Salehi is in China for three days according to the semi-official Fars News Agency, which noted that the highlight of the trip is to be the signing of a memorandum of understanding with Chinese officials stipulating that Beijing will help Iran upgrade and redesign Arak.
The visit indicates that China will take a leading role in the heavy water reactor's redesign.
The AEOI head was to meet with the chairman of the China Atomic Energy Authority (CAEA) Xu Dazhe on Wednesday evening, and with Chinese Foreign Minister Wang Yi the following evening, according to the Mehr News Agency.
Salehi will also visit several nuclear facilities and research centers in China during his visit.
Salehi said a working group is to be set up to design the Arak heavy water reactor.
"Since the issue of designing the the Arak reactor has been raised in the Joint Comprehensive Plan of Action (JCPOA), and China has been designated as Iran’s negotiating side in this regard, it is necessary to discuss the matter seriously with the Chinese side,” he said.
He noted that in addition to China, the U.S. will also be part of the task force on the Arak reactor, adding that other members of the P5+1 or countries outside the group like South Korea can also participate in the project if approved by the Islamic Republic and the other six countries.
Iran and the P5+1 -- the United States, Russia, China, France, Britain, and Germany -- finalized the text of an agreement called the JCPOA in the Austrian capital, Vienna on July 14.
Elsewhere in his remarks, the top Iranian official pointed to Sino-Iranian cooperation on small "multifaceted” 100-MW power stations, saying that the two sides are slated to finalize their negotiations during his trip.
Among the "outstanding features of these power stations are electricity generation, the production of industrial steam, and desalination”, Salehi said, expressing hope that the two countries will be able to sign a memorandum of understating in this respect.
Iran’s nuclear chief further described relations between Tehran and Beijing as "special,” saying Sino-Iranian ties have been promoted considerably in recent years, given the existing international situation.
AEOI deputy chief and spokesperson Behrouz Kamalvandi on Tuesday said two or three small nuclear plants can be built one next to the other to construct a medium size nuclear plant.
The Arak reactor was a key point in nuclear talks, given that the heavy-water nuclear facility is almost completed.
In the nuclear deal sealed last month, Iran agreed to remove the reactor core from Arak and redesign it with new technology provided by world powers so as "to minimize the production of plutonium and not to produce weapon-grade plutonium in normal operation".
While Iran is to main full control over the site's management, spent fuel is to be shipped out of the country according to the accord. Iran agreed in the agreement not to build a new heavy water reactor for 15 years.
Late last month, Iran announced construction on two new nuclear facilities in a southeast region on the Indian Ocean.