Method of manufacturing a radioactive-substance storage member, billet for use in extrusion of the same, and square pipe

Abstract

An aluminum powder is mixed with a neutron absorber powder through cold isostatic press to form a preliminary molding. The preliminary molding is then subjected to sintering under no pressure in vacuum. After sintering, a billet is subjected to induction heating and hot extrusion to form a square pipe.

1 - 16 . (canceled)  
     
     
         17 . A method of manufacturing a radioactive-substance storage member for use in storage of a radioactive substance, the method comprising: 
 mixing an aluminum powder with a neutron absorber powder;    pressing the mixed powder to form a preliminary molding; and    sintering the preliminary molding under no pressure in an inert gas ambience.    
     
     
         18 . The method according to  claim 17 , wherein the preliminary molding has a weight density of more than 75% and less than 95%.  
     
     
         19 . The method according to  claim 17 , wherein the mixing includes mechanical alloying.  
     
     
         20 . The method according to  claim 19 , wherein the mechanical alloying includes ball milling, the ball milling using a ball having a major constituent identical to an element previously added to a sample in order to add the element from the ball into the aluminum matrix by the wearing of the ball during the ball milling.  
     
     
         21 . The method according to  claim 18 , further comprising, after the extruding, leaving the square pipe or plate in that extruded state or naturally aging the square pipe or plate, the square pipe of plate which configures a basket for accommodating an aggregate of spent fuel or the rod to be inserted in a guide pipe for spent fuel.  
     
     
         22 . The method according to  claim 19 , further comprising, after the extruding, leaving the square pipe or plate in that extruded state or naturally aging the square pipe or plate, the square pipe of plate which configures a basket for accommodating an aggregate of spent fuel or the rod to be inserted in a guide pipe for spent fuel.  
     
     
         23 . A method of manufacturing a radioactive-substance storage member for use in storage of a radioactive substance, the method comprising: 
 mixing an aluminum powder with a neutron absorber powder;    pressing the mixed powder to form a preliminary molding;    sintering the preliminary molding under no pressure in an inert gas ambience to form a billet;    heating the billet using an induction heating unit; and    extruding the induction-heated billet using dies to form a square pipe or plate which configures a basket for accommodating an aggregate of spent fuel or a rod to be inserted in a guide pipe for spent fuel.    
     
     
         24 . The method according to  claim 23 , wherein the preliminary molding has a weight density of more than 75% and less than 95%.  
     
     
         25 . The method according to  claim 23 , wherein the mixing includes mechanical alloying.  
     
     
         26 . The method according to  claim 25 , wherein the mechanical alloying includes ball milling, the ball milling using a ball having a major constituent identical to an element previously added to a sample in order to add the element from the ball into the aluminum matrix by the wearing of the ball during the ball milling.  
     
     
         27 . The method according to  claim 23 , further comprising, after the extruding, leaving the square pipe or plate in that extruded state or naturally aging the square pipe or plate, the square pipe of plate which configures a basket for accommodating an aggregate of spent fuel or the rod to be inserted in a guide pipe for spent fuel.  
     
     
         28 . A method of manufacturing a radioactive-substance storage member for use in storage of a radioactive substance, the method comprising: 
 mixing an aluminum powder with a neutron absorber powder;    pressing the mixed powder to form a preliminary molding;    sintering the preliminary molding under no pressure in an inert gas ambience to form a billet;    extruding the billet using the heat during the sintering to form a square pipe or plate which configures a basket for accommodating an aggregate of spent fuel or a rod to be inserted in a guide pipe for spent fuel.    
     
     
         29 . The method according to  claim 28 , wherein the preliminary molding has a weight density of more than 75% and less than 95%.  
     
     
         30 . The method according to  claim 28 , wherein the mixing includes mechanical alloying.  
     
     
         31 . The method according to  claim 30 , wherein the mechanical alloying includes ball milling, the ball milling using a ball having a major constituent identical to an element previously added to a sample in order to add the element from the ball into the aluminum matrix by the wearing of the ball during the ball milling.  
     
     
         32 . The method according to  claim 28 , further comprising, after the extruding, leaving the square pipe or plate in that extruded state or naturally aging the square pipe or plate, the square pipe of plate which configures a basket for accommodating an aggregate of spent fuel or the rod to be inserted in a guide pipe for spent fuel.  
     
     
         33 - 37 . (canceled)