ADVANCED SODIUM COOLED FAST REACTOR BN V. Poplavsky. А. Tsiboulya. А. Каmaev (IPPE. Obninsk) B. Vasiliev. Yu. Каmanin. А. Тimofeev (ОКBМ. N.Novgorod) V. Еrshov. К. Suknev (SPbАEP. St. Petersburg)

Introduction Mastering and development of SFR : implementation BN-350 BN-600 BN МWth 1470 МWth 2100 МWth Under construction Design BMN-170 BN-600М BN-1600 studies 400 МWth 1520 МWth 3850 МWth

Key tasks of new designs BN Achievement of up-to-date safety level; - Implementation of the fuel cycle based on mixed uranium-plutonium and demonstration of its closure and MA incineration Advanced BN -Assurance of competitiveness with further safety improvement - Commercial implementation of advanced fuel cycle

Basic areas of development Max use of gained experience (pool type reactor design. three- circuit heat removal system. design of the main components) Increase of unit power up to 1800 MWe (taking into account trends in the development of thermal reactor design etc.) Increase of thermal efficiency up to ~ 46 % Decrease of the number of systems and components Aiming at high efficiency fuel cycle using high density fuel

Choice of power unit parameters I circuit II circuit Efficiency Phenix* 560/400°С 512/246°С(17.7МPa) 44.5/42.4% Super- Phenix 545/395°С 487/237°С (18.2МPа) 41.5/39.5% EFR °C 490/240°C (18.4МPа) 41.7/39.6% BN-600* 550/377°С 505/240°С (13.7МPа) 42.5/40% BN /354°С 490/210°С (13.7МPа) 41.9/38.8% BN-1800* 575/410°С 525/270°С (25МPа) 46.2/44.5% * - steam reheat by sodium

Reasons for adoption of high parameters mastered technology of the third circuit (fossil fuel plants) successful operating experience of Phenix and BN-600 reactors possibility of introduction of Cr 16Ni11Мo3 steel for high temperature structures instead of Cr18Ni9 steel Tasks related to assurance of high parameters development of high temperature radiation resistant steel for the fuel element cladding development of SG design for supercritical parameters

Main arrangement approaches all primary components and systems are located in the reactor vessel (  =17m): · З primary pumps+ 6 IHX (common suction header) · 2 cold traps cooled by nitrogen · sodium quality control devices number of secondary loops (and SG) - 6 (bellows) DHRS – Air heat exchangers connected to each secondary loop with continuously operating EM pumps number of turbine generators - 1

1 - reactor; 2 -IHX; 3 – pressure compensator; 4 – hydraulic lock; 5 – primary pump; 6 – EM pump; 7 – air heat exchanger; 8 – steam generator; 9 - reheater; 10 – secondary pump; 11 – cold trap; 12 – water heat exchanger BN-1800: flow diagram

Main components Primary pumps (3) – centrifugal, submerged design, 7.8 МW Secondary pumps (6) - centrifugal, submerged design, 2.3МW IHX (6) – counter-flow design with tube bends for thermal expansion compensation CRDM (19 CR, 13 SR. 5 PSR) – electromechanical design SG (6 EV-SH +6 RH) – counter-flow, straight-tube design The most important goal of components development is to assure max life time and min repair work with high reliability (for the plant: 60 years life time, load factor  0.9)

BN-1800 reactor

Reactor core Pancake type (Н=0.8m; D=5.2m) with the upper sodium plenum Nitride fuel. Fuel element  8.6х0.55 mm. SA 184х3.5 mm Single enrichment (~15% Pu+MA in equilibrium state) q e max =41/30 kW/m (468 SA/174 SA) Т об max =3(4)х500 ef, days. В max =12.2% h.а. Temperature and power reactivity effect = -0.9%. Burn-up reactivity effect = -0.3%. SVRE = +0.2% BR = (without blanket – with blanket)

Map of the BN-1800 reactor core

Characteristics of steam generator

Refueling system Fresh fuel storage and cooling pool for one reactor loading In-vessel refueling system · Straight type refueling mechanism · L-type refueling mechanism · vertical elevator Ex-vessel refueling system (without fresh and spent fuel storage drums) · SA transfer mechanism located on the rotating table · cells for SA heating - 5 · cells for SA washing - 3 · inclined elevator

1. Механизм перегрузки L - образного типа 2. Поворотные пробки 3. Колонна СУЗ 4. Механизм перегрузки прямого типа 5. Элеватор загрузки – выгрузки 6. Машина перегрузочная 7. Стол поворотный 8. Привод стола поворотного 9. Гнезда разогрева 10. Гнездо свинцовой отмывки 11. Гнезда паровой отмывки 12. Механизм извлечения защитной пробки 13. Механизм герметизации пеналов 14. Бассейн выдержки 15. Наклонный подъемник шахты выдачи 16. Поворотная печь 17. Наклонный подъемник склада свежего топлива 18. Склад свежего топлива 19. Реактор Refueling system of the BN-1800 reactor

High safety assurance design approaches adopted for the BN-600 and BN-800 assurance of passive operation of CR in case of temperature increase improvement of DHRS reliability (permanent readiness state) no primary sodium piping improvement of confinement systems

Metal consumption of BN-1800 reactor plant, t/МWe

BN-1800 power unit

Technical and economical characteristics of BN-1800

Conclusion BN-1800 reactor power unit meats requirements for breeder of 21 st century: * its economical characteristics are comparable with those of VVER * it assures BR=1-1.3 and possibility of МА incineration * it assures high efficiency of non-proliferation (closed fuel cycle with МА) * it is characterized by high safety Key areas of R&D work * development of new structural materials for the fuel element cladding and high density fuel element design * development of vessel-type steam generator design for supercritical parameters Estimated design development period ~7-10 years