The main objective of the paper is to verify the discrete random walk (DRW) and thecontinuous random walk (CRW) Lagrangian Particle Tracking models as a tool to calculatedeposition in nuclear fuel assemblies of Boiling Water Reactors, where the sophisticatedgeometry of the spacer does not permit at present a more computationally expensivealternative. The models have been applied for a wide range of flow conditions and for variousfluids including air-water, steam-water and helium-water flows. In general, the best agreementof predictions with measurements has been obtained for air-water flows. The majordiscrepancy of the models with experimental data has been noted for the high-pressure watervaporflows. Under such conditions the models over-predict the drop deposition rates by anorder of magnitude. It is concluded that the models require further development to beapplicable to BWR conditions. In particular, it is suggested the the drop-wall interactionmodel is improved. The comparison between the two models have shown a betterperformance of CRW model in cases of air-olive oil, air-water and helium-water flows. In case of steam-water at high pressure the behavior of the two models is very different. The major finding of the paper is that a favourable comparison of either model to air-water flowconditions does not prove a good performance at BWR conditions.