Standard sample for hydrogen element in zirconium and zirconium alloy as well as preparation method and application of standard sample

Abstract

The invention discloses a hydrogen element standard sample in zirconium and zirconium alloy and a preparation method and application thereof. Advanced processes such as magnetic confinement glow plasma hydrogen permeation and high-temperature argon protection homogenization treatment are adopted, and the problems of control and nonuniformity of hydrogen elements in zirconium and zirconium alloy are successfully solved; homogeneity inspection is carried out by adopting a variance method, and the result shows that the hydrogen element standard sample has good homogeneity; according to eight domestic qualified laboratories, different principles and reliable analysis methods are adopted for cooperative valuing, and valuing results are accurate and reliable. A comparison result shows that the main technical indexes of the hydrogen element standard sample reach the advanced level of domestic similar standard samples.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical analysis and detection of zirconium and zirconium alloys, and in particular to a standard sample of hydrogen element in zirconium and zirconium alloys, and a preparation method and application thereof. Background Art

[0002] Zirconium alloys have small thermal neutron absorption cross section, good high temperature strength, excellent corrosion resistance in high temperature and high pressure water, good thermal conductivity and processing performance, and good thermal conductivity and processing performance. 2 Due to the good compatibility of fuel pellets, it is widely used as cladding material for various reactor types such as pressurized water reactors, boiling water reactors and heavy water reactors. Zirconium alloy cladding tubes may fail due to various reasons, including corrosion, creep, mechanical interaction between fuel pellets and cladding, and deviation from nucleate boiling. Cladding tube failure is often caused by a combination of factors. Among them, one of the failure mechanisms is hydrogen embrittlement, also known as hydrogen embrittlement. This hydrogen embrittlement is caused by the diffusion of hydrogen or deuterium (an isotope of hydrogen) atoms into the cladding tube to precipitate zirconium hydride, causing material performance degradation. Therefore, the hydrogen content in zirconium alloys must be strictly controlled during the production process.

[0003] The main method for characterizing the hydrogen content in zirconium alloys is the thermal conductivity method, which is a relative analysis method and requires the use of hydrogen standard samples to calibrate the instrument in order to accurately detect it. The hydrogen standard samples currently on sale are hydrogen standard samples in titanium and titanium alloys, and there are no hydrogen standard samples in zirconium and zirconium alloys. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention provides a standard sample of hydrogen element in zirconium and zirconium alloys, and a preparation method and application thereof.

[0006] In the first aspect, the present invention provides a method for preparing a standard sample of hydrogen in zirconium and zirconium alloys, such as Figure 1 As shown, the following steps are included:

[0007] (a) obtaining zirconium or zirconium alloy that meets the requirements, wherein the mass content of hydrogen in the zirconium or zirconium alloy is less than 0.001%;

[0008] (b) subjecting the zirconium or zirconium alloy to a plasma hydrogenation treatment so that the zirconium or zirconium alloy reaches a preset hydrogen content;

[0009] (c) homogenizing the sample obtained in step (b);

[0010] (d) Cutting the sample obtained in step (c), and obtaining a standard sample of hydrogen in zirconium and zirconium alloys after confirming that the sample is qualified.

[0011] Furthermore, the zirconium or zirconium alloy that meets the requirements is obtained by processing the zirconium or zirconium alloy through smelting, forging, extrusion, rotary forging / rolling processes, and is used after passing non-destructive inspection, surface inspection, and chemical composition inspection.

[0012] Furthermore, the zirconium alloy includes one of a zirconium alloy wire, a zirconium alloy tube, and a zirconium alloy strip.

[0013] Furthermore, in step (b), the plasma hydrogenation treatment process is: at a vacuum degree of 1.0×10 -4 ~1.0×10 -3 Pa magnetic confinement glow plasma device, high purity hydrogen and argon were introduced, and the plasma density was 6.80×10 21 ~4.45×10 22 ions / m 3 Plasma hydrogenation is carried out under the condition of bombardment time of 10 to 40 minutes, wherein hydrogen is the reaction gas and argon is the non-reaction gas.

