Authors & Affiliations
1. A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
2. National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow, Russia
Sorokin A.P. – Deputy Director of Safety Department, Dr. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering.
Konovalov M.A. – graduate student, National Research Nuclear University "Moscow Engineering Physics Institute".
The research work on a purification system of liquid metal with sodium coolant advanced NPP is aimed on increasing efficiency and capacity purification system, built-in the reactor vessel. Suggestion is usage of hot trap instead of cold trap in a primary circuit for purification coolant at normal operational regimes and in idle regimes from dissolved oxygen, which is pose danger due to high cor-rosion activity. However cold traps are capable to perform purification of sodium from hydrogen and tritium and retain them along with purification sodium from oxygen. The research results, performed earlier, shows that the increased concentration of hydrogen in sodium, up to concentration of 50 ppm, don't influence on nuclear and physical characteristics of the reactor. In the primary circuit of NPP the limitation factor of maintaining concentration hydrogen at the level lower than 50 ppm is crystallization of hydrogen impurity at the lower temperature of the circuit, which is equal 250°C the idle operational regime, as well as formation a caustic phase in the presence an oxygen, which is raising corrosion intensity of constructional materials corrosion in dozens of times. Main danger of tritium is associated with radiational safety of environment (feed water, introduces into the environment and diffusion tritium through pipelines into the environment). We have analyzed behavior of hydrogen and tritium in circuit of advanced NPP of high power in various regimes of operation, considering information mentioned before. It’s been shown, that concentration of hydrogen in sodium doesn't exceed a solubility limit at 250°C and concentration of tritium in the feed water arriving to environment doesn't exceed standards of safety in modes during plant start-up works and after abnormal coolant pollution, using the “fast cleaning mode” even if there is no purification systems in the primary circuit. However during purification in the idle mode it is necessary to use of small-sized cold traps for hydrogen removal or use hydrogen purification system with the pump through special membranes. More acceptable option, according to authors, is the use of purification system with a pump.
fast reactor, regimes of operation, sodium coolant, purification, hydrogen, tritium, cold trap, hot trap, oxygen, concentration, temperature, Solubility, crystallization, evacuation, corrosion of structural materials
1. Alekseev V.V., Kovalev Yu.P., Kalyakin S.G., Kozlov F.A., Kumaev V.Ya., Kondratiev A.S., Matyukhin V.V., Pirogov E.P., Sergeev G.P., Sorokin A.P., Torbenkova I.Yu. Sistemy ochistki natrievogo teplonositelya AES s reaktorom BN-1200 [Systems for cleaning the sodium coolant of the nuclear power plant with the BN-1200 reactor]. Teploenergetika - Thermal Engineering, 2013, no. 5, pp. 9-20.
2. Kozlov F.A., Alekseev V.V., Kovalev Yu.P., Kumaev V.Ya., Matyukhin V.V., Orlova E.A., Pirogov E.P., Sorokin A.P., Shcherbakov S.I. Issledovaniya v obosnovanie sistemy ochistki natriya dlya bystrykh reaktorov [Studies in support of the sodium purification system for fast reactors]. Atomnaya energiya - Atomic Energy, 2012, vol. 112, no. 1, pp. 18-24.
3. Kozlov F.A., Konovalov M.A., Sorokin A.P. Ochistka getterami zhidkometallicheskikh sistem s natrievym teplonositelem ot kisloroda [Purification of liquid metal systems with sodium coolant from oxygen by getters]. Teploenergetika - Thermal Engineering, 2016, no. 5, pp. 1-7.
4. Kozlov F.A., Sorokin A.P., Alekseev V.V., Konovalov M.A. Tekhnologiya vysokotemperaturnogo natrievogo teplonositelya v yadernykh energeticheskikh ustanovkakh dlya vodorodnoy energetiki [Technology of high-temperature sodium coolant in nuclear power plants for hydrogen power]. Teploenergetika - Thermal Engineering, 2014, no. 5, c. 1-9.
5. Alekseev V.V., Sorokin A.P., Orlova E.A., Kondratiev A.S., Torbenkova I.Yu., Varseev E.V. Massoperenos i korroziya stali v natrii pri vysokikh kontsentratsiyakh vodoroda [Mass transfer and corrosion of steel in sodium at high hydrogen concentrations]. Obninsk, IPPE Publ., 2014. pp. 73-83.
6. OST 95 10582-2003. Natriy reaktornoy chistoty dlya reaktorov BN. Tekhnicheskie trebovaniya i metody kontrolya primesey [Sodium of reactor purity for BN reactors. Technical requirements and methods for controlling impurities]. Obninsk, IPPE Publ., 2003.
7. Normy radiatsionnoy bezopasnosti (NRB-99/2009) [Norms of radiation safety (NRB-99/2009)]. Available at: http://profbeckman.narod.ru/RR0.files/L16_5.pdf (accessed 01.08.2017).
8. Kozlov F.A., Poplavsky V.M., Alekseev V.V., Tsikunov A.G., Vorobyeva T.A. Modelirovanie massoperenosa tritiya v trekhkonturnoy YaEU s natrievym okhlazhdeniem [Simulation of the mass transfer of tritium in a three-circuit NPS with sodium cooling]. Atomnaya energiya - Atomic Energy, 2005, vol. 98, no. 3, pp. 175-182.
9. Alekseev V.V. Massoperenos tritiya i produktov korrozii konstruktsionnykh materialov v konturakh s natrievym teplonositelem. Diss. dokt. tekhn. nauk [Mass transfer of tritium and corrosion products of structural materials in circuits with sodium coolant. Dr. tech. sci. diss]. Obninsk, IPPE Publ., 2002.