The paper analyses possible types, shapes and locations of defects in a life cycle according to such factors of a urea reactor as material, structure, manufacture approach, work environment, operating medium and failure mode. Then suitable nondestructive testing methods are chosen to test a urea reactor on service on the basis of characteristics of various nondestructive testing methods. And test procedures are optimized which not only ensure urea reactor safety operation, but also reduce test time and minimize plant stand-by loss caused by a test.