Translated by ChatGPT, edited by Sinocism.com.

Source: Study Times | Author: Peng Xianjue (彭先觉), member of the Chinese Academy of Engineering and expert in nuclear physics and nuclear energy | October 21, 2026

Peng Xianjue is an expert in nuclear physics and nuclear energy who was elected a member of the Chinese Academy of Engineering in 1999. He formerly served as director of the Science and Technology Committee of the China Academy of Engineering Physics, director of the National Expert Committee on Magnetic Confinement Fusion, and vice president of the Chinese Nuclear Society. He has long conducted theoretical research and design on nuclear weapons and made important contributions to bringing the design level of China's nuclear weapons into the world's advanced ranks on major indicators. In 2008, he originated the concept of the Z-pinch fusion-fission hybrid reactor (Z-FFR). He has received four first prizes, two second prizes, and two third prizes of the State Science and Technology Progress Award.

彭先觉，原子核物理学与核能专家。1999年当选为中国工程院院士。曾任中国工程物理研究院科技委主任，国家磁约束聚变专家委员会主任，中国核学会副理事长。长期从事核武器理论研究和设计，为我国核武器设计水平在主要指标上进入世界先进行列作出了重要的贡献。2008年，原创性提出Z箍缩聚变裂变混合堆（Z-FFR）概念。曾荣获国家科技进步奖一等奖4项、二等奖2项、三等奖2项。

Energy is the most important material foundation for human survival and development. Obtaining clean, economical, convenient, and lasting energy is an important goal toward which countries around the world are striving. Among future energy sources, the development and application of fusion energy has particular importance. China has included the development of fusion energy science and technology in its national long-term plan and 15th Five-Year Plan, striving to take the destiny of future energy into its own hands.

能源是人类生存发展最重要的物质基础。获得清洁、经济、便利、持久能源，是当前世界各国为之努力奋斗的重要目标。在未来能源中，聚变能的开发应用有着特别重要的意义。我国已把发展聚变能源科学技术列入国家长期规划和“十五五”规划之中，力争把未来能源的命运掌握在自己的手中。

Basic principles of nuclear fusion

核聚变的基本原理

Nuclear energy includes nuclear fission and nuclear fusion. Nuclear fission is the splitting of one heavy atomic nucleus into two or more medium-mass nuclei, while nuclear fusion combines two light nuclei into one heavier nucleus. Whether in nuclear fission or fusion, the energy comes from a loss of mass before and after the nuclear reaction. According to Einstein's mass-energy relation, the conversion of this mass contains enormous energy.

核能包括核裂变与核聚变。核裂变是1个重的原子核分裂成2个以上中等质量原子核，而核聚变是2个轻原子核结合成1个较重原子核。不论是核裂变还是核聚变，其能量来源都是核反应前后发生了质量亏损，按照爱因斯坦的质能关系式，这些质量转换蕴含着巨大能量。

The conditions required for nuclear fusion are extremely demanding, mainly because powerful Coulomb repulsion exists between atomic nuclei. The nuclei participating in the reaction must have enough kinetic energy to approach one another and create an opportunity for fusion to occur. Generally, only light nuclei with very small atomic numbers have a relatively high probability of such a reaction. For example, fusion between the hydrogen isotopes deuterium and tritium is the easiest fusion reaction to achieve and is therefore a focus of scientific research. The main way to increase the probability of fusion is to heat deuterium-tritium fuel to temperatures above 100 million degrees. At that point the fuel is in a plasma state, and large numbers of nuclei increase the opportunity for reactions through random collisions. Nuclear fusion is therefore also called a thermonuclear reaction. Familiar names such as thermonuclear weapons (hydrogen bombs) and the International Thermonuclear Experimental Reactor (ITER) derive from this.

核聚变发生的条件非常苛刻，主要原因是原子核间存在强大的库仑斥力，参加反应的原子核必须具有足够的动能才能彼此靠近，从而有机会发生聚变反应。通常只有原子序数很小的轻核才有较大的概率发生此类反应。例如，氢的同位素氘和氚之间的聚变反应是最容易发生的，也是科学家研究的重点。增加聚变反应概率的主要方法是把氘氚燃料加热至上亿度的高温，此时燃料处于等离子体状态，大量原子核通过无规则碰撞增加反应机会，故核聚变反应又称热核反应。大家熟知的热核武器（氢弹），国际热核聚变实验堆（ITER）等名称都是由此而来。

For a fusion energy system, the first concern is energy gain. The ratio of energy released by fusion to external energy input is generally called scientific fusion gain. Going a step further, the ratio of electrical energy generated by fusion to external electrical energy input is called engineering fusion gain. There is also the more intuitive concept of “ignition,” like a match lighting a torch. It refers to a state in which, after external auxiliary measures are removed, energy released by thermonuclear reactions alone maintains or continuously raises the system's temperature and the fusion reaction becomes self-sustaining. The well-known historic breakthrough in “ignition” achieved by the US National Ignition Facility (NIF) at the end of 2022, for example, reached a scientific fusion gain of 1.5.

对于一个聚变能源系统，我们首先关心的是能量增益问题。通常把聚变释放的能量与外界输入的能量之比叫做聚变科学增益。进一步，聚变发出的电能与外界输入的电能之比叫聚变工程增益。还有一个形象化的概念是“点火”，犹如火柴点燃火把。它指的是外界辅助手段撤销后，仅依靠热核反应放能使系统温度维持不变或持续上升，聚变反应得以自持进行的状态。比如，我们熟知的美国国家点火装置（NIF）2022年底实现“点火”的历史性突破，聚变科学增益达到1.5。

Main technological paths for controlled nuclear fusion

可控核聚变的主要技术路线

There are two main routes for achieving artificial controlled nuclear fusion on Earth: inertial-confinement fusion and magnetic-confinement fusion. Some approaches lie between the two, known as magneto-inertial confinement, but these can be placed into the first two categories according to their principal characteristics.

在地球上实现人工可控核聚变途径主要有惯性约束聚变和磁约束聚变两类。也有一些途径介于二者之间，即所谓的磁惯性约束，但可依据其主要特征归入前面两类。

First is inertial-confinement fusion. It uses energy supplied by a driver to implode and compress a pellet containing deuterium-tritium fuel, bringing it to high temperature and high density and thereby into a state of ignition and self-sustaining burn. Constrained by the inertia of its high-speed inward motion, the fuel releases sufficient energy before it has time to disperse significantly. The entire process is completed on a nanosecond timescale. Inertial-confinement fusion operates in pulses, with each pellet releasing energy equivalent to a miniature hydrogen-bomb explosion. By controlling the scale and frequency of energy release and through the design of the target chamber and blanket, the system can operate safely on a quasi-continuous basis. Our research shows that to achieve fusion energy release on the gigajoule scale, a driver must deliver more than 10 megajoules of energy to the pellet in roughly 10 nanoseconds. At present, only Z-pinch electromagnetic drivers and lasers possess this capability. Laser-fusion technology is used primarily in weapons physics and high-energy-density physics research and, in principle, does not support energy applications. Z-pinch driver technology is straightforward, inexpensive, abundant in energy, highly efficient in conversion, and has the potential for long-lifetime repetitive operation. It is better suited for development into fusion-fission hybrid energy, enhancing overall competitiveness.