JP2790138B2 - Cladding tubes, spacers and channel boxes for highly corrosion resistant nuclear fuels, their fuel assemblies, and their manufacturing methods - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel zirconium
Cladding, spacers and tubes for nuclear fuel using
Related to the tunnel box, its fuel assembly and its manufacturing method.
I do. [0002] Among zirconium-based alloys, fuel cladding tubes
The alloy used for Zircaloy-2 (Sn: 1.20)
To 1.70 wt%, Fe: 0.07 to 0.20 wt%, C
r: 0.05 to 0.15 wt%, Ni: 0.03 to 0.0
8 wt%, O: 900-1400 ppm, residual Zr, but F
e + Cr + Ni: 0.18 to 0.24 wt%) and zirca
Roy-4 (Sn: 1.20 to 1.70 wt%, Fe: 0.
18 to 0.24 wt%, Ni: 0.0007 wt% or less,
O: 900 to 1400 ppm, residual Zr provided that Fe + Cr:
(0.28 to 0.37 wt%). Development of these alloys
The latitude is ASTM, STPN No. 368 (1963) pp3
-27. In this paper, Zircaloy-1
(Zr-2.5wt% Sn alloy), Zircaloy-3A (Z
r-0.25wt% Sn-0.25Fe alloy), Zircalo
B-3B (Zr-0.5 wt% Sn-0.4 wt% Fe alloy
Gold), Zircaloy-3C (Zr-0.5 wt% Sn-0.2)
wt% Fe-0.2 wt% Ni alloy) and Ni-Free
Zircaloy-2 (Sn: 1.20-1.70 wt%, F
e: 0.12 to 0.18 wt%, Cr: 0.05 to 0.15
wt%, Ni: 0.007 wt% or less).
You. These alloys other than Zircaloy-2 and Zircaloy-4
The problems are as follows. Zircaloy-1 is F
Since it does not contain e, Cr, and Ni, it has low corrosion resistance.
Zircaloy-3 series can reduce the amount of Sn added.
And improve the manufacturability and reduce the amounts of Fe and Ni added.
It is an alloy whose corrosion resistance has been improved by increasing the
Lower than Lucaloy-2, down to about 75%. Ni-F
ree Zircaloy-2, by removing Ni,
Low corrosion resistance in steam at 510 ° C. Zircaloy-4
Is to improve the corrosion resistance of Ni-Free Zircaloy-2
This is an alloy with an increased Fe content.
Amount of Fe is required, and the neutron absorption cross section increases.
Is bad. [0003] For the purpose of adding the above alloy elements of Zircaloy,
It is also discussed as follows. Sn is mechanical
Improved properties and in sponge zirconium
The adverse effect of nitrogen contained in steel on corrosion resistance
To be added. Fe, Cr and Ni are mainly corrosion resistant
This is an alloy element added for improvement. Zr-2.5
wt% Sn alloy and Zr-1.8 wt% Sn alloy
e, a ternary alloy containing Cr and Ni alone, and Zr
Using a binary alloy containing Fe, Cr and Ni alone
400 ° C steam and 315-360 ° C hot water resistance
Dietary habits are being studied. According to the results, Fe alone was added.
Optimum amount of 0.22wt%, optimum value of Cr alone
Is 0.1 wt%, and the optimum value of the single addition amount of Ni is 0.22 wt%.
%Met. The effect of compound addition of each element was also studied.
As a result, the optimum total added amount of Fe, Cr and Ni is 400 ° C.
0.35wt% in steam, 0.3 in 360 ° C water
wt%. Based on the above results
The alloy composition of the current Zircaloy-2 and Zircaloy-4 is
It has been determined. [0004] Zirca confirmed to have high corrosion resistance as described above.
A fuel cladding tube made of Roy-2 and Zircaloy-4 is BWR
When used in an environment, ASTM, STP No. 633 (19
77) 236-280, 295-311
As described in Nodula Corrosion
It is clear that papular local corrosion occurs
Was. When the burnup of nuclear fuel is increased,
The part where the reaction occurs expands, interconnects, and eventually separates.
Therefore, it is important to prevent the generation of nodular corrosion
It has become an indispensable technology for increasing the burnup of fuel. JP-A-58-95247, ANS TRANSACTION Vo
l.34 (June 1980) pp.237-238, J. Electr
ochem. Soc. Electrochemical Science and Technolog
y, According to February 1975, pp 199-204
And the nodular corrosion occurring inside this furnace outside the furnace
To be reproduced by the accelerated corrosion test of
Suitable for hot steam environment, 400 ℃ steam or
Nodular Collage
Inability to assess Zircaloy's sensitivity to
It was revealed. In this improved corrosion test method,
Evaluation of Calloy-2 and Zircaloy-4
It is also evident that a lotion will occur, and even higher
A clad tube with nodular corrosion resistance is required
Was. US Pat. No. 2,772,964 discloses Sn0.1.
