Ural icebreaker passes construction milestone

01 August 2018

Zio-Podolsk, a subsidiary of Russian state nuclear corporation Rosatom, has completed the welding of four hydrochambers to the reactor body of the Ural nuclear-powered icebreaker. Announcing the milestone on 30 July, Zio-Podolsk said this was “the most complex technological welding operation” in the manufacture of the reactor vessel, taking a full 17 days.

Welding the hydrochambers took 17 days (Image: Rosatom)

Ural is one of three vessels of Project 22220 - featuring RITM-200 reactors - that will be able to break through ice 3 meters thick as they escort vessels across the Arctic Ocean. The others are Arktika and Sibir.

Arktika was the first nuclear icebreaker to be fully built in modern-day Russia. It was launched at the Baltic Shipyard in Saint Petersburg in June last year. The Atomflot state unitary enterprise said in February this year it expects Arktika to enter first operational service in mid-2019. Sibir and Ural are scheduled for delivery in 2020 and in 2021, respectively.

Alexander Morozov, chief welder at Zio-Podolsk, said the operation involved two stages, two for welding and one for radiographic control.

"Among the complexities, I would highlight the constrained working conditions in a special assembly and welding pile, the non-rotational position of the welded seams, and deep cutting - the thickness of the seam is 82 mm," he said.

The manufacture of hydrochambers for the second reactor of the Ural icebreaker have also been completed and are scheduled to be welded to the reactor body this month.

RITM-200 is a "radically new" reactor facility for Russia’s icebreaking fleet, Zio-Podolsk said.

"It has a unique energy-efficient integrated layout that ensures the placement of the main equipment directly inside the steam generating unit casing. This means it is half the weight, one-and-a-half times more compact and 25 MW more powerful than the currently used reactor systems for the icebreaker fleet of the KLT type.

"In particular, this provides improved technical characteristics for the new icebreakers in terms of speed of ice cover. The steam generating unit reliably operates under the influence of a rolling amplitude of ± 45º and pitching with an amplitude of ± 15º, and also with a long roll to 30º. The life of the reactors is 40 years, the safety of their work is provided by a protective shell of steel, water and concrete. Re-loading of nuclear fuel occurs once every seven years."

The hydrochambers are an integral part of the reactor vessel and in future will involve installation of central electric pumps. They are designed to circulate the cooling medium of the internal cavity of the reactor and each one has a mass of 4.5 tonnes.

Researched and written by World Nuclear News