Abstract: A novel PRD (pressure relief device) design called fuse plug which is creep-resistant and leakage-free is developed to improve the thermal response of PRD to fire when it is used as a temperature safety device for valves, cylinders, pressurized pipes, or any pressure vessels, the new design being the combination of geometrical configuration of PRD structure and composite technology wherein the low-melting matrix alloy is dispersed with strong/stiff reinforcing agents such as cut-wire type aggregates/cylinders and such composite alloy is contained in a threaded/rugged cavity with the length/diameter ratio being greater than a minimum. The new design employs a disc-type seal T backed by the composite alloy, thus allowing the use of this new design for cylinders of poor thermal conductivity.