Klinov D.A., Gulevich A.V., Eliseev V.A., Malysheva I.V., Buryevsky I.V.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
In the pre-Chernobyl period, the task of fast reactors was to provide fuel for the intensive development of nuclear energy with a deficit of natural uranium: short doubling time, high HF, high heat intensity, short campaign. After the Chernobyl accident, the main thing was to ensure safety, including in beyond design basis and postulated accidents. Modern fast sodium reactors must, on the one hand, satisfy the
safety requirements in design and beyond design basis accidents (in accordance with the requirements of GEN-IV), and on the other, be competitive in comparison with water reactors and other energy
sources. The article discusses the methods of transformation of the core of existing and planned Russian fast reactors to meet these requirements. The safety of these reactors in design and beyond design basis
accidents is ensured by rejecting the upper end shield and replacing it with a sodium cavity, which allows reducing the NER and ensuring the input of negative reactivity when sodium boils. Such an core is implemented in BN-800 and the designed BN-1200. Improving the competitiveness (increasing the duration of the fuel campaign and KIUM) of the designed and existing reactors is ensured by switching to radiation-resistant clad steel EK164 (currently sold in BN-600, planned in BN-800) and the transition to the core with an axial layer of depleted uranium dioxide (planned for BN-800 and BN-1200). In BN-1200, due to the abandonment of a number of switchgear elements and optimization of the design, a one-and-a-half reduction in metal consumption is achieved. For fuel economy, a ″thick″ fuel rod with a diameter of 9.3 mm and a fuel campaign of 4 years have been adopted. This reduces the annual consumption of fuel rods and fuel assemblies by 2–2.5 times. Both events require modernization of the core. Each of these events allows you to increase the duration of the campaign by 25 %, and the implementation of both measures (transition to new steel and the introduction of a layer) will allow you to increase the campaign and reduce fuel consumption by more than 50 %. The introduction of the axial layer does not require core expansion, which gives additional fuel savings. But the axial layer should not be located in the central plane of the core, but with a shift of 3–5 cm
downward. This will improve many characteristics of the core: increase fuel enrichment by a quarter and, as a result, proportionally reduce the neutron flux and radiation damage to the claddings of fuel elements; increase the fuel campaign to 5 years; to reduce the reactivity margin for burnout, without compromising the effectiveness of the control systems, to increase the micro-campaign to 1 year; to level the heat-release field in the vertical direction, to reduce the maximum heat intensity; to improve the course of beyond design basis accidents like ULOF. This method of reducing the rate of accumulation of a damaging dose is equally effective for both MOX and nitride fuels, which makes it possible to unify the core design.
1. Orlov V., Slesarev I., Zaritsky S. et al. The Theoretical Possibility of Doubling Time Reduction in a Fast Reactors by Using Heterogeneous Configurations of Various Types of Fuel. Proc. on Conf. Fast Reactor Physics. Vienna, IAEA, 1980, vol. 2, pp. 469–480. IAEA-SM-244/76
2. Troyanov M.F., Matveev V.I., Novozhilov A.I. et al. The concept of core of fast energy reactors. Optimization of the physical characteristics of the BN-1600 reactor. Proc. International Symposium on Fast Reactor Physics IAEA-SM-244/81. Aix-en-Provence, France, 1979. (In Russian).
3. Bobrov S.B., Danilychev A.V., Eliseev V.A. et al. Ways of development of fast energy reactors with a high reproduction rate. Atomnaya energiya - Atomic Energy, 1983, vol. 54, no. 4, pp. 269. (In Russian).
4. Bobrov S.B., Kazachkovskij O.D., Matveev V.I., Trojanov M.F. Sravnitel'nye parametry toplivnogo cikla bystryh reaktorov s razlichnoj aktivnoj zonoj [Comparative parameters of the fuel cycle of fast reactors with different cores]. Atomnaya energiya - Atomic Energy, 1989, vol. 64, no. 1, pp. 56–61.
5. Kiryushin A.I., Vasiliev B.A., Matveev V.I. et al. Evolyutsiya aktivnoy zony reaktora BN-600 [Evolution
of the BN-600 reactor core].
Trudy dvustoronnego seminara po fizike bystrykh reaktorov [Proc. bilateral
seminar on fast reactor physics]. Japan, 1992.
6. Matveev V.I., Danilychev A.V., Eliseev V.A. et al. Physical Concept Development of Power Fast Reactor of Maximum attainable Safety Level. Proc. Int. Topical Meeting ″Sodium Cooled Fast Reactor Safety″.
Obninsk, 1994, vol. 3, pp. 4–37.
7. Matveev V.I., Chebeskov A.N., Krivitsky I.Yu. Results of Benchmark Calculations of a Fast Power Reactor with Sodium Void Reactivity Close to Zero. Proc. consultancy on "Benchmark Calculation of Sodium Void Reactivity Effect in Fast Reactor Core". Vienna, 1992.
