In an interview with IRNA, Behrouz Kamalvandi said, “Necessary arrangements have been made to rebuild the damaged shed at the Natanz nuclear facility and a bigger shed with more advanced equipment is to replace it.”
More centrifuge machines, he added, were supposed to be produced at the damaged shed, which was inaugurated following Washington’s withdrawal from the Iran nuclear deal – officially known as the Joint Comprehensive Plan of Action (JCPOA) – in May 2018 and exactly two days after Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei ordered the AEOI to make preparations for the enrichment of uranium up to a level of 190,000 SWU without delay.
Of course, Kamalvandi said, the facility did not operate at full capacity due to the JCPOA limitations, but this shed was to undergo further development and this project was ongoing until the day when the incident happened.
In his order to the AEOI in June 2018, the Leader said, “It seems from what they say that some European governments expect the Iranian nation to both put up with sanctions and give up its nuclear activities and continue to observe limitations [on its nuclear program]. I tell those governments that this bad dream will never come true.”
The landmark nuclear deal was reached between Iran and the US, Britain, France, Russia, China plus Germany – in 2015. However, in May 2018, US President Donald Trump unilaterally withdrew his country and later reimposed the sanctions that had been lifted against Tehran and began unleashing the “toughest ever” fresh sanctions.
Kamalvandi said the accident at the nuclear complex caused “significant” damage and could slow the production of centrifuges used to enrich uranium.
"There were no victims... but the damage is significant on a financial level," he said.
The AEOI spokesman emphasized that the incident has caused no stoppage in Iran's enrichment work, adding, however, it may slow down development and manufacture of advanced machines in the medium term.
He noted that the damaged shed housed measuring equipment and precision tools, part of which was destroyed in the incident and another part was damaged.
The damaged equipment cannot be used anymore in view of the work they do, even if the incident had taken place on a smaller scale, the official said.
"God willing, and with constant effort... we will compensate for this slowdown so that the rebuilt site will have even more capacity than before," Kamalvandi added.
"As announced by the secretariat of [Iran's] Supreme National Security Council (SNSC), the country's security authorities have found out the cause of the incident, but they do not want to make it public for the time being due to security-related considerations, he said.
The incident happened on Thursday at a warehouse under construction at the Natanz complex, but caused no casualties or radioactive pollution, according to the Islamic Republic's nuclear body.
The AEOI had earlier released a photo purportedly from the site, showing a one-story building with a damaged roof, walls apparently blackened by fire and doors hanging off their hinges as if blown out from the inside.
The International Atomic Energy Agency said on Friday that the location of the fire did not contain nuclear materials and that none of its inspectors was present at the time.
SNSC spokesman Keyvan Khosravi said on Friday that the "main cause" of the incident had been determined and would be announced at an appropriate time.
He added that experts from different sectors had started investigating "different hypotheses" about the incident.
“Due to some security considerations, the cause and manner of this incident will be announced at a proper time.”
Natanz is a uranium enrichment center located in the city of the same name in Isfahan Province, some 250 kilometers (155 miles) south of the capital Tehran.
It is among the sites now being monitored by the International Atomic Energy Agency (IAEA) under the JCPOA.
Iran agreed to curb its nuclear program in exchange for the removal of most international sanctions in the 2015 nuclear deal.
Iran has gradually reduced its commitments to the accord since the US pullout.
The deal only allows Iran to enrich uranium at its Natanz facility with just over 5,000 first-generation IR-1 centrifuges, but Iran has installed new cascades of advanced centrifuges.
Press TV, AFP, and Reuters contributed to this story.