18.01.2019  The Kursk NPP Information and Public Relations Department

The second piece of the ‘melt trap’ has been installed at the Kursk NPP-2 construction site

A cantilever truss, the second bulky piece of a molten core catcher, has been installed at the Kursk NPP-2 construction site.

On January 17, 2019, the cantilever truss weighing 145 tons with a diameter of over 9 meters was installed at its design position under the reactor vault of an innovative 3+ generation power block No.1, which is being constructed in accordance with the VVER-TOI* project.

The molten core catcher is a unique development introduced by Russian nuclear power experts. The ‘melt trap’ forms the fourth level of the power block’s defense in depth and serves as one of the most important technical means for handling heavy accidents beyond the design basis related to a core disruption and a spread of corium (fuel-containing and engineering materials) outside of the reactor vessel.

‘We started the installation of the melt trap back in November. At that point of time, we installed the isolator. Then, we installed the so-called ‘filling component’, the sacrificial materials, inside the isolator. We also erected the 7-meters’ tall reactor vault around the vessel, which required over 85 tons of fitting, concrete-enveloped it and got it prepared for the installation of the cantilever truss’, Alexey Volnov, the chief engineer of the Kursk NPP-2, said.

A cantilever truss is designed to protect the vessel and the utilities of a molten core catcher from any destructions of the corium. Besides, this tool is required to arrange the utilities – the water supply, the vapor disposal, the measurement facilities, the ventilation, etc. It also has special corridors to examine the ‘trap’.
The cantilever truss will be enlarged in the future by welding connection legs and operating corridors, with the total mass of the tool reaching 200 tons. The total estimated weight of the whole ‘melt trap’ is 721.130 tons.

‘It will take us three-four weeks to install the cantilever truss, following which we will start installing the bottom plate, the third bulky piece of the device. The plate will protect the whole construction from the corium’s heat exposure’, Alexey Volnov, the chief engineer of the Kursk NPP-2, noted. ‘These works run on schedule, so we do not foresee any challenges with the installation of bulky equipment’.

According to the state order for 2019, the ‘melt trap’ has to be fully installed by April.

*The Kursk NPP-2 3+ generation power blocks No.1 and No.2 are the pilot power blocks that are being constructed in accordance with the VVER-TOI project (water-cooled power reactor, typical, optimized, informative). This is a new project launched by the Russian designers (ASE Group, an engineering devision of the Rosatom State Corporation) based on the VVER-1200 NPP technical solutions. 3+ generation power blocks boast higher cost/performance ratios. For example, the capacity has been increased up to 1255 megawatt, which is 25% higher compared to the power blocks of the previous generation (VVER-1000). The major equipment’s durability has increased 2 times, while the number of staff required was decreased by 30-40% thanks to the high level of automation. The VVER-TOI caters for lower construction costs, shorter construction time frames and low maintenance costs compared to other 3+ generation power blocks.
The new Kursk NPP-2 power blocks comply with the most up-to-date security standards set by the IAEA. 

The Rosenergoatom Joint-Stock company is the project owner and the technical employer of the facility. The JSC ASE EC is the general designer and the general contractor on the project.

At present, the 2nd, the 3rd and the 4th power blocks of the Kursk NPP operate at the capacity set forth in the operation schedule. The 1st power block is under scheduled maintenance. The background radiation at the Kursk NPP and within its location area is at the normal operational level and does not exceed the natural background.

The most up-to-date information about the radiation situation around the Russian NPPs and other nuclear facilities is available online at www.russianatom.ru

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