# US 10,119,181 B2 · Treatment process for a zirconium alloy, zirconium alloy resulting from this process and parts of nuclear reactors made of this alloy

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- Number: US 10,119,181 B2
- Document ID: US10119181B2
- Status: Granted
- Kind: B2
- Application number: 14/759,791
- Filed: 2013-01-11
- Published: 2015-12-10
- Granted: 2018-11-06
- Earliest claimed: 2013-01-11
- Assignees: Areva Np
- Applicants: Areva Np
- Inventors: Pierre Barberis; Pascal Guerin; Pascaline Fremiot
- Web page: https://patentgrep.com/patent/US10119181B2

## CPC

- C22C 16/00: Alloys based on zirconium
- C22F 1/186: {of zirconium or alloys based thereon}
- G21C 3/07: characterised by their material, e.g. alloys
- G21C 3/30: Assemblies of a number of fuel elements in the form of a rigid unit
- G21C 21/00: Apparatus or processes specially adapted to the manufacture of reactors or parts thereof (in general section B, e.g. B23)
- Y02E 30/30: Nuclear fission reactors
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A treatment process for a zirconium alloy is provided. The process includes the following steps: a zirconium alloy ingot is prepared, the composition of which is: 0.40%≤Nb≤1.05%; traces≤Sn≤2%; (0.5Nb−0.25) %≤Fe≤0.50%; traces≤Ni≤0.10%; traces≤(Cr+V) %≤0.50%; traces≤S≤35 ppm; 600 ppm≤O≤2000 ppm, preferably 1200 ppm≤O≤1600 ppm; traces≤Si≤120 ppm; traces≤C≤150 ppm; the remaining being Zr and unavoidable impurities; the ingot undergoes at least one reheating and hot shaping step, and possibly a reheating and quenching step following a hot shaping step; optionally the hot-shaped ingot undergoes an annealing; the hot-shaped and possibly annealed ingot undergoes at least one cycle of cold rolling-annealing steps; the annealing of at least one of the cold rolling-annealing steps being performed at a temperature comprised between 600° C. and the lowest of either 700° C. or (710−20×Nb %)° C., and the annealings of the other cold rolling-annealing steps, if any, being performed at a temperature not higher than 600° C. Also provided are a Zr alloy so obtained, and part of a fuel assembly for a light water nuclear reactor made of it.

## Claims

### Claim 1

A treatment process for a zirconium alloy for use in a nuclear reactor, comprising:
preparing a zirconium alloy ingot, the zirconium alloy ingot having a composition of which is in weight % or weight ppm:
0.40%≤Nb≤1.05%;
traces ≤Sn≤2%;
(0.5 Nb−0.25) %≤Fe≤0.50%;
traces ≤Ni≤0.10%;
traces <(Cr+V) %<0.50%;
traces ≤S≤35 ppm;
600 ppm≤O≤2000 ppm;
traces ≤Si≤120 ppm;
traces ≤C≤150 ppm;
If 0.50%≤Nb≤1.05%, then (Cr+V) %≤(0.2 +3/4Fe−1/4Nb) %; and
the remaining being Zr and unavoidable impurities;
at least one step of reheating and hot shaping the zirconium alloy ingot;
at least one cycle of cold rolling-annealing steps on the zirconium alloy ingot after the at least one step of reheating and hot shaping, a last annealing of the at least one cycle of cold rolling-annealing steps being a final annealing step which gives a product formed therefrom a final stress-relieved, partially recrystallized or completely recrystallized condition,
the annealing of at least one of the cold rolling-annealing steps being performed at a temperature comprised between 650° C. and the lowest of either 700° C. or (710−20×Nb %)° C., and the annealings of the other cold rolling-annealing steps, if any, being performed at a temperature not higher than 600° C.

### Claim 2 (depends on 1)

The treatment process as recited in claim 1 wherein the at least one step of reheating and hot shaping the zirconium alloy ingot includes a reheating and quenching step following a hot shaping step.

### Claim 3 (depends on 1)

The treatment process as recited in claim 1 further comprising an annealing the ingot after the at least one step of reheating and hot shaping the zirconium alloy ingot.

### Claim 4 (depends on 1)

The treatment process as recited in claim 1 wherein (0.02+1/3Fe) %≤(Cr+V) %.

### Claim 5 (depends on 1)

The treatment process as recited in claim 1 wherein 0.50%≤Nb≤1.05%, and (0.02+1/3Fe)%≤(Cr+V)%≤(0.2 +3/4Fe−1/4Nb)%.

### Claim 6 (depends on 1)

The treatment process as recited in claim 1 wherein the at least one cycle of cold rolling-annealing steps is at least two cycles of cold rolling-annealing.

### Claim 7 (depends on 1)

The treatment process as recited in claim 1 wherein the temperatures and durations of the reheating and annealing steps are chosen so that arithmetic mean sizes of the precipitates is between 50 and 250 nm.

### Claim 8 (depends on 1)

The treatment process as recited in claim 1 wherein the composition of the prepared zirconium alloy ingot is: 1200 ppm≤O≤1600 ppm.

### Claim 9

A zirconium alloy having a composition in weight% or weight ppm comprising:
0. 40%≤Nb≤1.05%;
traces≤Sn≤2%;
(0.5 Nb−0.25)%≤Fe≤0.50%;
traces ≤Ni≤0.10%;
traces ≤(Cr+V)%≤0.50%;
traces ≤S≤35 ppm;
600 ppm≤O≤2000 ppm;
traces ≤Si≤120 ppm;
traces ≤C≤150 ppm;
if 0.50%≤Nb≤1.05%, then (Cr+V)%≤(0.2 +3/4Fe−1/4Nb) %;
(0.02+1/3Fe)%≤(Cr+V)%; and
the remaining being Zr and unavoidable impurities;
wherein the zirconium alloy has undergone treatments comprising at least one hot shaping step and at least one cycle of cold rolling-annealing steps, the annealing of at least one of the cold rolling-annealing steps having been performed at a temperature comprised between 650° C. and the lowest of either 700° C. or (710−20×Nb%)° C., and wherein the annealings of the other cold rolling-annealing steps, if any, having been performed at a temperature not higher than 600° C., and in that its microstructure is deprived of β-Zr phase.

### Claim 10 (depends on 9)

The zirconium alloy as recited in claim 9 wherein 1200 ppm ≤O≤1600 ppm.

### Claim 11 (depends on 9)

A fuel cladding tube for a fuel assembly for a light water nuclear reactor, the fuel cladding made of the zirconium alloy as recited in claim 9.

### Claim 12 (depends on 9)

A guide thimble for a fuel assembly for a pressurized water nuclear reactor, the guide thimble made of the zirconium alloy as recited in claim 9.

### Claim 13 (depends on 9)

A fuel channel for a fuel assembly for a boiling water nuclear reactor, the fuel channel made of the zirconium alloy as recited in claim 9.

### Claim 14 (depends on 9)

A grid for a fuel assembly for a light water nuclear reactor, wherein the grid made of the zirconium alloy as recited in claim 9.

### Claim 15 (depends on 9)

A water channel for a fuel assembly for a boiling water nuclear reactor, wherein the water channel made of the zirconium alloy as recited in claim 9.

### Claim 16 (depends on 1)

The treatment process as recited in claim 1 wherein the partially recrystallized or completely recrystallized condition is formed by more than 10% of recrystallized grains.