Register to reply 
2 energy groups 
Share this thread: 
#1
Oct1413, 01:34 AM

P: 11

Assumptions
1) a=absorption 2) f=fission 3) ∅=neutron flux 4) time independent 5) group 1, fast neutrons 6) group 2, thermal neutrons 7) All fission neutron are boring in fast group 8) All neutrons created by thermal group, thus vƩf2 exists vƩf2 does not 9) Down scattering occurs but up scattering does not, Ʃ1→2 exists, Ʃ2→1 is zero From the prof produced 2 equations (1) (Ʃa1+Ʃ1→2)*∅1 + v*Ʃf2*∅2=0 (2) Ʃa2*∅2 + Ʃ1→2*∅1=0 (1) Equation says the total neutron density of all fast neutrons(including ones scattered) is equal to the neutrons generated by thermal fission. This is correct by assumptions 7) and 8). (2) I do not understand equation 2, why is the neutron density of the amount of slow neutrons absorbed equal to the neutron density of scattered neutrons? Thank in advance 


#2
Oct1413, 04:59 AM

Mentor
P: 11,928

In equilibrium (!), the number of thermal neutrons is constant. Absorption removes as many thermal neutrons as scattering produces new thermal neutrons.



#3
Oct1413, 12:09 PM

P: 11

sorry
7) All fission neutron are born in fast group 


#4
Oct1413, 12:10 PM

P: 11

2 energy groups
8) All neutrons created by thermal group, thus vƩf2 exists vƩf1 does not



Register to reply 
Related Discussions  
Direct Coupling of Energy Groups, Multigroup Neutron Diffusion  Engineering, Comp Sci, & Technology Homework  0  
Group Theory Question involving nonabelian simple groups and cyclic groups  Calculus & Beyond Homework  1  
Energy of Functional Groups  Chemistry  3  
Join high energy phyics research groups  Career Guidance  0  
Groups, Normalizer, Abstract Algebra, Dihedral Groups...help?  Calculus & Beyond Homework  12 