~ 2.5%, at least one of Fe, Ni and Cr 2
% Or less, the balance being substantially composed of Zr.
Absent. As a technique for improving the corrosion resistance of current Zircaloy,
JP-A-51-110411, JP-A-51-110412 and
Beta quench described in JP-A-58-22364
Manufacturing process including heat treatment technology and β-quench process
Are known. Beta quench means that zircaloy is α + β
Heat quenching from high temperature in the phase temperature range or β phase temperature range
This is a process that precipitates in the alloy by performing this process.
Intermetallic compound phase (Zr (Cr, Fe) _Two , Zr
_Two (Ni, Fe), etc.) are miniaturized or partially dissolved. This
Although β-quench technology improves corrosion resistance,
Zircaloy remains in contact with Ti, Fe, Cr and Ni
Including a martensite structure (needle structure)
The ductility is low, and to improve the ductility, β
After quenching, alternating between cold working and annealing
To obtain a recrystallized structure. Manufacture of fuel cladding
Taking the process as an example, the melted ingot is hot forged
(About 1000 ° C), solution treatment (about 1000 ° C), hot
After forging (about 700 ° C), cylindrical by hot extrusion
Formed into billets (usually called base tubes)
Β-quench on the pilgamill cold rolling and annealing
The process is alternately repeated three times. Beta quench, then add
If the process and annealing are repeated several times,
Coarse metal in Zircaloy alloy with high corrosion resistance
An inter-compound phase precipitates and the corrosion resistance decreases. Therefore fuel
Zirconium-based alloys used as cladding are processed and
High corrosion resistance without change in corrosion resistance due to heat and heat treatment
Is desirable. SUMMARY OF THE INVENTION The corrosion resistance of Zircaloy is
The above-mentioned prior art to be improved is based on heat treatment.
Reexamination of alloy composition from the viewpoint of preventing duracorrosion
No consideration has been given to the
Inability to prevent duracorrosion and water
There is a problem that elementary absorption characteristics are high. An object of the present invention is to suppress the occurrence of nodular corrosion.
Nuclear fuel coating with improved corrosion resistance and hydrogen absorption characteristics
Clad tubes, spacers and channel boxes and their fuel assemblies
The body as well as the process for its production are provided. [0009] In order to achieve the above object,
In addition, the present invention relates to a cladding tube for a nuclear fuel and a tube for a nuclear fuel assembly.
Of the channel boxes for pacers and nuclear fuel assemblies
At least one, by weight, 1.2 to 2% tin, 0.2 iron
0-0.55%, chrome 0.05-0.15% and nickel
0.03 to 0.16%, with the balance being substantially zirconia.
With an (iron / nickel) ratio of 1.4 to 10.
That is, it is made of a zirconium-based alloy. [0010] The present invention also provides a nuclear fuel pellet in a cladding tube.
Fuel rod in which the fuel rods are stored, and the upper part holding both ends of the fuel rod
And lower tie plate, between the upper and lower tie plate
For arranging the fuel rods provided at predetermined intervals at predetermined intervals.
, The fuel rod, upper tie plate, lower tie plate
Channel box consisting of a square tube that houses the spacer and spacer
And the fuel rods held in the upper tie plate
For reactors equipped with a handle for carrying the whole unit together
In the fuel assembly, the cladding tube, the spacer, and the channel are provided.
At least one of the flannel boxes is by weight, tin 1.2-2
%, Iron 0.20 to 0.55%, chromium 0.05 to 0.15
% And nickel 0.03 to 0.16%, the balance being substantially
Zirconium, and the (iron / nickel) ratio is 1.4
By using a zirconium-based alloy that is 10 to 10
is there. Further, the present invention provides a fuel assembly for a nuclear reactor as described above.
When manufacturing the body, the cladding, spacers and channels
At least one of the boxes is by weight, tin 1.2 to 2
%, Iron 0.20 ~ 0.55%, chromium 0.05 ~ 0.15%
And 0.03 to 0.16% of nickel, with the balance being substantially
Made of zirconium with an (iron / nickel) ratio of 1.4 to
After the final hot plastic working of the zirconium based alloy which is 10
Before the first cold plastic working, the temperature including β phase or α phase and β phase
In the temperature range, apply a process of heating and holding for a short time and then quenching,
The cold plastic working and the annealing treatment are alternately repeated,
After forming a zirconium-based alloy thin material,
It is to be applied. Tin is the strength and corrosion resistance of zirconium-based alloys.