8. Evaluation of Benchmark Calculations on a Fast Power Reactor Core with Near Zero Sodium Void Effect. Vienna, 1994. IAEA-TECDOC-731
9. NP-082-07. Pravila yadernoy bezopasnosti reaktornykh ustanovok atomnykh stantsiy [Nuclear Safety
Rules for NPP Reactor Plants]. Moscow, Federal Service for Environmental, Technological and Nuclear
Supervision Publ., 2008, no. 1 (47), pp. 52–77.
10. Klinov D.A., Kamaev A.A., Mikhailov G.M. et al. Raschetno-eksperimental'nyy analiz neytronno-fizicheskikh kharakteristik aktivnoy zony reaktora BN-800 na etapakh fizicheskogo puska i posleduyushchego osvoeniya proektnoy moshchnosti [Calculation and experimental analysis of the neutron-physical
characteristics of the core of the BN-800 reactor at the stages of physical start-up and subsequent development of design capacity]. Trudy Mezhdunarodnoy konferentsii po bystrym reaktoram i sootvetstvuyushchim toplivnym tsiklam [Proc. Int. Conf. on Fast Reactors and Related Fuel Cycles (FR17)]. Yekaterinburg, 2017.
11. Alekseev P.N., Balandin A.L., Dekusar V.M. et al. Razvitie fiziko-tekhnicheskikh resheniy po proektu BN-1200 v kontekste povysheniya konkurentosposobnosti tekhnologii BN [Development of physical and technical solutions for the BN-1200 project in the context of increasing the competitiveness of BN technology]. Voprosy Atomnoy Nauki i Tekhniki. Seriya: Yaderno-reaktornye konstanty - Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2018, no. 2, pp. 71–83.
12. Nikitina A.A., Ageev V.S., Leontiev-Smirnova M.V. et al. Razvitie rabot po konstruktsionnym materialam aktivnykh zon bystrykh reaktorov [Development of work on structural materials of core of fast reactors]. Atomnaya energiya - Atomic Energy, 2015, vol. 119, no. 5, pp. 292–300.
13. Schekelin S.E., Tashlykova O.L. Nuclear power plants with fast neutron reactors with sodium coolant. Part 1. The manual under the general. Yekaterinburg, UrFU Publ., 2013 (In Russian).
14. Vasiliev B.A., Evseev Y.Ya., Matveev V.I. etc. Bringing the BN-600 reactor core into stationary overload
conditions. Proc. French-Soviet seminar "Computational and experimental studies in the physics of fast
neutron reactors". Cadarache, France, 1983 (In Russian).
15. Corners V.V. The radiation resistance of DUO of steels irradiated with high-energy xenon ions. Minsk, Belarus, BSU Publ., 2013. (In Russian).
16. Vasiliev B.A., Vasyaev A.V., Zverev D.L. et al. Razvitie proekta energobloka novogo pokoleniya s reaktorom BN-1200 [Development of a new generation power unit project with a BN-1200 reactor]. Trudy
Mezhdunarodnoy konferentsii po bystrym reaktoram i sootvetstvuyushchim toplivnym tsiklam [Proc. Int.
Conf. on Fast Reactors and Related Fuel Cycles (FR17)]. Yekaterinburg, 2017.
17. Vasiliev B.A., Shepelev S.F., Ashshirmetov M.R. et al. Razrabotka proekta energobloka s RU BN-1200 [Development of a design for a power unit with a BN-1200 reactor]. Trudy Mezhdunarodnoy konferentsii
po bystrym reaktoram i sootvetstvuyushchim toplivnym tsiklam [Proc. Int. Conf. on Fast Reactors and
Related Fuel Cycles (FR13)]. France, 2013.
18. Matveev V.I., Khomyakov Yu.S. Technical physics of fast reactors with sodium coolant. Textbook for universities. Moscow, Publishing house MPEI, 2012 (In Russian).
19. Rachkov V.I., Poplavsky V.M., Tsibulya A.M. et al. The concept of a promising power unit with a fast sodium reactor BN-1200. Atomnaya energiya - Atomic Energy, 2010, vol. 108, no. 4, pp. 201–206 (In Russian).
20. Poplavsky V.M., Matveev V.I., Eliseev V.A. et al. Studies on influence of sodium void reactivity effect on the concept of the core and safety of advanced fast reactor. Journal of nuclear science and technology, 2011, vol. 48, no 4, pp. 538–546.
21. Poplavsky V.M., Matveev V.I., Eliseev V.A. et al. Investigation of the effect of the sodium void reactivity effect on the technical and economic characteristics and safety of a perspective fast reactor. Atomnaya energiya - Atomic Energy, 2010, vol. 108, no. 4, pp. 230–235 (In Russian).
