Days after it arrived in Bulgaria, Westinghouse’s American nuclear fuel was licensed by the Bulgarian Nuclear Regulatory Agency (NRA).
This is a mandatory condition in order for Kozloduy NPP to use fuel other than Russian. Thus, for the first time in the history of the nuclear power plant, the two 1,000-megawatt units will operate with fuel that is not from the Russian company TVEL. This is a turning point in the 50-year history of the nuclear power plant and no doubt comes with many challenges. At least because of the fact that, for a certain period of time, Russian and American fuel will have to work together. The evaluation period of the new fuel itself took a long period of time, not only because of the complexity and security requirements, but also in Europe there are very few other VVER reactors on which fuel from the American company “Westinghouse” has been tested. It was important for it to happen right now, since the Kozloduy NPP no longer has Russian fuel for Unit 5. The process of fully switching to the new type of fuel will take four years, but given the economic relationship with Russia after the start of the war in Ukraine, fuel diversification was imposed as the only possible option. Advertising The first refueling with the new fuel will take place this month as soon as Unit 5 enters scheduled maintenance. Due to the change, scheduled rehabilitation will take longer than the standard 3-4 weeks. Recharge At the moment, only the Russian TVEL had the right to supply fuel to the Kozloduy NPP – with the designation TVSA for the 5th unit and TVSA-12 for the 6th unit. The last charge with available cartridges for unit 5 was carried out a year ago, and even then it was clear that the reactor would need new fuel to avoid having to order it from Russia again. The situation with the 6th reactor is different, as Kozloduy NPP has 4 more recharges – until 2028. Kozloduy NPP: Recharging The units are not loaded all at once, but only 25% of the cartridges are replaced each year. So the recharge cycle is four years. Therefore, it is not possible to suddenly change all the fuel from one type to another, and the diversification process also lasts 4 years (in steps of 25%). During this period, mixed fuel is used, and this is exactly what complicates the operation in terms of control and management systems. Westinghouse also plans to install its own Beacon control and monitoring systems once the fuel is in use. This does not negate the need for the already installed Russian systems, since in reality 75% of the reactor will still operate with Russian fuel at TVEL. And the 6th block – at least for a few more years. There, the expectations are that the diversification will be with French fuel of “Framatom”. In theory, it would be possible to replace all cartridges in the reactor at the same time, so that there would be no problem with joint monitoring. However, in practice this is impossible. In addition to the fact that hundreds of millions of euros will be lost from the unused Russian fuel that must be removed, there is really no way or where to store the still unused cartridges. They are highly radioactive (unlike new and not yet activated cartridges), and Bulgaria does not have such a repository. Currently, only fully spent cartridges are temporarily stored at the NPP site. The new reactors Bulgaria has already started work on the new reactors at the Kozloduy NPP, the equipment of which will be provided by Westinghouse. It recently became clear that the constructor will be the South Korean company “Hyundai”. Both the fuel and the new blocks were imposed by decisions of the National Assembly, which gave rise to a number of disputes as to whether the situation was being acted politically rather than expertly. The FEED project has probably already been completed, as the head of the plant in Kozloduy, Valentin Nikolov, stated two months ago to “Capital” that the engineering itself is expected to begin soon. The metro is being expanded with two stations in Lyulin for BGN 142 million. Cities The metro is being expanded with two stations in Lyulin for BGN 142 million. The Ministry of Internal Affairs and the Prosecutor’s Office targeted the journalist Dimitar Stoyanov Politics The Ministry of Internal Affairs and the Prosecutor’s Office targeted the journalist Dimitar Stoyanov Where is the Writers’ Quarter in Sofia? Things Where is the Writers’ Quarter in Sofia? At the same time, different opinions are circulating in Europe based on Westinghouse refuelings already carried out in smaller VVER-440 reactors, in which there were initial technical malfunctions. The assurances for the Bulgarian side come that in the Czech plant in Temelin, the fuel change was already carried out in VVER-1000, such as the reactors in Kozloduy, and it is working successfully.
Newsessentials Blog 
Posted on April 25, 2024
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