plotting mesh in the depletion problem

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rullyh
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plotting mesh in the depletion problem

Post by rullyh » Thu Jul 19, 2012 7:58 am

Dear all,

I am a new user of serpent . I do a depletion mode of fuel assembly and activate "mesh" plot on the input. But on the _mesh output files, the correct picture only appears in the first step, while in the next step there are only some dots appearing, there is no picture on it.

What was the problem?? And what should I do to fix it?

Thank you very much


Rully

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Jaakko Leppänen
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Re: plotting mesh in the depletion problem

Post by Jaakko Leppänen » Thu Jul 19, 2012 12:18 pm

Did you let the calculation finish? The mesh plot is reproduced every 50 cycles, so the first plot that you get may contain a lot of statistical noise.
- Jaakko

rullyh
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Re: plotting mesh in the depletion problem

Post by rullyh » Fri Jul 20, 2012 10:15 am

Yes, I let the calculation finished. The first step means first step of burn up, not the first step of cycles. Sorry for misunderstanding


Thanks,

Rully.

Jukka Mettälä
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Re: plotting mesh in the depletion problem

Post by Jukka Mettälä » Mon Jul 23, 2012 3:23 pm

Have you properly defined the materials you are burning?

I once noticed that if I have all the pins in assembly of the same material, the whole assembly seems to vanish after few burnupsteps.

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Jaakko Leppänen
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Re: plotting mesh in the depletion problem

Post by Jaakko Leppänen » Tue Jul 24, 2012 2:04 pm

This shouldn't happen. Could you send me an example input where this problem occurs?
- Jaakko

Jukka Mettälä
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Re: plotting mesh in the depletion problem

Post by Jukka Mettälä » Wed Jul 25, 2012 11:17 am

Sorry for confusion, I said it wrong.

I remembered that it was about material names but actually it was the pin names.
So with the same material I meant that all the pins in lattice have the same name.

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Jaakko Leppänen
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Re: plotting mesh in the depletion problem

Post by Jaakko Leppänen » Fri Jul 27, 2012 5:41 pm

I'm confused... The input you sent me produces the mesh plots correctly for each burnup step. Did you by any chance run your calculation in parallel MPI mode?
- Jaakko

rullyh
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Re: plotting mesh in the depletion problem

Post by rullyh » Sat Jul 28, 2012 5:03 am

Yes, I used mpi parallel CPU. Possibly, that's the problem. It consumed lots memory

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Jaakko Leppänen
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Re: plotting mesh in the depletion problem

Post by Jaakko Leppänen » Sat Jul 28, 2012 1:25 pm

I think it's more of a normalization issue. The color scheme is fixed after the first step, in order to reflect the changes in flux and power from step to step. The coefficient used to normalize the distributions is somehow incompatible in MPI mode.

Two questions:

1) Did you let the calculation finish, or did you interupt it before the end?
2) Could you repeat the calculation in non-MPI mode and see if the problem persists?

The first question is related to the fact that Serpent collects results from MPI tasks at the end of the transport simulation. All results printed and plotted before that reflect the results from the main task, which might explain the strange results.
- Jaakko

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Jaakko Leppänen
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Re: plotting mesh in the depletion problem

Post by Jaakko Leppänen » Wed Aug 01, 2012 4:53 pm

I found the problem... The distributions used for producing the mesh plots are reset only for the main MPI task, so when run in parallel mode, data keeps accumulating from step to step. The solution is to add lines:

Code: Select all

  /* Reset mesh plots */
  
  mpl = (long)DATA[DATA_PTR_MPL0];
  while (mpl > VALID_PTR)
    {
      /* Reset flux distribution */
      
      ptr = (long)DATA[mpl + MPL_PTR_FLX];
      for (n = 0; n < (long)(DATA[mpl + MPL_NX]*DATA[mpl + MPL_NY]); n++)
	DATA[ptr + n] = 0.0;

      /* Reset fission rate distribution */
      
      ptr = (long)DATA[mpl + MPL_PTR_FISSRATE];
      for (n = 0; n < (long)(DATA[mpl + MPL_NX]*DATA[mpl + MPL_NY]); n++)
	DATA[ptr + n] = 0.0;

      /* Next plot */

      mpl = (long)DATA[mpl + MPL_PTR_NEXT];
    }
in resetstat.c. Two new long-type variables, mpl and n, must be added in the variable list. This bug fix will be included in the next uprate (1.1.18).

I moved this topic from "users" to "bug reports".
- Jaakko

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