In the present work, the physical behavior of integral data in infinite medium has been evaluated for incident fusion neutrons with the help to the 3-D Monte Carlo code. In a fusion reactor blanket with finite dimension, the integral quantities will be more or less different from the infinitive medium results, depending on the neutron leakage fraction. Design studies foresee the reduction of the neutron leakage out of the blanket as possible in order to prevent the nuclear heating in super conducting fusion magnets and to keep all neutrons primarily in the coolant. The most important materials in fusion technology, namely tritium, beryllium, lead, thorium, and uranium have been investigated in infinitive medium. The main purpose of this work is to calculate the integral tritium breeding ratio, U-233 breeding rate, Pu-239 breeding rate, heat release, neutron multiplication ratio through (n,x) and fission (when applicable) reactions in those mixtures which are composed when first UO2 and ThO2 are mixed with natural lithium (Nat.Li) or Li-6 for a volume fraction from 0 to 100%. Then the variable UO2-Nat.Li (UO2 mixed with Nat.Li) and UO2-Li-6 (UO2 mixed with Li-6) compositions will be mixed with Beryllium (Be) and Lead (Pb) for a volume fraction from 0 to 100%. However, the variable TO2-Nat.Li (ThO2 mixed with Nat.Li) and ThO2-Li-6 (ThO2 mixed with Li-6) compositions will be mixed with Be and Pb for a volume fraction mentioned above. (C) 2002 Elsevier Science Ltd. All rights reserved.