[0014] Furthermore, in step (c), the homogenization process is as follows: placing the hydrogenated sample in a reactor, first performing vacuum treatment, and evacuating the sample to a vacuum degree of less than 1.0×10 -3 Pa, then introduce high-purity argon, heat to 450-550℃ and keep warm for 10-20h.

[0015] The homogenization process allows the hydrogen element to diffuse evenly in the sample, obtaining a sample with a preset hydrogen content.

[0016] Furthermore, in step (d), determining whether the test is qualified is: mixing the cut samples evenly, performing a fixed value analysis on the hydrogen content according to preset test requirements, and determining that the test is qualified when it is determined that the hydrogen content meets the preset requirements.

[0017] Cutting the sample means reprocessing the sample into columnar, ring-shaped or sheet-shaped samples, and mixing the cut samples evenly for testing, so that the test is more accurate.

[0018] Furthermore, a uniformity test is also included before uniform mixing, wherein the uniformity test is to cut, mix and clean the zirconium or zirconium alloy, and then perform a uniformity test on the data to be analyzed according to the technical specifications of the standard sample to determine whether the uniformity requirements are met.

[0019] The cut sample can be cleaned by soaking the sample in alcohol or acetone to remove oil stains and impurities on the surface.

[0020] Furthermore, after determining that the test is qualified, the stability test of the standard sample is also carried out within a preset time.

[0021] Furthermore, after the test is confirmed to be qualified, production assessment of standard samples is also included.

[0022] In a second aspect, the present invention proposes a standard sample of hydrogen element in zirconium and zirconium alloys prepared by the method proposed in the first aspect.

[0023] In a third aspect, the present invention proposes the use of the standard sample of hydrogen element in zirconium and zirconium alloys prepared by the method proposed in the first aspect or the standard sample of hydrogen element in zirconium and zirconium alloys proposed in the second aspect in chemical analysis and detection of zirconium and zirconium alloys.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The present invention uses advanced processes such as magnetic confinement glow plasma hydrogenation and high-temperature argon protection homogenization treatment to successfully solve the problems of hydrogen element control and unevenness in zirconium and zirconium alloys; the variance method is used to perform uniformity inspection, and the results show that this hydrogen element standard sample has good uniformity; eight qualified domestic laboratories use different principles and reliable analysis methods to collaboratively determine the value, and the determination result is accurate and reliable; the comparison results show that the main technical indicators of this hydrogen element standard sample have reached the advanced level of similar domestic standard samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 The present invention is a flow chart of the method for preparing standard samples of hydrogen in zirconium and zirconium alloys. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0029] The present invention is specifically described below in conjunction with embodiments.

[0030] Example 1

[0031] S1: Select Φ2.6mm zirconium tube (Zr-4), in which the mass percentage of hydrogen element is 0.0002%, and the remaining elements meet the requirements of zirconium tube composition.

[0032] S2: Place the zirconium tube in S1 in a magnetic confinement glow plasma device with a vacuum degree of 1.0×10 -4Pa, high-purity hydrogen and argon were introduced, and the plasma density was 6.80×10 21 ions / m 3 The ion bombardment time is 10 min for hydrogenation to obtain the sample prepared by plasma hydrogenation.

[0033] S3: Place the sample prepared by plasma hydrogenation obtained in S2 in a reactor with a vacuum degree of 1.0×10 -4 Under 370 Pa conditions, high-purity argon gas was introduced, heated to 450°C, and kept warm for 10 hours to homogenize the hydrogen element, so as to obtain a zirconium tube with a preset hydrogen content, which was then cut into 2.5 mm long columnar samples.

[0034] The standard sample number prepared in this example is Zr-H-1.

