MCNP

I spent most of last week and today learning MCNP and figuring out how to get it to do what I want. All I can say is that whenever we were unceremoniously thrown into the MCNP swimming hole in the hopes that we could swim, it would have been very nice to have these two primers.

Updates

Today's stupid mistake was not remembering that MCNP's energy bins are described in units of MeV, not eV like those in SCALE are. I was confused why the flux above 20 eV was zero, and I even went and asked two people and was about to forward them my input file before I realized my mistake.

I usually have a hard time being coherent. If I have time to think about something and write it down, and I don't have to write it down very precisely, I'm ok. More formal papers and the like are pretty difficult because one can't get away with the stream-of-thought and highly parentheticalized stuff that I usually write. As far as just talking to my mentor out of the blue, unless I'm prepared with notes, I probably sound like a lunatic.

There have been several seminars that the NSTD puts on; today's was on the ENDF libraries. I don't think any of our classes at school have mentioned the effort that goes into evaluated nuclear data files, or most of the details of resonances and self-shielding and so forth. It was really insightful, and would've been nice to have had at the beginning of the summer instead of now when I'd already learned by trial and error and asking questions what most of the details about the resonance processing code that SCALE uses are.

Ultimate today definitely made up for Monday's. On Monday, there were maybe 20 people there, most of whom didn't seem to enjoy the game. Today, though, there were ten of us at first, with the final head count being 16 by the end of the game. That's the right number so that everyone can stay involved and needs to be involved in order for the game to be good; the field isn't so dense with people that all throwing is unreasonable. It's fun to hit the ground running all-out. And by hit the ground, I mean fall down and slide and look awesome. Not awesome is other people getting confused by thinking my glasses are the frisbee and knocking them off my face. But they're still ok.

And I'm irritated that sonic charges $.30 for a cup of tap water. Pft.

Smoretastic

The latest odd thing I did in my spare time was to create a little marshmallow-cooking furnace out of aluminum foil. The chocolate goes on a separate piece of foil that sits on top of it so that it's not rock-hard whenever it's bitten into. It makes a very even, light toast even without rotating it, since I suppose the incident thermal radiation is so uniform. Near-IR shows up as blueish purple to my digital camera, apparently.

Oops

I completely forgot to wish everyone a happy pi day, and to tell you all to "beware the ides of march!"

Today I made homemade ice cream. Yum.

And I learned yesterday another incredible way of increasing my sugar intake. Buy sugar cubes, saturate them with lime juice, and pop them in your mouth before they fall apart. <3 This is most delicious and sugar-tastic.

CO2 sequestration

Today I came up with a great idea for burying our carbon dioxide.

Inject it as a high-pressure gas into liquid sugar. And sell it.

Deeelicous. I forgot how awesome pop rocks are.

Radium Ore Revigator

One thing I did while visiting Louisiana with family was go to a rural museum where they had lots of artifacts from the area from the '30s through the mid-19th century. There was one particularly interesting one (from a rad health point of view) was a "Radium ore revigator" which, according to this website, put vigor into "tired or wilted water," which, amusingly enough, isn't far from the modern-day quackery that you'll find in ads in the back of popular science.

So random

Gmail decided that the following advertisement was relevant to my email:

Are you a Random Badger?
Then you will feel at home in the comforting glow of Badgerville.
www.weareallbadgers.com

I just... don't get it. It would be hilarious but I think I've stumbled upon something so random it's just more "huh?" than "ha!".

I like vacation.

Reactor startup

Today I had the fun of being a reactor trainee operator. Exciting. Procedures: unlock the SS scram buttons, engage magnet power, withdraw transient to 100%, withdraw RR to ~40%, start withdrawing shim safeties in gang until reactor reaches critical (not exceeding a 20 second period while doing so), withdrawing SS until 1 MW power, ignore John the ex-Navy annoying senior operator's comments and false alarms and coffee spills, engage servo. Oh yeah! I completely forgot about getting to announce over the PA that the reactor is being engaged and/or steady. It made me feel important. On the way down, disengage servo, hit alarm silence button, lower SS in gang along with TR and RR. And, of course, continue to ignore John.

I also made a microwave s'more. It was gooey.

It is also very cold outside (at least for Texas; it's in the high 30's). I need gloves, a hat, and a heavy coat. Because, biking in this weather? Brrrrrr.

Pulse

Today we were supposed to pulse the nuclear science center's reactor -- that is, to blow $1.50 worth of a control rod (called the "transient rod") out of the reactor, making about a 15 ms pulse of 1000 MW of energy at peak. Well, in order to do this according to our guidelines, we need to have the reactor critical at 300W with the transient rod all the way in. Unfortunately, the reactor operators had turned the reactor on that morning at exactly at the right time to put us at the peak of the Xenon curve. This added enough negative reactivity to prevent our reactor from going critical even with all four shim safety rods and the regulating rod out. So, we turned the reactor up to 1MW in an effort to burn off some of the Xe-135, but that also increased our fuel temperature which also lowered the reactivity of the reactor.

In sum:

• To get the reactor critical at 300 W, we had to remove all rods but the TR completely, and remove the TR to about 5%, which is about $0.20 of reactivity removal.
• When we took the reactor up to 1MW, where the fuel temperature is about 600 deg F instead of 100 deg F at 300 W, we managed to burn off at least $.02 of Xenon, but of course the thermal reactivity coefficient made our reactor a lot less reactive.
• We inserted the SS rods back to about 92% and the TR back to 0% to bring the reactor power back down.
• At about 300 W, we took the shim safeties out again, in the hopes that our reactor period would be positive (a slightly supercritical configuration instead of a subcritical one). Alas, our period was still the -80.6 second one characteristic of the longest-lived delayed neutron group.
• Therefore, our reactor is lame because it doesn't have enough fresh fuel in it.

This is the first time I've been really sad over missing out on a lab like this. Pulsing the reactor is awesome to watch, and I've been looking forward to this lab for months, actually.

Quote of the day

Girl is talking about how at the farm, she had to once stick her gloved hand up a cow to check to see if it was pregnant.

The dude in front of me, incredulously: "Why didn't you just put your ear right next to it and listen for a little moo in the big moo?!"

That guy cracks me up.