The Middle East Technical University Defocusing Beamline (METU-DBL) is being constructed in order to perform single event effects tests for the electronic components in accordance with the European Space Agency (ESA) European Space Components Coordination (ESCC) No. 25100 standard. The aim of this beamline is to provide a suitable test area at the end of the beamline using the beam elements, such as collimators and magnets. Shielding is a crucial precaution for the safety of the radiation workers and the protection of the electronic components from the detrimental effects of radiation. In the METU-DBL, shielding studies have started with the first protective collimator because the proton beam hits the collimator, resulting in secondary particle production that increases the dose level in the research and development (R&D) room. The shielding studies of the first protective collimator used in the pretest setup of the METU-DBL are presented in this study. The whole beamline was defined in the FLUKA simulation program to calculate the absorbed radiation dose and make shielding designs. Various shielding designs were studied in FLUKA and the 15th one was selected as a suitable shielding design for the first protective collimator. This shield was manufactured and mounted on the first protective collimator and used in 20 irradiations during the pretests. At the end of 20 irradiations, it was observed that the shield is effective at decreasing the dose level in the R&D room.