[0035] Example 2

[0036] S1: Select Φ2.6 mm zirconium alloy wire (Zr-4), wherein the mass percentage of hydrogen element is 0.0009%, and the remaining elements meet the zirconium alloy composition requirements.

[0037] S2: Place the zirconium alloy wire in S1 in a magnetic confinement glow plasma device with a vacuum degree of 1.0×10 -4 Pa, high-purity hydrogen and argon were introduced, and the plasma density was 7.80×10 21 ions / m 3 The ion bombardment time was 16 min for hydrogenation to obtain the sample prepared by plasma hydrogenation.

[0038] S3: Place the sample prepared by plasma hydrogenation obtained in S2 in a reactor with a vacuum degree of 1.0×10 -4 Under 370 Pa conditions, high-purity argon gas was introduced, heated to 500°C, and kept warm for 12 hours to homogenize the hydrogen element, so as to obtain zirconium alloy wire with a preset hydrogen content, which was then cut into 2.5 mm long columnar samples.

[0039] The standard sample number prepared in this example is Zr-H-2.

[0040] Example 3

[0041] S1: Select Φ8mm zirconium alloy pipe (Zr-2), in which the mass percentage of hydrogen element is 0.0009%, and the remaining elements meet the zirconium alloy composition requirements.

[0042] S2: Place the zirconium alloy tube in S1 in a magnetic confinement glow plasma device with a vacuum degree of 1.0×10 -4 Pa, high-purity hydrogen and argon were introduced, and the plasma density was 1.50×10 22 ions / m 3The ion bombardment time is 25 min for hydrogenation to obtain the sample prepared by plasma hydrogenation.

[0043] S3: Place the sample prepared by plasma hydrogenation obtained in S2 in a reactor with a vacuum degree of 1.0×10 -4 Under 370 Pa conditions, high-purity argon gas was introduced, heated to 500°C, and kept warm for 12 hours to homogenize the hydrogen element, so as to obtain a zirconium alloy tube with a preset hydrogen content, which was then sheared into 2.5 mm long columnar samples.

[0044] The standard sample number prepared in this example is Zr-H-3.

[0045] Example 4

[0046] S1: Select Φ8mm zirconium alloy pipe (chemical composition (mass fraction / %) is 0.2Sn, 0.2Fe, 0.1Cr, 1.2O, 0.01C, and the rest is Zr), wherein the mass percentage of hydrogen element is 0.0009%, and the other elements meet the zirconium alloy composition requirements.

[0047] S2: Place the zirconium alloy tube in S1 in a magnetic confinement glow plasma device with a vacuum degree of 1.0×10 -4 Pa, high-purity hydrogen and argon were introduced, and the plasma density was 2.80×10 22 ions / m 3 The ion bombardment time is 30 min for hydrogenation to obtain the sample prepared by plasma hydrogenation.

[0048] S3: Place the sample prepared by plasma hydrogenation obtained in S2 in a reactor with a vacuum degree of 1.0×10 -4 Under 370 Pa conditions, high-purity argon gas was introduced, heated to 550°C, and kept warm for 20 hours to homogenize the hydrogen element, so as to obtain a zirconium alloy tube with a preset hydrogen content, which was then sheared into 2.5 mm long columnar samples.

[0049] The standard sample number prepared in this example is Zr-H-4.

[0050] Example 5

[0051] S1: Select a δ0.66 mm zirconium alloy strip (chemical composition (mass fraction / %) is 0.4-0.6 Nb, 0.4-0.6 Sn, 0.25-0.35 Fe, 0.01-0.02 Si, and the rest is Zr), wherein the mass percentage of hydrogen element is 0.0007%, and the other elements meet the zirconium alloy composition requirements.

[0052] S2: The zirconium alloy strip in S1 is placed in a magnetic confinement glow plasma device with a vacuum degree of 1.0×10 -4Pa, high-purity hydrogen and argon were introduced, and the plasma density was 4.40×10 22 ions / m 3 The ion bombardment time was 14 min for hydrogenation to obtain the sample prepared by plasma hydrogenation.

