Bug in JEFF3.2 Am241 data

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makopec
Posts: 2
Joined: Tue Jun 13, 2017 11:28 am

Bug in JEFF3.2 Am241 data

Post by makopec » Wed Jun 21, 2017 10:50 am

I run FISPACT 3.20 with the following files:

files:
# gamma attenuation data
absorp /home/mariusz/FISPACT-II-3-20/ENDFdata/decay/abs_2012

# index of nuclides to be included
ind_nuc /home/mariusz/FISPACT-II-3-20/ENDFdata/JEFF32data/jeff32_decay12_index

# Library cross section data
xs_endf /home/mariusz/FISPACT-II-3-20/ENDFdata/JEFF32data/jeff32-n/gxs-709

# Library probability tables for self-shielding
prob_tab /home/mariusz/FISPACT-II-3-20/ENDFdata/TENDL2015data/tal2015-n/tp-709-294

#fluxes
fluxes fluxes

# Library decay data
dk_endf /home/mariusz/FISPACT-II-3-20/ENDFdata/decay/decay_2012

# Library fission data
fy_endf /home/mariusz/FISPACT-II-3-20/ENDFdata/JEFF32data/jeff32-n/jeff311nfy

# Library regulatory data
hazards /home/mariusz/FISPACT-II-3-20/ENDFdata/decay/hazards_2012
clear /home/mariusz/FISPACT-II-3-20/ENDFdata/decay/clear_2012
a2data /home/mariusz/FISPACT-II-3-20/ENDFdata/decay/a2_2012

# collapsed cross section data (in and out)
collapxi COLLAPX1
collapxo COLLAPX1

# condensed decay and fission data (in and out)
arrayx ARRAYX1
…………………………………………………………………………………………………………………………………………….
fluxes:
0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
(repeated 88 times)
0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 3.5000E+13 0.0000E+00
0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
(repeated 27 times)
0.0000E+00
1.00
MY SPECTRUM FOR THERMAL ENERGY
…………………………………………………………………………………………………………………………………………….
collapse.i:
<< -----collapse cross section data----- >>
CLOBBER
GETXS 1 709
FISPACT
* COLLAPSE jeff32-n/gxs-709 decay12 index
PRINTLIB 4
END
* END OF RUN
…………………………………………………………………………………………………………………………………………….
fisprun:
echo 'Running collapse with JEFF3.2 709-xs'

fispact collapse
…………………………………………………………………………………………………………………………………………….

The data for Am241 (n,g) in the collapse.out file was:

Am241 (n,g ) n 0m 6.91622E+01+- 0.00000E+00

It is probably the value for Am241 (n,g) Am242m, but the name of the result nuclide is corrupted. What is more important, there is no data for the Am241 (n,g) Am242 reaction where the xs should be ca 10 times larger.

The same runs done for ENDFB-7.1 and JENDL-4.0 libraries give the following results:
ENDF:
Am241 (n,g ) Am242m 6.77809E+01+- 5.00000E+00
Am241 (n,g ) Am242 6.10028E+02+- 5.00000E+00
JENDL:
Am241 (n,g ) Am242m 7.04921E+01+- 0.00000E+00
Am241 (n,g ) Am242 6.07317E+02+- 0.00000E+00

and these results are ok.

User avatar
Michael Fleming
Site Admin
Posts: 22
Joined: Thu Sep 08, 2016 10:51 am

Re: Bug in JEFF3.2 Am241 data

Post by Michael Fleming » Thu Jun 22, 2017 3:02 pm

Hello,

As your title implies, the issue is with a bug in the JEFF-3.2 Am241 file. FISPACT-II reads the IZAP entry from the MF=10 data and as the entry in the JEFF-3.2 neutron Am241 file has IZAP = 0 the code prints this as a neutron with zero mass, and since the LFS is not zero you get a isomer, as well. If you are interested in this the ENDF-6 manual chapter 10 provides details.

To fix this the Am241 file must be corrected. I have attached a modified Am241 file with lines 9437 and 9676 corrected. This will produce the desired output. Simply replace the Am241 in the folder:

Code: Select all

ENDFdata/JEFF32data/jeff32-n/gxs-709/
with the one attached.

Let me know how it goes.

Best regards,

Michael
Attachments
Am241g.asc
(785.4 KiB) Downloaded 236 times
Michael Fleming, PhD
D3/1.56 Culham Science Centre
UK Atomic Energy Authority
Abingdon, OX14 3DB
+44 (0) 1235 466884
michael.fleming@ukaea.uk

makopec
Posts: 2
Joined: Tue Jun 13, 2017 11:28 am

Re: Bug in JEFF3.2 Am241 data

Post by makopec » Fri Jun 23, 2017 10:12 am

Thank you for the quick reply. Now the results for Am241 are correct.

Mariusz

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