핵동력 우주추진 기술개발 동향

박홍영,강윤형,김정수,양수석 한국추진공학회 2022 한국추진공학회지 Vol.26 No.6

핵추진 시스템의 개념 및 특징들을 소개하고 해외 핵동력 우주추진 기술개발 동향을 정리하였다. 핵추진 원료로 사용되는 우라늄은 비에너지가 매우 높아 기존 화학추진방식 대비 우수한 비추력 성능을 내고, 탑재되는 연료의 양을 줄일 수 있어 장거리 탐사 시 매우 유리한 이점을 가지고 있다. 이러한 이유로, 최근 우주개발 선도국에서 핵추진 기술 연구에 박차를 가하고 있는바, 우주개발 경쟁에서의 우위를 점하기 위해서도 핵동력을 이용한 추진기관의 개발이 반드시 필요하다고 판단된다. In this paper, the concept and characteristics of the nuclear propulsion system were introduced and the state of the art for the nuclear-powered space propulsion in abroad were summarized. Since uranium used in nuclear propulsion has a very high energy density per unit mass, it has exceptional specific impulse performance compared to the existing chemical propulsion method and can reduce the amount of fuel loaded, thereby having advantage for long-distance exploration. For this reason, advanced countries in space development are recently spurring to the research of nuclear propulsion technology, and it is judged that the development of a propulsion engine using nuclear power is absolutely necessary in order to gain an competitive edge on the space development.

A Study on the Nuclear Powered Vessels

( Kwi Joo Lee ),( Jung Sun An ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.2

The concept of nuclear-powered merchant ships has been blooming in the naval architecture community for more than four decades now. But the recent developments in commercial shipping include bigger, faster and more powerful ships, where nuclear propulsion may prove an option worth considering. The development of advanced ship deigns along with the nuclear power opens an opportunity for high-speed maritime transportation that could create new markets and recover a fraction of the high value goods currently shipped only by air. Despite perceived hazards, inherently safe nuclear propulsion plants can be deigned for next generation merchant ships employing the newest technology. Combining an existing and well proven gas turbine plus heat exchangers with inherently safe nuclear technology for energy conversion promises a viable alternative propulsion solution for various tonnage typed vessels. This paper is an effort to reveal the advantageous position of nuclear propulsion over conventional propulsion methods for merchant vessels.

미해군 원자력추진 프로그램으로부터 얻은 미래 원자력추진 잠수함 확보를 위한 기술 및 정책적 교훈

박진원(Jin-Won Park) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.9

지난 2000년대 초 우리 정부는 원자력추진 잠수함을 전략자산으로 확보하고자 하는 첫 시도를 한 바 있다. 원자력추진 잠수함의 획득은 척당 수조 원대에 이르는 초기획득비와 막대한 연간 운영비, 주변국을 포함한 국제사회의 동의, 전 국민적 합의, 전문인력 양성을 포함한 기술인프라 조성 등의 도전을 극복해야 한다. 미 해군은 1950년대부터 에너지부 중심의 정부 부처와 공동으로 원자력추진 함정의 획득을 위해 노력 해왔으며, 1982년에는 그동안의 노력을 통합하고 미래를 준비하기 위해 미 해군 원자력추진프로그램이라는 행정명령을 제정한 바 있다. 미 해군 원자력추진프로그램은 미 정부 내 원자력과 관련된 에너지부와 미 해군의 조직 구성, 관리자의 권한과 책임 등에 관해 규정하고 있으며, 관련된 전 국가적 노력을 통합하고 있다. 본 논문은 미 해군 원자력추진 프로그램의 구성과 성과를 분석하여 우리의 미래를 준비하기 위한 타산지석의 귀중한 지혜를 얻고자 작성되었다. 국력이나 군사력의 규모가 달라 일대일로 추종할 수는 없지만 그들의 과거와 현재를 잘 참고한다면 최소한 그들이 겪었을 시행착오에 투입한 노력과 시간만큼은 단축할 수 있을 것이다. In the early 2000s, the Korean government first attempted to acquire nuclear-powered submarines as strategic assets. Acquisition of nuclear-powered submarines must overcome the challenges of the initial costs and operating costs of trillions of US dollars per ship, must be agreed to by the international community (including neighboring countries) and in a national consensus, and must have an established technical infrastructure (including manpower). The US navy has been working with governments that want to acquire nuclear propulsion warships since the 1950s, and in 1982, they enacted an executive order called the United States Naval Nuclear Propulsion Program to consolidate efforts and prepare for the future, which sets out the organizational structure, authority, and responsibilities of US governmental management, and integrates national efforts. This paper is to gain valuable wisdom from the U.S. Naval Nuclear Propulsion Program by analyzing all of its histories and contributions, thereby providing valuable lessons for a future program in Korea. It might not be possible to follow the U.S.A. one-on-one because of the scale of national and military forces, but at least we can avoid time and effort spent on trial and error.

