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Persistent dilemma

Two options – 1) to keep going with the current slow/inefficient way of doing things, or 2) to spend some time on developing much better/smarter/faster tools. There is always lack of time and the second way seems too time-consuming… but then, God, it comes up every now and then, and if I would have done it at once long time ago, I could save so much time and efforts… And now it is back again… And what should I choose this time? Hmmm…


When one uses MATLAB and Ruby at the same time, the first one feels like a continuos torture. Even the simplest operations are incredibly harder to perform with MATLAB, variable printing being a good example. In order to improve this, I have written a better function to do the job. Since it is one of the most common operations, my code is much more cleaner and easy to read, than if there would be numerous disp’s and sprintf’s throughout the code. View full article »

Serpent is a great user-friendly MC neutron transport code, which helps to calculate many characteristics of a reactor core/assembly/pin model in a faster and more convenient way, than MCNP does. However, there are also quite many tasks, which Serpent cannot do yet. In such cases (and also for benchmarking), one needs to use MCNP for calculating the data required – for example, non-fission heating of materials; power distribution per pin in a full-core model; fixed source problems (incl. high-energy physics with MCNPX), etc.
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After a Serpent input has been converted into MCNP format, one typically needs to add tallies in order to get required characteristics of the model. Assuming that the original Serpent input geometry may change during model development, the MCNP tallies must be checked/updated every time these changes happen because some cell numbers used in the tallies may also change. It is probably not a big deal, but I don’t like wasting time on this activity, since it can be easily done automatically.
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It is an easy thing, but came to me just recently. Often when processing results of MCNP or Serpent calculations I was annoyed by necessity to define MATLAB functions in a separate file, even if I don’t use them anywhere else. Well, it has an obvious solution – make the main script as a function (just be careful choosing its name). Then all single-use functions can be located in the same file:
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If you are trying to run a background job on Mac using “at now”:

at now < commandfile

and nothing happens apart the following message

job 1 at Wed Sep 29 19:12:40 2010

then the background jobs are probably disabled (by default in OS X 10.6.x). In order to activate them, you need to run:

sudo launchctl load -w /System/Library/LaunchDaemons/

Another way of running calculations in background would be using “&” symbol at the end of your command line, i.e.:

someprog > logfile &

At some point of reactor design development, there is a need to present the model to other people. 2D-plots of core cross-sections sure do some part of the job, but a nice 3D plot always has a stronger effect. For MCNP code there are two programs which can generate such plots – Visual Editor and Moritz Geometry Tool. Honestly, I have no experience of making 3D plots with any of them. I normally use VisEd for making 2D plots to check my MCNP models. This is already quite time-demanding procedure for a full-core model, since VisEd uses MCNP code to make plots. All my attempts to make a 3D plot resulted in crashing software or it was doing something infinitely long time. Let me know if you have a better experience!
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Computer codes for reactor core modeling, such as MCNP and Serpent, allow to define various geometries and therefore use a general language/format to input model parameters. This unique flexibility requires to set quite many parameters/cards, and if the user works with a certain narrow class of reactors, this becomes unnecessary.
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In order to calculate the power peaking factor for my ADS model, I have slightly modified F17 tally from the previous post to include the total fission heating
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I have created a Yahoo! Pipe collecting news published in major Swedish news media about nuclear power. Let me know if there is a good RSS feed to add to this pipe.

Subscribe to the RSS feed Subscribe

Because the source feeds (e.g. DN, SvD etc.) are limited by the lates news, the pipe may show nothing (related to nuclear power). Use a RSS reader (e.g. Google Reader) to collect the news appearing in the pipe. In the meanwhile, will try to find a better solution.

UPDATE2: Here is a better feed