World's first land-based small modular nuclear reactor passes key test

China’s ACP100 small modular reactor (SMR), also known as Linglong One, has successfully completed its cold functional testing at the Changjiang site in Hainan province. This milestone, announced by the China National Nuclear Corporation (CNNC), marks the first time a commercial land-based SMR has passed a safety review by the International Atomic Energy Agency (IAEA). The cold functional test verifies the installation and operation of all systems and pipelines under pressure without nuclear fuel, ensuring the integrity and leak-proofing of the primary circuit. This achievement paves the way for subsequent hot functional tests, which will simulate thermal conditions by raising the reactor coolant system’s temperature to validate operational readiness before fuel loading. The ACP100 is a 125 megawatt electric (MWe) integrated pressurized water reactor designed for a 60-year lifespan with a two-year refueling cycle. Beyond electricity generation, it can provide regional heating, seawater desalination, and industrial steam supply, earning it the nickname “n