Eskom confirmed this and awaits further directives from the government.
Friday was the deadline for all bidding companies to submit Request for Information documentation to Eskom.
The court decision has also affected the deadline for the issuing of the Request for Proposals in June.
Head of Rosatom in Southern Africa, Viktor Polikarpov, told Independent Media nothing had changed with their plans to bid for the nuclear programme.
He said they would not want to comment on the case because it was a matter involving government and civil society, who took the matter to court.
Energy Minister Mmamoloko Kubayi has said she is still studying the judgment, and would not comment on whether to appeal against the court decision or not.
Kubayi will appear before MPs on Tuesday, where she will face questions on the nuclear programme.
Polikarpov said the nuclear process was not in their hands, but in the hands of the government.
“We are prepared on the bidding, but much will depend on the government, how it will sort out the court issue,” he said.
Eskom spokesperson Khulu Phasiwe said the court decision had effectively nullified the process.
Everything would now depend on what government did.
He said it was the Department of Energy that was taken to court and not Eskom.
“The reason Eskom stepped in was because we have expertise. We, as Eskom, are going to take the cue or our directive from the department.
“It will be up to the department how we are going to proceed from now on,” said Phasiwe.
He said it was clear that everything had to be nullified and started from scratch if the government still wanted to continue with the nuclear programme.
The judgment found the process followed was unlawful and unconstitutional.
Phasiwe said the data collected from Requests for Information would have given them all the statistics on the bidding companies.
Before she was sacked last month former Energy Minister Tina Joemat-Pettersson told Parliament in March that more than 20 companies had submitted their RFIs to Eskom.
She said at the time these companies had expressed keen interest in bidding.
Rosatom is one of the companies that submitted its RFI to Eskom.