Nuclear fuel rod and manufacturing method
A nuclear fuel rod comprises nuclear fuel contained in a cladding, the cladding comprising a tube and two plugs, the tube extending along a central axis and having two ends, each plug being attached to a corresponding end of the tube by sealing the end of the tube. The tube is covered by a tube coating extending over the entire length of the tube from one end of the tube to the other.
1 . Nuclear fuel rod comprising nuclear fuel, a cladding, and end plugs,
the cladding comprising a tube extending along a central axis and having two ends,
the tube being covered by a tube coating,
wherein the tube coating extends over the entire length of the tube from one end of the tube to the other end,
each end plug being fixed to a respective end of the tube, sealing the respective end in a leak-tight manner,
at least one end plug of the end plugs being welded to a respective end of the tube without affecting the shape of an interface between the tube and the at least one end plug,
the at least one end plug being at least partially covered by an end plug coating prior to the welding,
the end plug coating and the tube coating are made of the same material, and
the end plug coating and the tube coating are contiguous at an interface between the end plug coating and the tube coating.
2 . The nuclear fuel rod according to claim 1 , wherein the tube is made of a zirconium based material.
3 . The nuclear fuel rod according to claim 1 , wherein each plug is made of a zirconium based material.
4 . The nuclear fuel rod according to claim 1 , wherein the tube coating is made of a chromium based material.
5 . The nuclear fuel rod according to claim 1 , wherein the at least one end plug is welded to the respective end of the tube without reworking the interface by a mechanical or chemical process with material removal.
6 . The nuclear fuel rod according to claim 1 , wherein each end cap plug being fixed to the tube without the presence of an eutectic at a junction
between the tube and the end plug, or
between the tube coating and the end plug coating.
7 . The nuclear fuel rod according to claim 1 , wherein the end plug coating is made of a chromium based material.
8 . Assembly comprising a nuclear fuel rod cladding tube and an end plug,
the cladding tube is configured to contain nuclear fuel therein,
the cladding tube extending along a central axis and having a first end and a second end,
the cladding tube comprising an outer surface extending over the entire length of the cladding tube between the ends,
wherein the outer surface is covered by a tube coating,
a weld arrangement fixing the end plug to an end of the cladding tube, sealing the end in a leak-tight manner,
the end plug being fixed to the end of the cladding tube without affecting the shape of an interface between the cladding tube and the end plug,
an outer surface of the end plug is at least partially covered by an end plug coating prior to the end plug being fixed to the cladding tube,
the end plug coating and the tube coating are contiguous at an interface between the end plug coating and the tube coating, and
the end plug coating and the tube coating are made of the same material.
9 . A method of manufacturing a nuclear fuel rod,
the nuclear fuel rod comprising nuclear fuel, a cladding, and end plugs,
the cladding comprising a tube extending along a central axis and having two ends,
the tube being covered by a tube coating,
wherein the tube coating extends over the entire length of the tube from one end of the tube to the other end,
each end plug being fixed to a respective end of the tube, sealing the respective end in a leak-tight manner,
at least one end plug of the end plugs being welded to a respective end of the tube without affecting the shape of an interface between the tube and the at least one end plug,
the at least one end plug being at least partially covered by an end plug coating prior to the welding,
the end plug coating and the tube coating are made of the same material, and
the end plug coating and the tube coating are contiguous at an interface between the end plug coating and the tube coating;
the method comprising:
producing the tube and the end plugs, with each end plug being coated with the end plug coating; and
welding by electric resistance welding the at least one end plug to the respective end of the tube.
10 . The method according to claim 9 , wherein each end plug is welded onto the tube by electric resistance butt welding.
11 . The method according to claim 9 , wherein the electric resistance welding of the at least one end plug is carried out with a current comprised between 10 kA and 20 kA.
12 . The method according to claim 9 , wherein the welding by electric resistance of the at least one end plug is carried out while applying the at least one end plug against the respective end of the tube under a pressing force between 200 daN and 400 daN.
13 . The method according to claim 9 , wherein the welding by electric resistance of the at least one end plug is carried out while applying the at least one end plug against the respective end of the tube under a pressing force between 250 daN and 350 daN.
14 . The method according to claim 9 , wherein the electric resistance welding of the at least one end plug is carried out by applying an electric current for a length of time between 10 ms and 30 ms.
15 . The method according to claim 9 , wherein the welding is carried out without reworking the interface between the tube and the at least one end plug by a mechanical or chemical process involving removal of material.
16 . The method according to claim 9 , wherein the welding includes welding each end plug onto the tube, without forming an eutectic at a junction between the tube and each end plug.