This report describes methodology and functionality of a software framework (NEMOS - Nuclear Event Monitoring Simulator) developed to simulate the response of sensor networks, which are intended to detect, identify, and locate nuclear explosions and other nuclear events. The Python-based software simulates the response of networks that can consist of seismic sensors, infrasound detection sensors, and several types of radioactivity instruments (GM - tubes measuring dose rate, NaI- sensors measuring isotope-specific activity; either stand-alone or in the vicinity of an air sampling filter; aerosol stations equipped with an HPGe detector, and finally, two types of radioxenon measurement systems). NEMOS use a nuclear source vector and atmospheric transport calculations in combination with various detector response models to simulate the radioactivity measurements. A nuclear explosion source vector has been developed that takes into account fission products and neutron activation in weapon material as well as in surrounding media. In the case of HPGe and NaI measurements, a full simulation of measured spectra is performed. HPGe spectra are analysed with respect to nuclide specific activities and activity concentrations using standard radionuclide analysis software, and NaI data is treated using a more basic technique. The responses (detection capability and location accuracy) of the seismic and infrasound sensors are calculated using empirical models. A large number of nuclear explosions located in and around Sweden, as well as in Europe, were simulated with respect to atmospheric dispersion of aerosols and noble gases. Network responses from these explosions can be used in a statistical analysis designed to evaluate different network configurations with respect to verification capability. The analysis include calculation of parameters such as reporting time, detection and location capability, and the capability to identify whether an explosion is nuclear in nature or not. The framework can also be used to produce interactive maps that show the calculated dispersion fields and which sensors in the network that are detecting the event. The maps also show detailed measurement data from the individual sensors. In addition, direct effects can be illustrated. The maps, which can be viewed in any web browser, can also be useful when planning and conducting exercises, as well as in general discussions on nuclear weapons effects.