Content of 1.2% or more in order to improve
Over 2%, no more remarkable effect is obtained.
In order to reduce the workability, the content is limited to 2% or less. Especially,
1.2-1.7% is high in workability, strength and corrosion resistance
Is a balanced range. Iron improves corrosion resistance in high-temperature, high-pressure water,
Necessary to increase hydrogen absorption characteristics and strength
And 0.2% or more is required. However, over 0.55%
Increases the neutron absorption cross section and lowers cold plastic workability
Therefore, it should be 0.55% or less. In particular, 0.
0.2 to 0.3% is better than 0.2 to 0.35% for these characteristics.
Lanced fuel cladding tube and space
Cold-forming thin members in the heat sink and channel box.
Suitable for manufacturing by repeated processing and annealing
It is. Nickel is high temperature and high pressure without increasing hydrogen absorption
It improves corrosion resistance in water.
It is important. That is, even if iron alone is added,
Improved food quality, but coexists with nickel to contain iron
The amount can be significantly reduced. However, Ni does not absorb hydrogen.
Since it is an element that increases the yield, it should be 0.15% or less.
You. In particular, 0.05 to 0.11% has a low hydrogen absorption rate and a high hydrogen absorption rate.
Corrosion resistance is obtained. (Iron / nickel) ratio depends on hydrogen absorption rate
Has a lot to do with it. If this ratio is less than 1.4, hydrogen
Absorption rate increases, and conversely, even if it exceeds 10, the hydrogen absorption rate is low.
This ratio should be between 1.4 and 10 as below is not obtained
It is. In particular, 1.4 to 8, more than 2 to 4, iron and nickel
Excellent characteristics of both corrosion resistance and hydrogen absorption rate
It is a balanced range with high cold plastic workability.
This ratio is important when the above-mentioned Fe content is 0.2% or more.
Which is obtained as a result of the correlation with the Ni content.
is there. [0015] The intermetallic compound of tin and nickel exhibits corrosion resistance.
Indispensable to improve the final hot plastic working
The subsequent coexistence temperature of α phase and β phase or rapid cooling from β phase
Formed by subsequent annealing
Growth of iron-nickel-zirconium intermetallic compounds
And improve corrosion resistance and hydrogen absorption characteristics.
You. In particular, the Sn-Ni intermetallic compound is 0.2 μm or less.
Particle size is preferred. In the present invention, the zirconium-based alloy is α
Fine gold of tin and nickel in zirconium grains of the phase
Intergeneric compounds and iron-nickel-zirconium intermetallic compounds
Is deposited in the α-phase zirconium crystal grains.
An intermetallic compound of tin and nickel having a particle size of 0.2 μm or less and
, Nickel and zirconium with a particle size of 0.1 to 0.5 μm
Precipitation of intermetallic compounds and the combination of iron and nickel
Weighing 0.3-0.4 weight, pressure 10.3MP
a for 8 hours in steam at 410 ° C.
45mg increase in corrosion when kept for 16 hours in steam at ℃
/ Dm ^Two Having non-nodular corrosion, pressure
Hold at 410 ° C steam for 8 hours with force of 10.3MPa
And water when kept in steam at 510 ° C. for 16 hours.
Preferably, the elemental absorptivity is 15% or less. Nuclear fuel pellets are stored in the fuel cladding tube.
Made of a zirconium-based alloy at both ends of the cladding tube
The end plug is welded and an inert gas is sealed in the cladding tube.
ing. This end plug is also a zirconium-based alloy of the present invention.
Is applied. [0018] The present invention relates to a method of burning a zirconium-based alloy.
After the fuel cladding is hot-worked, the fuel cladding is
From α + β phase temperature or β phase temperature range of ruconium based alloy
Quenching, then cold working and annealing
It is preferably produced by repeating.
In particular, rapid cooling from the α + β phase temperature
It is preferable because its workability is higher than that of β phase quenched.
No. The alloy is quenched from the aforementioned β phase or α + β phase
Preferably, the treatment is performed after hot plastic working.
It is preferable to apply it before subsequent cold plastic working, especially the first cold plastic working.
