SCALE Software Coordinator
This topic has been migrated from the SCALE 5 ORIGEN notebook.
Date: Mon Apr 26 17:28:21 2010
Please teach me how calculate the (alpha,n) reaction yield at origen-arp.
SCALE Software Coordinator
Dear Naoyuki Hachiya
The (alpha,n) neutron calculation will be performed automatically if the neutron source is requested. In origen arp the fuel specification does not automatically include the non-uranium matrix, e.g., oxygen (because not all fuels are the same). Since (alpha,n) neutrons come from reactions with light elements, these elements must be present in the composition definition and so must be added by the user. The user may specify, in the decay case form of the graphical user interface, that the calculation use a pre-defined uo2 matrix. In this case, no light elements are needed as the code assumes oxygen is present. However, if a "problem specific" calculation is requested then the light elements must be defined in order to get an (alpha,n) source. Note that the option to perform a problem dependent (alpha,n) calculation is not an option in origen2.
I hope this answers your question. Feel free to contact me if you need further assistance.
Sincerely
Ian Gauld
SCALE Software Coordinator
Dear Ian Gauld
Thnaks for your answer for my question.
I have already calculated alpha nuetron using origen-arp6.0 and origen2 for UO2 assembly.I understood the unit of alpha nuetron production yield is n/alpha disintegration for scale6 and as is n/g.sec for origen2 didnt it? For n/g.sec using origen2 ratio isn't specificaly then I tried conversion from n/alpha disintegration for scale6 below steps.
first calcurate alpha nuetron by origen-arp6 set option NN2 to 3$ a11 3
second sumation alpha nuetron production rate all aplha particle for o17 and o18 for compare actinide
third the actinide weight calcuerate from the number of atom
fourth divide sumation alpha nuetron production rate by the actinide weight then the number of n/g.sec for scale6
fifth compare the n/g.sec for origen2 and the number obtain from fourth step.
these step is correct ? @If there are incorrect points please @indicate error points. @
Sincerely
Naoyuki Hachiya
SCALE Software Coordinator
Dear Naoyuki Hachiya
OrigenArp will automatically calculate the (alpha,n) production rate as n/s/basis for you. The printout from setting the 3$ entry is only to provide more details of the calculation if required by the user. You do not need to add the contributions from each target nuclide. After the neutron calculations are completed, the neutron sources from spontaneous fission, (alpha,n) reactions, delayed neutrons, plus the total, are printed for each nuclide and for the entire material. The n/s calculations are for the basis of the calculation (e.g., if you start with the mass of uranium for an entire assembly, then the neutron source is n/s/assembly). Any basis can be selected by the user, so this is very lexible. If you need to compare with older origen2 results, scale by the mass (grams) of uranium in your calculation.
I hope this helps
Sincerely
Ian Gauld
SCALE Software Coordinator
Dear Ian Gauld
Thnaks for your answer for my questions. Please teach me again.
1. (alpha,n) reaction's yeild
I have already calculated alpha nuetron using origen-arp6.0 and origen2 for UO2 assembly.I understood the unit of (alpha,n) reaction's yield is (n/alpha disintegration) for scale6 and as is( n/g.sec) for origen2 didnt it? For (n/g.sec) using origen2 ratio isn't specificaly then I tried conversion from (n/alpha disintegration) for scale6 to divide sum of (n/alpha disintegration) to nuclide weght(g). Is it result.
2. The spurce of (alpha,n) reaction's yeild at SCLE6 please teach me the source of (alpha,n) reaction's yeild at SCLE6
Sincerely
Naoyuki Hachiya
SCALE Software Coordinator
The neutron source printed by ORIGEN in SCALE is neutrons/s/basis. The neutron yield per alpha particle, and per disintegration, is also printed as information to the user. These neutron source methods are adopted from the SOURCES code as documented in the manual. The source of the neutron yield data comes from many different sources, also documented in the manual. There is a paper that may provide some additional information. I hope this helps.
http://www.ornl.gov/~webworks/cppr/y2001/pres/113058.pdf
Ian