This paper presents a number of verification case studies for a recently developed sensitivity/uncertaintycode package. The code package, ROMUSE (Reduced Order Modeling based Uncertainty/SensitivityEstimator) is an effort to provide an analysis tool to be used in conjunction with reactor core simulators,in particular the Virtual Environment for Reactor Applications (VERA) core simulator. ROMUSE has beenwritten in Cþþ and is currently capable of performing various types of parameter perturbations andassociated sensitivity analysis, uncertainty quantification, surrogate model construction and subspaceanalysis. The current version 2.0 has the capability to interface with the Design Analysis Kit for Optimizationand Terascale Applications (DAKOTA) code, which gives ROMUSE access to the various algorithmsimplemented within DAKOTA, most importantly model calibration. The verification study isperformed via two basic problems and two reactor physics models. The first problem is used to verify theROMUSE single physics gradient-based range finding algorithm capability using an abstract quadraticmodel. The second problem is the Brusselator problem, which is a coupled problem representative ofmulti-physics problems. This problem is used to test the capability of constructing surrogates viaROMUSE-DAKOTA. Finally, light water reactor pin cell and sodium-cooled fast reactor fuel assemblyproblems are simulated via SCALE 6.1 to test ROMUSE capability for uncertainty quantification andsensitivity analysis purposes