First criticality reached at Kakrapar-4
Unit 4 at India’s Kakrapar nuclear plant has achieved initial criticality, Nuclear Power Corporation of India Ltd. (NPCIL) has announced. This latest milestone in the country’s ambitious nuclear power program was reached early on December 17.
“The criticality was achieved after meeting all the stipulations of the Atomic Energy Regulatory Board (AERB), which had issued clearance after a rigorous review of safety of the plant systems,” the announcement stated. “Several experiments/tests will now be conducted at [Kakrapar-4] and the power level raised in steps, in line with the clearances of the AERB, ultimately culminating in operation of the unit at full power.”
The Indian-designed 700-MW pressurized heavy water reactor’s sister unit, Kakrapar-3, entered commercial operation on June 30 after achieving initial criticality in July 2020 (and becoming the first PHWR-700 to produce electricity in the process).
According to the announcement, NPCIL chairman and managing director Shri B. C. Pathak, who witnessed the event from the station’s control room, said that “achievement of criticality of [Kakrapar-4], within six months of commercial operation of Unit 3, was a significant achievement,” adding that “together with the smooth operation of [Kakrapar-3], it demonstrated the strength of NPCIL in all facets of nuclear power viz design, construction, commissioning, and operation.”
The plant: In addition to the two PHWR-700 units, the Kakrapar facility—located along the western coast of India in the state of Gujarat—houses two 202-MWe four-loop PHWRs. Units 1 and 2 entered commercial operation in August 1993 and September 1995, respectively.
PHWR plans: India has plans for an additional 14 PHWR-700s. Following the commencement of Unit 4’s fuel load in October, NPCIL said, “With the successful and stable operation of [Kakrapar-3], the capability of NPCIL in setting up of indigenous reactors of PHWR technology of this size is validated and paves the path for early completion of the remaining 14 reactors, beginning with Units 7 and 8 of Rajasthan Atomic Power Project at Rawatbhata in Rajasthan.”
The Rajasthan plant is home to five operating units—one 187-MWe CANDU PHWR (Unit 2) and four 202-MWe four-loop PHWRs (Units 3–6). Rajasthan-1, a 90-MWe CANDU unit, has been off line since 2004 but has yet to be declared permanently closed.
