초록 ▼

● 2012년 5차 campaign 동안 진공용기 bottom에 설치된 in-vessel cryo-pump의 임시 냉각라인을 이용하여 cryo-panel(4.5K)냉각을 수행함.
● 액체 질소로 냉각 되는 thermal shield 냉각라인을 수정하여 플라즈마 실험기간 동안 지속적으로 냉각함으로써 진공 용기 내부의 불순물을 효과적으로 제거 하여 플라즈마 발생 및 유지에 결정적인 역할을 수행하였음.
● In-vessel cryo-pump에 4.5 K 액체 헬륨을 공급하기 위하여 2006년 이후 가동 중지 되었던 ICC 사이

● 2012년 5차 campaign 동안 진공용기 bottom에 설치된 in-vessel cryo-pump의 임시 냉각라인을 이용하여 cryo-panel(4.5K)냉각을 수행함.
● 액체 질소로 냉각 되는 thermal shield 냉각라인을 수정하여 플라즈마 실험기간 동안 지속적으로 냉각함으로써 진공 용기 내부의 불순물을 효과적으로 제거 하여 플라즈마 발생 및 유지에 결정적인 역할을 수행하였음.
● In-vessel cryo-pump에 4.5 K 액체 헬륨을 공급하기 위하여 2006년 이후 가동 중지 되었던 ICC 사이트의 1 kW 헬륨 냉동기를 점검 및 보완 하였음.
● Active pumping을 위한 냉각 scheme과 향후 헬륨 ash 제거를 위하여 3.7K 헬륨 공급이 가능한 sub cooler 및 cold compressor 설계를 완료하였음.

Abstract ▼

Development of the in-vessel cryo-pump (IVCP) for the Korea Superconducting Tokamak Advanced Research (KSTAR) was launched in the middle of 2008 according to in-vessel component upgrade plan to enhance the plasma performance by exhausting neutral particle(H2, D2 and H/D ions). The basic study was pe

Development of the in-vessel cryo-pump (IVCP) for the Korea Superconducting Tokamak Advanced Research (KSTAR) was launched in the middle of 2008 according to in-vessel component upgrade plan to enhance the plasma performance by exhausting neutral particle(H2, D2 and H/D ions). The basic study was performed for optimization of the number of pump and configuration in the vacuum vessel based on the cryo-condensation pump of the DIII-D. Various researches continuously implemented to find the operating requirements and cooling scheme using liquid helium. Finally, the engineering design was terminated in early 2009, which was followed by subsequent fabrication, and installation of the IVCP in the vacuum vessel by early start of 2010. Two IVCPs were installed behind outboard divertor both at top and at bottom sides of the vacuum vessel (r=2,000 mm, z=±1,395 mm) with up-down symmetry, and were supported by the 16 vertical and radial supports in every 22.5 degree. The IVCPs were designed to have a pumping speed of 25,000 l/sec per each, and throughput of 20 torr l/sec at 1 mbar. For the effective exhaust of the neutral particle, the cryo-panel is operated below 4.5 K with two phase helium and the inner/outer thermal shield is operated with liquid nitrogen to minimize heat load from the high temperature vacuum vessel. The cool down of the lower IVCP was started using the temporary coolant supply system since 2011. During the 5th campaign, the lower IVCP thermal shield was operated in order to reduce the hydro-impurity in the vacuum vessel from Sep. 20th in 2012. Consequentially, H2O residual pressure was reduced effectively below 2.03x10^-9 mbar from 4.62x10^-8 mbar and plasma start-up was enhanced. Thus, temporary liquid nitrogen supply line was modified to continuous cool down during plasma experiment and it was operated for 43 days during 5th campaign.
To analysis of IVCP cool down and warm up property, the cryo-panel was operated by using liquid He dewar(1000lter).
For the stable supply of the liquid helium during the plasma experiment, a helium refrigeration system is required. Thus, the 1 kW helium refrigeration system (HRS) should be conditioning for re-operation because it had been used to supply supercritical helium for the KSTAR SC model coil test and had been shut down for 5 years since 2007. The conditioning of the compressor system, oil removal system, cold box, and utility systems was carried out as following procedure. The compressor system is made as a package design with a compressor, an electrical motor and its control panel. At first, bearings of the electric motor were replaced and the motor was tested without connection of compressor. And the test of the helium compressor was performed after replacing of Breox oil and other consumables. Impurities in the cold box should be removed because it operates in cryogenic temperature. The test of cold box was performed after the conditioning of helium process circuits and replacing of the vacuum pump lubricant. As a result of the performance test, the LHe production rate was 250 liter/hr during the nominal operation mode and 150 liter/hr during the impure helium recovery operation mode.

목차 Contents

• 표지 ... 1
• 제 출 문 ... 2
• 보고서 요약서 ... 3
• 요 약 문 ... 4
• SUMMARY ... 7
• CONTENTS ... 9
• 목 차 ... 10
• 제1장 연구과제의 개요 ... 11
• 제1절 연구개발의 필요성 ... 11
• 제2절 연구개발의 목적 ... 11
• 제3절 연구개발이 범위 ... 12
• 제2장 국내외 기술개발 현황 ... 13
• 제1절 국외 연구동향 ... 13
• 제2절 국내 연구동향 ... 15
• 제3장 연구개발내용 및 결과 ... 17
• 제1절 In-vessel cryo-pump 헬륨 생산 시스템 점검 ... 18
• 1. 개 요 ... 18
• 2. 유지보수 ... 22
• 3. 시스템 Conditioning ... 31
• 4. 시 운전 ... 40
• 5. 시 운전 결과 ... 45
• 6. 팽창 터빈 내부 구조 비교 분석 ... 50
• 제2절 In-vessel cryo-pump 냉매 분배 시스템 ... 56
• 제3절 2012년도 운전 결과 ... 62
• 1. 액체 질소 라인 수정 ... 62
• 2. 진공배기 결과 ... 63
• 3. 냉각 결과 ... 64
• 4. ICP의 Thermal shield 냉각 ... 64
• 제4장 목표 달성도 및 관련 분야에의 기여도 ... 66
• 제5장 연구개발결과의 활용 계획 ... 67
• 제6장 참고문헌 ... 67
• 부록1 국내 및 국외 학술회의 발표 자료 ... 69
• 부록2 1 kW HRS P&ID_Compressor ... 69
• 부록3 1kW HRS P&ID_Cold Box #1 & Purifier ... 70
• 부록4 1kW HRS P&ID_Cold Box #2 ... 71
• 부록5 저널 게제 논문 ... 72