Nuclear fuel loading into the core of VVER-12000 reactor has started at Novovoronezh NPP. It is carried out in the framework of the first criticality programme that is now running at the innovative Unit 6 (Novovoronezh Phase II, Unit 1). The plant personnel have started working as prescribed by the reactor operating license granted by Rostechnadzor on March 23.
The first phase of the first criticality programme of the power unit made to the AES-2006 design was preceded by a number of activities, in particular, transportation of shrouds with fuel assemblies (FAs) from the fresh fuel storage to the reactor department and check on preparedness of the personnel and equipment. Only after that the first assembly was loaded at 03H28M on March 24. Loading has entered its active phase on March 25.
The procedure is carried out in accordance with the programme of the first routine loading of the reactor core approved by the plant chief engineer and coordinated with the start-up scientific supervisor (NRC Kurchatov Institute), general designer of the reactor (OKB Gidropress), and Atomtekhenergo.
Safety is the main requirement to the new power unit start-up, says Novovoronezh Plant Manager Vladimir Povarov. At the stage of first criticality, to ensure additional safety, fuel assembly dummies were loaded into the core and the neutron flux monitoring instrumentation was installed.
He also explained that such loading pattern was radically different from those which had been used at pilot power units before. “It is not standard load at all. We load nuclear fuel into the core, which is partly filled with fuel assembly dummies, for the first time, to enhance safety,” he said. The Plant Manager expressed his assurance that this power unit would become a reference one and would facilitate dynamic development of nuclear power.
Fedor Tatarkin, Leading Engineer from the Novovoronezh Branch of JSC Atomtekhenergo and Head On-Duty of the first standard loading, explained that the loading operation was structured so that at the first stage fresh fuel comprised about one third of all loaded assemblies, the rest are FA dummies. Then, the fuel will be loaded one-by-one instead of fuel assembly dummies in the remaining cells in accordance with the operating schedule.
On the whole, the first criticality programme of a power unit includes: delivery, the reactor assembling, attaining rated parameters, necessary criticality experiments, rendering the reactor critical and running experiments to confirm design data of the fuel charge. All further stages will be related to getting permits from Rostechnadzor for subsequent stages: the reactor assembling, switching on reactor coolant pumps needed to render the reactor hot and conducting a set of tests at minimum controlled power.
