In 1982, Wang and his colleagues began to research Low Temperature NHRs. It was his wish that any reactor they developed should not only be safe, but also able to generate district heating to help solve China's energy problems. The team spent a year discussing proposals, visiting and investigating different types of heating reactors in Europe, before finalizing their own design.

Their 5MW Nuclear Heating Reactor (NHR-5) went into operation in 1989. Low temperature, low pressure and low power density, it featured a natural circulation mechanism to remove residual heat, as well as the hydraulic-driven design of control rods. Many key technological breakthroughs were made.

The NHR-5 is considered to be forward-looking, as using natural circulation in a water-cooled nuclear energy system later became one of the main technological trends of the 21st century. The project also won first prize of China's State Scientific and Technological Progress Award in 1992.

In 1981, Wang was working at Germany's Juelich Nuclear Research Centre as a visiting scholar, when he came across the modular High Temperature Gas-Cooled Reactor (HTGR), a newly developed concept proposed primarily in Germany, which was based on the lessons learned from the Three Mile Island accident. It was designed to eliminate the possibility of a core meltdown.

In 1982, he returned to China and was appointed deputy director of the Institute of Nuclear Energy Technology at Tsinghua University. While developing the Low Temperature NHR, he also began to plan development of an HTGR.

Wang decided to focus on a modular reactor based on "pebble bed technology", which uses spherical fuel elements known as "pebbles". The pebbles are piled up to form a bed, which serves as the reactor core.

Between 1987 and 1990, Wang and his team made important breakthroughs in key technologies related to helium coolants and fuel elements. In 1992, the State Council approved the building of an experimental 10MW HTGR at Tsinghua University. The reactor reached criticality in 2000 and full power operation in 2003. Its completion ushered in a new generation of nuclear energy systems that effectively eliminate the possibility of reactor core meltdown.

At the first session of the 10th National People's Congress, the HTGR was introduced in the 2003 Government Work Report as one of the four major scientific and technological achievements influencing the world. It also won Wang first prize in the State Scientific and Technological Progress Award again in 2006.

He Jiankun, former Tsinghua executive vice-president, said Wang's scientific achievements have paved the way for clean energy as China strives to become carbon neutral.

He said that nuclear power emits zero carbon and can ensure the safe and stable operation of the power grid. Being inherently safe, Modular HTGR can also generate hydrogen while producing electricity, which can be used to replace fossil fuels as a heat source.