Fixing MCNPX Fatal Error: Too Many Numbers First Entry

In summary, when trying to create an example from this pdf, the code PFRAC=F1,F2,F3,. means what?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.
  • #1
emilmammadzada
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TL;DR Summary
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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  • #2
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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  • #3
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.
 
  • #4
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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  • inp.txt
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  • #5
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?
 
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  • #6
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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  • #7
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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  • reactest.txt
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  • reactwithburnup.txt
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  • #8
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.
 
Last edited:
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  • #9
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.
 
  • #10
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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FAQ: Fixing MCNPX Fatal Error: Too Many Numbers First Entry

1. How do I fix the MCNPX Fatal Error: Too Many Numbers First Entry?

The MCNPX Fatal Error: Too Many Numbers First Entry occurs when the input file contains too many numbers in the first entry. To fix this error, you will need to check your input file and make sure that the first entry only contains the necessary numbers for the simulation. Remove any extra numbers that may have been accidentally added.

2. Why does the MCNPX Fatal Error: Too Many Numbers First Entry occur?

The MCNPX Fatal Error: Too Many Numbers First Entry occurs when the input file is not properly formatted. The first entry in the input file should only contain the necessary numbers for the simulation, and any additional numbers can cause this error to occur. It is important to carefully check the input file for any formatting errors.

3. Can I fix the MCNPX Fatal Error: Too Many Numbers First Entry without changing my input file?

In most cases, the MCNPX Fatal Error: Too Many Numbers First Entry can only be fixed by modifying the input file. However, if the error is caused by a typo or small mistake, you may be able to fix it by simply correcting the mistake in the input file. Otherwise, you will need to make necessary changes to the input file to fix the error.

4. How can I prevent the MCNPX Fatal Error: Too Many Numbers First Entry from occurring?

To prevent the MCNPX Fatal Error: Too Many Numbers First Entry, it is important to carefully check and double check your input file before running the simulation. Make sure that the first entry only contains the necessary numbers and that there are no typos or formatting errors. It may also be helpful to use a text editor or software that can help identify any errors in the input file.

5. Is the MCNPX Fatal Error: Too Many Numbers First Entry a common error?

The MCNPX Fatal Error: Too Many Numbers First Entry is a relatively common error that can occur when running simulations using MCNPX. It is often caused by small mistakes in the input file, but can also be caused by other factors such as incorrect software settings. With careful attention to detail and proper troubleshooting, this error can be easily resolved.

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