); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (B.M. )1 School of Engineering, University of Liverpool, Liverpool L69 3 GCH, UK; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (A.P. ); b.merk@liverpool. (BUC) method. Application of the burnup credit method can reduce costs of spent fuel management, for example, by increasing storage or transport tasks capacity or by removing absorbing panels and thereby reducing the costs associated with cash manufacturing [4]. The burnup credit method can be applied on different levels such as actinides only, actinides and fission products or integral burnable absorber [5]. On the first two levels, credit is taken for the set of specific nuclides (major actinides on the first level, and additional minor actinides and fission products on the second level) defined in [6] as suitable for burnup credit as they play a major role in the system's reactivity reduction and have a comprehensive experimental data. On the last, integral burnable absorber level, the credit is taken for the reactivity reduction at the maximum reactivity value of the fuel assembly (FA) with burnable absorber (poison) in comparison with the fresh fuel approach. For poisoned FAs (gadolinia in the case of BWRs), the initially low reactivity increases up to certain value (peak reactivity) and then declines after the absorber is burnt. The given BUC approach is often referred to as peak reactivity. The safety criteria for burnup credit are based on the loading curve of the analysed system. The loading curve determines the minimal fuel assembly burnup as a function of its initial enrichment under which the assembly can be placed into the storage or transport system [7]. The loading curve should be estimated for each licensing condition, such as different assembly cooling times. Another important part of the BUC analysis is the validation of the codes used for depletion and criticality analysis along with their nuclear data libraries. The study [8] performed as the part of this project showed that even well-known lattice codes can produce noticeably different results. Hence, the burnup credit method is more complicated in comparison with fresh fuel approach in terms of regulatory requirements, computational methods, as well as software verification and validation, but can potentially gain a significant benefit for spent fuel management. BWRs are of particular interest for the burnup credit analysis due to their complex assembly design (e.g., multiple rod geometries and compositions per fuel assembly) in comparison with pressurised water reactors (PWRs) and being less researched, despite the global deployment of BWR technology [9].