold atmospheric plasma (CAP) and electroporation (EP) applied to the surface of cancerous tissue are new methods that are minimally invasive, safe, and selective. These approaches, both independently and synergistically, have been shown to deplete cancer cell populations, but the signaling mechanisms of death and their timelines of action are still widely unknown. To better understand the timeframe of signaling events occurring upon treatment, human cancer cell lines were treated with CAP, EP, and combined CAP with …

Comparison Of Pm-Hip To Cast Alloy 625 For Nuclear Applications, Alexander L. Bullens, Keyou Mao, Janelle P. Wharry, Esteban Bautista

The Summer Undergraduate Research Fellowship (SURF) Symposium

PM-HIP, or Powder Metallurgy and Hot Isostatic Pressing, metals have been a low cost alternative to forged and cast structural metals within various industries. The nuclear industry has recently developed interest in PM-HIP alloys, but further research needs to be done to quantify their mechanical properties and characterize the microstructure. Specifically, we must understand the mechanical and microstructural evolution of PM-HIP materials after long-term operation at the elevated temperatures that PM-HIP components will experience in service. We focus on Ni-base alloy Inconel 625, and compare the PM-HIP version to the cast version. Our methodology consists of annealing samples to various …

Irradiation-Induced Nanocluster Evolution, Didier Ishimwe, Matthew J. Swenson, Janelle P. Wharry

The Summer Undergraduate Research Fellowship (SURF) Symposium

Oxide dispersion strengthened steel (ODS) and commercial ferritic-martensitic (F-M) alloys are widely accepted candidate structural materials for designing advanced nuclear reactors. Nanoclusters embedded in the steel matrix are key microstructural features of both alloy types. Irradiation from nuclear fusion and fission affects the morphology of these nanoparticles, altering the performance of the alloys and potentially decreasing their usable lifetime. Thus, it is important to understand the effect of irradiation on these nanoparticles in order to predict long-term nuclear reactor performance. It was found that the evolution of nanoclusters in each material is different depending on the experimental irradiation parameters. The …

Numerical Simulations Of Transcritical Natural Convection, Ruiwen Wei, Carlo Scalo, Mario Tindaro Migliorino, Kukjin Kim, Jean-Pierre Hickey

The Summer Undergraduate Research Fellowship (SURF) Symposium

In modern engineering applications, system overheating is a key issue that needs to be solved with efficient and reliable cooling technologies. Among the possible mechanisms that these are based on, natural convection cooling is one of the most frequently employed, with applications ranging from cooling of computer micro-components to large nuclear reactors. While many studies have been performed on natural convection employing supercritical or subcritical fluids, little attention has been given to fluids in their transcritical regime. The latter has the potential to yield high performances while avoiding detrimental effects of two-phase systems (e.g. cavitation). In the present study, 2D …

Verification Of Tfit Code Numerical Method For Flow Excursion Simulation, Patrick S. Foster, Subash Sharma, Martin L. Bertodano

The Summer Undergraduate Research Fellowship (SURF) Symposium

This research is aimed towards accurately modeling and predicting the onset of the two-phase flow excursion instability using the code TFIT (Two Fluid Interfacial Temperature). In order to do this we first had to show that the numerical diffusion of the code’s finite difference equations could be reduced to an insignificant level by decreasing the mesh size.

Understanding and being able to accurately model flow excursion can help us understand how to prevent the potential negative effects of this instability. We are using a two-fluid model with physics-based closure relations. The results will be validated against the experimental data available …

Investigating Tantalum As A Plasma-Facing Component For Nuclear Fusion Reactors, Arvind Sundaram, Jitendra K. Tripathi, Theodore J. Novakowski, Ahmed Hassanein Ph. D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nuclear fusion is a potential source for producing unlimited environment-friendly energy. Tungsten (W) is selected as the primary candidate material for plasma facing component in nuclear fusion reactors due to its high melting temperature (3695 K), low sputtering erosion yield and strong mechanical properties. However, recent investigations on W have confirmed that it undergoes severe surface morphology changes during low energy He plasma and/or ion irradiation similar to a harsh fusion environment. Additionally, our previous studies indicate that tantalum (Ta) may show better resistance to the harsh radiation environment and is therefore worthy of investigation. Hydrogen retention properties, specifically deuterium …

