[en] The nuclear industry is a potential setting for steam explosion accidents; in this context, they are commonly referred to as fuel/coolant interactions (FCIs). Loss-of-coolant accidents that could lead to FCIs are considered to be unlikely. Nevertheless, FCIs are regarded as a potential hazard that contributes to the overall risk. One possibility for reducing FCI risk is to identify suitable additives for the emergency coolant water that prevent steam explosions or make them less violent. Results are presented from laboratory experiments that examined the ability of dilute aqueous solutions of poly(ethylene oxide) (PEO), a soluble drag-reducing polymer, to suppress spontaneous vapor explosions of molten tin. Experiments with pure water were carried out to provide a reference of comparison for the polymer solutions. The peak pressures measured in the most dilute PEO solutions spanned a much wider range than those for water, and pressure many times larger than any recorded in pure water were recorded-up to 240kPa. When the solution viscosity ratio was 1.25 or larger, however, spontaneous explosions were markedly suppressed; above η_r = 2.00, they were entirely eliminated