Key to manage high burn up fuel exists

In his analysis published by DNA on February 9, Mr Gopalakrishnan criticises again the EPR™ reactor, which is planned to be built by NPCIL at Jaitapur. In particular, he questions the fact that it would be “untested” and also that it is designed to use high-burn-up fuel. While recognising he’s fully entitled to his own views on the matter, some of the assertions he makes need to be corrected or updated.

First, Mr Gopalakrishnan criticises the choice of a new advanced technology for the reason it has not yet been put into operation.

However, Areva’s philosophy is quite similar to that adopted in India (as elsewhere) with the recent launching of the 700-MW PHWR’s construction after many years of successful operation of the 220-MW PHWR model.

When developing the EPR, Areva designed an evolutionary product (this is what the “E” in EPR stands for). It means that the innovative 1650-MW EPR design has been conceived through incremental improvements, which build up on the experience of operating reactors of the French 1475-MW N4 and German 1365-MW Konvoi designs. These reactors have generated, to date, more than one million gigawatt-hours. The EPR therefore benefits from extended operating experience, just like the Indian 700-MW PHWR benefits from its predecessors.

Next, the use of high-burn-up fuel is nothing new, as Pressurised Water Reactors (PWR) throughout the world now routinely achieve burn-ups above 50 GWd/tonne.

To only quote French utility EDF, which is operating 58 reactors totalling 63,000 MWe: “Progressively, a mix of 12 and 18 months cycle- lengths core managements has been implemented on the various series of the nuclear fleet. The maximum discharged burn-up of the fuel for all these new core managements has been raised up to 52 GWd/t for all UO2 and MOX fuel assemblies.” [EDF PWR FUELS — EDF Operating experience — Xavier Thibault, Thierry Meylogan, Eric Briard, Guy Chaigne (EDF DPI-France) — Proceedings of Top Fuel 2009 —Paris, France, September 6-10, 2009 — Paper 2153.] In other European countries (Germany, Switzerland, Belgium) maximum burn-up values can already exceed 50 GWd/t and the trend continues.

The increase from the 30-40 GWd/tonne level achieved in the past is supported by large R&D efforts as well as numerous in-situ tests in reactors.

For example, Areva developed the M5 alloy for fuel cladding, specifically designed for high burn-ups at the request of EDF. It is already gathering extensive operational track-record.

But what are the benefits from increasing the burn-up level of nuclear fuel? The main objective is to generate more electricity from a given quantity of uranium, which allows for a more rational use of a natural resource. In the process, the volume of spent fuel to be transported, stored and reprocessed will also be reduced, as well as the amount of ultimate nuclear waste to be disposed of. Indeed, the activity contained in spent fuel and waste will be higher, but its management is well mastered under existing industrial processes.

For wet storage, existing pools in Europe already store used fuels with high burn-ups. For long-term dry storage, Areva designs transport and storage casks in conformity with IAEA safety standards and taking into account the characteristics of high-burn-up fuel. Concerning reprocessing, La Hague plant in France currently deals with high-burn-up spent fuel. Authorisations still have to be granted, when needed, for reprocessing on an industrial scale fuel with burn-up of 60 GWd/t, but feasibility demonstration has been performed and process is well mastered.

The Areva Generation 3+ reactors are designed for high safety and performance, but also for natural resource savings. Hence, the EPR reactor enables to save 18% of uranium compared to Generation 2 reactors. At the same time, fuel burn-up levels reached in those reactors are well within safety and operational margins, and the technical solutions to manage high-burn-up spent fuels already exist.

The writer is CMD, Areva India Pvt Ltd