Thicknesses in Pin and Vertical stack definition

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Thicknesses in Pin and Vertical stack definition

Postby Andrei Fokau » Fri Jul 23, 2010 4:21 pm

Sometimes, it is more handy to set distances instead of absolute positions in Pin and Vertical stack definition. Pin radii are all positive, therefore negative values could mean the distance to the previous radius
Code: Select all
pin 1
fuel -0.5   % equivalent to 0.5
void -0.05  % eq. to 0.55
clad  -0.1   % eq. to 0.65
coolant

If the number of layers is large and one needs to change one of the internal radii, then the other radii are recalculated by computer, not user.

Concerning Vertical stack, I don't see a good solution yet, since layer lower positions can be negative. However, I would appreciate to have such option (lattice type 10?), because the number of layers can be significant and recalculation of their absolute positions just takes time, potentially introducing errors.
Last edited by Andrei Fokau on Thu Sep 02, 2010 3:15 pm, edited 1 time in total.
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Re: Distances in Pin and Vertical stack definition

Postby Jaakko Leppänen » Sat Aug 21, 2010 3:56 pm

I'll add this feature for fuel pins and particles in the next update.

Vertical stacks are handled differently, because they are basically lattice structures. I'll look into that later.
- Jaakko
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Re: Distances in Pin and Vertical stack definition

Postby Andrei Fokau » Sun Aug 22, 2010 1:59 am

Jaakko Leppänen wrote:I'll add this feature for fuel pins and particles in the next update.

Jaakko, could you also allow a mixed definition (just in case if some layers must be fixed):
Code: Select all
pin 1
fuel -0.5   % equivalent to 0.5
void  0.55  % eq. to -0.05
clad -0.1   % eq. to 0.65
coolant
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Re: Distances in Pin and Vertical stack definition

Postby Andrei Fokau » Sun Aug 22, 2010 2:45 am

Jaakko Leppänen wrote:Vertical stacks are handled differently, because they are basically lattice structures. I'll look into that later.

One more thing which would be great to have in the vertical stack is filling by a material. Actually, vertical stacks have more in common with pins (nests?) than with lattices. Would it be better to define vertical stack in the following way:
Code: Select all
vstack 1
reflector  -150
plenum     -100
fill 11     100
plenum      200
reflector 

surf 11 inf
cell 11 11 fuel -11

set gcu 11

This definition also makes setting of the first infinite section more straight forward, since it probably always starts at minus infinity. Transformation of universe coordinates can be done by trans card. Origin of universes can be set on the upper boundary, with exception for the last layer (or vice versa).

Vertical stack as a lattice would make more sense if it is equi-distant infinite structure, which is filled by a set of universe numbers as the other lattice types.
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Re: Distances in Pin and Vertical stack definition

Postby Jaakko Leppänen » Sun Aug 22, 2010 2:27 pm

Pin and particle objects are actually special cases of nests, which can be defined as:

nest <i> <surf>
<mat1> <d1>
<mat2> <d2>
...

where <surf> is the type of nested surface and <d1> <d2> etc. are the parameters. The material entries can be replaced by universes using the fill-command.

Nest should work with all surface types, characterized by a single parameter (and possibly coordinates). A pin definition:
Code: Select all
pin 1
void   0.08000
fuel   0.37800
void   0.38800
clad   0.45750
water   


is equivalent with:
Code: Select all
nest 1 cyl
void   0.08000
fuel   0.37800
void   0.38800
clad   0.45750
water


They should also work with planar surface, which allows you to stack material or universe layers.

The new feature with negative entries will allow mixed definitions with "closed" nest types (doesn't make sense with planar surfaces, which may actually have negative coordinates).

I'm sorry about the unclear writing, I'm typing this in a hurry.
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Re: Distances in Pin and Vertical stack definition

Postby Andrei Fokau » Sun Aug 22, 2010 4:11 pm

Jaakko Leppänen wrote:Pin and particle objects are actually special cases of nests, which can be defined as:

nest <i> <surf>
<mat1> <d1>
<mat2> <d2>
...

where <surf> is the type of nested surface and <d1> <d2> etc. are the parameters. The material entries can be replaced by universes using the fill-command.

Nest should work with all surface types, characterized by a single parameter (and possibly coordinates). ...
They should also work with planar surface, which allows you to stack material or universe layers.

The new feature with negative entries will allow mixed definitions with "closed" nest types (doesn't make sense with planar surfaces, which may actually have negative coordinates).

This is absolutely awesome! Words fail me trying to express all my appreciation to you for making Serpent. Your code is definitely the coolest and most user-friendly reactor code ever, eventually starting the new generation of reactor computing.

The missing section about nests in the Serpent manual needs to be written one day, so other users can experience this excellent feature.
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