Update

They should have never wanted us to use this new UTK theme.  I'm putting it everywhere.  The UT,  by the way, is supposed to "emulate the shape of Tennessee".

Two weeks David's graduation in Syracuse, I'm excited for the break.  This weekend I plan to go to Regionals in Georgia.  Should be a good show.  Florida currently has the 1 seed (above UCF, Florida beat UCF at sectionals) and Tennessee escaped as the 5 seed overall in Pool D.  Pool C has both Georgia and Georgia Tech - that would not be a fun pool.

Happy Birthday David!

High Temperature Gas Reactor Coupled with Hydrogen Production

I think if small modular reactors are to take off (and I may be jaded, but probably not in the US*) then there will be needed not for electricity but for process heat applications, as LWR's (light water reactors) cannot reach those temperatures.  I looked into using a high temperature gas reactor (~700 C and above) to produce hydrogen. The system I tried to model is below, as well as the simulink models that worked.

Image from INL.

Implemented HTR-10

Implemented Fuel Cell

Originally I wanted to the steam generator / helical intermediate heat exchanger, but it turned out that I had algebraic loops which made my simulation very slow and not converge.  In any case, I thought it was really nifty.

*In order to get an AP1000 built Westinghouse had to first start construction in China.  And while some site preparations are underway in the US (Vogtle and Bellefonte), the ones in China are much farther along because of the regulations (we also had to give them the technology to make the fuel - which is currently made in only 1 spot in the US).  As regulations don't exist for SMR's this is a very big question for US implementation.

Return of the Pie Chart

How much are your memories worth to you? I have a final project which is to calculate the dose that person's returning to the Fukushima site inside the exclusion zone would receive. I'm not going to lie; I think that most dose rate calculations are bogus - it is a whole bunch of fudge factors. To adapt to having a spacious selection of parameters values I used a Monte Carlo propagation of the uncertainty; it is a neat little method in which you just select each variable from its underlying PDF and then construct a PDF / CDF of the final results.

So, starting with the source data:

Air Contamination (Bq/ cubic meter)

 This actually agreed pretty well with a decay estimated fly over data by the NNSA.  I-131 has an 8 day half life, so you won't see any of it.  These are also good examples of what I mean of the Monte Carlo propagation of uncertainty - each Monte Carlo trial yielded a different estimate of the contamination, which I then binned.  It is also a nice little example of the product of uniform distributions.

Most of the actual dose rate results are boring, so I will only show the dose from eating fish, because it had a skewed distraction.

Finally, a pie chart of the contribution of each pathway.

Dose Rate by Pathway. Don't eat the veggies.

In conclusion, for less than 20 mrem/yr (and much lower if you don't snack along the way) you could go back and get your stuff. I think it would be worth it.  For comparisons, at about 60 rem 5% of exposed individuals may vomit. 

Disclaimer: I'm  a grad student running on 1 3/4 cylinders fuel by go-go juice and magic go-go juice.

Optimal Detector Thickness

As you may recall from the previous post I was investigating the making a layered detector, and I plotted the contribution of a particular film as a function of how far the film was in the detector.  This lead to the idea to ask what would be the best use of material - by making the detector thinner we could avoid some of the low contributions of reactions on the back of the detector.

I held the volume of the detector constant, and adjusted the length and width.  If we make our detector half of what the current He-3 footprint is (which means we need to make them twice as wide) our efficiency goes from 3.1 to 4.6.

Interaction Rate's in a DHS-DNDO Detector

My Master's Thesis is "due" tomorrow, and today I was just finishing up my MCNPX simulations.  And while I should have done this about a month ago, the results are still pretty nifty.  The following figure shows the effect of moderating a Cf-252 source with a 0.5 cm of lead and 2.5 cm of HDPE.  What is neat is that the 2.5 cm of HDPE (lead won't moderate neutrons much because of a neutron cannot impart much recoil energy to the a lead nucleus) is that the spectra is essentially thermalized - the peak is around 0.025 eV, which if you recall is the kinetic energy of room temperature particles predicted by the Boltzmann Distribution.

The detector assembly is composed of a bunch of layers of thin (less than 100 microns) films each separated by acrylic.  The following two plots show the effects of the different layers.  The first layer see's the most neutrons, but doesn't have the largest contribution to the reactions because it only sees them from the front - there isn't much effect of the reflector.  As you go farther into the detecor the number of neutrons crossing a film decrease (it is not because the films absorbs them, only about 20 neutrons are absorbed in all 120 of the films) but rather neutron's escape and scatter out of the detector.

This is probably my favorite plot of my thesis

I looks like I will graduate with a Masters either in May or Summer, and then hopefully (finger's crossed) I can get out of here by May 2013.  Have to do work.

Number 3

Turkey Rankings are out:
We grow for Koch's, who are 23 in the nation, and 3rd in PA at 12.9 Million live pounds. Jandil is #24, with around 10 million live pounds.  For comparison Cargill Value Added Meats (yes, value added meats) processed 1.10 billion pounds.

I setup my theme on my Windows Laptop to automatically download NASA's Image of the Day through an RSS feed.  If my desktop background changes randomly (say every n minutes), and it downloads a new screen desktop background every day, how many times will the first background image show up after d days? 

Research wise I'm playing with CMake and Visual Studio with ROOT and Geant4.  I got Geant4 to run, but having linking problems with ROOT.  Sometimes I find myself missing makefiles and the simpler world of one build environment.