[en] Non-destructive Testing has been widely used in oil and gas industries, aircraft, and especially the nuclear reactor in the period leading to the nuclear power plant. It also allows parts and materials to be inspected and measured without damaging them. These tests are very important in determining and identifying the discontinuity and defects found on a materials and parts of an object. Techniques used in this test are the radiographic and liquid penetrating testing to inspect the reactor parts in reactor cooling system to avoid the reactor to fail in operation. By using radiographic testing, x-ray source have been used in the tests conducted to determine the flaws of the internal of an object. While the test of liquid penetrating testing used dye penetrant to identify defects on the surface. These tests will reduce the harm that might occur in the future to the objects or materials. (author)