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

1. A method of manufacturing a radioactive-substance storage member for use in storage of a radioactive substance, the method comprising steps of:

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 ambience that can prevent the preliminary molding from oxidizing;

extruding the preliminary molding to form a square pipe or plate; and

leaving the square pipe or plate in that extruded state or naturally aging the square pipe or plate so that the square pipe or plate is stable at a high temperature over a long period of time, wherein the square pipe or plate configures a basket for accommodating an aggregate of spent fuel or a rod to be inserted in a guide pipe for spent fuel.

2. The method according to claim 1 , wherein the preliminary molding has a weight density of more than 75% and less than 95%.

3. The method according to claim 1 , wherein the mixing includes mechanical alloying.

4. The method according to claim 3 , wherein the mechanical alloying includes ball milling, the ball milling using a bail 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.

5. A method of manufacturing a radioactive-substance storage member for use in storage of a radioactive substance, the method comprising steps of:

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 vacuum to form a billet by elevating a sintering temperature step by step;

heating the billet using an induction heating unit;

extruding the induction-heated billet having a weight density of 75% to 95% using dies to form a square pipe or plate;

performing a tensile reformation;

cutting away unsteady parts and evaluation parts; and

configuring a basket for accommodating an aggregate of spent fuel or a rod to be inserted in a guide pipe for spent fuel.

6. The method according to claim 5 , wherein the preliminary molding has a weight density of more than 75% and less than 95%.

7. The method according to claim 5 , wherein the mixing includes mechanical alloying.

8. The method according to claim 7 , 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.

9. The method according to claim 5 , 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.

10. A method of manufacturing a radioactive-substance storage member for use in storage of a radioactive substance, the method comprising steps of:

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 vacuum to form a billet by elevating a sintering temperature step by step;

extruding the billet having a weight density of 75% to 95% using the heat during the sintering to form a square pipe or plate;

performing a tensile reformation;

cutting away unsteady parts and evaluation parts; and configuring a basket for accommodating an aggregate of spent fuel or a rod to be inserted in a guide pipe for spent fuel.

11. The method according to claim 10 , wherein the preliminary molding has a weight density of more than 75% and less than 95%.

12. The method according to claim 10 , wherein the mixing includes mechanical alloying.

13. The method according to claim 12 , 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.

14. The method according to claim 10 , 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.