Chain Depletion

User Support
1

Hello,

Please, someone can tell me if the depletion chain generated by the script “openmc-make-depletion-chain” (which creates the file “chain_endfb71.xml”) can be used to analyze advanced systems such as liquid salt cooled reactors?

Thanks,

Javier

2

Hi Javier,

The main drawback to that script is that your capture branching ratios will not match the true spectrum of your problem. Instead, I would first recommend using either the Fast Spectrum ENDF/B-VII.1 Chain or Fast Spectrum Simplified Chain found at https://openmc.org/depletion-chains/. Alternatively, if you have a more representative collection of isomeric branching ratios, you can apply these to any depletion chain using the openmc.deplete.Chain.set_branch_ratios method.

Regards,

Andrew

3

Hi Andrew,

Thanks for your reply, now, I am having a new issue. In a previous post, it was recommended setting the OPENMC_CROSS_SECTIONS environment variable, I did it and my depletion analysis was running. Today, I restarted the computer and I am having again the error message “OSError: No cross_sections.xml specified in materials.” I followed the steps to set up the OPENMC_CROSS_SECTIONS environment variable but it is not working.

Any idea on what may be happening?

Javier

4

Hi Javier,

That exception is only raised if the OPENMC_CROSS_SECTIONS is not set. You can see the code where that comes from here (notice the check first for OPENMC_CROSS_SECTIONS):
https://github.com/openmc-dev/openmc/blob/f4e46fd620ddb96755f73df6d2d079ea694ae8a6/openmc/deplete/operator.py#L694-L708

To double check, you could open a Python interactive prompt and make sure it can see the environment variable. For example, on my machine this is what I get:

~ $ python
Python 3.7.5 (default, Oct 31 2019, 12:53:15)
[GCC 9.2.1 20191008] on linux
Type “help”, “copyright”, “credits” or “license” for more information.

import os
os.environ[‘OPENMC_CROSS_SECTIONS’]
‘/opt/data/hdf5/nndc_hdf5_v15/cross_sections.xml’

Best regards,
Paul

5

Hi Paul,

Thanks for replying.
One more time, I followed what was suggested but unfortunately the problem persists. Please, see what I did:

6

Hi guys,

Now, I defined the environment variable modifying the.bashrc file and it is working. It seems I was doing wrong. Here what I did:

~ vi .bashrc ~ vi .bashrc
export OPENMC_CROSS_SECTIONS=/path/to/cross_sections.xml
~$ source .bashrc

Thanks,
Javier