# Negative Buckling

Under what conditions would negative buckling (B^2) be possible?

QuantumPion
Gold Member
Never. Buckling is a function of physical parameters (sphere radius, reaction cross-sections, diffusion coefficient), none of which can ever be negative.

Astronuc
Staff Emeritus
Buckling of a structure (mechanical analysis) is not the same as 'buckling' with respect to the neutron flux in a nuclear reactor.

I believe B2 < 0 implies the system is subscritical.

Let B2 = (νΣf - Σa)/D = (k - 1)/L2, then the buckling is negative if k < 1, or Σa > νΣf.

Ref: http://www.nuceng.ca/br_space/2015-..._flux_shape_in_various_reactor_geometries.pdf

Geometric buckling would not be negative.

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