Achievements and future directions in the reactors physics and nuclear safety research

A historical overlook is presented with respect to inception and development of reactor physics research and on the job training in Romania. First these activities were carried out at the Institute for Atomic Physics and Institute for Power Reactors (IRNE) in Bucharest and afterward at the Institute for Nuclear Technologies, later on transformed in the Institute of Nuclear Research at Pitesti. CYBER Computer installed at Pitesti allowed formation in as early as 1971 reactor specialists who worked out computer programs for neutron physics calculations. These specialists were able to assimilate the characteristic of CANDU 6 type reactor as well as the AECL methodology of simulating processes of CANDU reactor physics. At present four programs are under way. These are: 1. The nuclear reactor physics; 2. The nuclear facility safety; 3. Safety analyses for the transport and radioactive waste disposal; 4. Analyses for radiation shielding and biological protection. There are presented results of the work associated to the CANDU type reactor: 1. Adapting and improving the code system for neutron and thermohydraulic calculation for CANDU type reactor, as supplied by AECL; 2. The IRNE manual for CANDU reactor neutron designing; 3. Final sizing of shim rods of Cernavoda NPP Unit 2; 4. Tests and measurements of reactor physics at the Cernavoda NPP Unit 1 commissioning; 5. Simulation and independent analysis of thermosiphoning carried out at Cernavoda NPP Unit 1 commissioning; 6. Static and dynamical response of the detectors in the CANDU reactor core and their time evolution following the burnup in the neutron flux and their ageing effects; 7. PSA studies at Unit 1; 8. Safety analyses for the radioactive waste disposal at Saligny repository. Also, reported are the results of the work associated to the TRIGA reactor, as follows: 1. Flux measurements and neutron computations necessary in the reactor commissioning; 2. Cleaning up controversial issues relating to neutron flux measurements; 3. Enrichment rate determination for the Romanian fuel to be tested in TRIGA - SSR; 4. Neutron monitoring in irradiation testings; 5. The TRIGA - SSR conversion from the HEU type fuel to the LEU type fuel. Also, reported is the work on the multi-zone reactor, a research reactor providing facilities of irradiation with both thermal and fast neutron. An important achievement of the INR - Pitesti in the field of reactor physics was the development of methods, algorithms and original computation programs many of which are known world wide. Mentioned are the codes: TIME, EXTERMINATOR, CITATIONS, ANISN, WIMS, TWOTRAN, THERMOS. LASER, HEROIC, MULTICELL, PIJXYZ GRENADE, DIREN. The last two sections deal with the international cooperation and the prospective directions of work. Among the last ones mentioned are: - Preparations for Cernavoda NPP Unit 2 Commissioning; - Risk analyses for Cernavoda NPP Unit 1 and Unit 2; - Advanced reactors and advanced fuel burnup cycles