In the HYLIFE-II inertial confinement fusion reactor the deposition of high energy neutrons in protective molten salt jets can induce a pressure rise of several hundreds of megapascal in the liquid jets almost instantly. The subsequent relaxation of the liquid jets is very important in determining of changes of the liquid blanket configuration. The result of this relaxation process directly affects the gas dynamics, the condensation conditions and the chamber design. A 1-D compressible analysis was performed for the Flibe cylindrical jets in the HYLIRE-II reactor. The numerical results show that those jets which are close to the target will break up due to the large initial pressure buildup. The study also reveals that the jets will tend to break into large annulus/annuli rather than thousands of small droplets. A simple analysis for slab jets is also conducted in this work.