CS201252B1 - Alloy based on zirconium for nuclear reactors - Google Patents

Description

The present invention relates to a zirconium-me3-iron-molybdenum-vanadium pentagonal zirconium alloy useful for advantageous properties for the coating of fuel elements of nuclear reactors in a hot water environment or superheated pores.

At present, two types of zirconium alloys are industrially applied to the coating tubes of nuclear fuel. 3e it is a five-alloy zirconium-tin-iron-

z - chromium - nickel, two - component zirconium - niobium alloy. Indicative composition of these Alloys moves within limits: zirconium - tin - iron - chrome - nickel: 1.20 - 1.70 wt. % tin 0.07 - 0.20 wt. % iron 0.05 - 0.15 wt. % chromium 0.03 - 0.08 wt. % nickel zirconium - niobium: 0.90 - 1.10 wt. % niobium. Both types of elitins ea used in pressurized water reactors, where I work in the environment pressure

water temperature below 300 ° C. 3eou are not resistant to steam at temperatures of 400 - 500 ° C.

Several new types of zirconium elitins have been reported in patent and technical literature. However, only three have the information needed to compare properties

201 252

201 2S2 o the proposed «cast iron. However, these alitins have not yet been applied in practice. 3de of three-component alloys of the type zirconium - copper3 - iron, zirconium - chromium - iron with direct bearing <

zirconium - me3 - iron i

1.10 - 1.30 haot. % media

0.20-0.40 wt. % iron zirconium - chromium - iron i

1.00 - 1.20 haot. % chromium

0.10 - 0.15 wt. % of iron and quadruple alloy zirconium - niobium - cin - chromium - iron, molybdenum,

and the composition of i 0.50 - 1.00 haot. % niobium 0,05 - 0.10 wt. % gout 0,01 - 0.05 wt. % of chromium 0,02 - 0.05 wt. % irons

The main disadvantages of these alloys, in particular the two alloys used hitherto in technical practice, are their low corrosion i.e. oxidation and hydration resistance in the superheated steam environment at higher temperatures. This makes it impossible to increase the operating temperatures of the nuclear reactors when using these elltin.

The above-mentioned disadvantages are eliminated by the zirconium elite for nuclear reactors according to the invention, which is based on the fact that it contains the alloying elements copper, iron, molybdenum and vanadium in an amount of 0.1 to 0.8% by weight of copper, 0.1 to 0.8% by weight. iron, 0.2 to 1.0 wt.% molybdenum, 0.1 to 0.8 wt.% vanadium, the remainder being zirconium.

The total amount of alloy is between 1.2 and 2.8% by weight.

The attained vlaatnoati result from the interaction of all four alloying elements in the zirconium.

The main advantages of the zirconium alloy according to the invention have been its very good corrosion resistance, especially in the superheated steam environment while maintaining sufficient mechanical properties.

Exemplary embodiments and comparisons of the inventive alloys and the alloys known to date are shown in the following tables.

Table 1.

Oxidation rate / mg / dm. day/

Alloy / haot. % / water 300 ° C steam 400 ° C steam 500 ° C ilitiny podle Zr-0.7 Cu-0.4 Fs-0.7 Mo-0.1 V 0.15 0.18 0.66 of the invention Zr-0.3 Cu-0.4 Fe-0.7 Mo-0.4 V 0.08 0.18 1.12

201 252

Zr-1.2 Sn-0.15 Fe-0.1 Cr-0.05 Ni 0.08 1.40 9.60 Known Zr-1.2 Cu-0.3 Fe 0.06 0.22 1.00 alloys Zr-1.1 Cr-0.1 Fe 0.07 0.28 0,8-1,5 Zr-1.0 Nb 0.10 0.60 5.31 Zr-0.5 Nb-0.06 Sn-0.5 Cr-0.04 Fe 0.05 0.56 - Table 2 Speed hydridation (ppm / day) for a sample thickness of ~ 1 mm Alloy / wt. % / water 300 ° C steam 400 ° C steam 500 ° C alloys Zr-0.7 Cu-0.4 Fs-0.2 Mo-0.4 V 0.34 0.14 0.53 according to invent Zr-0.5 Cu-0.3 Fe-0.95 Mo-0.25 V 0.25 0.29 0.48 Zr-1.2 Sn-0.15 Fe-0.1 Cr-0.05 Ni - 0.68 13.00 Zr-1.2 Cu-0.3 Fe 0.50 1.80 Known Zr-1.1 Cr-0.1 Fe 0.25 0.40 3.40 alloys Zr-1 Nb 6.15 1.58 10.90 Zr-0.5 Nb-0.06 Sn-0.5 Cr-0.04 Fe 0.20 0.74 -

Table 3.

Mechanical properties

Alloy / wt. % / Deň: 18 ° C 400 ° C 450 ° C Pt / MPa / 0.2 / MPa / /% / Pt / MPa / 0.2 / MPa / /% / Pt / MPa / 0.2 / MPa / /% / alloys according to Zr-0.7 Cu-0.4 Fe- 0.7 Mo-0.4 V 400 220 40 and· 205 60 invention zu Zr-0.9 Cu-0.3 Fe0.95 Mo-0.55 V 420 250 31 - - - 205 - 58 Zr-1.2 Sn-0.15 Fe 0.1 Cr-0.05 Ni 471 382 22nd Known Zr-1.2 Cu-0.3 Fe 441 382 31 186 167 '48 - - - Zr-1.1 Cr-0.1 Fe 350 200 45 170 55 alloys Zr-1 Nb 539 ^X 390 412 ^X 220 15 * 37 205 115 35 - - - Zr-0.5 Nb-0.06 Sn0.5 Cr-0.04 Fe 470 350 - - - - - - -

Note: the mechanical properties are largely influenced by the admixture content and the metallurgical history of the material, for example, data denoted by x apply to an alloy with a higher oxygen content of about 500 ppm.

Claims (2)

SUBJECT OF THE INVENTION 1. A zirconium alloy for nuclear reactors, characterized in that it encircles the alloying metal elements iron, not 9, molybdenum with vanadium in an amount of 0.1 to 0.8% by weight of iron; 0.1 to 0.8% by weight of the medium, 0.2 to 1.0% by weight of molybdenum, 0.1 to 0.8% by weight of vanadium, the remainder being zirconium. 2. The zirconium alloy according to claim 1, characterized in that the content of the alloying metal elements lies within a range of approx. 1.2 to 2.8% by weight and the remainder being zirconium.