Power unit No. 5 of the Zaporozhye NPP is transferred from the “hot shutdown” mode to the “cold shutdown” mode, reported International Atomic Energy Agency (IAEA). The nuclear power plant plans to determine the reason for the detection of boron in the cooling circuit. In “hot shutdown” mode, only one of the station’s six reactors will remain for steam production and heating.
“Cold shutdown” is a safe state of a nuclear reactor when it is shut down at low pressure and low temperature of the cooling water. In the “hot stop” mode, the water is heated from the idle reactor.
The transition of the reactor plant to the “cold shutdown” mode began on November 20. According to plans, it was supposed to be completed the next day, November 21. The boron concentration in the affected cooling circuit was reported by the IAEA to be within specification limits. No radioactivity was detected in the second circuit, the agency noted.
Zaporozhye NPP is the largest nuclear power plant in Europe, has six power units with a total capacity of 6 GW. The station is located near the city of Energodar in the Zaporozhye region on the shore of the Kakhovka reservoir. Russian troops took control of the station at the beginning of the military operation in Ukraine. After the announcement of the annexation of the territory of the Zaporozhye region to Russia, the station was transferred to the ownership of the Russian Federation.