a reactor operative for compressing vapor(s) and obtaining supercritical fluid(s) and/or subcritical fluid(s), for bringing supercritical fluid(s) and/or subcritical fluid(s) into contact with organic matter and/or other reactant substance(s), for causing occurrence of chemical reaction(s), and for causing expansion and decompression of the fluid(s) including product(s) produced as a result of chemical reaction(s), the reactor including cylinder(s) and piston(s) provided at such cylinder(s) and operative to sequentially actuate by operating such piston(s) to cause compression of fluid(s); operating the piston(s) in reverse direction(s) following the chemical reaction(s) of the reactant substance(s) to lower temperature(s) and pressure(s); removing, from the cylinder(s), fluid(s) including the produced product(s); and, delivering new charge(s) of vapor(s) to the cylinder(s); and

explosive disintegration apparatus(es) that rapidly depressurize reactant substance(s) while same is or are immersed in high-pressure saturated fluid(s); organic substance(s) and/or other reactant substance(s) being pulverized by such explosive disintegration apparatus(es) for use in said reactor.