Unit 1 of a new high-temperature gas-cooled (HTGR) nuclear plant in China’s eastern coastal province of Shandong has been connected to the grid – marking the start of electricity generation for what state-run China National Nuclear Corporation said is the first high-temperature reactor in the world to begin operation.
The two-reactor plant is also the first to make use of pebble bed reactor (PBR) technology developed by CNNC. The gas-cooled is a Generation-IV high-temperature reactor design with twin reactor modules of 100 MW each driving a single 200-MW steam turbine.
In PBR technology, the reactor core is formed from graphite pebbles that contain specially designed fuel particles.
China holds intellectual property rights for the HTR-PM technology. The Chinese-designed reactor uses tri-structural isotropic (Triso) coated particle fuel, which is expected to ensure increased safety. The Triso fuel design contains tiny uranium particles that are coated with layers of carbon and silicon carbide (SiC). The SiC layer can retain fission products below 1,600°C.
The reactor uses graphite as a moderator, while helium of low radioactivity level will serve as a coolant.
The reactors have individual primary loops and shared auxiliary facilities, including fuel handling and helium purification systems. They feature a single zone pebble-bed cylindrical core and independent control rod and absorption ball shutdown systems. The passive residual heat removal system improves reactor safety features, CNNC said.
Additional information about Gen. IV SMR: The gas-cooled HTR-PM is a small modular nuclear reactor under development in China. SMRs are designed to be manufactured at a plant and transported to a site to be installed. Modular reactors will reduce on-site construction and increase containment efficiency and enhance safety due to use of passive safety features that operate without human intervention, a concept already implemented in some conventional nuclear reactor types. The term SMR refers to the size, capacity and modular construction only, not to the reactor type and the nuclear process which is applied.
Quick facts about Generation IV reactors:
– It is significantly more fuel-efficient than current nuclear power.
– Does not leave long lived radioactive wastes.
– Designed never to cause accidents with severe consequences. No scenarios are allowed where a malfunction within the facility or an external event leads to release of radioactive material to the surroundings.
–The system as a whole – reactors and fuel cycle facilities – shall be economically competitive as compared to current nuclear power and to other means of power production. – The fuel cycle is designed so that diversion of fissile material for weapons production is unattractive.