The thermal shock effects that occur in a fast burst reactor (FBR) during its operation are analyzed. The thermoelastic displacement equation for radial motion is solved for a reactor initially at rest and having stress-free boundaries. Numerical results are presented for the dynamic displacements and stresses that occur in the White Sands Missile Range FBR for a burst of 1.2 × 1017 fissions, a pulse width of 39 µs with the peak power reached in 119 µs.