It is good to apply it before cold forming. Α + β phase is 790-950 ° C., β phase is 95
At temperatures below 1100 ° C above temperatures above 0 ° C, these temperatures
It is more preferable to perform rapid cooling with running water, spray water or the like. Special
Before the first cold plastic working,
Local heating by high frequency heating is preferred
No. As a result, the inner surface of the tube has a high ductility and the outer surface has
In addition, those having low corrosion resistance and low hydrogen absorption rate can be obtained. α + β phase
Is selected at a temperature at which the β phase is mainly formed. β phase
Does not change even after quenching, and has low hardness and high ductility.
Quenching from the part that changed to β phase
Are formed, and the cold workability is low. However, the α phase is slightly
High cold plastic workability by mixing
And low corrosion resistance and low hydrogen absorption.
heating at a temperature that results in an area ratio of 80 to 95% as a β phase,
Rapid cooling is preferred. Heat in a short time, 5 minutes or more
Of these, particularly within 1 minute is preferable. Prolonged heating causes crystal grains
As it grows, precipitates are formed, reducing corrosion resistance
So bad. The annealing temperature is preferably 500 to 700 ° C.
And particularly preferably 550-640 ° C. Below 640 ° C
Has high corrosion resistance. This heating is in a high vacuum
It is preferred to do so. The degree of vacuum is 10 ^Four -10 ^Five Torr preferred
The oxide film is substantially formed on the alloy surface by annealing.
Those which are not formed and have a colorless metallic luster on the surface are preferred. Burning
The annealing time is preferably 1 to 5 hours. [0023] TIG, laser beam, electron beam welding
It is preferable to perform welding, especially TIG welding.
No. The end plug and the cladding tube are preferably made of the same material.
An inert gas is enclosed at 1 to 3 atm. Welds remain welded
Used in As a material for a cladding tube, in addition to corrosion resistance, water
Considering element absorption characteristics, mechanical properties, neutron absorption characteristics, and manufacturability
Must be taken into account. (Corrosion Resistance) The oxide film on the surface of Zircaloy is made of gold.
It is an n-type semiconductor of a genus excess (oxygen deficiency) type, and its composition is
ZrO deviated from stoichiometric composition _2-x It is. Excess metal
The ions are compensated by equivalent electrons and
The poor part is inherent in the oxide film as an anion defect. acid
Elementary ions exchange positions with this anionic defect.
And diffused inside, and zirconium ion
Forms new oxides and corrosive
Go on. Such a uniform oxidation on the entire surface of the cladding tube
Oxide film with strong passive properties on the surface as it proceeds
Are formed, and the oxide film growth rate slows down over time,
It has excellent corrosion resistance. Fe and alloying elements
And Ni are ZrO _2-x Zr ion position and location of ion lattice
Is an element that forms an anion defect
But uniform distribution of oxide film growth rate
Has the effect of forming a uniform protective coating. The β quench in the manufacturing process is based on the alloy
This has the effect of making the distribution of elements more uniform. Annealing etc.
Heat treatment in the α phase temperature range of
Promotes and coarsens the precipitate. Coarsened intermetallic
When the compound phase precipitates, a deficient part of the alloy element is generated in the surrounding area.
As a result, the oxide film growth rate becomes non-uniform. Oxide film thickness
Unevenness is a cause of uneven internal stress in the oxide film.
This may cause cracks due to this uneven stress.
You. Cracking shorts the corrosive environment with Zircaloy metal
Cause local oxidation, that is, nodular corrosion
Becomes Therefore, in order to prevent nodular corrosion,
α + β quench or β quench allows uniform Fe
And Ni are dispersed, and the concentration is reduced by precipitation.
Sufficient Fe and Ni are added to the alloy to prevent
Need to be In particular, Ni
Finer intermetallic compound phase Sn having a particle size of about 0.01 μm
・ Has the property of being uniformly dispersed in crystal grains as Ni
It is essential to prevent nodular corrosion
Element. The Sn-Ni intermetallic compound phase has a high phase temperature.
When annealing is performed for a long time in the range, Zr _Two (Ni ・ F
e) to reduce the corrosion resistance. Therefore, the Sn-Ni intermetallic compound phase is 0.1%.
Do not use heat treatment conditions that do not allow the growth to exceed 2 μm.
I have to. (Hydrogen absorption characteristics) Water causing material embrittlement
The element needs to have a small absorption amount. As mentioned above
Ni is an indispensable element for improving corrosion resistance.
