KSTAR 해외 연구진 주목, KSTAR Overseas Researchers Attention

세계적인 우리 초전도핵융합연구장치 KSTAR가 해외 연구진으로부터 주목받고 있다. 한발 앞선 업그레이드, 우수한 성능에 힘입어 해외 실험 신청이 크게 늘었다.

한국핵융합에너지연구원(원장 오영국)에 따르면 오는 3월까지 진행되는 KSTAR 실험 캠페인에서 해외 제안으로 진행 중인 실험은 전체 87개 중 절반에 가까운 41개(약 47%)다.

이전보다 크게 늘었다. 마지막으로 외부 실험 제안을 받은 2022년에는 58개 실험 중 해외 건이 15개로 26%였다. 올해 수로는 3배 이상, 비율로는 2배 가까이 증가했다.


먼저 2023년 외부 실험 제안을 받지 않은 것이 적잖은 이유로 작용했다. 핵융합연은 2022년 장치 중심 '토카막' 진공용기 내부 '디버터(진공용기 위·아래 표면에서 플라즈마를 받아내는 부분)'를 탄소 소재에서 텅스텐으로 업그레이드했다.

이후 장치 안정화를 위해 2023년 캠페인에서는 외부 실험 제안을 받지 않았다. 당시 기회를 얻지 못한 해외 연구진이 이번에 KSTAR를 찾았다.

새로 갖춘 텅스텐 디버터도 인기 이유다. 텅스텐은 내열 특성이 뛰어날 뿐 아니라 핵융합 연료인 수소와 잘 반응하지 않아 탄소보다 월등하다. 텅스텐 디버터 설치는 세계 선도 사례로, 해외에서도 이목을 끌어 많은 실험 제안으로 이어졌다.

무엇보다 KSTAR의 특성·우수성이 가장 큰 인기 이유다. '초전도 토카막' 방식인 KSTAR는 초전도체를 쓰지 않는 장치보다 운전 시간이 몇 배 이상 길다. 통상 수십초 이상 장시간 플라즈마 방전 실험이 가능하다.

플라즈마 불안정성을 확인하려면 장시간 운전이 필수여서 KSTAR와 같은 초전도 토카막 장치를 찾을 수밖에 없다.

더욱이 KSTAR는 같은 방식인 중국 '이스트(EAST)', 프랑스 '웨스트(WEST)'보다 플라즈마 성능이 좋다.

정해진 자기장 압력으로 얼마나 큰 플라즈마 압력을 가둘 수 있는지 나타내는 비율인 '플라즈마 베타' 수치가 높다. 바꿔 말하면 KSTAR가 생성한 플라즈마 온도·밀도가 더 높다.

연구진은 해외에서의 인기가 고무적이라는 입장이다.

 

 

 

KSTAR, a global superconducting fusion research device, is attracting attention from overseas researchers. Thanks to the upgrade and excellent performance, applications for overseas tests have increased significantly.

According to the Korea Institute of Fusion Energy (Director Oh Young-guk), 41 out of 87 experiments (about 47%) are underway with overseas proposals in the KSTAR experiment campaign, which will run until March.

The figure has increased significantly from the previous one. In 2022, when an external test proposal was received, 15 out of 58 experiments were conducted overseas, accounting for 26%. The number has more than tripled this year, and the ratio has nearly doubled.


The fact that it did not receive an external test proposal for 2023 was one of the reasons. In 2022, the Nuclear Fusion Research Institute upgraded the device-oriented Tokamak vacuum container's "Diverter (the part that collects plasma from the upper and lower surfaces of the vacuum container) from carbon material to tungsten.

Later, in order to stabilize the device, the 2023 campaign did not receive any external experimental proposals. Overseas researchers who did not get the opportunity at the time visited KSTAR this time.

The new tungsten diverter is also popular. Tungsten is superior to carbon because it not only has excellent heat resistance properties but also does not react well with hydrogen, a fusion fuel. The installation of tungsten diverter is a leading example in the world, attracting attention from overseas as well, leading to many suggestions for experiments.

Above all, KSTAR's characteristics and excellence are the biggest reasons for its popularity. KSTAR, a "superconducting tokamak" method, operates several times longer than devices without superconductors. Usually, long plasma discharge experiments are possible for more than tens of seconds.

A long operation is essential to confirm plasma instability, so we have no choice but to find a superconducting tokamak device such as KSTAR.

Moreover, KSTAR has better plasma performance than China's "EAST" and France's "WEST," which are the same methods.

The plasma beta value, which is the ratio of how large plasma pressure can be trapped with a set magnetic field pressure, is high. In other words, the plasma temperature and density produced by KSTAR are higher.

The researchers say their popularity abroad is encouraging.