Document Details

(733 K)

Time behavior of a critical reactor pulsed with a large square wave source

REPORT

1962 Oct 02

12 p.

UCRL-ID-125507

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

1997 Mar 28

2009 Nov 09

In a previous Naval Application memorandum, a discussion was given of what happens to the power level of a reactor when an instantaneous, very large neutron source is introduced. The motivation for the problem arises from the question of what happens when a nuclear bomb is detonated near a reactor powered missile. This present memorandum looks at the same problem as that which is discussed in the previous memorandum but in slightly more detail. The results obtained are essentially the same as those of the previous memorandum with somewhat more attention given to the nature of the assumptions made. The kinetics model used is the space-time separable, one delayed group model. Space-time separability is almost certainly a poor assumption in this case. When a very large neutron wavefront impinges on a reactor, the subsequent short time behavior can hardly be that predicted by this simple model. One would expect very large local power densities in one part of the core before another part would see anything unusual. The other assumption, one delayed group, is not necessary but makes the mathematics simpler and in view of the first assumption is probably quite acceptable. In spite of these simplifications the model gives results which should have,qualitative physical relevance.