It is an element that increases the amount of hydrogen absorption as the addition increases. Hydrogen gas
The generation of heat is a phenomenon associated with corrosion, and oxidation (corrosion)
The less the amount, the less the amount of hydrogen gas generated. Of oxygen ions
Electrons move in the opposite direction to internal diffusion, and hydrogen ions
It is reduced by hydrogen to hydrogen gas. One of this hydrogen gas
Part is absorbed inside to form hydride and cause hydrogen embrittlement
Becomes Zr _Two (Ni ・ Fe) type intermetallic compound phase exists
Then, the cathode polarization reaction is promoted, and the hydrogen gas absorption amount is reduced.
Zr (Cr.Fe) _Two Or ZrFe _Two Mold gold
When the intergeneric compound phases are present simultaneously, the cathodic polarization reaction
Is suppressed. Also, Zr _Two Ni / Fe in (Ni.Fe)
The ratio decreases as the amount of Fe added increases,
The polarization reaction is suppressed. Therefore, a predetermined amount or more of Fe
It must be added, and its amount should be 0.2 wt% or more.
It is. (Neutron absorption cross section) Thermal neutrality compared to Zr
Large amounts of Fe and Ni with large
Means that thermal neutrons that contribute to power generation are absorbed and power generation efficiency is reduced
Is not preferred. Neutral equivalent to current Zircaloy
In order to obtain the cross-sectional area of the child absorption, the Ni content is 0.16 wt.
% And the Fe content should be 0.55 wt% or less.
In particular, the alloy addition amounts of Fe and Ni are set within the range of the following equation.
Preferably. ## EQU1 ## 0.55 _XNi +0.3 _XFe ≦ 0.165 (Manufacturability, mechanical properties) Hot and cold workability deteriorates
Then, cracks occur during manufacturing. When Ni is added, Zr
_Two An intermetallic compound of (Ni.Fe) precipitates. Improved corrosion resistance
The effective Sn-Ni intermetallic compound phase has an α-phase temperature range.
Does not coarsen even though the heat treatment in _Two (Ni ・ F
e) The intermetallic compound phase coarsens and reduces workability. Coarse
In order to prevent the size increase, the Ni addition amount should be 0.16 wt% or less,
It is preferable to make the micronization by β-quench. mechanical nature
Is almost the same as manufacturability. Excessive addition of Ni
Then, ductility decreases. BEST MODE FOR CARRYING OUT THE INVENTION Zirconium for nuclear reactor
Table 1 and Table 2 by vacuum arc melting using a sponge
An alloy having the indicated alloy composition (% by weight) was melted. The rest is Zr
It is. [Table 1] [Table 2] Each ingot is hot-rolled (700 ° C.),
After annealing (700 ° C for 4 hours), α + β phase temperature
Temperature range (900 ° C) and β phase temperature range (1000 ° C)
After holding for 1 minute, a quenching treatment of water cooling was performed. Cold pressure
Rolling (working rate: 40%) and intermediate annealing at 600 ° C for 2 hours
By repeating the shito three times, a 1mm thick plate is obtained.
Was. This plate was heated to an α phase temperature range (53
0,620,730 ° C) for 2 hours.
It was subjected to a corrosion test. Corrosion test, pressure: 10.3 MP
a) in water vapor, and the temperature and time are determined in a BWR environment.
JP-A-58-95 suitable for reproducing nodular corrosion
Performed under the conditions disclosed in No. 247. That is, 41
After holding the specimen in steam at 0 ° C for 8 hours,
While maintaining the temperature constant, the steam temperature was increased to 510 ° C.
The specimen was kept in hot and high-pressure steam at 0 ° C for 16 hours.
It is a way to carry. Regarding the hydrogen absorption characteristics, the method described below is used.
Was evaluated. Zr + 2H _Two O → ZrO _Two + 2H _Two Oxide (ZrO) _Two ) Is formed and at the same time
Generates hydrogen gas. Measure weight gain due to oxidation
The number of moles of water that has reacted with Zircaloy
The number of moles of hydrogen gas that can be generated correspondingly
Can be requested. Included in specimen after corrosion test
Measure the amount of hydrogen by chemical analysis and calculate the number of moles of absorbed hydrogen
Then, by calculating the ratio of generated hydrogen to absorbed hydrogen,
The hydrogen absorption rate was determined. FIG. 1 shows the occurrence of nodular corrosion.
The circles in the figure indicate noge regardless of the final annealing temperature.
No corrosion was observed on the surface and side surfaces,
45mg / dm ^Two This indicates that X mark
Causes nodular corrosion on the surface or side
Corrosion increase is 50mg / dm ^Two That was more than
Show. Alloy that can prevent nodular corrosion from Fig. 1
The composition is high Ni, high Fe in the region divided by the dotted line in the figure.
