Radiation between heated rods

lego

Hi!

I ask for your advices. I try to calculate a radiation problem with the CFX-5.6 with Monte-Carlo model, but I think the MC model of the CFX-4.3,4 is the same. So I have heated rods in a vessel. There is dry steam of high temperature (t>1000 C) inside. The steel vessel is cooled from outside, so I think modeling it as opaque wall of 1.0 Emissivity and of some fixed temperature is OK (the heated rods have to be much hotter). But how should I model the heated rod's surfaces? Whit which type of boundary condition? I know the net heat flux from the rods to the domain. The main goal to state the rod surface temperatures in which they emit this heat flux. The problem is that there is quite close interaction between the rods because they are in a quite tight lattice, so the rods heat each other.

The geometry is something like this:

----------I*****O*****II**OOO**II*****O*****I----------

Where "-" and "I" are walls of the vessel and "O" : is one of the heated rods.

Thanks in advance for your help!