Hello @fsabab,

My question is actually more about the different methods of normalization in OpenMC.

How many are there? What are their differences and how can I change them? For example, in Serpent2, there are 4 ways of calculating the deposited energy (“set edepmode” command in Serpent2 : Input syntax manual - Serpent Wiki).

What I am trying to do is explain the huge differences I encountered across tallies for the same system between Serpent2 and OpenMC.

Here is my code :

##################################################

#
Materials definition

mat = openmc.Material()

mat.add_nuclide(‘Ga69’,2.0517e-2)

mat.add_nuclide(‘Ga71’,1.3615e-2)

mat.add_nuclide(‘Pu239’,9.1951e-1)

mat.add_nuclide(‘Pu240’,4.3465e-2)

mat.add_nuclide(‘Pu241’,2.8975e-3)

mat.set_density(‘g/cm3’,15.61)

materials = openmc.Materials([mat])

materials.export_to_xml()

#
Geometry defintion

sphere = openmc.Sphere()

inside = -sphere

sphere.r = 6.39157

sphere.boundary_type = ‘vacuum’

fuel = openmc.Cell()

fuel.fill = mat

fuel.region = inside

geometry = openmc.Geometry([fuel])

geometry.export_to_xml()

#############################################

The exact same specifications and the same database (ENDF B VII.1) are used for both codes.

And here are the tallies results :

OpenMC :

flux 4.6985563774625545 0.00012531146042234445

inverse-velocity 3.741619004300651e-09 1.7010891996524724e-13

heating 55506645.00148293 1436.9080313350564

k_combined 1.0008284918766601 2.4688889916300313e-05

beta eff 0.002045324880571339 1.0802094095533329e-08

Serpent2 :

impKeff 1.000857 4.182993652567228e-05

totPower 65965093.75000001 2720.8168904348677

totFlux 4.69654775 0.0001713967881097879

adjIfpAnaBetaEff 0.0018457935 7.719006695098435e-06

adjIfpLifetime 2.8785955e-09 1.0152401509507941e-12

How can we explain the differences, especially between the power/heating and inverse-velocity/lifetime ?

Thank you for your help.