It can be seen that it exists on the side. The dotted line is 0.15Fe + 0.2
It is a diagram calculated | required by 5Ni = 0.0375. FIG. 2 shows the effect of Fe and Ni content on the increase in corrosion.
FIG. 3 is a diagram showing the influence of the amount. As shown in the figure,
Corrosion in the steel significantly decreased with the increase of Fe and Ni contents.
It turns out to be less. In particular, by adding a trace amount of Ni
Corrosion gain rapidly decreases. Fe content around 0.2%
With the addition of 0.03% Ni, the corrosion increase was 45 mg /
dm ^Two Below, nodular corrosion did not occur. FIG. 3 shows the effect of the amount of Fe added on the hydrogen absorption rate.
It shows the effect. In the figure, the symbol △ indicates the amount of Ni added: 0.1.
The hydrogen absorption rate of the alloy of 11 wt% is shown.
Amount: Indicates the hydrogen absorption rate of 0.05 wt% alloy. In the figure
Dotted lines omit α + β quench or β quench
The experimental results for the alloy are shown. The solid line indicates the heat treatment process.
Hydrogen absorption of alloys that have undergone α + β quenching
The yield is shown. By applying α + β quench from FIG.
It can be seen that the hydrogen absorption rate can be reduced to 11% or less.
You. FIG. 4 shows the effect of the amount of Ni added on the hydrogen absorption rate.
Show the effect. The amount of Fe added is in the range of 0.20 to 0.24 wt%.
In the box. If the Ni content is 0.16 wt% or less, hydrogen absorption
The yield is as low as 11% or less, but more than 0.2% by weight.
Then, the hydrogen absorption rate rises rapidly and reaches as high as 40%. Yo
Therefore, the amount of Ni added should be 0.16 wt% or less.
You. FIG. 5 shows the effect of (Fe / N) on the hydrogen absorption rate.
i) Diagram showing the effect of the ratio. As shown in FIG.
If the amount is less than 0.20%, the mark with a circle and the mark with a triangle indicate (Fe / N
i) Although no influence by the ratio is observed, the F of 0.20% or more
For the e content, the (Fe / Ni) ratio should be at least 1.4.
I know there is. As mentioned above, Fe and Ni absorb hydrogen
Since the effect on the rate has a completely opposite effect, these
Finding that ratios in elements have important relationships
Was. Fe content is less than 0.2% and Ni content is less than 0.2%.
At contents greater than 2%, there is no correlation between these elements.
However, when the contents of both are opposite to each other, there is a correlation between the two.
It has. For the alloy No. 38, the amount of Fe added was 0.48.
It is an alloy that has been increased to wt%. The corrosion gain of this alloy is 4
3mg / dm ^Two And the hydrogen absorption rate was 12%. this thing
From the viewpoint of corrosion resistance and hydrogen absorption, the amount of Ni added
In the range of 0.16 wt% or less, the amount of Fe added is 0.2 w
t% or more, it may be increased to 0.55 wt%
Recognize. However, the total amount of Ni and Fe is 0.64% or less.
High plastic content causes a sharp drop in cold plastic workability
Therefore, as described above, a member that is thinned by cold plastic working
It is clear that this is not preferred. Between Fe and Ni
The total amount is preferably 0.64% or less, more preferably 0.40% or less. The α + β quenched alloy No. 34
Observation of the precipitates with a transmission electron microscope showed that tin and
An intermetallic compound with nickel was detected and α-phase zirconia
Is uniformly dispersed and precipitated in the crystal grains
Was done. The precipitate is Sn _Two Ni _Three Precipitate, particle size about 10n
m. However, for the same material α
This precipitate is not observed in those without + β quenching
Was. It should be noted that the α + β quenched
After hot plastic working, the precipitates of Sn and Ni
No exposition was seen. (Embodiment 1) This embodiment is a fuel cladding for a nuclear reactor.
This is a study of the tube manufacturing process. 5 shown in Table 3
Arc ingots with different alloy compositions (% by weight)
It was produced by dissolution. [Table 3] After the two vacuum arc melting operations, the temperature was set to 1050 ° C.