[0053] S3: Place the sample prepared by plasma hydrogenation obtained in S2 in a reactor with a vacuum degree of 1.0×10 -4 Under 370 Pa conditions, high-purity argon gas was introduced, heated to 550°C, and kept warm for 20 hours to homogenize the hydrogen element, so as to obtain a zirconium alloy strip with a preset hydrogen content, which was then cut into 3×3 mm long sheet samples.

[0054] The standard sample number prepared in this example is Zr-H-5.

[0055] The samples prepared in Examples 1 to 5 were mixed evenly, 15 samples were taken for uniformity test, and the analysis data were processed according to the requirements of YS / T409 Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products. The sample uniformity is shown in Table 1.

[0056] Table 1:

[0057]

[0058]

[0059] According to the requirements of YS / T 409 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products", for the determination method with given repeatability limit, the standard deviation S of a limited number of measurements can be calculated and compared with the repeatability limit r of the measurement method. When 1.5S≦r, the uniformity initial inspection is deemed to be qualified, and when 1.5S>r, the uniformity initial inspection is deemed to be unqualified. As can be seen from Table 1, the uniformity inspections of the samples obtained in Examples 1 to 5 are all qualified.

[0060] The 15 samples obtained from Examples 1 to 5 were inspected on a LECO hydrogen analyzer, and all standard samples passed the uniformity test.

[0061] In summary, it can be seen that the uniformity of the samples prepared in Examples 1 to 5 of the present invention is acceptable.

[0062] Samples that have passed the composition uniformity inspection are subjected to fixed value analysis in accordance with the requirements of YS / T 409 Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products. Qualified laboratories, industry representatives, and regional representatives are selected to participate in the fixed value analysis, and accurate and reliable analysis methods are selected for collaborative fixed value analysis.

[0063] Determining whether the test is qualified specifically includes mixing the cut samples evenly, performing a fixed value analysis on the hydrogen content according to the preset test requirements, and determining that the test is qualified when it is determined that the hydrogen content meets the preset requirements.

[0064] The data reported by each analytical unit is checked for abnormal values ​​within the group and between units according to the allowable difference of the national standard method. If necessary, the original laboratory can be asked to recheck the suspicious values. Then the data is processed using the following methods. Then the standard value and expanded uncertainty of each group of data are calculated.

[0065] (1) Normality test: Shapiro-Wilk

[0066] The original data after removing suspicious values ​​were summarized and the Shapiro-Wilk method was used to conduct a normality test on all the data reported by each collaborative unit.

[0067] Calculation formula:

[0068] If W<W(a,n), it does not obey normal distribution, otherwise it is normal.

[0069] All data were tested to be normal or nearly normal.

[0070] (2) Outlier test: Grubbs

[0071] When the data obeys normal distribution or approximate normal distribution, the average value of each group of data is regarded as a single measurement value to form a new group of data. Use Grubbs method to test.

[0072] Here, the significance level α is 0.05 and the critical value is 2.126. Calculate the maximum residual and the minimum residual. If both are less than the critical value, keep them all.

[0073] (3) Equal precision test: Cochran criterion

[0074] This standard sample uses the Cochrane criterion to test whether the results of each group are of equal precision.

[0075] Cochrane criterion test formula:

[0076] If Cmax≤C(a, m, N), it means that each group of data has equal accuracy.

[0077] If Cmax>C(a, m, n), it indicates that the data set has poor precision.

[0078] The test shows that all data are of equal or approximately equal precision.

[0079] (4) After processing each group of data, calculate the arithmetic mean and single measurement standard deviation of each group of data, and round off the significant figures of the standard value according to GB / T 8170 "Data Rounding Rules".

