Safety Ensuring in the Design of Small and Medium Sized NPPs

Transcription

1 Technical Meeting on Challenges in the Application of the Design Safety Requirements for Nuclear Power Plants to Small and Medium Sized Reactors Vienna, 4-8 September 2017 Safety Ensuring in the Design of Small and Medium Sized NPPs V.M. Belyaev, A.N. Pakhomov, K.B. Veshnyakov

2 OKBM Reactor Technologies: Experience and Development Foundation of proven technologies and development Great experience in development and operation of marine reactor plants Experience is the best of all evidences F. Bacon Key fields of activities: - Standardization of engineering decisions for the entire power range; - Increase of reliability, safety, manoeuvrability; - Reduction of the scope of maintenance, increase of service operation between repairs. Great experience in development and operationof nuclear icebreakers reactor plants Experience in development and fabrication of reactor plants for the floating nuclear power plants Total number of reactor plants is 20 pcs. (including 7 RPs installed on the acting nuclear icebreakers). More than 50 years of 3 generations of nuclear icebreakers operation in the Arctic region. Total operating time is more than 400 reactor-years. Two innovation RITM-200 RPs have been supplied for the first of a kind multipurpose nuclear icebreaker. Two RPs have been supplied for the FNPP Academician Lomonosov confirming the efficiency of combining the functions of Chief Designer and Complete Supplier of KLT-40S RP. Proven reactor technologies and innovation solutions are available. 2

3 Marine Technology-Based Small and Medium NPP Designs Developed by JSC "Afrikantov OKBM" KLT ABV Thermal power MW Electric power 4-10 MW Unified reactor plants with integral reactors and 100 % natural circulation in the primary circuit for land-based and floating NPPs Thermal power 150 MW Electric power 38.5 MW Serial modular reactors of nuclear icebreakers and ships, for floating and land-based NPPs 3 Design ABV Type KLT Type RITM Type VBER Type Refueling Interval, years Service life, years * Development stage - The final design is developed for the prototype reactor plant and Volnolom floating NPP(1993). - The feasibility study is developed for construction of the floating NPP with ABV-6M for the Far North (settlement Tiksi, settlement Ust-Kamchatsk, 2006) and the thermal NPP for Kazakhstan (City of Kurchatov, 2007). - The land-based prototype test facility is in operation with 100% natural circulation (at FSUE NITI ). - The final design in being developed for a transportable reactor plant under the contract with Minpromtorg (RF Ministry of Industry and Trade) * In 2011, a complete delivery was completed of two reactor plants for the first floating NPP Academician Lomonosov *-possibilityofextensionupto60years * (complete delivery in 2016) are being manufactured. Serial deliveries of reactor units for two consequent nuclear ice- Two reactor plants for the first multipurpose icebreaker breakers willbein2017 and Technical and commercial proposal for the two-unit NPP with VBER-300 Reactor Plant (2002) - Preliminary design of the reactor plant approved by Scientific and Technical Board No. 1 and State Nuclear Supervision Body (GosAtomNadzor) (2004) - Technical assignment for the NPP design and for final designs of the reactor plant, automated process control system and heat-generating plant; Feasibility, Economy and Investment studies for NPP with VBER-300 RP at Mangistaus Region in Kazakhstan ( ). -Developmentofthe100>600 MW VBERRPpowerrange ( ). - Research and development work on the NPP design with VBER-460/600 RP( ). - Development of the VBER-600/4 RP based uponthe heat exchange loop with increased capacity ( ) RITM Thermal power 175 MW Electric power up to 50 MW Integral reactor with forced circulation for the multipurpose nuclear icebreaker, floating and land-based NPPs VBER Thermal power MW Electric power MW Modular reactor based upon marine technologies for landbased and floating NPPs

4 Application of Small Nuclear Power Sources FLOATING PLANTS GROUND-BASED PLANTS UNDERWATER POWER UNITS MODULAR-TRANSPORTABLE POWER UNITS Autonomous heat and power supply to the consumers of hard-to-reach areas Power supply to oil-production platforms Desalinated water supply(in cooperation with desalination units) 4