원자력 우주추진 기술 고찰

조남경(Namkyung Cho),양수석(Sooseok Yang) 한국추진공학회 2023 한국추진공학회지 Vol.27 No.5

Nuclear space propulsion has the advantage of superior specific impulse compared to the currently widely used chemical propulsion, the system can be simplified by omitting the oxidizer system, and has the ability to improve performance in the future. The high specific impulse makes missions that are only possible with large chemical propulsion launch vehicles possible with medium-sized launch vehicles. This paper describes the characteristics of nuclear propulsion that are different from chemical propulsion and introduces the nuclear propulsion system and key components. Nuclear thermal propulsion and electric propulsion, and a bimodal system and a hybrid system that combines chemical propulsion and nuclear propulsion are introduced. Also, the development aspects of nuclear propulsion as well as test facility and launch safety of the nuclear power propulsion system are discussed.

The importance of nuclear energy for the expansion of world's energy demand

Guk, Erdogan,Kalkan, Naci Techno-Press 2015 Advances in energy research Vol.3 No.2

This paper describes nuclear energy technologies for the solution of long term energy problem with better reliability. A short overview about nuclear energy applications are explained with a basic analysis of energy. Furthermore, industrial application, space application of nuclear systems and ship propulsion in nuclear energy application are demonstrated in more detail. This report also includes some examples of the experienced nuclear power plant to identify energy production. The general purpose of the article is to understand how efficiently nuclear systems generates energy, and solve the world's increasing energy demand in our century.

INNOVATIVE CONCEPT FOR AN ULTRA-SMALL NUCLEAR THERMAL ROCKET UTILIZING A NEW MODERATED REACTOR

남승현,PAOLO VENNERI,김용희,이정익,장순흥,정용훈 한국원자력학회 2015 Nuclear Engineering and Technology Vol.47 No.6

Although the harsh space environment imposes many severe challenges to space pioneers,space exploration is a realistic and profitable goal for long-term humanity survival. One ofthe viable and promising options to overcome the harsh environment of space is nuclearpropulsion. Particularly, the Nuclear Thermal Rocket (NTR) is a leading candidate for neartermhuman missions to Mars and beyond due to its relatively high thrust and efficiency. Traditional NTR designs use typically high power reactors with fast or epithermal neutronspectrums to simplify core design and to maximize thrust. In parallel there are a series ofnew NTR designs with lower thrust and higher efficiency, designed to enhance missionversatility and safety through the use of redundant engines (when used in a clusteredengine arrangement) for future commercialization. This paper proposes a new NTR designof the second design philosophy, Korea Advanced NUclear Thermal Engine Rocket(KANUTER), for future space applications. The KANUTER consists of an Extremely HighTemperature Gas cooled Reactor (EHTGR) utilizing hydrogen propellant, a propulsion system,and an optional electricity generation system to provide propulsion as well as electricitygeneration. The innovatively small engine has the characteristics of high efficiency,being compact and lightweight, and bimodal capability. The notable characteristics resultfrom the moderated EHTGR design, uniquely utilizing the integrated fuel element with anultra heat-resistant carbide fuel, an efficient metal hydride moderator, protectively coolingchannels and an individual pressure tube in an all-in-one package. The EHTGR can bebimodally operated in a propulsion mode of 100 MWth and an electricity generation modeof 100 kWth, equipped with a dynamic energy conversion system. To investigate the designfeatures of the new reactor and to estimate referential engine performance, a preliminarydesign study in terms of neutronics and thermohydraulics was carried out. The resultindicates that the innovative design has great potential for high propellant efficiency andthrust-to-weight of engine ratio, compared with the existing NTR designs. However, thebuild-up of fission products in fuel has a significant impact on the bimodal operation of the moderated reactor such as xenon-induced dead time. This issue can be overcome bybuilding in excess reactivity and control margin for the reactor design.

