Process and plant for destroying solid-propellant rocket motors
View Patent ↗Described is a process and a plant for destroying rocket motors, including in particular the following steps and stations: cutting of the motor into sections; cooling of the sections containing propellant by immersion in a cryogenic liquid; and fragmenting and extraction of the cooled propellant by elastic deformation of the casing of the section. The propellant fragments are recovered for subsequent treatment and the casings are deactivated before being scrapped.
1. A process for destroying a solid-propellant rocket motor of a cast-bonded type, the motor having an axis, a casing, and a block of propellant including a binder, comprising:
cutting up the motor into sections perpendicular to the axis;
withdrawing sections not containing the propellant;
cooling sections containing the propellant to a temperature of at least about 20° C. below a glass transition temperature range of the propellant binder;
fragmenting the propellant and separating the propellant from the casing of each section containing the propellant by elastic deformation of the casing, thereby emptying the casing of the propellant;
recovering the emptied casing sections;
deactivating propellant residues of the empty casing sections; and
recovering the fragmented propellant for a subsequent treatment.
2. The process of claim 1 , wherein the sections containing propellant have a length/outside diameter ratio of less than or equal to 2.5.
3. The process of claim 2 , wherein the motor is cut up by at least one high-pressure liquid jet.
4. The process of claim 2 , wherein the sections containing propellant are cooled by immersion in a cryogenic liquid.
5. The process of claim 1 , wherein the motor is cut up by at least one high-pressure liquid jet.
6. The process of claim 5 , wherein, for cutting up the motor, the latter is immersed in a tank containing the same liquid as that used for supplying a spray rail delivering several jets that are prepositioned relative to the motor.
7. The process of claim 1 , wherein the sections containing propellant are cooled by immersion in a cryogenic liquid.
8. The process of claim 7 , wherein the cryogenic liquid is liquid nitrogen.
9. The process of claim 7 , wherein the sections containing propellant are cooled to a temperature between about −100° C. and about −80° C.
10. The process of claim 7 , wherein each empty section is deactivated by burning off traces of propellant residues, with recovery and scrubbing of flue gases.
11. The process of claim 7 , wherein each empty section is deactivated by immersing the section in a liquid that dissolves the oxidizing charge.
12. The process of claim 1 , wherein one or more fragments of propellant are collected in a receptacle.
13. The process of claim 1 , wherein the elastic deformation is carried out on the casing of each cooled section with the axis of the cooled section being vertical.
14. The process of claim 13 , wherein the axis of the casing of the cooled section is held vertical by a jack having its axis horizontal.
15. The process of claim 14 , wherein the jack is a hydro pneumatic jack.
16. The process of claim 14 , wherein the jack bears on the casing about one third along a length of the casing starting from the bottom of the cooled casing section.
17. The process of claim 1 , wherein the elastic deformation is carried out by driving the casing of each cooled section between two rolls forming a rolling mill.