The situation at the Zaporizhzhia nuclear power plant – the largest of its kind in Europe located in the Ukrainian city Enerhodar – has risen fears of a nuclear disaster after bouts of shelling. 

At least six incoming shells were recorded on Wednesday in the area of the nuclear power plant as a result of shelling by Ukrainian troops, TASS reported citing Vladimir Rogov, a member of the chief council of the Zaporizhzhia Region military-civilian administration. The Ukrainian side has not commented on the issue.

"The shelling can damage the nuclear power plant. It's certainly true, but most likely it is not the reactor itself directly that will be damaged. The reactor is well protected. It has a powerful body and a reinforced concrete shell. The reactor cooling system can be damaged as a result of which in principle, a rather severe accident is possible," radiochemist Boris Zhukov expressed his concern, adding that unstable radionuclides, such as iodine-131 and cesium-137, would leak.

The plant, controlled by Russian forces since March, has come under fire repeatedly in recent weeks, with both Ukraine and Russia blaming each other for the attacks. 

Russia on Thursday said the shelling was a "provocation" timed to coincide with a visit to Ukraine by U.N. Secretary-General Antonio Guterres this week. The assertion was dismissed by a senior Ukrainian official, Reuters reported on Thursday. 

About 50 percent of the electricity needed in Ukraine is supplied by nuclear power plants. The Zaporizhzhia nuclear power plant, which has continued to operate by Ukraine staff since Russia's control, has six nuclear reactors and generates about 25 percent of Ukraine's total electricity generation.

Ukraine set up a crisis center to deal with the possible emergency situation at the Zaporizhzhia nuclear power plant, Ukrinform reported on Wednesday, citing the country's Energy Minister Herman Galushchenko.

The crisis headquarters will work round the clock to monitor the situation at the nuclear power plant, Galushchenko said. 

In early August, Rafael Grossi, head of the International Atomic Energy Agency (IAEA), said the plant is "completely out of control" under the ongoing conflict between Russia and Ukraine, and called on the two sides to prove an inspection and repairs by IAEA experts.

In a statement on Thursday, Russia's Defense Ministry said there are no Russian heavy weapons at the Russian-controlled nuclear reactor complex, or in nearby districts, while Ukraine has said that Russia has deployed artillery in and around the plant.

Guterres has called for the establishment of a demilitarized zone around the plant.

"We are talking about the security of the world, not just the security of Ukraine, Belarus, Russia, and neighboring countries," Martinique, a volunteer in humanitarian work in Enerhodar, told CMG. 

(With input from Reuters)