[0080] (5) Standard value and expanded uncertainty:

[0081] Since the tests are of equal precision, the standard value and expanded uncertainty are calculated using the following method:

[0082] Arithmetic total mean (standard value):

[0083] Standard deviation of a single measurement:

[0084] Standard deviation of the arithmetic mean:

[0085] Standard deviation caused by inhomogeneity (inhomogeneity uncertainty):

[0086] When F < 1,

[0087] Combined uncertainty:

[0088] Expanded uncertainty u:

[0089] Where K is the inclusion factor determined by the confidence probability and the degrees of freedom. Here K is 2.37 (a=0.05, confidence level; V=7, degrees of freedom).

[0090] The result of the standard sample determination is represented by (standard value, expanded uncertainty). The standard samples of sample numbers Zr-H-1, Zr-H-2, Zr-H-3, Zr-H-4, and Zr-H-5 were analyzed and tested according to the above method. The standard samples were tested by themselves, and the results are as follows, as shown in Table 2.

[0091] Table 2:

[0092] Grouping element Standard value Single measurement standard deviation Expanded uncertainty Zr-H-1 H 0.0044 0.00012 0.0002 Zr-H-2 H 0.0073 0.00056 0.0003 Zr-H-3 H 0.0183 0.00013 0.0008 Zr-H-4 H 0.0354 0.00303 0.0009 Zr-H-5 H 0.0230 0.00013 0.0007

[0093] The standard sample was sent to the laboratory for testing, and the test results of the 8 laboratories were statistically analyzed to obtain the following Table 3.

[0094] Table 3:

[0095]

[0096]

[0097] From the above content, it can be seen that the standard sample meets the requirements.

[0098] Stability test: The standard sample was followed up three times within one year. Each time the measurement was carried out, various conditions were controlled to make them consistent, and a high-precision method was selected so that the difference between the measurement results would focus on reflecting the part of the error caused by the material change. If the deviation of the test results of this standard sample at different time intervals is less than the precision of the analytical method, then the standard sample is considered to be stable within the time interval.

[0099] According to previous follow-up investigations on zirconium alloy gas element standard samples, their stability is at least ten years, so the validity period of this standard sample is set at ten years.

[0100] Conduct production assessment on standard samples.

[0101] (1) In order to test the quality of the developed standard samples, the standard samples were compared on two hydrogen analyzers, LECO RH600 and H836. The test results are shown in Table 4 below.

[0102] Table 4:

[0103]

[0104]

[0105] After testing with two hydrogen determination instruments, the data obtained were consistent with the chemical test results, indicating that the composition design of the three single-point calibration samples was reasonable, the uniformity was good, and the determination was accurate and reliable.

[0106] (2) The standard samples were sent to the National Titanium Testing Center for testing. The test results are as follows: the tested hydrogen standard samples have a reasonable composition design, good uniformity, and accurate and reliable values; the hydrogen standard samples are suitable for the composition analysis of zirconium sponge, zirconium ingots, zirconium rods, zirconium plates, and zirconium tubes, and the use effect is good.

[0107] The method of the present invention can be used to prepare standard samples of hydrogen in zirconium and zirconium alloys. The standard samples of hydrogen in zirconium and zirconium alloys prepared by the present invention are mainly aimed at zirconium control rods, zirconium plates and other products widely used in the atomic energy industry in China. The analysis error and stability problems caused by different analytical instruments in different production, research and use units are solved. The composition design takes into account the application and promotion of a series of products such as sponge zirconium, zirconium ingots, zirconium rods, zirconium plates, and zirconium pipes. The identification and analysis results are as follows:

[0108] 1) The composition design of the standard sample of hydrogen in zirconium and zirconium alloys can meet the analysis requirements of zirconium sponge, zirconium ingot, zirconium rod, zirconium plate and zirconium tube.

[0109] 2) The problems of hydrogen element control and unevenness in zirconium and zirconium alloys were successfully solved by using advanced processes such as magnetic confinement glow plasma hydrogenation and high-temperature argon protection homogenization treatment.

