[en] The checking of fuel cladding integrity and uranium contamination level was performed using delayed neutron cladding rupture detection system (DRG). This checking is important for the start up procedure of the reactor. The technique of DRG depends on monitoring the delayed neutron emitters such as Br-87 (t_1/2=54.5 sec) and l-137 (t_1/2=24 sec) in the coolant of the reactor. As a requirement for the start up two tests for checking fuel cladding integrity were performed. A comparison between the obtained data and the recommended data by the vendor are tabulated. Additional data were obtained at higher power. Accordingly, it can be concluded that the activities detected were due to the uranium contamination of cladding surfaces. Results confirmed that no rupture existed on the claddings