[en] The aims of this project were to develop a method to measure the amount of ⁵⁹Ni in stainless steel and to determine the detection limit for this method. ⁵⁹Ni is produced by neutron activation in the construction material close to the core in a nuclear reactor and it is important to know the amount of ⁵⁹Ni present as it governs the classification of the waste. If the amount of ⁵⁹Ni is known at different locations in relation to the core, it is also possible to refine the calculation models of the neutron flux in the reactor. Accelerator mass spectrometry, an ultra-sensitive method for measuring small concentrations of radionuclides as well as stable nuclides, has been used in this investigation to determine the concentration of ⁵⁹Ni (and thereby the activity) in stainless steel. As the cobalt content in stainless steel is the main contributor to the background in a measurement of ⁵⁹Ni, a method for the chemical extraction of nickel from stainless steel, including a purification step to reduce the cobalt content in the sample, has been developed. The detection limit for ⁵⁹Ni has been determined to 100±30 Bq per gram nickel (100±30 Bq/g) with the present status of the system