5 Floating NPP Based on FPU with Two KLT-40S RPs THE DESIGN OF THE SMALL COGENERATION NUCLEAR POWER PLANT (CNPP) IS PILOT. THE FPU IS BEING TESTED. RP EQUIPMENT SUPPLY WAS COMPLETED IN THE NPP STARTUP DATE IS SUPPLY TO CONSUMERS IS AS FOLLOWS ELECTRIC POWER 20A70 MW HEAT 50A146 Gcal/h Small CNPP FPU with KLT-40S RPs SPENT FUEL AND RADWASTE STORAGE REACTOR PLANTS STEAM-TURBIN E PLANTS UNDERWATER TRENCH 145X45 DEPTH, 9 M HYDRO ENGINEERING FACILITIES HEAT POINT DEVICES FOR DISTRIBUTING AND TRANSFERRING ELECTRIC POWER TO CONSUMERS HOT WATER CONTAINERS SALT WET STORAGE CONTAINER 5

6 Floating NPPs are a New Class of Power Sources The power unit comprises two reactor plants, two turbine plants, electricpower system, refueling complex, nuclear fuel and radioactive waste storage, accommodations. An autonomous power unit is mounted on the non-self-propelled barge. The number of offshore facilities and requirements for them are minimal. The power unit is supplied to the operation site by water on a turnkey basis after completed acceptance tests. After completion of four cycles, it is transported to a specialized enterprise to be repaired. It is possible to change the power unit location site. After decommissioning on termination of the service life, the floating power unit is transported to its disposal site providing retention of the green lawn state in the floating NPP operation area. 6

7 Safety Related KLT-40C RP Design Features SG and MCP are connected with reactor through short nozzles There are no lengthy primary circuit pipelines of big diameter Steam generator vessel operates under the primary circuit pressure No safety valves to protect the steam generator vessel from excess pressure; No primary coolant release while localizing a tube system leak Use of Canned main circuit pumps: Absence of primary coolant leaks Absence of the sealing water system Absence of the lubrication system Linking-up of all make-up system nozzles with hot sectors of primary circuit; Presence of restrictions Maximum scale of possible primary circuit depressurization is 25 mm 7

8 Promotion Ways to Increase FPU Commercial Appeal Optimization of RP systems FPU with KLT-40S RP Exclusion of accommodation from the FPU design At shore settlement Exclusion of refueling complex and storage of spent fuel and solid radwaste from the FPU design Total assigned life time -40 years Time to intermediate repair - 12 years Time between core refueling years Refueling complex and Spent Fuel storage on the FPU board Floating technical support and maintenance base with transportation to FPU location Maintaining of FPU operation without refueling at the location site till dock(factory) repair 8

9 Advanced FPU a New Concept of its Operation Multipurpose icebreaker FPU with RP KLT-40S Service life 40 years 1 medium repair Core power margin up to 7TW h Reduction of RP R&D duration and cost due to standardization of RP for multipurpose icebreaker and FPU Standardization of the main technical decisions and equipment for NPP and FPUasawhole Service life 40 years 2 medium repairs Core power margin up to3 TW h Ensuring of operation without refueling at location site till dock(factory) repair Refueling complex and Spent fuel storage at the FPU board Advanced FPU with RITM-200М RP 9

10 RITM-200М RP. Main Engineering Solutions 1. The RP has integral design of the reactor with forced circulation of the primary coolant and remote gas pressure compensation system. 2. Composition and structure of the RP systems are designed considering experience gained while developing the previous plant generation, requirements of the up-to-date norm safety documentation, ToR requirements with regard to weight-dimensional characteristics and reduction of liquid radwaste. 3. The main design approach is rational combination of passive and active safety means and trains, optimal use of the normal operational and safety systems. Passive pressure reduction and cooling down systems are introduced (efficiency of the systems is confirmed by bench testing); Pressure compensation system is divided in two independent groups to minimize diameter of coolant leak; Main circulation path of the primary circuit is located in a single vessel; Header scheme of primary coolant circulation is introduced, which ensures advanced vitality of the plant during SG and MCP failures. 10

