[en] Reactor TRIGA MARK II is Jozef Stefan Institute's research reactor. It has been operating since 1966. A probabilistic approach of reactor safety estimation was used first in 1989 when a Probabilistic Safety Analysis (PSA) of the reactor was performed. A lack of reactor component data was found as the major problem in probabilistic assessment. It was decided to continue the work with specific data base development. The project has been divided in two phases. In the first phase specific data from year 1985 to 1990 were collected. In the second phase the collected data were treated. The comparison of generic and specific data showed significant difference between the generic and specific data and leads to a conclusion that a generic data based PSA has a limited credibility indicating that there is a need to build a specific data base for research reactors. The TRIGA MARK II research reactor has three major purposes: operator training, research involving neutrons and isotope production. The paper represents specific data base formation for TRIGA MARK II research reactor in Podgorica. Specific data on reactor scrams, components operation and human errors were collected. The data of fifteen components were estimated by classical and Bayesian method. The results of both methods are very different. Because of good specific data the results of classical methods were preferred. The comparison of specific and generic data showed that there is a great need to build a specific data base for research reactors. It is expected to use the specific data for existing PSA of TRIGA MARK II reactor reevaluation and optimisation of its operation. (authors)