<commit_before>---
layout: post
title: Research 
cover: kittenparty.jpeg
date:   2014-10-18
categories: posts
---

## Hybrid Methods in Neutron Transport

Is my current research area of interest.  

## Mars Rover Neutron Source

The Mars rover neutron source can be designed to adequately provide enough neutrons for 39Ar/40Ar geochronology. 

## PB-FHR Central Reflector

The bulk of my Master's work was focused on determining the lifetime of a large reactor component in a pebble bed, fluoride salt-cooled, high temperature reactor. The technology relevant to this  reactor is currently being investigated  by an Integrated Research Project (IRP) between MIT, University of Wisconsin, Madison, and UC Berkeley. UC Berkeley has been spearheading the core design for this reactor; the current design is the PB-FHR MK-1. In this design, the fueled pebbles are in an annular configuration around a graphite central reflector. The central reflector provides moderation for the neutrons, but also provides flowpaths for crossflow of the coolant in the core.   

The earliest designs of the MK-1 had the central reflector constructed of a solid block of graphite. Given that this component is essentially in the center of the core, it will see extremely high temperatures and fluences. Furthermore, the effective moderation of the central reflector will lead to strong fluence gradients in both the axial and radial directions of the reflector. This will lead to enormous stress buildups due to radiation-induced swelling in the graphite. 

My analysis concluded that without redesign, the central reflector will require replacement frequencies that render the Mk-1 design unfeasible. The analysis was performed using MCNP5 and COMSOL multiphysics.  

![Central Reflector](/images/StressMises.gif)

## PB-FHR Test Reactor

Designing the test reactor to match physics of the commercial PB-FHR design is exceedingly difficult. 

## 99-Mo production

The production of 99-Mo in small, light water reactors is possible. <commit_msg>Adding descriptions of rover source and 99Mo production<commit_after>---
layout: post
title: Research 
cover: kittenparty.jpeg
date:   2014-10-18
categories: posts
---
## Past/Present and Future Areas of Research Interest:

I have a wide variety of research interests. My past experience (listed in detail below) spans several sub-disciplines of nuclear engineering. For my future work, I would like to continue broadening my research experience. While not completely comprehensive, I am interested in the following topics: 
- Neutron Transport Methods
- High Performance Computing
- Applications of Nuclear Physics
- Neutronics/Thermal-Hydraulics and Neutronics/Materials Multiphysics
- Reactor Core Design 

## Hybrid Methods in Neutron Transport

Is my current research area. My PhD work will be in this field.  

## Mars Rover Neutron Source

39Ar/40Ar geochronology is a widely used technique to datermine the age and history of geological samples. This method is well suited to old samples with complex thermal histories. However, this technique requires a fast neutron source to initiate the 39K(n,p)39Ar reaction. My work on this project was to design a low-mass, high-flux, fast-flux neutron source to send on future rover missions designed specifically for 39Ar/40Ar geochronology. My collaborators and I determined that it was feasible to design a neutron source for this purpose, but shielding the rover and terrestrial body from the source would be the biggest obstacle in designing a mass-feasible device.   

## PB-FHR Central Reflector

The bulk of my Master's work was focused on determining the lifetime of a large reactor component in a pebble bed, fluoride salt-cooled, high temperature reactor. The technology relevant to this  reactor is currently being investigated  by an Integrated Research Project (IRP) between MIT, University of Wisconsin, Madison, and UC Berkeley. UC Berkeley has been spearheading the core design for this reactor; the current design is the PB-FHR MK-1. In this design, the fueled pebbles are in an annular configuration around a graphite central reflector. The central reflector provides moderation for the neutrons, but also provides flowpaths for crossflow of the coolant in the core.   

The earliest designs of the MK-1 had the central reflector constructed of a solid block of graphite. Given that this component is essentially in the center of the core, it will see extremely high temperatures and fluences. Furthermore, the effective moderation of the central reflector will lead to strong fluence gradients in both the axial and radial directions of the reflector. This will lead to enormous stress buildups due to radiation-induced swelling in the graphite. 

My analysis concluded that without redesign, the central reflector will require replacement frequencies that render the Mk-1 design unfeasible. The analysis was performed using MCNP5 and COMSOL multiphysics.  

![Central Reflector](/images/StressMises.gif)

## PB-FHR Test Reactor

In addition to desining the core for a commercial PB-FHR, the FHR-IRP has been investigating a test reactor that reflects the physics of the large, commercial-scale PB-FHR. For this project I attempted to design a 20 MWth, 1m3 test reactor FHR that had the same reactivity coefficients and neutron energy spectrum as the commercial core. I determined that while it was possible to get close to the same neutron energy spectrum to the PB-FHR, it was very difficult to match reactivity coefficients between both cores.      

## 99-Mo production

As an undergraduate I worked on a research project with the objective to produce 99-Mo in small, low power, light water research reactors. For this project, I performed parametric studies to maximize the 99-Mo produced in a target design.   
{'fraction_non_alphanumeric': 0.03546221380616285, 'fraction_numerical': 0.009640213461869513, 'mean_word_length': 4.602700096432016, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 3, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
{'dir': 'git-commits-cleaned', 'id': '1527900', 'n_tokens_mistral': 1487, 'n_tokens_neox': 1322, 'n_words': 841}