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Hi every body, i'm working and calculating the keff, and total

by tiepngh
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tiepngh
#1
Mar5-12, 09:22 PM
P: 5
hi every body, i'm working and calculating the keff, and total fission produced in critical accident in the cylindrical model. If critical mass is roached.
I calculated variable multiply coefficient (keff) by MCNP 5.
also total fission produced i don't know how to calculate this variable,
I really need your help.
thanks you very much for your help.
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wizwom
#2
Mar6-12, 07:47 AM
P: 71
Quote Quote by tiepngh View Post
hi every body, i'm working and calculating the keff, and total fission produced in critical accident in the cylindrical model. If critical mass is roached.
I calculated variable multiply coefficient (keff) by MCNP 5.
also total fission produced i don't know how to calculate this variable,
I really need your help.
thanks you very much for your help.
Well, you could just take the fuel depletion in atoms...
Astronuc
#3
Mar6-12, 08:27 AM
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Quote Quote by tiepngh View Post
hi every body, i'm working and calculating the keff, and total fission produced in critical accident in the cylindrical model. If critical mass is roached.
I calculated variable multiply coefficient (keff) by MCNP 5.
also total fission produced i don't know how to calculate this variable,
I really need your help.
thanks you very much for your help.
Total fission would be the integral of Ʃf and flux ∅(x) over the volume and time. One could reasonably assume a Gaussian pulse and mostly a prompt neutron flux.

tiepngh
#4
Mar21-12, 11:46 PM
P: 5
Hi every body, i'm working and calculating the keff, and total

Quote Quote by Astronuc View Post
Total fission would be the integral of Ʃf and flux ∅(x) over the volume and time. One could reasonably assume a Gaussian pulse and mostly a prompt neutron flux.
thanks for your answer,
and could you show me about Ʃf clearly, eg i want to calculate with thermal neutron(E < 6.625e-7 MeV), and fission cause of U235. how is Ʃf?
Thanks you !
Astronuc
#5
Mar22-12, 01:24 PM
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Quote Quote by tiepngh View Post
thanks for your answer,
and could you show me about Ʃf clearly, eg i want to calculate with thermal neutron(E < 6.625e-7 MeV), and fission cause of U235. how is Ʃf?
Thanks you !
What is the initial form of the material? Solid metal, ceramic, or a aqueous solution? One can estimate the reactivity from keff-1.

Ʃf = NU235 * σf

and N is the atomic density of the material.
tiepngh
#6
Mar26-12, 11:13 PM
P: 5
Quote Quote by Astronuc View Post
What is the initial form of the material? Solid metal, ceramic, or a aqueous solution? One can estimate the reactivity from keff-1.

Ʃf = NU235 * σf

and N is the atomic density of the material.
Thanks you very much, i have calculate critical model with solution material, one things i don't know that σf, and could you show me how to find it?
Solution : UO2(NO3)2 . 6 H2O.
Astronuc
#7
Mar27-12, 07:02 AM
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Quote Quote by tiepngh View Post
Thanks you very much, i have calculate critical model with solution material, one things i don't know that σf, and could you show me how to find it?
Solution : UO2(NO3)2 . 6 H2O.
I would expect it is in a library of cross-sections in MCNP 5.

Otherwise, http://www.nndc.bnl.gov/sigma/index....dfb7.1&nsub=10 - and find (n,total fission).

There will be no delayed neutrons.
tiepngh
#8
Mar30-12, 02:38 AM
P: 5
Quote Quote by Astronuc View Post
I would expect it is in a library of cross-sections in MCNP 5.

Otherwise, http://www.nndc.bnl.gov/sigma/index....dfb7.1&nsub=10 - and find (n,total fission).

There will be no delayed neutrons.
Many thanks, and i will try to finish my problem....thanks again!


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