Fusion

Discussion on physics, models and calculation methods

Fusion

Postby M.K. » Mon Mar 12, 2018 12:08 pm

Hello!

I am new to Serpent and I would like to know if there are people who have tried fusion simulations with it.
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Re: Fusion

Postby Jaakko Leppänen » Mon Mar 12, 2018 7:20 pm

We have done some fusion neutronics calculations, and the group in Culham is pretty active. What kind of an application do you have?
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Re: Fusion

Postby M.K. » Tue Mar 13, 2018 7:27 pm

We would like to simulate our neutron detector calibration procedure. For this reason I was wondering if I can turn to someone specific for questions.
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Re: Fusion

Postby Jaakko Leppänen » Wed Mar 14, 2018 8:09 am

I think it is best to post your question here. Serpent has hundreds of users and we don't know what everyone is doing.
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Re: Fusion

Postby M.K. » Fri May 25, 2018 1:31 pm

Dear users,

I have a few simple questions to begin with:

1. In the tutorial (calculating the flux energy spectrum) why is the y-axis named "energy integrated neutron flux" if there is still energy dependence?
2. I am trying to build a simple torus geometry but I can't understand the plots. I expect something different as an output. Is there something tricky with this type of surface or am I confused in regards to the plots?
3. Instead of specifying a number of neutrons in a certain direction is it possible to provide all the necessary information about Pu-238 and use it as an external source?

Best Regards!
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Re: Fusion

Postby Jaakko Leppänen » Sat May 26, 2018 11:05 am

1) All Monte Carlo result estimates are integrated over the variable. I guess the axis name just implies that the results are integrated over energy inside each bin.

2) Can you post your geometry plot of the torus input? The Geometry plotter in Serpent produces strange results if the plot plane coincides with material surfaces, but this is most likely not the case here.

3) Have you looked at the radioactive decay source option?
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Re: Fusion

Postby M.K. » Tue May 29, 2018 2:56 pm

Thank you, Jaakko!

I haven't checked the radioactive decay source option, will do!

Regarding the geometry, I clarified my confusion but further encountered an overlap.
Thought this will be a simple way to specify a certain layer of material:

surf 1 torz 0 0 0 150 150 100
surf 2 torz 0 0 0 150 145 95

set acelib "$SERPENT_DATA/xs/sss_jeff311u.xsdata"

mat tungsten -19.3
74184.03c -1

cell 1 0 void -1
cell 2 0 tungsten 1 -2
cell 3 0 outside 2

src 5 sp 0 0 0 sd 0 1 0 se 10

set nps 500000

plot 1 500 500 0 -300 300 -300 300

plot 2 500 500 0 -300 300 -300 300

plot 3 500 500 0 -300 300 -300 300

Best Regards!
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Re: Fusion

Postby Jaakko Leppänen » Fri Jun 15, 2018 5:20 pm

cells 2 and 4 define the same space (inside of cyl2).
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Re: Fusion

Postby M.K. » Fri Jun 15, 2018 5:41 pm

Thank you, Jaakko!

I managed to solve this but I tried another case with the same routine and when I plot it shows only the infinite space when I suppose it should show the geometry of the cylinders instead. Is this correct?

surf sINF inf
surf cyl1 cylz 0 0 30
surf cyl2 cylz 0 0 15

mat water -1.0 rgb 200 200 255
1001.03c 2.0
8016.03c 1.0

mat tungsten -19.3
74184.03c -1

cell 1 0 fill 1 -sINF
cell 2 1 water -cyl2
cell 3 1 tungsten cyl2 -cyl1
cell 5 0 outside sINF

src 5 se 15
set nps 5000

plot 1 500 500

plot 2 500 500

plot 3 500 500
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Re: Fusion

Postby Jaakko Leppänen » Sun Jun 17, 2018 7:51 pm

The problem is that when you define the outer boundary using the infinite surface, Serpent cannot determine the bounding box for the geometry. This means that some default very large values are used, which causes problems for the source sampling routine and the geometry plotter.

Try replacing surface sINF with some finite surface.
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