Why Am I Getting a Fatal Error and Warnings in MCNP6?

[khary23]

Hello,
I am working through the MCNP6 manual and am experiencing the following error as well as warning when trying to run the sample problem from the manual.
The fatal error I get is
"fatal error. 1 entries not equal to number of cells = 4."
From the IMP card. My entry for that card is
IMP:N 1 1 1 0
which is exactly what they have in the manual.
After that I get the following error.
"warning. Default xsdir_mcnp6.1 not found. Switching to backup, xsdir

bad trouble in subroutine ixsdir of imcn

data file xsdir does not exist"
But I do see xsdir in the MCNP_DATA directory so I am a bit confused about that. I have upload the output file with the errors in case I have not properly explained what's going on.

 

[PSRB191921]

hi
for your fatal error it is because you have twice "imp:n". one in line 22 and the other line 23. Remove line 22.
In MCNP6 "Xsdir" must be named "xsdir_mcnp6.1" so renamed the file "xsdir". But it is Strange I think that MCNP6 was not install correctly.

 

[khary23]

This is very strange. As you can see from the screen shot below IMP:N is only in line 24. I think I will uninstall and reinstall and see if that helps. Thanks for your help.

 

[PSRB191921]

sorry,
too difficult to read. Can you copy/paste your file (or put a ascii file) ?

 

[khary23]

Here it is a a notepad file. Thank you for looking at it.

 

[khary23]

I wanted to add that I looked and the file "xsdir_mcnp6.1" does exist in the MCNP_DATA folder.

 

[PSRB191921]

first you have 2 imp:n !
in block 1
Sample Problem Imput Deck
C cell cards for sample problem
1 1 -0.0014 -7 IMP:N=1
2 2 -0.786 -8
3 3 -1.060 1 -2 -3 4 -5 6 7 8
4 0 -1:2:3:-4:5:-6
C end of cell cards for sample problem

must have
1 1 -0.0014 -7 $ IMP:N=1

second you have a cukie cutter :
instead of
C Surface Cards
C Begining of surfaces for cube
1 PX -5 $ 5cm negitive of x=0
2 PX 5 $ 5cm positive of x=0
3 PY 5
4 PY -5
5 PZ -5
6 PZ 6
C End of Cube surfaces
C Begin Sphere Surfaces
7 S 0 -4 -2.5 0.5 $ oxygen sphere
8 S 0 4 4 0.5 $ iron sphere
C End sphères

you msut have :

5 PZ 5
6 PZ -6

and after it's ok (see file)
​

 

[khary23]

I have no idea how the IMP:N=1 got into the cell card, thank you so much for pointing it out!

One last question why is
5 PZ -5
6 PZ 6 incorrect and

5 PZ 5
6 PZ -6 Correct?

 

[PSRB191921]

One last question why is
5 PZ -5
6 PZ 6 incorrect and

5 PZ 5
6 PZ -6 Correct?

because you write in block 1 :
3 3 -1.060 1 -2 -3 4 -5 6 7 8
so "-5" is on the left of geometry "5 PZ -5" but "PZ -5" is the left plan of your geometry
and 6 is on the right of geometry "6 PZ 6" but "PZ 5" is the right plan of your geometry

 

[PSRB191921]

is it ok with my modification ?

 

[khary23]

because you write in block 1 :
3 3 -1.060 1 -2 -3 4 -5 6 7 8
so "-5" is on the left of geometry "5 PZ -5" but "PZ -5" is the left plan of your geometry
and 6 is on the right of geometry "6 PZ 6" but "PZ 5" is the right plan of your geometry

That makes complete sense. Thank you

 

[khary23]

is it ok with my modification ?

That makes complete sense. Thank you

Yes! Again thank you!