On the properties of the chord length distribution, from integral geometry to reactor physics

In a couple of recent papers, Sjöstrand [Ann Nucl Eng 29 (2002) 1607] and Kruijf and Kloosterman [Ann Nucl Eng 30 (2003) 549] addressed the question of the meaning of the average chord length in reactor physics. This paper offers a link between integral geometry (where chord length distribution and its properties come from) and its applications in reactor physics. In particular we specify which relations between chord length moments and simple geometric properties of the body remain valid for non-convex bodies. Monte Carlo simulations illustrates these points.