[0110] 3) The variance method was used to check the uniformity, and the results showed that this hydrogen element standard sample had good uniformity.

[0111] 4) The value is determined through collaboration by eight qualified laboratories in China using different principles and reliable analytical methods. The results are accurate and reliable.

[0112] 5) According to the stability of similar standard samples and the stability of the research unit, this hydrogen element standard sample has good stability.

[0113] 6) The comparison results show that the main technical indicators of this hydrogen element standard sample have reached the advanced level of similar domestic standard samples.

[0114] The development process of standard samples complies with the requirements of GB / T15000 "Guidelines for Standard Samples" and YS / T409 "Technical Specifications for Standard Samples for Nonferrous Metal Product Analysis".

[0115] The standard sample of hydrogen element in zirconium and zirconium alloy prepared by the invention is used for calibration of quality control detection instruments for zirconium and zirconium alloy.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms may be for different embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0117] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0118] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing a standard sample of hydrogen in zirconium and zirconium alloys, characterized in that: The following steps are involved: (a) obtaining zirconium or zirconium alloy that meets the requirements, wherein the mass content of hydrogen in the zirconium or zirconium alloy is less than 0.001%; (b) subjecting the zirconium or zirconium alloy to a plasma hydrogenation treatment so that the zirconium or zirconium alloy reaches a preset hydrogen content; (c) homogenizing the sample obtained in step (b); (d) Cutting the sample obtained in step (c), and obtaining a standard sample of hydrogen in zirconium and zirconium alloys after confirming that the sample is qualified.

2. The method according to claim 1, characterized in that The zirconium or zirconium alloy that meets the requirements is obtained by processing zirconium or zirconium alloy through smelting, forging, extrusion, rotary forging / rolling processes, and is used after passing non-destructive inspection, surface inspection, and chemical composition inspection. The zirconium alloy includes one of zirconium alloy wire, zirconium alloy pipe, and zirconium alloy strip.

3. The method according to claim 1, characterized in that In step (b), the plasma hydrogenation treatment process is: at a vacuum degree of 1.0×10 -4 ~1.0×10 -3 Pa magnetic confinement glow plasma device, high purity hydrogen and argon were introduced, and the plasma density was 6.80×10 21 ~4.45×10 22 ions / m 3 Plasma hydrogenation is carried out under the condition of bombardment time of 10 to 40 minutes.

4. The method according to claim 1, characterized in that In step (c), the homogenization process is as follows: placing the hydrogenated sample in a reactor and evacuating the reactor to a vacuum degree of less than 1.0×10 -3 Pa, then introduce high-purity argon, heat to 450-550℃ and keep warm for 10-20h.

5. The method according to claim 1, characterized in that In step (d), the determination of whether the test is qualified is: mixing the cut samples evenly, performing a fixed value analysis on the hydrogen content according to the preset test requirements, and determining that the test is qualified when it is determined that the hydrogen content meets the preset requirements.

6. The method according to claim 5, characterized in that Before uniform mixing, a uniformity test is also included. The uniformity test is to cut, mix and clean the zirconium or zirconium alloy and then perform a uniformity test on the data to be analyzed according to the technical specifications of the standard sample to determine whether it meets the uniformity requirements.

7. The method according to claim 5, characterized in that After the test is confirmed to be qualified, the stability of the standard sample will be tested within a preset time.

8. The method according to claim 5, characterized in that After the test is confirmed to be qualified, production assessment of standard samples is also included.

9. A standard sample of hydrogen in zirconium and zirconium alloys, characterized in that: The method is prepared by any one of claims 1 to 8.

10. Use of the standard sample of hydrogen in zirconium and zirconium alloys prepared by the method according to any one of claims 1 to 8 or the standard sample of hydrogen in zirconium and zirconium alloys according to claim 9 in chemical analysis of zirconium and zirconium alloys.

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