11 KLT-40S and RITM-200М RP. Comparative Characteristics Characteristic KLT-40S RITM-200М Total assigned service life, h/year 300,000/40 320,000/40 Assigned life time/service life till factory repair, h/years 100,000/12 160,000/20 Number of medium repairs 2 1 Mass of two RPs in the containment, t Containment dimensions for two RPs LхWхH, m 12х17.2х12 6.8х14.6х16.0 Core refueling interval, years 2.5 (3.0) 10 RCP power, kw 4х152 4х97 Minimal coolant temperature during hydraulic test at the end of operation, 0 С Passive heat removal, h 24 Time until core uncovery in a passive accident scenario with primary leakage, h

12 Arrangement of KLT-40S RP and RITM-200M RP in the Containment KLT-40S RITM-200М RPweightinthecontainment-1870t RPdimensionsinthecontainment 12х7.9х12m 12 RPweightinthecontainment-1300t RPdimensionsinthecontainment 6.8х6.7х16.0m

13 KLT-40S and RITM-200М RP. Comparative Characteristics Characteristic FNPP with two RP KLT-40S RITM-200М 1 Electric power(el.), MW 38.5х2 50х2 2 Staff ratio (for FRU), per/mw(el.) FNPP/FPU Construction cost, rel.units 1/1 0.75/ FNPP/FPU construction unit cost, rel.unit/mw(el.) 1/1 ~ 0.58/0.5 5 Energy prime cost, rel.un/mw*h

14 SAFETY CONCEPT The safety concept of the reactor plants is based on state-of-the-art defensein-depth principles combined with developed properties of reactor plant selfprotection and wide use of passive systems. Properties of intrinsic self-protection are intended for power density selflimitation and reactor self-shutdown, limitation of primary coolant pressure and temperature, heating rate, primary circuit depressurization scope and outflow rate, fuel damage scope, maintaining of reactor vessel integrity in severe accidents and form the image of a passive reactor, resistant to all possible disturbances. The RP designs were developed in conformity with Russian laws, norms and rules for ship nuclear power plants and safety principles developed by the world community and reflected in IAEA recommendations. 14

15 Safety Levels FUEL COMPOSITION 2 FUEL ELEMENT CLADDING 3 PRIMARY CIRCUIT 4 RP CONTAINMENT 5 PROTECTIVE ENCLOSURE 15

16 Emergency Reactor Shut Down System 4 System of liquid absorber injection (pumps and valves are connected to emergency diesel generators) 1 Reactor 2 CRD mechanisms 3 System of liquid absorber injection 4 Make-up and born control systems 5 Electric power circuit-breaker by pressure 16 Electromechanical system of reactivity control. Automatic insertion of absorber rods in the core under gravity Electric power circuit-breakers by pressure provide de-energizing of CPS drive mechanisms (reactor shutdown): by pressure increase in the primary circuit by pressure increase in the containment

17 Emergency Reactor Heat Removal Systems Design option (KLT-40S) 1Reactor 2 Steam generator 3 Reactor coolant pump 4 Water tank with in-built heat exchangers 5 Purification and cooling down system 6 Technological condenser 6 Technological condenser Purification and cooling down system Hydraulically operated distributors Opening of pneumatically driven valves of ECCS passive trains by primary circuit overpressure (cooldown) Passive cooling trains with water tanks and in-built heat exchangers ensure reliable cooling during 24 hours without tank make-up. 17

18 Emergency Reactor Heat Removal Systems Steam to atmosphere Design option (RITM-200М) Steam to atmosphere Air heat exchanger Steam Steam Water Steam generator Water Heat exchanger Application of combined systems with heat transfer to water and air with no time limitations Core 18

19 Emergency Core Cooling Systems Passive emergency core cooling system Emergency make-up system (pumps and valves are connected to emergency diesel generators) Reactor 2. Steam generator 3. Reactor coolant pump 4. ECCS hydraulic accumulator 5. Makeup system 6. Recirculation system Recirculation and repair cooling down system 1 (pumps and valves are connected to emergency diesel generators) 19

