Evaluation of computer codes for nuclear safety analyses in the Czech Republic

The paper informs about the system of evaluation of computational programs for nuclear safety analyses in the Czech Republic as implemented by the State Office for Nuclear Safety (SUJB) in the Czech Republic. The quality and capability of qualified use of computer programmes in nuclear safety assessment processes is as important as the quality and qualification of any nuclear safety-relevant component and is subject to the legislative requirements contained, i.a., in SUJB Decree No. 408 on Management System Requirements. The procedure for evaluating computational codes is contained in the SUJB VDS 030 Internal Guideline for Evaluation of Computer Codes for Nuclear Safety Analyses. A key document of the evaluation process is a test protocol in which the applicant - code user - demonstrates how the code is able to simulate selected test cases (experiments, operational data, simulations with other approved calculation codes), as well as its own ability to apply the code competently without a negative user effect. The test process does not replace validation & verification process done by authors of the code. As examples, results of test cases for the evaluation of TRACE code in high temperature helium application, ATHLET code in supercritical water application, and MELCOR code in the application for selected PHEBUS and STEM experiments are provided. (author)