Trying to generate a Hexagonal lattice of fuel pin.

User Support
1

Hello, I am trying to generate a hexagonal lattice of my fuel pin. The below code I am using and I always get maximum number of particle leak and the lattice has no define outer parameter. I just want a lattice of 7 fuel rod with 1.5 pitch. This works when my surface 21,22,23,24 has 1.5 in them. But the geometry plat I got would not show full radius of all the fuel rod. Please help. Thanks.

<?xml version="1.0"?>

<hex_lattice id=“5” n_rings=“2” >

0.0 0.0

1.5

2

2 2

2

2 2

2

</hex_lattice>

2

Hi Sharif (and Mohammed),

The first problem I notice with this model is that multiple surfaces are defined to be the same (for example, surfaces 2, 5, and 8 are all the same). There should only be one unique definition of a given surface. The second problem is that you need to tell OpenMC how to handle lattice positions that are “outside” of the defined positions. This is handled by setting an outer universe on the <hex_lattice> element (see the description here). The outer universe can simply be a cell with no material and no defined region. When I add such an outer universe, I am able to get your model to run (and plotting works as well). I’ve attached a zip file with a fixed model that should work. Here’s what the plot should look like:

hexlat.png

Best regards,
Paul
​

hexlattice.zip (1.96 KB)

3

Thank you so much Dr :pray:

4

Thank you very much Paul Romano. This is exactly what I was trying to achieve. Now, If I want to design my container of water with a radius of 15cm and a steel surrounding of .25cm. I am trying to do the below code in addition to your code. Please look into this. The container height is 220. So I create 2 surfaces of -110 and 110. Also, for the bottom of the container, I make the water height of -109.75 and 109.75. Below is an image that shows what I want to achieve but for the hex lattice of 7 fuel pin. The image shows one fuel pin. I want the full hex lattice of 7 pins. Please, can you guide? This is I am doing. Also, In your sample project, you haven’t done the tally of the flux. Please, can you guide us to do that?

<?xml version="1.0"?>

<hex_lattice id=“5” n_rings=“2” >

0.0 0.0

1.5

2

2 2

2

2 2

2

3

</hex_lattice>

I and Mohammad are the new Openmc learner. You have been a great help. Thank you very much.

5

I forgot to add the image. Here it is. Thanks.

Screen Shot 2018-04-21 at 1.25.16 AM.png
Screen Shot 2018-04-21 at 1.25.16 AM.png633×633 46.7 KB

6

Hello, Dr. Paul Romano. Can you please guide us on this? Thank you.

7

Hello, Dr. Paul Romano. Can you please guide us on this? I want a hexagonal lattice of our fuel pin with surrounding water and the steel tank. The code that Iwe are using is given in the other email and also here. Thank you.

Regards,
Sharif Abu Darda, Mohammad Talhi

geometry.xml (1.76 KB)

8

Hi Sharif,

See the attached version of your model, which should now contain the 7 hex lattice pins in the middle of the container.

Best regards,
Paul

geometry.xml (1.84 KB)