20 Innovative Safety Systems Active and passive EHRS - A single initiation algorithm in active and passive modes -Effective passive heat removal under low temperature in the primary circuit Containment against high pressure(1 МPa) -Counterpressure on the coolant leaking from reactor 20 RP safety ensuring during unlimited period of time using passive means in all types of accidents including LOCA of more than three days

21 System of Emergency Pressure Decrease in Containment Conditioning system blower SEPD (preservation of safety barrier containment) -is based on the passive operating principle -interconnects areas in the containment -condensates the steam on heat exchangers in the containment and due to barbotage 21

22 Analysis of a Postulated Severe Accident Retention of the molten corium in the reactor vessel Reactor pressure vessel Molten corium Reactor caisson Results of the sever accident analysis -Absence of submelting of the RPV wall -Reliable heat removal from the reactor bottom outer surface is ensured -Reactor mechanical properties are maintained at the level sufficient to ensure load bearing capacity despite appeared temperature difference -Radiation dose for population in case of beyond design accident with severe core damage does not exceed 5 msv Cooling water supply 22

23 Resistance to External Impacts The RP is substantiated to be resistant to external impacts: Rolls and tilts in accordance with the requirements of the Russian Maritime Registry of Shipping; Impact resistance of not less then 3 g; Reactor shutdown and containment preservation in case of flood, including in case of turnover; Crash of a helicopter with the mass of 10 t from the height of 50 m. The performed comprehensive analysis of the FPU resistance in case of natural impacts has demonstrated that there are no radiation consequences: In case of a seismic impact of up to X-XIIdegrees with vertical acceleration not exceeding 1.8 m/s 2 ; Within 24 hours for sure after full FPU blackout; In case of a tsunami due to appropriate location site selection and the use of purpose-built hydraulic structures. 23

24 Radiation and Environmental Safety BUFFER AREA PROTECTIVE ACTION PLANNING AREA 1 km POPULATION RADIATION DOSE RATE UNDER NORMAL OPERATION CONDITIONS AND DESIGN BASIS ACCIDENTS DOES NOT EXCEED 0.01% OF NATURAL RADIATION BACKGROUND POPULATON IS ALLOWED TO LIVE IN THE PROTECTIVE ACTION PLANNING AREA. NO COMPULSORY EVACUATION PLANNING AREA 24

25 Non-proliferation Issues KLT-40 S with Refueling at a Site Fuel complex Exporting country Waste storage Reprocessing Discharge of spent fuel Fabrication of fresh fuel Loading of fresh fuel into the reactor Third country Fresh fuel transportation FNPP transportation with fresh fuel inside the reactor Importing country Local infrastructure Floating NPP Fresh fuel loading Reactor Industrial complex FNPP repairing Retired FNPP disposal New FNPP construction FNPP transportation with spent fuel inside the reactor and storage Spent fuel unloading Temporary fuel storage 25

26 Non-proliferation Issues KLT-40 S with Refueling at a Site Fuel complex Exporting country Waste storage Reprocessing Unloading and temporary storage of spent fuel Fabrication of fresh fuel Loading of fresh fuel into the reactor Third country Importing country Local infrastructure FNPP transportation with fresh fuel inside the reactor Floating NPP Industrial complex FNPP repairing Retired FNPP disposal New FNPP construction Reactor FNPP transportation with spent fuel inside the reactor 26

27 Conclusion JSC Afrikantov OKBM has developed and is implementing innovative Reactor plant designs enabling to create a power range of NPPs of various applications and arrangements. The designs provide high technical-and-economic indices, referentiality of the applied technical solutions and their safety is well substantiatedand confirmed by many years operation of analogues and prototypes. RITM-200M Reactor plant has advantages from the viewpoint of safety, weight-size parameters and technical-and-economic indices. From the viewpoint of non-proliferation, FNPP with reactors, which operate without refueling at a site, are the most attractive.proliferation resistance of such NPPs may be estimated to be very high. 27