• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.65-70
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• 1996

중수로용 핵연료봉의 봉단마개 부위는 열.기계적 작용에 의해 핵연료봉 파손이 쉽게 발생할 수 있는 취약 부위로 알려져 있다. 따라서, 핵연료봉 설계시 봉단마개 부위의 열.기계적 거동을 해석하고, 이 결과를 설계에 반영하여 파손 가능성이 없음을 확인하여야 한다. 여기에서는 중수로용 개량 핵연료인 CANFLEX-NU 핵연료봉 봉단마개에서의 열.기계적 거동을 해석하였는데, 이 결과 CANFLEX-NU 핵연료봉은 출력이 매우 낮아서 열중성자속 집중을 고려하더라도 봉단마개 부위 건전성을 충분히 유지하는 것으로 나타났다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.687-692
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• 1995

중수로용 핵연료봉의 주요 파손부위는 피복관 원주방향 주름부위와 봉단마개-피복관 용접 부위로 알려져 있다. 중수로용 개량핵연료인 CANFLEX 핵연료 개발시, 이러한 핵연료봉 부위들에 대한 건전성이 입증되어야 한다. 이에따라 CANFLEX-NU 핵연료봉의 피복관 원주 방향 주름부위 및 피복관-봉단마개 용접부위에 대한 정상상태 운전시의 건전성을 평가한 결과, 정상상태 운전시는 핵연료봉의 건전성이 유지가 됨을 알 수 있었다.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.2
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• pp.85-91
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• 1998

In nuclear fuel manufacturing process, end-closure welding has long been recognized as requiring very high integrity. In this basic study, ECT(eddy current testing) method for end-closure welding has been developed to detect end cap weld discontinuities for nuclear fuel safety. In order to improve the inspection reliability, the maximum scanning speed and the maximum frequency is investigated for end-closure welding inspection. The bandpass filter(0-250Hz) is used for removing noise effects. This study shows that ECT method is effective and sensitive for the detection of small defect(0.35mm diameter).

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.262-266
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• 1998

하나로 핵연료의 피복관과 봉단마개 재료로 사용되는 Aluminum 1060의 전자빔 용접부의 비드 특성을 조사하기 위하여 bead-on-plate 용접을 하였다. 비드의 단면을 절단하여 가속전압, 빔 전류, 용접속도에 따른 비드의 폭과 용입 깊이의 변화를 측정하고 용접부에 발생한 용접결함을 관찰하였다. 실험결과 가속전압과 범 전류의 증가에 따라 용입 깊이는 직선 비례적으로 계속 증가하였지만 비드폭은 그 증가율이 감소하는 경향이었다. 용접속도의 증가에 따라서 비드 폭과 용입깊이는 감소하는 경향을 보였다. 또한 범 출력이 높은 용접부의 root부에 다수의 porosity 가 발생하는 것을 관찰 할 수 있었으며 핵연료 봉단 마개의 porosity와는 다른 것을 확인하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.279.2-279
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• 2002

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1377-1380
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• 2008

An irradiation test of a nuclear fuel rod having external and internal tube structure was planned for a performance. To establish fabrication process satisfying the requirements of irradiation test, micro-TIG welding system for fuel rods was developed, and preliminary welding experiments for optimizing process conditions of fuel rod was performed. Fuel rods with 15.9mm diameter and 0.57mm wall thickness of cladding tubes and end caps have been used and optimum conditions of endcap welding have been selected. In this experiment, the qualification test was performed by tensile tests, helium leak inspections, and metallography examinations to qualify the endcap welding procedure. The soundness of the welds quality of a dual cooled fuel rods has been confirmed by mechanical tests and microstructural examinations.

• Proceedings of the KWS Conference
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• 1996.05a
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• pp.219-222
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• 1996

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.85-86
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• 2012

• Journal of Welding and Joining
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• v.7 no.2
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• pp.60-69
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• 1989

The present study was aimed at investigating the effect of welding parameters such as welding current, electrode force(or squeeze force) and parts cleaning on the sound weld, and establishing the most reliable weld conditions for HWP(Heavy Water Reactor) fuel end capping with the resistance upset butt welding. Major results obtained are as follows. 1. The amount of sound weld was increased with increasing weld current(5.0-11KA) because the activated diffusion with increasing heat generation played an important role in eliminating the porosity and weld line in the weld interface. 2. It was found that weld current was not significantly influenced by the electrode force although the increase of it caused a slight increase of weld current and upset deformation. 3. Acetone rinsing before drying for the Zircaloy-4 end cap cleaning produced the reliable sound weld because it would remove the remaining solvent and surface films, and provided the uniform contact between the end cap and the tube. 4. The optimum welding conditions for fuel end capping by a resistance upset hytt welding are obtained as follows. weld current: 10-11KA, electrode force: 62-90KPa parts cleaning: vapor degreasing.rarw.water, acetone rinsing.rarw.drying.

• Journal of Welding and Joining
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• v.15 no.6
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• pp.85-95
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• 1997

This study is to investigate the optimum conditions of Nd:YAG laser beam welding for Zircaloy-4 end cap closure by optical fiber transmission. Laser welding parameters which affect the penetration depth and bead width were experimentally examined using the various beam radius by the beam quality analyzer, joint geometries of end cap and the laser parameters which mean pulse width, repetition rate and pulse energy. Also, an optimum welding speed and the effect of assistant gas with varying the flow rate of He were investigated. We found that the laser average power for the end cap welding will be 230W and rotation speed must not exceed 8 RPM, the best position of focus using optical fiber with 600.mu.m will be 2 to 3mm below the surface of the material.