Fixing MCNPX Fatal Error: Too Many Numbers First Entry

AI Thread Summary
The application is encountering a "Fatal error too many numbers first entry" due to multiple typos in the input file, particularly in line 25, which includes missing periods and an exponent. The user is attempting to add a burn-up card to a reactor model in MCNP but is facing issues with geometry errors and volume calculations for certain cells. It is suggested that the volume for cell 1 should be explicitly defined using a vol card, which resolved some errors, while the MATVOL parameter is necessary for the BURN card due to the lattice structure. The discussion also touches on the need for correct syntax in the OMIT line and the importance of ensuring that the burn times are properly included in the input file. Overall, the user is working through various errors to successfully implement the burn-up card in their reactor simulation.
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When I run the application, I get an error message. This message: Fatal error too many numbers first entry. What could be the reason?MCNPX
When I run the application, I get an error message. This message: Fatal error too many numbers first entry. What could be the reason?
 

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Continued lines are 5 spaces, not 3.

Line 25,
Code:
     94241 60c 3 3997e 94241.60c 3.3997e-4
Seems to have 3 typos. 2 missing .'s and a missing exponent.

You have a duplicate mt3 card, one with a typo.

The source is being rejected, and I'm not seeing it by eye. Usually means a geometry error. I'll continue to look at it.
 
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Alex A said:
Continued lines are 5 spaces, not 3.

Line 25,
Code:
     94241 60c 3 3997e 94241.60c 3.3997e-4
Seems to have 3 typos. 2 missing .'s and a missing exponent.

You have a duplicate mt3 card, one with a typo.

The source is being rejected, and I'm not seeing it by eye. Usually means a geometry error. I'll continue to look at it.
I want to add a burn up card to the sample reactor in mcnp. For this, I wanted to learn how to add a nail to the burn up card first.
 
Your ksrc is the 'other' side of cell 3, on the edge of or into the void. Changing it to "ksrc 0 0 150" fixes that.

mcnpx gave me an error that makes me think we might need an ignore line. mcnp6 is running the kcode, which might take a while. So this is mostly fixed.
 

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Alex A said:
Your ksrc is the 'other' side of cell 3, on the edge of or into the void. Changing it to "ksrc 0 0 150" fixes that.

mcnpx gave me an error that makes me think we might need an ignore line. mcnp6 is running the kcode, which might take a while. So this is mostly fixed.
https://mcnp.lanl.gov/pdf_files/la-ur-09-2051.pdf The application I tried to make an example is from this pdf PFRAC=F1,F2,F3,. what does this code mean?
 
The ksrc line is an error in the document that has a different correct description later on. KSRC 0 0 182.5 is the middle of the pin location.
 
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Alex A said:
The ksrc line is an error in the document that has a different correct description later on. KSRC 0 0 182.5 is the middle of the pin location.
my aim is to add burn up card to this reactor. but i don't know how to do it
 

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The six lines immediately after the BURN card are variables that belong to it, so they need five spaces or MCNP/X will think they are commands.

The OMIT line has been messed with, look up the syntax and fix it. You may need to add additional nuclides that X has no tables for. That may be a BOPTS issue, X can ignore those kinds of errors.

Some of the cells are badly specified, and I've tweaked them to be limited in z to give them finite calculable volume. X still complains
Code:
fatal error.  zero volume for burn cell        1. use vol card.
which I did to every cell with no calculated volume except the void cell (which is infinite). I also added a MATVOL=28426.299 parameter to the BURN, which is needed when a lattice is being used. Now I am stuck because this error is not going away. I will try again tomorrow.

Edit,
Literally giving cell 1 a vol card with the value it calculated itself solves the error.
 
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yes i am getting the same error in the code. It works without a burn card. It's probably a problem with the vol card in this code.
 
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Alex A said:
The six lines immediately after the BURN card are variables that belong to it, so they need five spaces or MCNP/X will think they are commands.

The OMIT line has been messed with, look up the syntax and fix it. You may need to add additional nuclides that X has no tables for. That may be a BOPTS issue, X can ignore those kinds of errors.

Some of the cells are badly specified, and I've tweaked them to be limited in z to give them finite calculable volume. X still complains
Code:
fatal error.  zero volume for burn cell        1. use vol card.
which I did to every cell with no calculated volume except the void cell (which is infinite). I also added a MATVOL=28426.299 parameter to the BURN, which is needed when a lattice is being used. Now I am stuck because this error is not going away. I will try again tomorrow.

Edit,
Literally giving cell 1 a vol card with the value it calculated itself solves the error.
How can I add a vol card to this input file?
 
  • #11
Don't make new threads for this problem. My line reads like this,
Code:
1     1   0.068525    -18 1 -2              vol=136.011  u=1         $ Fuel Pin

1 and -2 are limits in Z to make the volume finite so the program can calculate the volume itself. At that point it still didn't run to the end. I then just fed this value back into the line with the vol= part.
 
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  • #12
Alex A said:
Don't make new threads for this problem. My line reads like this,
Code:
1     1   0.068525    -18 1 -2              vol=136.011  u=1         $ Fuel Pin

1 and -2 are limits in Z to make the volume finite so the program can calculate the volume itself. At that point it still didn't run to the end. I then just fed this value back into the line with the vol= part.
Should I add a vol card for other cells or only the first cell is enough for this reactor?
 
  • #13
That is only cell with material 1 in it. BURN was told about material 1, so you don't need any other cell.

According to the manual you need a MATVOL with the BURN card, because this is a lattice. I'm assuming that value is 209 * 136.011. I'm not familiar with BURN, so it now runs but I don't know enough to be sure the result is correct.
 
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  • #14
Alex A said:
That is only cell with material 1 in it. BURN was told about material 1, so you don't need any other cell.

According to the manual you need a MATVOL with the BURN card, because this is a lattice. I'm assuming that value is 209 * 136.011. I'm not familiar with BURN, so it now runs but I don't know enough to be sure the result is correct.
vol=136.011 how did you calculate this? is there a formula or something?the code didn't work either, I did the same
 

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  • #15
You can do it with maths, cell 1 is formed from surface 18, which is cz, a cylinder and you know the radius.

MCNP will try to calculate the volume of every cell. If you read through the output file, you'll see the list. What they are or why the program failed to work it out.

I made the volume finite by adding 1 and -2, and then I simply read the output file.
 
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  • #16
Alex A said:
You can do it with maths, cell 1 is formed from surface 18, which is cz, a cylinder and you know the radius.

MCNP will try to calculate the volume of every cell. If you read through the output file, you'll see the list. What they are or why the program failed to work it out.

I made the volume finite by adding 1 and -2, and then I simply read the output file.
Do you add burn time in your input file?the application gave an error in the burn time part
 
  • #17
You already have two burn times in your input file, 50 days and 200 days.
 
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  • #18
Alex A said:
You already have two burn times in your input file, 50 days and 200 days.
I guess I need to use ksrc instead of sdef, but I couldn't see keff values either.
 

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  • #19
emilmammadzada said:
vol=136.011 how did you calculate this? is there a formula or something?the code didn't work either, I did the same
Alex A said:
That is only cell with material 1 in it. BURN was told about material 1, so you don't need any other cell.

According to the manual you need a MATVOL with the BURN card, because this is a lattice. I'm assuming that value is 209 * 136.011. I'm not familiar with BURN, so it now runs but I don't know enough to be sure the result is correct.
Why do you multiply the value by 209 in matvol. What does the number .209 mean?
 
  • #20
BURN needs the volume of fuel. That is the volume of one fuel rod core multiplied by the number of rods, which I think is 209.
 
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