After forging at room temperature and cooling to room temperature,
Apply heat treatment for 1 hour and cool in water
Was. Continue to forge at 700 ° C, cool and reheat
Annealing was performed at 700 ° C. for 1 hour. Grind the surface Cu
Apply coating and hot extrude at 650 ° C, then remove Cu coating
I left. This tube is called a base tube and has an outer diameter of 63.5 mm,
The dimensions are 10.9 mm. This tube is a high frequency induction coil
Heated by passing through
Water on the pipe surface from the water ejection nozzle
And quenched. Maximum heating temperature has α + β phase
910 ° C. and the holding time at 860 ° C. or more is 10 seconds, 9
The average cooling rate from 10 ° C to 500 ° C is about 100 ° C /
s. The pipe subjected to the induction hardening treatment is Pilami
Rolling and intermediate annealing three times alternately
The outer diameter is 12.3mm and the wall thickness is 0.86mm.
And Intermediate annealing is all 10 ^Five In Torr vacuum
The temperature was 600 ° C and 650 ° C in order, and the final baking was performed.
The annealing temperature was 577 ° C. Cold rolling degree (tube cross section
Product reduction rate) is 77%, 77%, 70%, respectively
there were. In this process, alloy No. 5 in Table 3
Because black cracks occurred during the second cold rolling,
Subsequent processing and heat treatment were stopped. From this, N
When i is added at 0.2 wt% or more, the cold workability decreases.
It turns out that it is not preferable. Both cladding tubes are annealed
As a result, substantially no oxide is formed on the surface of the tube.
It had a metallic luster in color. The fuel cladding tube having undergone the above manufacturing process is drawn.
It was subjected to a tension test (room temperature and 343 ° C.) and a corrosion test. table
4 shows the result. [Table 4] The tensile properties of the cladding of any alloy composition
Although it was almost the same, the Ni content was 0.01 wt%.
Has low corrosion resistance and requires more than 0.03 wt% of Ni
It turns out that there is. No. 2 to No. 4 which had high corrosion resistance
In the metallographic structure of the cladding tube, the particle size is around 0.01 μm.
Α-phase Zr crystal in which Sn-Ni intermetallic compound phase is recrystallized
It was finely dispersed in the grains. (Embodiment 2) In the case of No. 4 shown in Embodiment 2,
Using a cladding tube made of gold and using the same alloy for the end plug
Thus, the fuel rod shown in FIG. 6 was manufactured. Fuel rod is clad tube 1,
Liner 2, upper end plug 3, nuclear fuel pellet (eg UO _Two )
4, plenum spring 5, welded part 6, lower end plug 7
It is mainly composed of The end plug was forged in the β phase temperature range and annealed.
Things. The welding was performed by TIG welding. Rye
The nut 2 is made of dull Zr and has a thickness of 100 μm or less.
You. The liner 2 is inserted into the billet during hot extrusion, and
Cold plastic working and annealing repeated during clad tube production
To a desired thickness. The fuel rod is a nuclear fuel assembly 10 shown in FIG.
And stored in the reactor core. Nuclear fuel assembly 1
0 is the channel box 11, the nuclear fuel rod 14, the lifting
Hand 12, top plate 15, bottom plate (not shown)
Mainly composed of Also, if not shown
Fuel rods are fixedly arranged at predetermined intervals in the fuel assembly 10
Spacers are used.
Similarly, by repeating hot and cold plastic working
It is constituted by a thin plate of the obtained No. 4 alloy. More
This embodiment is similar to the spacer for the channel box.
It is constituted by the alloy obtained in the above. According to this embodiment, the cladding tube, the spacer,
Each of the channel boxes is made of the alloy of the present invention
Resulting in a longer life and higher burnup
To the collection of According to the present invention, corrosion resistance is excellent and hydrogen absorption
Since the production of fuel cladding with low yield is obtained,
Improves reliability and can greatly extend the life in the furnace
Thus, high burnup of nuclear fuel can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the effects of Fe and Ni on the occurrence of nodular corrosion.