Development Of An Unmanned Aerial System For Radiation Mapping In Nuclear Facilities, Jackson Ball, Guangying Jiang, Robert Bean

The Summer Undergraduate Research Fellowship (SURF) Symposium

Efficiently planning a decontamination and decommissioning (D&D) operation at a nuclear facility requires detailed information on the conditions present. In the wake of a disaster, or just years of abandonment, a facility’s layout may have dramatically changed, making previous facility drawings unreliable, and radioactive particles may have been spread over the site, contaminating equipment and structures. Rather than tasking workers with mapping and characterizing the contamination, which can take days or weeks and poses a health and safety risk to the workers, mapping the site and locating contamination can be done remotely by an unmanned aerial vehicle (UAV), which would …

Fluence Dependent Surface Modification On Tungsten Coatings Using Low Energy Helium Ion Irradiation At Elevated Temperatures, Cheng Ji, Jitendra K. Tripathi, Theodore J. Novakowski, Valeryi Sizyuk, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nuclear fusion is the most promising renewable energy source for the near future. It can provide a large amount of energy using a very small amount of fuel, as compared with that of the coal, oil, or nuclear fission. The chain reaction in nuclear fusion produces the energy and fuel, from hydrogen isotopes available in see water. Tungsten (W) is a leading candidate material for the plasma-facing component (PFC) in nuclear fusion reactors such as ITER (international thermonuclear experimental reactor), because of its high melting point, high yield strength, low erosion and low hydrogen isotope retention. Recent studies showed deeply …

Tfit Modeling Of Wave Propagation For Flow Excursion, Brachston Grubbs, Krishna Chetty, Martin Bertodano

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the nuclear power industry, the Two-Fluid Model (TFM) is mainly used in the simulation of Loss of Coolant Accident (LOCA). The Two-Fluid Model is a wave mechanics formulation that may also be used to analytically perform stability analysis, which requires numerous assumptions and simplifications. This project aimed to advance the TFIT-TFM simulations in the modeling of the flow excursion instability. By using the TFIT computational code, simulation results can be obtained without the need for assumptions and simplifications. In this project, a simulation was performed to verify the nonlinear wave propagation capability of TFIT. During the verification process, the …

Computer Modeling Of Graphene Field Effect Transistors, Drew M. Ryan, Robert S. Bean

The Summer Undergraduate Research Fellowship (SURF) Symposium

Graphene has been the centerpiece of numerous research projects since its discovery in 2004, greatly due to its multitude of unique properties. Its variable conductivity, relative strength, and electron mobility make graphene a prime candidate for applications in the field of radiation detection. While work has been performed in the past on testing radiation detection using graphene using Graphene Field Effect Transistors (GFET), due to its limited size, fabricating GFETs can be tedious and costly. Therefore, a need arose for a way to test potential GFET designs without the cost and limitations of fabricating GFETs for each test iteration. Using …

Cold Atmospheric Pressure Plasmas For Food Applications, Michael V. Lauria, Russell S. Brayfield Ii, Ronald G. Johnson, Allen L. Garner

The Summer Undergraduate Research Fellowship (SURF) Symposium

Successfully distributing shelf food requires treatment to eliminate microorganisms. Current chemical methods, such as chlorine wash, can alter food quality while only being effective for a limited time. Cold atmospheric pressure plasmas (CAPs) can eradicate the microorganisms responsible for food spoilage and foodborne illness. Optimizing CAP treatments requires understanding the reactive species generated and relating them to eradication efficiency. Recent studies have used optical emission spectroscopy (OES) to determine the species generated in a sealed package that would hold food. In this study,we supplement the OES results with optical absorption spectroscopy (OAS) using the same gases (helium, nitrogen, compressed air, …

