Recrystallization Rate Measurement Method of Zirconium Alloy Cladding of Nuclear Fuel Rod Using EBSD Pattern Quality

• US 20190154600A1
• Filed: 07/20/2018
• Published: 05/23/2019
• Est. Priority Date: 11/17/2017
• Status: Active Grant

• Current Assignee: KEPCO Nuclear Fuel Co., Ltd.
• Original Assignee: KEPCO Nuclear Fuel Co., Ltd.
• Inventors: Jung, Tae Sik, Mok, Yong Kyoon, Kim, Yoon Ho, Lee, Chung Yong, Jang, Hun
• Granted Patent: US 10,641,719 B2
• Time in Patent Office: Days
• CPC Class Codes: G01N 2223/053 back scatter
• CPC Class Codes: G01N 2223/0561 diffraction cameras
• CPC Class Codes: G01N 2223/418 electron microscope
• CPC Class Codes: G01N 2223/602 crystal growth
• CPC Class Codes: G01N 23/203 Measuring back scattering
• CPC Class Codes: G01N 23/2251 using incident electron beams, e.g. scanning electron microscopy [SEM]
• CPC Class Codes: G01N 33/20 Metals
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

The present invention relates to a recrystallization rate measurement method of zirconium alloy cladding of a nuclear fuel rod, the method including: step 1 of irradiating SEM electron beams at a given scanning interval onto a first specimen to a third specimen which were electrolytically polished and obtaining electron backscattered signals therefrom by an EBSD camera; step 2 of converting electron backscattered signals obtained in step 1 into pattern quality values, respectively, and generating the pattern quality values as frequencies by a specified interval; step 3 of obtaining pattern quality frequencies (B+D) which are a portion of a whole frequency distribution of the second specimen, and pattern quality frequencies (D+E) which are a portion of a whole frequency distribution of the first specimen; and step 4 of obtaining the recrystallization rate of the second specimen with an equation of

$X^{\prime }=\frac{\left(B+D\right)}{\left(D+E\right)}\times 100,\%.$

Claims

1. A recrystallization rate measurement method of zirconium alloy cladding of a nuclear fuel rod, the method comprising:

irradiating SEM electron beams at a given scanning interval onto a completely recrystallized first specimen, a partially recrystallized second specimen to be measured for recrystallization rate, and an as-deformed third specimen which were electropolished and obtaining electron backscattered signals therefrom by an EBSD camera (step

     1);

converting the electron backscattered signals obtained from the first specimen to the third specimen into pattern quality values, respectively, by using an EBSD software and generating the pattern quality values as frequencies by a specified interval (step

     2);

obtaining pattern quality frequencies (B+D) deviated from the frequency distribution of the third specimen among a whole frequency distribution of the second specimen, and pattern quality frequencies (D+E) deviated from the frequency distribution of the third specimen among a whole frequency distribution of the first specimen (step

     3); and

obtaining the recrystallization rate of the second specimen with an equation of

2. The method of claim 1, wherein an area which SEM beams are entered into each of the first specimen to the third specimen in step 1 is 100 μ

m×

100 μ

m.

3. The method of claim 1, wherein the fixed scanning interval in step 1 is 200 to 300 nm.

4. The method of claim 1, wherein the interval of the pattern quality values in step 2 is 100 to 1,000.