Recent content by rpp

I removed the beginning and ending brackets. Next, I don't see any materials defined in your input. You should use "mat" cards to define fuel, fuel1, clad, helium, water, etc. Look on the Serpent webpage for examples.

I don't see your output files, but I think you have a conceptualization problem. For burnup calculations, ther burnup is an input (usually specified as energy per mass of heavy metal), and the code will calculate the isotopic distribution and k-effective. It sounds like you ran three cases and...

A lot has certainly changed. One area that has seen a lot of development is in Monte Carlo codes. MCNP used to be the only code used, but now people seem to be moving towards Serpent and OpenMC. MCNP is still the gold standard and the developers continue to make big improvements in the code...

What exactly are you trying to do? Do you want to produce a pretty picture? Calculate the total fission rate for the reactor? Or calculate the fission rates in particular parts of the core? While fmesh is very nice for making a plot, I've found that it isn't very useful for extracting real...

This is a very ambitious science fair project, and it sounds like your stepdaughter is pretty creative. I'll just answer one part of your question - why this wouldn't work. First, the main reason that the Oklo reactor worked is that the uranium enrichment when Oklo was active than it is today...

This is a fairly complicated calculation and you need more information to do it correctly, specifically you need to know the densities (usually in g/cc). You also need to know the "plutonium vector" of the plutonium oxide. Does the uranium oxide contain any U234 or U236? If you know the...

In nuclear engineering terminology, the "scalar flux" is usually the angular flux integrated over all angles. Technically the angular flux is also a scalar value, but it is the flux with direction "omega". I think this agrees with what you are saying, but the term "scalar" may cause some...

The reactor is composed of fuel and heat pipes. The fuel generates heat, the heat pipes then transport the heat to a heat exchanger, which then heats up the gas. There are no moving parts in the reactor itself. There is moving fluid in the heat pipes, but this isn't considered "moving...

What is the purpose of these calculations? One-group diffusion theory is going to have "limited accuracy". If you are just doing a back of the envelope calculation, this is fine and you can find values of one-group cross sections and L^2 and D in most introductory reactor physics books. (The...

To give a few more hints, search for "interactive plotter" in the manual and use the "ip" option on the command line.

I don't think FMESH is going to work for you because FMESH uses an x-y-z grid and your reactor geometry is hexagonal. Even if your reactor was on a square grid, it still uses circular fuel rods, so FMESH isn't going to work. What are you transferring to the CFD calculation? As @Grelbr42...

I'm not sure what your final objectives are, but this assembly is at room temperature. I've attached an input for a 16x16 case that uses a fuel temperature of 900 K and all other temperatures are set at 600 K. Unfortunately, this doesn't use lattices and the pin diameters are slightly different...

I just looked at your previous posts, and it looks like several people have tried to help you set up your MCNP cases, but you don't appear to understand the very basics of how to set up the code. Instead of randomly "trying things", I suggest sitting down with an example input and going through...

There are many problems with this input. Have you tried to look in the manual and example problems? I would start with one of the example problems distributed with the code and try to understand how it works. The "fatal error" message tells you exactly what the problem is. The keyword...

I'm not sure if this is the problem or not, but the first thing I noticed is that you need single blank lines after the cell card definitions and after the surface card definitions to define the different "input blocks". Insert a blank line after line 10, and after line 21 (which will be 22 if...