Temperature Dependent Surface Modification Of Tungsten Exposed To High-Flux Low-Energy Helium Ion Irradiation, Antony Q. Damico, Jitendra K. Tripathi, Theodore J. Novakowski, Gennady Miloshevsky, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nuclear fusion is a great potential energy source that can provide a relatively safe and clean limitless supply of energy using hydrogen isotopes as fuel material. ITER (international thermonuclear experimental reactor) is the world first fusion reactor currently being built in France. Tungsten (W) is a prime candidate material as plasma facing component (PFC) due to its excellent mechanical properties, high melting point, and low erosion rate. However, W undergoes a severe surface morphology change when exposed to helium ion (He⁺) bombardment under fusion conditions. It forms nanoscopic fiber-form structures, i.e., fuzz on the surface. Fuzz is brittle …

Modeling Of Ion/Target Interactions In Plasma Facing Components Of Fusion Reactor, Nicole Neto Godry Farias, Tatyana Sizyuk, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nuclear fusion is a promising source of clean energy that can be one of the key future suppliers of the world’s increasing power demand. One of today’s main challenges faced by scientists and engineers regarding nuclear reactors is to design plasma-facing components (PFCs) that can withstand extreme conditions of temperature, pressure, and ions/particles irradiation. Material evolution and damage of PFCs are strongly related to the bombardment and diffusion processes of ions resulting from fusion fuel, i.e., deuterium and tritium and reaction products, i.e., helium. However, work is still needed in order to understand fuel diffusion in the presence of helium …

Radiation Tailored Polymers For Detectors, Adhesive-Coatings And Other Industrial Uses, Anna M. Earley, Alex Bakken, Rusi P. Taleyarkhan

The Summer Undergraduate Research Fellowship (SURF) Symposium

The ever growing importance of humans to depend on renewable resources has shifted the focus of consumers, producers, and even politicians to more sustainable answers. Furthermore, pressure on the oil and natural gas industry has elevated the status of biopolymers in this regard. Polylactic acid (PLA) is unique polymer that offers unique abilities for tailored property derivation; thereby, enabling one to replace many engineered polymers and provide a sustainable solution as a nontoxic renewable resource. As a bioplastic, the tailoring of PLA under various conditions is important to the application and integration into current industry uses. After irradiating high molecular …

Graphene Field Effect Transistor For Radiation Detection On A Micron To Millimeter Scale, Peter C. Lamm, Robert Speer Bean, Zachary Shollar

The Summer Undergraduate Research Fellowship (SURF) Symposium

Novel technology in radiation detection is critical to advancing radiation detectors for their many applications. Graphene has shown to be able to change its conductivity in the presence of an electric field; this makes it an excellent candidate to be used as a radiation detector for the detection of the charges generated during radiation interactions. Research has been done on making micron scale graphene field effect transistors (GFET) with graphene on a Si/SiO₂ wafer, but it is critical that we try to increase the scale. Unknowns persist in scaling graphene to millimeter sizes. This study plans to elucidate any …

Effect Of Helium Ions Energy On Molybdenum Surfaces Under Extreme Conditions, Joseph Fiala, Jitendra K. Tripathi, Sean Gonderman, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Plasma facing components (PFCs) in fusion devices must be able to withstand high temperatures and erosion due to incident energetic ion radiations. Tungsten has become the material of choice for PFCs due to its high strength, thermal conductivity, and low erosion rate. However, its surface deteriorates significantly under helium ion irradiation in fusion-like conditions and forms nanoscopic fiber-like structures, or fuzz. Fuzz is brittle in nature and has relatively lower thermal conductivity than that of the bulk material. Small amounts of fuzz may lead to excessive contamination of the plasma, preventing the fusion reaction from taking place. Despite recent efforts, …