초록 ▼

- 전열관 곡관부 형상변화 측정용 신형 와전류 탐촉자 검사기술 세계 최초로 개발
- 실측치 대비 측정오차 ±0.05 mm 이내의 우수한 형상측정 정밀도 확인 및 검증
- 곡관부 축방향 자연균열 제어 제작기술을 국내 최초로 개발
- 곡관부 내면결함 검출에 최적화된 와전류 검사코일 설계 및 특성 검증 완료
- 전열관 곡관부 결함 조기검출용 신형 와전류 탐촉자 시제품 설계 및 제작완료
- 결함 검출능이 기존 대비 약 35% 향상된 우수한 조기진단 성능 달성
- 곡관부 형상/결함 동시 측정용 와전류 탐촉자

- 전열관 곡관부 형상변화 측정용 신형 와전류 탐촉자 검사기술 세계 최초로 개발
- 실측치 대비 측정오차 ±0.05 mm 이내의 우수한 형상측정 정밀도 확인 및 검증
- 곡관부 축방향 자연균열 제어 제작기술을 국내 최초로 개발
- 곡관부 내면결함 검출에 최적화된 와전류 검사코일 설계 및 특성 검증 완료
- 전열관 곡관부 결함 조기검출용 신형 와전류 탐촉자 시제품 설계 및 제작완료
- 결함 검출능이 기존 대비 약 35% 향상된 우수한 조기진단 성능 달성
- 곡관부 형상/결함 동시 측정용 와전류 탐촉자 코일/구조 설계요건 최적화 완료
- 최적화 설계반영 곡관부 정밀진단용 신형 와전류 탐촉자 시제품 2종 제작 성공
- 비선형 초음파 신호처리용 웨이브렛 변환 프로그램 개발 완료
- 피로 자연균열의 비선형 초음파 영상 생성 및 신뢰성 확보
- 비선형초음파 공명신호 수집 및 분석시스템 구축 완료
- 비선형 충격음향 결함진단시스템 제작, 충격파형에 의한 비선형성을 입증
- 매설배관을 모사한 직경 2.5 및 6 인치 장거리 매설배관 목업 설계 및 제작 완료
- 탈부착이 가능한 유도초음파 발생용 자기변형 밴드 시제품 제작 완료
- 매설배관 목업에 대해 자기 바이어스 감도 및 초음파 에너지 감쇄 특성자료 생산
- 매설배관 검사시 비틀림 진동 T(0, n) 모드가 가장 유리한 최적 조건임을 판명

(출처 : 보고서 요약서 3p)

Abstract ▼

Ⅳ. Results of the project

1. Development of technology for simultaneous diagnosis of geometry and defect in u-bend region of steam generator tube

(1) Detailed design of coil and probe body for profilometry of u-bend region

Two types of probe for profilometry were designed consid

Ⅳ. Results of the project

1. Development of technology for simultaneous diagnosis of geometry and defect in u-bend region of steam generator tube

(1) Detailed design of coil and probe body for profilometry of u-bend region

Two types of probe for profilometry were designed considering various radius of u-bends in steam generator tubes of Korean Standard Nuclear Power Plants (KSNP). The probe was designed to rotate and move along the tube. The diameter of the coil unit was determined from the real value of tube ovality in u-bend region, and the centering feet were designed into two type considering the radius of u-bends. Two profilomety coils were arranged to have an angle of 90 degrees to measure the absolute and differential values of ovality simultaneously.

(2) Manufacture of prototype probe for profilometry and performance test

Three types of protype probes were manufactured to inspect the low radius u-type tubes and high radius square type tubes in KSNP steam generators. The calibration process and standard tube for converting the eddy current signal to the quantitative radius value were developed. The performance test showed that the probe had an excellent measuring accuracy of ±0.05 mm, compared to the real measured values.

(3) Development of technology for improvement of defect detectability in u-bend region

Row-1 u-bend tubes with radius of 3 inches were manufactured with the same bending process applied to the manufacturing of KSNP steam generator tubes. Technology of manufacturing and control of natural crack in the u-bend tube were successfully developed and the applicability of the technique was verified by comparing the similarity of signals from the real plant cracks and the simulated cracks.

(4) Design improvement of coil and probe body for defect detection in u-bend region

By comparing the sensitivity of signal amplitude with test frequency for the standard tube of notches, the improved design of test coil having best detection capability for the inner surface defect in u-bend region was developed. Also the test coils were manufactured according to the improved design, and it was confirmed that the performance of the coil meet the design target.

(5) Manufacture of prototype probe for defect detection and performance test

The prototype probes for optimized defect detection in u-bend region were manufactured and the signal to noise ratio was evaluated for the tubes with natural cracks. For the same size of small crack, the prototype probe was verified to have an excellent detectability, which is 35% higher than that of the commercially used probes.

(6) Optimization of probe design requirements for simultaneous diagnosis of geometry and defect in u-bend region

The manufacturing requirements of probe for simultaneous diagnosis of geometry and defect in u-bend region was optimized and two type of probes for earlier detection and root cause analysis were finally designed reflecting the optimized requirements.

