Abstract: Devices and methods are disclosed for contacting a hot reaction mass with water to initiate an explosive reaction. The reaction mass comprises a ceramic or intermetallic material that is produced by exothermically reacting a mixture of reactive elements. Suitable reaction masses include borides and/or carbides that are formed by reacting a mixture comprising B and/or C in combination with an element selected from Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W. Additional metals such as Al, Li, Mg, Zn, Cu, Be, Na, K, Ca, Rb, Y, U and Cs may also be present in the reactive mixture. In operation, the hot reaction mass is contacted with water to initiate an explosive water reaction and to produce large volumes of hydrogen containing gas.