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Automated burnup sequence

Posted: Thu May 27, 2021 12:57 am
by petraponya
Hello,

I would like to run automated burnup sequence. Is it possible to use the isotope inventory of fissile material for different burnup steps gotten from a previous burnup calculation (written in dep.m file)? So that I don't need to calculate the whole burnup cycle each time I run automated burnup sequence.

Thanks,
Petra

Re: Automated burnup sequence

Posted: Thu May 27, 2021 1:25 am
by Ana Jambrina
Check the restart options: ‘set rfw’ and ‘set rfr’.
Additionally, Serpent features several options to set an automated burnup sequence (based the restart capability), invoking variations through 'branch' cards. The automated burnup sequence (matrix) can be defined using the following options: 'casematrix', 'coef' or 'hisv' cards, depending on the purpose of the calculation.

Re: Automated burnup sequence

Posted: Thu Jun 24, 2021 5:18 pm
by bursar05
Hi Ana,

I'm getting this error while i'm using hisv card.

Input error in parameter "hisv" on line 21914 in file "input.txt":
Error in break points

Do you have any idea to fix this?

my burnup card;
-----------------------------------------------------------------------------------------------------------
set power 0.6197261E+06

dep daytot
7
18
54

branch Bchange1 repm waterB cool_801B repu DC13 DC15 norm 5.791340689
branch Bchange2 repm waterB cool_755B repu DC13 DC61 norm 9.246617804

hisv 2 1 Bchange1
3 1 Bchange2

set inventory
922340
922350
922360
922380
932370
942380
942390
----------------------------------------------------------------------------------------------------------

Re: Automated burnup sequence

Posted: Thu Jun 24, 2021 5:28 pm
by Ana Jambrina
The first value in the ‘hisv’ card corresponds to the burnup step associated with the historical variation. It should match one of the depletion steps in the sequence (e.g. in this case, 7, 18 or 54).

There is a bug in Serpent 2.1.32 related to the historical variations through the ‘hisv’ card. The new depletion sequence after the restart (break-point) is not correct, which might cause Serpent to fail. In addition, the material replacing option within the 'branch' card when performing historical variations results in a wrong depletion output if the swapping materials are defined as new materials. Mixtures are not affected.

Re: Automated burnup sequence

Posted: Sun Jul 04, 2021 2:43 pm
by bursar05
Hi,

I created a test case from the pin cell for precise testing of the 'hisv' card.
At first I run the 10-step burnup input with the 'set rfr' command(with script).
Then I tried the same steps in another input using the 'hisv' card.
When I compared the results, I found that it was pretty close.
I changed the boron concentration and power density on both inputs and only burned 1 material.


In which cases 'repm' command gives wrong result?


Have a nice day!

Re: Automated burnup sequence

Posted: Sun Jul 04, 2021 3:13 pm
by Ana Jambrina
Mixtures are not affected.

Note: The simulation runs as it supposed to. However, the '_dep.m' is not correctly printed caused by a mismatch between the listed nuclides before and after the restart (breakpoint).

Re: Automated burnup sequence

Posted: Sun Jul 04, 2021 8:20 pm
by augusto_vib
Ana Jambrina wrote:
Sun Jul 04, 2021 3:13 pm
Mixtures are not affected.

Note: The simulation runs as it supposed to. However, the '_dep.m' is not correctly printed caused by a mismatch between the listed nuclides before and after the restart (breakpoint).
So in the end, what is the conclusion? Could we actually use such automated branches with version 32 or not for depletion calculations?

Re: Automated burnup sequence

Posted: Sun Jul 04, 2021 8:51 pm
by Ana Jambrina
Here, there are two points to consider:

- The bug related to the print-out of the depletion out ‘_dep.m’ only is triggered if the variation is performed replacing new materials (mixtures are not affected). However, in both cases, the simulation itself is OK and, only the depletion output is incorrect.

- The depletion sequence is not rightly set because the restart resets out all previous information and, currently, Serpent cannot redefine it. E.g. this misbehaviour can be observed at the current and total number of depletion steps after the break-point. Nonetheless, this error only crushes the simulation in a few cases (or merely gives an error message at the end even if the simulation is completed correctly).

It is safe to say that the ‘hisv’ card in Serpent 2.1.32 works OK in most cases. Having said that, both problems have addressed and, the fix will be included in the next release version.

Re: Automated burnup sequence

Posted: Mon Jul 12, 2021 1:53 pm
by bursar05
Hi Ana,

One more question about replacement. For example I have 5 burnup steps, does these 'repm' and 'repu' commands change the texts in the first input or the ones written in the previous step?
-----------------------------------------------------------------------------------------------------------
branch Bchange1 repm waterB cool_801B repu DC13 DC15 norm 5.791340689
branch Bchange2 repm waterB cool_755B repu DC13 DC61 norm 9.246617804
branch Bchange3 repm waterB cool_703B repu DC13 DC62 norm 13.88654030
branch Bchange4 repm waterB cool_700B repu DC13 DC28 norm 13.94615705
branch Bchange5 repm waterB cool_652B repu DC13 DC04 norm 21.11386633

hisv 1 1 Bchange1
2 1 Bchange2
3 1 Bchange3
4 1 Bchange4
5 1 Bchange5
--------------------------------------------------------------------------------------------------------------

Re: Automated burnup sequence

Posted: Mon Jul 12, 2021 2:08 pm
by Ana Jambrina
The automated burnup sequence (based on the ‘branch’ card and its options) does not re-rewrite the input itself. Serpent internally applies the changes (based on the data provided) at the given configuration/burnup step.

The replace material option (‘repm’) overrides the replacing material name ‘mat2’ with the replaced material name ‘mat1’. The replace universe option (‘repu’) substitutes the cell pointer corresponding to the replacing universe uni2’ with the cell pointer corresponding to the replaced universe ‘uni1’. Meaning, the replacing material/universe is seen as the replaced material/universe at all effects. You can test the feature, e.g., using detectors. (Note that Serpent will print out an error message in the case of the material/universe not being defined in the geometry when re-configuring the model).

E.g. if you are using the 'hisv' card with series of variations (defined in the 'branch' card), each of them is applied at the listed burnup step. Serpent sets a break-point to 1) re-read the input file, 2) re-configure the model for the history variation and 3) read the restart file and taking the compositions from the previous step. From the screen output, you can see when the break-points take place and how the subsequent steps are applied. The output at each depletion step corresponds with its final stage, including any variations if were performed.