(7) Manufacture of optimized prototype probe (U-Probe)

Based on the probe design diagrams with optimized requirements, two type of prototype probes for simultaneous diagnosis of geometry and defect in u-bend region were successfully manufactured. For the preliminary performance test, the probe was applied to the u-tube specimens of KSNP steam generators, and the repeatability and applicability of the probe were verified with the results that the signal from the coil for defect detection meet the design target. The coil for the profilometry is under revision in the manufacturing process.

2. Development of nonlinear ultrasonic diagnostic technology for pipe and welds

(1) Development of nonlinear ultrasonic signal processing techniques

Nonlinear signal characteristics were clearly extracted by applying a non-stationary signal same as nonlinear ultrasonic signals.

(2) Development of imaging techniques for nonlinear ultrasonic signals

Establishment of nonlinear ultrasonic system including high power ultrasound generation, laser acquisition equipment for higher harmonics signals, and scanning device, etc. Confirmation of the harmonics components in an ultrasonic signal. Increases of the higher harmonic amplitudes in the cracked area can be explained as the increase of nonlinear coefficients.

(3) Establishment of nonlinear ultrasonic system for micro-defect diagnosis

Completion of laser and piezoelectric signal acquisition and processing system for ultrasonic resonance pattern. Completion of a portable nonlinear impulse response acoustic spectroscopy system with a laser vibrometer and impact hammer and confirmation of the crack detection capability.

(4) Evaluation of nonlinear ultrasonic defect signals

A nonlinear ultrasonic resonance system is assembled with a laser doppler vibrometer. Relative differences in the signal amplitude were extracted in the time domain. Impulse energy were generated by an impact hammer and signals were detected by a laser vibrometer. An acoustic nonlinearity was confirmed by the variation of resonance spectrum by a variation of impulse energy with an impact hammer.

3. Development of guide wave diagnosis system for long range buried pipe

(1) Manufacture a magnetostrictive band for generation of guided waves

Long range buried pipe mockup facilities with the pipe diameter of 2.5 inch and 6 inch were designed and fabricated. Test product of a magnetostrictive band for generation of guided wave were fabricated. The magnetostrictive band can be bonded and de-bonded to the pipe easily. Data for the magnetic bias sensitivity and ultrasonic attenuation were produced.

(2) Guided wave mode analysis for defect detection in a buried pipe

In order to set optimized condition for guided wave inspection of buried pipe, the dispersion curves of phase velocity and group velocity were modeled. Based on the dispersion curves, the degree of acoustic attenuations were expected by analysing the displacement vectors for each vibration modes on the outer surface of the buried pipe. Torsion vibration mode T(0, 1) is chosen because only circumferential displacements are present and the no radial and axial displacement are present in the mode.

(출처 : SUMMARY 12p)

목차 Contents

• 표지 ... 1
• 제 출 문 ... 2
• 보고서 요약서 ... 3
• 요 약 문 ... 4
• SUMMARY ... 10
• CONTENTS ... 17
• 목차 ... 19
• 표목차 ... 23
• 그림목차 ... 24
• 제 1 장 연구개발과제의 개요 ... 29
• 제 1 절 연구개발의 목적 ... 29
• 제 2 절 연구개발의 필요성 ... 29
• 제 3 절 연구개발의 내용 및 범위 ... 31
• 제 2 장 국내외 기술개발 현황 ... 32
• 제 1 절 국내 기술개발 현황 ... 32
• 제 2 절 국외 기술개발 현황 ... 34
• 제 3 절 연구결과의 위치 및 수준 ... 36
• 제 3 장 연구개발수행 내용 및 결과 ... 37
• 제 1 절 증기발생기 전열관 곡관부 형상 및 결함 동시 진단 신기술 개발 ... 37
• 1. 곡관부 형상검사 코일 및 구조 상세설계 ... 37
• 2. 탐촉자 1차 시제품 제작 및 성능평가 ... 42
• 3. 전열관 곡관부 결함 검출특성 향상 기술개발 ... 47
• 4. 곡관부 결함 검사 코일 및 구조 설계개선 ... 50
• 5. 탐촉자 2차 시제품 제작 및 성능 평가 ... 52
• 6. 형상/결함 동시 진단용 탐촉자 요건 최적화 ... 55
• 7. 최적화 탐촉자(U-Probe) 시제품 제작 ... 61
• 제 2 절. 배관 및 용접부 비선형 초음파 진단기술 개발 ... 70
• 1. 비선형 초음파 신호처리 기술 개발 ... 70
• 2. 초음파 결함신호 영상화 기술 개발 ... 72
• 3. 비선형 초음파 미세결함 진단 시스템 구축 ... 80
• 4. 비선형 초음파 결함탐지 성능 평가 ... 85
• 제 3 절. 매설배관용 장거리 유도초음파 진단장치 제작 ... 95
• 1. 유도초음파 발생용 자기변형 밴드 시제품 제작 ... 95
• 2. 매설배관 결함탐지를 위한 유도초음파 모드 해석 ... 103
• 제 4 장 목표 달성도 및 관련분야에의 기여도 ... 118
• 제 1 절 연구개발 목표의 달성도 ... 118
• 제 2 절 관련분야에의 기여도 ... 122
• 제 5 장 연구개발 결과의 활용계획 ... 126
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 127
• 제 7 장 참고문헌 ... 128
• 끝페이지 ... 128