Patent Number: 
Section: claims

1. A method of fabricating nuclear fuel elements, the method comprising:determining at least one technological uncertainty factor for nuclear fuel elements, using, for at least one fabrication parameter:a collective variation in the at least one fabrication parameter about a nominal value within a batch of fabricated elements, and in addition to the collective variation,an individual variation in the at least one fabrication parameter about a nominal value for an individual element; andfabricating the nuclear fuel elements based on the at least one technological uncertainty factor,wherein the technological uncertainty factor is determined for linear power density at a hot point FQE. 2. The method as recited in claim 1 wherein the collective variation is multiplied by a macroscopic sensitivity coefficient. 3. The method as recited in claim 2 wherein the individual variation is multiplied by a microscopic sensitivity coefficient. 4. The method as recited in claim 3 wherein the determining at least one technological uncertainty factor for nuclear fuel elements includes determining the technological uncertainty factor for linear power density at the hot point FQE according to a formula of:      F    Q    E    =      1    +                  1.645        1.96            ⁢                                    ∑            i                    ⁢                                          ⁢                      (                                                            α                  i                  2                                ⁢                                                      T                    i                    2                                                        μ                    i                    2                                                              +                                                θ                  i                  2                                ⁢                                                      TL                    i                    2                                                        μ                    i                    2                                                                        )                              where Ti and TLi respectively designate individual and collective variations in a fabrication parameter Fi, and αi and θi respectively designate the microscopic and the macroscopic sensitivity coefficients for the fabrication parameter, and where μi designates a mean for the fabrication parameter Fi. 5. The method as recited in claim 1 wherein the collective variation is a collective tolerance, a deviation between a mean of real values for the fabrication parameter within a batch of elements and nominal value being required to comply with the collective tolerance. 6. The method as recited in claim 5 wherein the individual variation is an individual tolerance, a deviation between a real value of the fabrication parameter for an individual element and a nominal value needing to comply with the individual tolerance. 7. A method of fabricating nuclear fuel elements, the method comprising:determining at least one technological uncertainty factor for nuclear fuel elements, using, for at least one fabrication parameter:a collective variation in the at least one fabrication parameter about a nominal value within a batch of fabricated elements, and in addition to the collective variation,an individual variation in the at least one fabrication parameter about a nominal value for an individual element; andfabricating the nuclear fuel elements based on the at least one technological uncertainty factor,wherein the technological uncertainty factor is determined for a hot channel FΔHE1. 8. The method as recited in claim 7 wherein the collective variation is multiplied by a macroscopic sensitivity coefficient. 9. The method as recited in claim 8 wherein the individual variation is multiplied by a microscopic sensitivity coefficient. 10. The method as recited in claim 9 wherein the determining at least one technological uncertainty factor for nuclear fuel elements includes determining the technological uncertainty factor for the hot channel FΔHE1 according to a formula of:      F          Δ      ⁢                          ⁢      H              E      ⁢                          ⁢      1        =      1    +                  1.645        1.96            ⁢                                    ∑            i                    ⁢                                          ⁢                      (                                                            α                  i                  2                                ⁢                                                      TL                    i                    2                                                        μ                    i                    2                                                              +                                                θ                  i                  2                                ⁢                                                      TL                    i                    2                                                        μ                    i                    2                                                                        )                              where TLi designates the collective variation in a fabrication parameter Fi, where αi and θi designate respectively the microscopic and the macroscopic sensitivity coefficients in the fabrication parameter, and where μi designates a mean for the fabrication parameter Fi. 11. The method as recited in claim 7 wherein the collective variation is a collective tolerance, a deviation between a mean of real values for the fabrication parameter within a batch of elements and nominal value being required to comply with the collective tolerance. 12. The method as recited in claim 11 wherein the individual variation is an individual tolerance, a deviation between a real value of the fabrication parameter for an individual element and a nominal value needing to comply with the individual tolerance.