Flow Network Modelling of a Nuclear Reactor Rocket

Vincent Britz,Bennie Du Toit,전형택 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12

Nuclear thermal propulsion (NTP) has been identified as the preferred propulsion technology for manned missions to Mars in NASA"s Design Reference Architecture (DRA) [1]. The ability to predict the system performance of a nuclear reactor rocket under a variety of operating conditions is a critical part in the development of NTP. The development of system models has the potential to reduce the design, testing, time and cost required to reach flight-ready status. In this study a commercial flow network tool, Flownex®, was used in the development of a system model to model a nuclear reactor rocket. The integrated mass, momentum and energy balance is solved using the continuity, momentum and energy equations applied to nodes and elements. These nodes and elements are the modular building blocks, typically semi-empirical and allow users to either select appropriate built-in correlations, or to define using specific equations through scripting. By using Flownex®, a nuclear reactor rocket could be modeled and various operating conditions could be investigated during steady-state and transient simulations.

500 kW 원자력 전기추진 시스템의 브레이튼 사이클 개념설계 및 해석

양수석,조남경 한국추진공학회 2024 한국추진공학회지 Vol.28 No.1

우주의 영역이 점차 확대되어 가고 있으며, 화성을 비롯한 태양계의 행성에 대한 유무인 탐사도 점차 많아질 것으로 예상된다. 이에 따라 화성 유인 탐사를 위하여 기존의 추진기관과는 다른 개념의 추진기관들이 연구되고 있다. 본 연구는 10톤 이상의 유무인 화성탐사선의 추진기관으로 사용 가능한 500 kW 원자력 전기추진 시스템의 브레이튼 사이클에 대한 개념설계 및 해석 결과이다. 원자로는 열용량 1511 kW의 UC계열 저농축 핵연료를 사용한다. 시스템의 효율 향상을 위하여 리쿠페레이터를 사용하여 시스템 내부에서 열 교환이 일어나며, 시스템의 열을 외부로 추출하기 위하여 가스 쿨러가 사용된다. 또한 시스템 외부로 추출된 열은 래디에이터를 통하여 우주로 방출된다. 500 kW의 전기를 생산하기 위하여 구심터빈과 원심압축기가 사용되며, 시스템의 작동유체는 헬륨-제논 혼합 기체를 사용한다. 시스템 해석 결과 브레이튼 사이클의 열효율은 33%, 래디에이터의 필요 면적은 390 m2로 계산된다. The realm of space is gradually expanding, so manned and unmanned exploration of planets in the solar system, including Mars, is expected to increase. Accordingly, the innovative propulsion systems with a different concept from existing propulsion engines are being studied for manned exploration of Mars. This study is the result of the conceptual design and analysis of the Brayton cycle of a 500 kW nuclear electric propulsion system that can be used for a manned or unmanned Mars exploration vehicle weighing more than 10 tons. The reactor uses UC series low-enriched nuclear fuel of 1511 kW thermal power. To improve system efficiency, heat exchange using a recuperator occurs inside the system, and a gas cooler is used to extract heat, from the system to the outside, which is emitted into space through radiators. A radial turbine and centrifugal compressor are used to produce 500 kW of electricity, and a helium-xenon mixture gas is used as the working fluid of system. As a result of system analysis, the thermal efficiency of the Brayton cycle is calculated to be 33%, and the required surface area of radiators is calculated to be 390 m2.

Design and transient analysis of a compact and long-term-operable passive residual heat removal system

박우성,유용환,강경준,정용훈 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.12

Nuclear marine propulsion has been emerging as a next generation carbon-free power source, for which proper passive residual heat removal systems (PRHRSs) are needed for long-term safety. In particular, the characteristics of unlimited operation time and compact design are crucial in maritime applications due to the difficulties of safety aids and limited space. Accordingly, a compact and long-term-operable PRHRS has been proposed with the key design concept of using both air cooling and seawater cooling in tandem. To confirm its feasibility, this study conducted system design and a transient analysis in an accident scenario. Design results indicate that seawater cooling can considerably reduce the overall system size, and thus the compact and long-term-operable PRHRS can be realized. Regarding the transient analysis, the Multi-dimensional Analysis of Reactor Safety (MARS-KS) code was used to analyze the system behavior under a station blackout condition. Results show that the proposed design can satisfy the design requirements with a sufficient margin: the coolant temperature reached the safe shutdown condition within 36 h, and the maximum cooling rate did not exceed 40 ◦C/h. Lastly, it was assessed that both air cooling and seawater cooling are necessary for achieving long-term operation and compact design.

Bimodal 방식 원자력 추진기관 고찰

조남경(Nam Kyung Cho),양수석(Su Seok Yang) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.4