Justification of the Safety of the Upgraded Reactor SM and the Main Results of the Experimental Research Program at the Start of the Reactor

6/05/2024 2024 - #02 Global safety, reliability and diagnostics of nuclear power installations

Paydulov A.V. Malkov A.P. Pimenov V.V. Vorobey A.O. Uzikov V.A. Polyakova T.A.

https://doi.org/10.26583/npe.2024.2.07

The paper focuses on the justification of SM reactor safety and a program of experiments once the reactor was launched after the refurbishment of its core and change in the neutron trap configuration.

The high-flux research reactor SM has the status of a unique scientific facility. A new configuration of its neutron trap allows for significant enhancement of its safety and widening of experimental capabilities.

The experiments performed at the critical assembly gave key data to justify safety of the refurbished reactor. To justify the core hydro-profiling, the coefficients of heat rate unevenness in typical core cells were determined in the activation experiments.

Once the refurbishment was completed, the fuel was loaded into the core stage by stage and experiments were performed in the refurbished reactor to specify its neutronic characteristics important for safety.

The reactor and its systems were prepared for the startup after the refurbishment; fuel assemblies were step-by-step inserted into the core.

The sensitivity and stability of new control- and-safety system equipment was tested.

The reactivity parameters of the refurbished SM core were evaluated by calculations and experiments. The efficiency values, calibration characteristics of control rods, reactivity margin and core subcriticality were determined. The temperature effect and power effects of reactivity were evaluated and their values were measured; the stationary poisoning with 135Xe and 149Sm were estimated.

The reactor was brought to the designed power on October 10, 2020 one month earlier than planned by the Project. All major refurbishment activities were performed by RIAR’s specialists, including design and development, manufacturing of core components, dismantling, start-up and commissioning. Reactor refurbishment will increase the scope of ongoing R&D and radioisotopes accumulation by 40%. The reactor has become more reliable and safer, its lifetime can be extended beyond 2040.

References

1. Krasnov Yu.A., Lichadeev V.V., Malkov A.P., Petelin A.L., Ryazanov D.K., Shimanskii G.A. Сomputational- experimental studies of the neutronics of the SM reactor with different variants of the neutron-trap arrangement. Atomic Energy. 2009, vol. 107, no. 2, pp. 77 – 84. DOI: https://doi.org/10.1007/s10512-009-9199-x
2. Malkov A.P., Krasnov U.A., Petelin A.L., Pimenov V.V. The influence of the neutron trap layout on the physical and operational characteristics of the reactor SM. Izvestiya vuzov. Yadernaya Energetika, 2010, no. 2, pp. 3 – 9 (in Russian).
3. Izhutov A.L., Petelin A.L., Malkov A.P., et al. The SM-3 reactor core modernization program. XXI Russian Conference «Safety of Research Nuclear Installations», Dimitrovgrad, May 20-24, 2019: Abstracts of reports. Dimitrovgrad, RIAR JSC Publ., p. 17. Available at: http://niiar.ru/sites/default/files/conproc/tezisy_dokladov_iyau_2019_.pdf (accessed Apr. 5, 2024) (in Russian).
4. Federal norms and rules in the field of atomic energy use. Rules of nuclear safety of research reactors. NP-009-17. Moscow, 2017 (in Russian).

SM reactor neutron trap neutron-physical characteristics core reactivity effects calibration characteristics

Link for citing the article: Paydulov A.V., Malkov A.P., Pimenov V.V., Vorobey A.O., Uzikov V.A., Polyakova T.A. Justification of the Safety of the Upgraded Reactor SM and the Main Results of the Experimental Research Program at the Start of the Reactor. Izvestiya vuzov. Yadernaya Energetika. 2024, no. 2, pp. 83-92; DOI: https://doi.org/10.26583/npe.2024.2.07 (in Russian).