Leakage probability

D. K. Trubey, H. Moran and A. M. Weinberg, An Estimate of the Non-Leakage Probability for Bare Aqueous Homogeneous U-235 Reactors, ORNL memorandum CF 57-11-15 (195.7). 

TABLE m. Comparison of Migration Areas (One Group Leakage Probability) with 0.387-in. Rods of 1.3% Enrichment... 

At criticality, the Interaction potential of the subcrits Iin must equal the neutron leakage probability Ig of u n-unit array, which is given as ... 

We may further conclude from these results that the probability that a neutron does escape from the reactor, i.e., the leakage probability pi, is given by... 

Losses of neutrons by absorption and leakage as they slow down to thermal the presence of the reflector introduces new absorbing materials and a new spatial dependence for the flux, leading to complicated expressions for the absorption and leakage probabilities. 

The reflector region of a reactor is not a multiplying medium but rather a zone where leaking fast neutrons are thermalized and partially reflected back into the core. The addition of a reflector to a reactor core results in an increased non-leakage probability and thus helps to keep Kgff up. The reflector also flattens the thermal flux out which is desired for even burnup of fuel. 

For the following neutron life cycle, calculate the fast fission factor, fast non-leakage probability, resonance escape probability, thermal non-leakage probability, thermal utilization factor, reproduction factor, Keff and core reactivity. 

The amount of water affects Kgff through thermal utilization factor, resonance escape probability, fast fission factor, and the non-leakage probabilities as shown in Figure 6.3(a), Of these factors, thermal utilization factor and resonance escape probability are affected more strongly. 

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