The aim of the present work is to study a full cone pressure swirl nozzle (pressure swirl nozzles) and its configuration on a spray header for the 700MWe Indian Pressurized HeavyWater Reactor (IPHWR) Containment Spray System (CSS) (a FOAK system). The Reynolds number (Re) effect on coefficient of discharge (C-d), spray cone angle, SMD (D-32), droplet size distribution, and droplet velocity is investigated for full cone pressure swirl nozzles. Studies are performed to optimize the nozzle configuration on the spray header and the distribution of mass flux. The mass flux density studies are carried out in patternater facilities at IIT Bombay and the Kakrapar Atomic Power Project (KAPP). Water at room temperature is used for the spray in experimental investigation. The nozzle characterization experimental studies are carried out for Re ranging from 1.43 x 10(5) to 2.49 x 10(5). A particle droplet image analyzer (PDIA) is used for the measurement of droplet velocity, SMD (D-32), and drop size distributions. A simple CCD camera along with a diode laser and patternater software is used for the measurement of the spray cone angle. The catch and time technique is used to measure coefficient of discharge. The droplet flux distribution at different Z/D-o and R/D-o is also performed. Nukiyama-Tanasawa distribution and log-normal peak shifted distribution show a reasonably good confirmation with the present experimental studies.