How rocket attacks lead to the shutdown of Ukrainian nuclear power plants, how nuclear plants operate in emergency situations, and what threatens the continuation of missile terror.
Preliminary estimates of the de-energization of all power units at four operating Ukrainian nuclear power plants have already been officially confirmed.
Nuclear generation in Ukraine is 15 operating power units with a total capacity of 13.835 GW. Namely:
- Zaporozhye NPP (ZNPP): 6 VVER-1000 power units
- Rovno NPP (RNPP): 4 power units (2 VVER-1000 and 2 VVER-440)
- Khmelnytsky NPP (KhNPP): 4 VVER-1000 power units
- South Ukrainian NPP (YuNPP): 4 VVER-1000 power units
In 2021, nuclear generation carried the main load in the energy system – its share increased by 4 percentage points to 55%. That is, for the country’s energy system, nuclear energy is the base.
“Yesterday’s strike had grave consequences. There was a blackout. All nuclear power plants in Ukraine were de-energized. This is the first time that all four Ukrainian nuclear power plants were de-energized at the same time,” Ukrainian Energy Minister Herman Halushchenko said at a critical meeting of EU energy ministers.
The minister also stressed that the world had never seen so many nuclear power plants simultaneously in blackout mode and urged not to leave such attacks of a terrorist country unanswered.
Director General of the International Atomic Energy Agency (IAEA) Rafael Mariano Grossi confirmed that Ukraine informed the IAEA about the forced operation of power units from diesel generators to supply electricity in shutdown mode.
“The total and simultaneous loss of external power supply to Ukrainian nuclear power plants leads to the fact that the situation with nuclear safety in the country is becoming increasingly precarious, complex and dangerous,” Grossi said.
Regarding the state of affairs at the occupied ZNPP, the IAEA reported that the emergency diesel generator stations worked from 15:30 on November 23 until almost 9 a.m. the next day, when they managed to get access to the main 750 kV line and the backup 330 kV line. The IAEA added that four units of the ZNPP now remain in cold shutdown mode, while the other two units are returning to a hot shutdown, which makes it possible to provide the nuclear power plant with steam and Energodar with heat.
De-energized reactors go into the “cold shutdown” mode, during which the generation of electricity stops. Because of this, there is a shortage of electricity in the energy system, which happened on November 23, 2022.
To provoke a shutdown of the nuclear power plant and a colossal shortage of electricity in Ukraine, Russian terrorists hit the key transformer substations and interrupt power lines. Since disconnecting the NPP from the network can have threatening consequences, the units are immediately connected to emergency diesel generators.
As Olga Kosharna, an expert on nuclear power, explained in a commentary with nuclear power, standby generators are turned on to bring the unit to a cold state, lowering the temperature of the primary circuit, which removes heat from a nuclear reaction, which takes 15 hours. Further, electricity is needed to operate pumps and other equipment. Focus’s interlocutor warns that if the generators fail, the countdown begins until the reactor core melts, which is fraught with consequences, as in Fukushima.
The repetition of terrorist attacks against Ukrainian nuclear power plants cannot be ruled out. Since the first precedent on October 11, attacks on the energy infrastructure have been repeated regularly. As soon as the Ukrainian side manages to somehow repair the damage, the terrorist country accumulates missiles for the next strike. “Since the Ukrainian and Russian energy systems were synchronized before the start of the war, the Russians are well aware of all the “thin spots” where they need to strike,” Olga Kosharna explains.
Recall that the previous missile attack, which took place on November 15, also aimed to de-energize Ukrainian nuclear power plants. Then the enemy managed to leave KhNPP without electricity for nine hours and partially restrict access to the RNPP network. Details about this event became known only from the IAEA report.