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OKB Gidropress research and experiment facility, a part of Rosatom engineering division Atomenergomash, has finished longevity testing of fuel assembly models with optimized hydro-uranium ratio for VVER-440 reactors. This new modification of second-generation nuclear fuel is developed for the Paks NPP in Hungary and Loviisa NPP in Finland within the contracts between TVEL Fuel Company of Rosatom and the foreign customers.

Longevity testing is one of the most essential milestones during nuclear fuel development especially important for the customers, since its results demonstrate behavior of structural materials in conditions similar to those inside the reactor core. In course of the testing, the behavior of the fuel assembly models was studied for 1500 hours in a coolant flow with the parameters as close as possible to the reactor conditions in terms of consumption, temperature, pressure and pressure pulsations

The test results were presented while the models were revised during the visit of the representatives of Forum Power and Heat (Finland), Paks NPP and the Hungarian regulatory organization. It was noted that the chosen technical solutions (for example, imitating the condition of burnt nuclear fuel) allowed to verify and confirm the performance of the new modification at all stages of nuclear fuel operation.

The new modification of second-generation VVER-440 nuclear fuel allows to increase the coolant volume inside the reactor core and optimize of the hydro-uranium ratio, which would have a positive impact for both technical and economic performance of the power unit.

“The new fuel for the Hungarian and Finnish NPPs is based on a unified solution. However, it would allow TVEL Fuel Company to create an exclusive final product to meet each customer’s own fuel cycle strategy and other individual requires. Our technical solution with higher uranium mass enables us and our customer either to make nuclear plant operation more economically efficient by reducing the amount of fuel assemblies, or to lower the level of uranium enrichment”, Alexander Ugryumov, Vice-President for R&D at TVEL JSC, commented.

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TVEL JSC signed an engineering services contract with MVM Paks Ltd. (Hungary) at the end of 2017 and an addendum with Fortum Power and Heat Oy (Finland) in early 2018. After the full testing cycle, start of batch production and licensing of the nuclear fuel, first deliveries of the new modification fuel assemblies to Hungary and Finland are expected to begin in 2021-2022.

TVEL Fuel Company of Rosatom includes enterprises of nuclear fuel fabrication, conversion and enrichment of uranium, production of gas centrifuges, as well as research and development organizations. TVEL is the only supplier of nuclear fuel to Russian NPPs. TVEL Fuel Company provides with nuclear fuel 72 power reactors in 14 countries, research reactors in 8 countries, as well as transport reactors of the Russian nuclear fleet. One in six power reactors in the world runs on TVEL's fuel. http://www.tvel.ru