Depletion error : did not sample any reaction for nuclide Pb204

User Support
1

Dear openmc experts,

I struggle with some problem with the depletion. I am working on running depletion on fix source calculation with the external source. The result come out like this

image
image1706×960 193 KB

Error : Did not sample any reaction for Pb 204

(I also try running depletion in eigenvaule calculation mode, this error still occurred.)
May someone had an idea what could be the problem?

FYI : I’m using jupyter notebook for running the problem for depletion using chain_endfb71_sfr.xml and ENDF/B-VII.1 as cross_section for this case.

2

@billytnp do you have a model you’re able to share that results in this behavior?

3

Dear @paulromano, sorry for lately reply.

I have sent you the script in your private message.

Thank you very much for your time,
thanapong

4

Hi @billytnp. It looks like the cause of this is the erroneous Be7 evaluation in ENDF/B-VII.1, which only has data up to 8.1 MeV. This nuclide gets automatically added to the model with the chain_endfb71_pwr.xml depletion chain. A quick solution is to edit chain_endfb71_pwr.xml and remove the Be7 nuclide so it doesn’t get added:

diff --git a/depletion/chain_endfb71_pwr.xml b/depletion/chain_endfb71_pwr.xml
index c88bc45..7861444 100644
--- a/depletion/chain_endfb71_pwr.xml
+++ b/depletion/chain_endfb71_pwr.xml
@@ -82,11 +82,6 @@
   <nuclide name="Be6" half_life="4.95326e-21" decay_modes="1" decay_energy="1372000.0" reactions="0">
     <decay type="p,p" target="He4" branching_ratio="1.0"/>
   </nuclide>
-  <nuclide name="Be7" half_life="4598208.0" decay_modes="1" decay_energy="49861.81" reactions="2">
-    <decay type="ec/beta+" target="Li7" branching_ratio="1.0"/>
-    <reaction type="(n,p)" Q="1644300.0" target="Li7"/>
-    <reaction type="(n,a)" Q="18992000.0" target="He4"/>
-  </nuclide>
   <nuclide name="Be8" half_life="8.18132e-17" decay_modes="1" decay_energy="91840.0" reactions="0">
     <decay type="alpha" target="He4" branching_ratio="1.0"/>
   </nuclide>
5

Dear @paulromano,

Thank you so much for your help, After I followed your suggestion, now I can run the depletion problem.
But another problem happens with the depletion result. I tried increasing the source rate from 1.97e12 to 1.27e20 or power from 50 MW to 100 MW, the irradiation time plot of actinide transmutation didn’t change values or trend. As an example shown below,

The result of 100MW , 500 particles, 20 batches , chain_endf_sfr.xml, source rate =1.9799e12

|240px;x157px;

The result of 100MW , 500 particles, 20 batches , chain_endf_sfr.xml, source rate =1.27e20

|227px;x147px;

However, the results of actinide transmutation still wrong but I want to clarify, what’s the problem that causes the result didn’t change even the parameters has been adjusted.

I have sent you the script, source file and chain file in your private message.

Thanks again,
Thanapong

6

@billytnp It looks like the problem is that you are creating an integrator instance and passing both power and source_rates arguments. You should pass one or the other but not both. If you want to deplete based on a source rate, you should not pass a power to the integrator since this will override the source rate that you specify.