Embodiments of the present application are directed to devices, systems and methods for irradiating fluids (e.g., blood) with ultraviolet light, and corresponding related components, systems and methods. In some embodiments of the invention, an ultraviolet blood irradiation (UBI) system is provided and may include an ultraviolet UV source providing a predetermined wavelength of radiation to provide a detrimental effect to virus and/or bacteria, an exposure chamber for exposing a predetermined volume of blood to radiation, a conduit between the UV source and the exposure chamber, a pump for pumping blood between a first location and a second location and a shutter assembly provided between the UV source and the exposure chamber providing time-metered irradiation of the blood in the chamber.