OREANDA-NEWS. November 22, 2007. On November 21, at the Czech plant Skoda JS a.s. (a part of OMZ Group) in Plsen, the journalists were first shown a mock-up of the Russian most advanced nuclear fuel TVSA-T which will be supplied to the Czech Temelin nuclear power plant. It was delivered to the Czech Republic for hydraulic tests. This is an important stage of preparing Russian advanced TVSA-T fuel for future deliveries because this fuel will replace the American Westinghouse-made fuel at Temelin commencing 2010.

TVSA-T is a make of the Russian advanced fuel TVSA for VVER-1000 reactors. It possesses higher operating reliability and resistance to deformations because of application of a number of new engineering solutions (including so-called "rigidity angles", mixing grid and anti-debris filter built in the tail piece). With that, the assemblies are filled with uranium-gadolinium fuel which ensures NPP operation in load-following modes (when reactor power is changed).

TVSA fuel has successfully operated at Kalinin NPP (Russia) since 1998. At present, over 60% of VVER-1000 reactors (16 power units in three countries: Russia, Ukraine and Bulgaria) are using TVSA fuel. The use of TVSA allows implementing latest fuel cycle strategies and reducing refueling period, thereby shortening scheduled outages of the plant.

A fuel assembly is a hexagonal structure over four meters long. Fuel rods with uranium dioxide pellets are fixed inside it. A total weight of one assembly is 750 kg. The mock-up differs from an actual assembly only in the pellets, which are made of lead instead of uranium, as in a real assembly.

The mock-up delivered to Plsen already passed a full series of complex mechanical, thermal and hydraulic tests in OKBM (Nizhni Novgorod, Russia). Now, these results will be verified at Skoda JS a.s. and then sent to the Czech regulatory authority to obtain a license for the new fuel.

The hydraulic tests are carried out in Plsen because the plant has special equipment ("hydraulic loop"), at which tests of Westinghouse fuel assembly made for Temelin NPP were done in 1993-1994. Thus, it will be possible to do an accurate comparison of hydraulic test results of both assemblies.

The Tests will be run from December till March. After that, the mock-up will be sent to Russia for a through analysis. In autumn 2008, it will be delivered to the Czech Republic again, to Temelin NPP where the plant personnel will be mastering to handle it. In parallel, reactor power control rod rests will be carried out.

In 2006, TVEL won an international tender for fuel supplies to the Czech Temelin NPP. TVSA-T will be supplied commencing 2009 and loaded into the reactor in 2010. The nuclear fuel is fabricated by JSC Mashinostroitelny Zavod (MSZ) in Elektrostal, which is a part of TVEL Corporation.