It is a figure which shows the influence of an alloy composition. FIG. 2 is a diagram showing the effect of Ni on corrosion increase. FIG. 3 is a diagram showing the effect of the amount of Fe on the hydrogen absorption rate. FIG. 4 is a diagram showing the influence of the amount of Ni on the hydrogen absorption rate. FIG. 5 is a diagram showing the effect of the (Fe / Ni) ratio on the hydrogen absorption rate. FIG. 6 is a sectional view of a fuel rod. FIG. 7 is a partial sectional view of a nuclear fuel assembly. [Description of Signs] 1 ... cladding tube, 2 ... liner, 3, 7 ... end plug, 4 ... nuclear fuel pellet, 6 ... welded part, 10 ... fuel assembly, 11 ... channel box, 12 ... lifting handle, 14 ... nuclear fuel rod,
15 ... Top plate.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G21C 21/00 G21C 3/34 Y (72) Inventor Jiro Kuniya 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. 72) Inventor Kimihiko Akahori 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd., Hitachi Research Laboratory (72) Inventor Isao Masaoka 4026 Kuji-machi, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratory, Ltd. Hitachi, Ltd. Hitachi Plant, Hitachi, Ltd. (72) Inventor Junjiro Nakajima 3-1-1, Sakaicho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Plant, Ltd. (56) References JP-A-60-67648 (JP, A) JP-A-60-82636 (JP, A) JP-A-58-25467 (JP, A) "High temperature water of Zircaloy" Influence of Alloying Components on Aerial Corrosion, ”Kakuma, 3 others, 1984 (22nd) Annual Meeting of the Atomic Energy Society of Japan (2nd volume), The Japan Atomic Energy Society, March 1984 Published on the 10th, p. 199 (58) Field surveyed (Int. Cl. ⁶ , DB name) G21C 3/06-3/07

Claims (1)

(57) [Claims] Nuclear fuel pellets are stored in a fuel cladding tube made of a zirconium-based alloy, and end plugs made of a zirconium-based alloy are welded to both ends of the cladding tube by welding. 1.2-2
%, 0.20 to 0.55% iron, 0.05 to 0.15% chromium and 0.03 to 0.16% nickel, with the balance substantially consisting of zirconium, with an (iron / nickel) ratio of 1. 4-1
A cladding tube for a highly corrosion-resistant nuclear fuel, comprising a zirconium-based alloy that is zero. 2. In a nuclear fuel assembly spacer for fixing a plurality of fuel rods in a channel box at predetermined intervals, the spacer is, by weight, 1.2 to 2% tin, 0.20 to 0.55% iron,
0.05 to 0.15% chromium and 0.03 to 0.1 nickel
6%, with the balance substantially consisting of zirconium,
A highly corrosion-resistant nuclear fuel assembly spacer, comprising a zirconium-based alloy having an (iron / nickel) ratio of 1.4 to 10. 3. In a channel box for a nuclear fuel assembly, in which a plurality of fuel rods are integrally housed in a rectangular channel box at predetermined intervals, the channel box is 1.2 to 2% tin and 0.20 to 0% iron by weight. .55%, chrome 0.05-
0.15% and nickel 0.03-0.16% with the balance substantially consisting of zirconium, (iron / nickel)
A channel box for a highly corrosion resistant nuclear fuel assembly, comprising a zirconium-based alloy having a ratio of 1.4 to 10. 4. A fuel rod containing nuclear fuel pellets in a cladding tube, upper and lower tie plates holding both ends of the fuel rod, a spacer for arranging the fuel rods provided between the upper and lower tie plates at predetermined intervals, Reactor fuel provided with a fuel rod, an upper tie plate, a lower tie plate and a channel box formed of a rectangular tube for accommodating a spacer, and a handle held by the upper tie plate for integrally transporting the entire fuel rod. In the assembly, at least one of the cladding tube, the spacer and the channel box is 1.2 to 2% tin and 0.20 to 0.55% iron by weight.
, 0.05 to 0.15% chromium and 0.03% nickel
A fuel assembly for a high corrosion resistant nuclear reactor, comprising 0.16%, the balance being substantially zirconium, and a zirconium-based alloy having an (iron / nickel) ratio of 1.4 to 10. 5. A fuel rod containing nuclear fuel pellets in a cladding tube, upper and lower tie plates holding both ends of the fuel rod, a spacer for arranging the fuel rods provided between the upper and lower tie plates at predetermined intervals, Reactor fuel provided with a fuel rod, an upper tie plate, a lower tie plate and a channel box formed of a rectangular tube for accommodating a spacer, and a handle held by the upper tie plate for integrally transporting the entire fuel rod. In the method of manufacturing an assembly, at least one of the cladding tube, the spacer, and the channel box is, by weight, 1.2 to 2% of tin and 0.20 to 1.0% of iron.
0.55%, 0.05-5.15% chromium and 0.5% nickel.
A zirconium-based alloy containing from 0.3 to 0.16%, with the balance substantially consisting of zirconium and having an (iron / nickel) ratio of from 1.4 to 10, after the final hot plastic working and before the first cold plastic working In the temperature range containing the β phase or the α phase and the β phase, subjected to a process of heating and holding for a short time, followed by rapid cooling, and then alternately repeated cold plastic working and annealing to form a thin material of the zirconium-based alloy. A method for producing a fuel assembly for a nuclear reactor, characterized by performing a forming process thereafter.