Advanced NuclearPower - AREVA

Nuclear Fuelis concerned, this means that operatingmodes such as load following, frequencycontrol and stretchout operation mustbe possible. Flexibility also meansthat plants must be capable of alteringtheir in-core fuel management strategieson short notice. Framatome ANP’sATRIUM 10 fuel assemblies, withtheir large margins to operating limits,are ideal for meeting these requirements.Even Higher ReliabilityDespite the increasing demands beingplaced on nuclear fuel today, fuelassembly reliability nevertheless hascontinued to increase in recent years.Average annual fuel rod failure rates havebeen under 2x10 -5 since 1991, with theaverage for the period from 1993 to2000 even dropping as low as 0.7x10 -5 .(Note that these failure rates includefailures from all causes, includingdebris.) According to the data availableso far, 2001 can be expected to be yetanother year of excellent fuel reliability.Two major contributing factors inthis area have been the introduction ofnew cladding materials and improvementsin fuel pellet quality. Thanks tothese advances as well as the excellentcapabilities of today’s core monitoringsystems, the probability of fuel rod failuresbeing caused by pellet-clad interaction(PCI) has been further reduced.To prevent debris-induced fretting,Framatome ANP has developed variouskinds of debris filters. All ATRIUM 10fuel assemblies, for example, are nowequipped with a lower tie plate withintegral debris filter – either SmallHoleor FUELGUARD – to ensure maximumreliability.Further PerformanceImprovement With ATRIUM 10XPThe enhanced properties of the nextgeneration, ATRIUM 10XP, will furtherimprove economic performance. Whilethe greatly improved thermal-hydraulicstability provides more operatingflexibility, a higher fuel weight helpsoptimize fuel cycle costs. Lead assemblieswill be loaded in a European plant in2002.ATRIUM 10 – by achieving a burnupof 71 MWd/kgU for four fuel assemblies,this design has set a new world recordin BWR fuel utilization.Number of Fuel Assemblies1,4001,2001,0008006004002000Burnup distributionof Framatome ANPBWR fuel assembliesoperated to burnup levelsabove 40 MWd/kgU(Status: August 2001)4041424344454647484950515253545658627071Average Discharge Burnup, MWd/kgU5045403530Highest ReloadBatch BurnupMean Value for FuelAssemblies Dischargedin Each Year251982 1984 1986 1988 1990 1992 1994 1996 19982000Year of DischargeThe average discharge burnups ofFramatome ANP’s BWR fuel assemblieshave increased by around 50% in thelast 20 years.Assembly Burnup MWd/kgUTotal number of fuelassemblies: 4,138Maximum rod burnup:76 MWd/kgUAdvanced Nuclear Power N O 3 January 2002 9