Heat exchanger equipment of TPPs & NPPs

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1 Heat exchanger equipment of TPPs & NPPs Lecturer: Professor Alexander Korotkikh Department of Atomic and Thermal Power Plants TPPs Thermal power plants NPPs Nuclear power plants

2 Content Steam Generator Sodium sodium HE Steam boiler

3 Introduction Steam generators are among the most responsible heat exchange equipment supplied to nuclear power plants..

4 Steam generators for NPPs with VVER reactors Steam generators for NPPs with VVER reactors are a recuperative heat exchanger with an immersed heat exchange surface made of horizontally arranged U-shaped heat exchange coils.

5 Modifications of SG Steam generators for power units with VVER- 440 and VVER-1000 reactors are produced for domestic and foreign nuclear power plants. At present, the ZiO-Podolsk Machine-Building Plant has manufactured and supplied more than 220 steam generators. Steam generators for NPPs with VVER-1000 are manufactured in two versions: PGV-1000M and PGV-1000U. *SG-steam generators

6 "ZiO-Podolsk machinebuilding plant

7 "ZiO-Podolsk Steam generators have been delivered to nuclear power plants in Russia, Ukraine, Armenia, Finland, Germany, Cuba, Bulgaria, Iran, China, India.

8 Technical characteristics of PGV-1000 PGV-1000M Thermal power, MW Steam capacity rate, kg/s PGV- 1000U Steam temperature at the outlet, C 278,5 278,5 Steam pressure, MPa 6,27 6,27 Steam humidity at the outlet,% 0,2 0,2 Feed water temperature, С Hydraulic resistance in the first circuit, MPa 0,12 0,17 Material of the coolant collector heat-resistant stainless steel SG length, m 14,75 14,75 Case diameter, m 4,21 4,21 Weight, ton heat-resistant stainless steel

9 Switching scheme PGV- 1000M

10 Location of SG in the hermetic shell 1 - "Hot" collector; 2 - "Cold" collector.

11 Conceptual arrangement of PGV-1000М

12 Problems of operation of the PGV-1000M at the NPP Cracks in connectors of cold collectors detected on SG No. 1 in 1988, 2SG-2 in 1989, 2SG-3 in This problem has been massive in all NPPs with VVER-1000 reactors since the end of Invalidity of the level meter readings due to clogging of the impulse line of 4 meter leveling vessel and installation of level meters from different sides of SG: the "cold" and "hot" ends of SG.

13 Problems of operation of the PGV-1000M at the NPP The problem of corrosion of the metal of SG pipe system from the side of the second circuit is the damage of the heat exchange tubes due to corrosion. The accumulation of sludge occurs in the region of 2-4 spacing grids from the "hot" collector towards the "cold" end, due to the small multiplicity of the circulation in this region.

14 Problems of operation of the PGV-1000M at the BalNPP The problem of corrosion of the metal of SG pipe system from the side of the second circuit is the damage of the heat exchange tubes due to hideout corrosion. The accumulation of sludge occurs in the region of 2-4 spacing grids from the "hot" collector towards the "cold" end, due to poor circulation in this region.

15 Steam generators PGN-200M for NPPs with FN reactor PGN-200M is a rectilinear heat exchanger consisting of eight sections connected in parallel to the working media. It is designed to produce high-pressure superheated steam.

16 Description of the steam generator PGN-200M Each section consists of 3 modules: an evaporator, a superheater and an intercooler, combined though pipelines on water, steam and sodium. The motion of the media in the steam generator is counter current. Sodium moves from top to bottom. The modulesshaped design makes it possible to quickly replace modules that have worked out their time and, if necessary, cut off problem modules without stopping the reactor.

17 Section of steam generator PGN-200M 1 - evaporator; 2 superheater; 3 - intermediate superheater; 4 - slab-displacer; 5 - removable cover; 6 - pipe board; 7 - bellows; 8 - nozzles of sodium inlet in the EV from SH and ISH; 9 - inlet chamber of coolant.

18 Thermal diagram of power unit 1-reactor; 2-main circulation pump of 1st circuit; 3- intermediate heat exchanger; 4- fuel assemblies; 5-steam generator; 6-buffer and collecting tanks; 7-main circulation pump of 2nd circuit; 8-turbine installation; 9- generator; 10-transformer; 11- condensers; 12-circulation pumps; 13-condensate pumps; 14-preheaters; 15-deaerator; 16-feed pump; 17-pond-cooler; 18-electricity supply to consumers.

19 Technical parameters of steam generator PGN-200M Evaporator heating surface, m (255x8) Heating surface of superheater, m (146x8) Heating surface of intermediate superheater, m (224x8) Total mass of steam generator in the "dry" state, ton 775 Total mass of steam generator in working state, ton 914

20 Technical characteristics of steam generator PGN-200M Parameter 1. Thermal power, MW 2. Sodium consumption rate, kg/s 3. Temperature of sodium, C at the entrance (not higher than) at the exit 4. Steam capacity rate, kg/s 5. Feed water temperature, C 6. Temperature of hot steam, C (not higher than) 7. Pressure of hot steam, MPa 8. Steam flow of intermediate superheater, kg/s 9. Steam temperature at the inlet of the interm. superheater, C 10. Temperat. of steam at the outlet of the interm. superheater, C 11. Temperat. of sodium at the inlet to evaporates C 12. Steam pressure at the inlet to the interm. superheater, Mpa Value

21 Brief characteristics of modules Name EV SH ISH 1. Diameter and wall thickness of pipes, mm 2. Length of pipes, mm 3. Number of heat exchange tubes, pcs. 4. Pitch of tubes along a triangle, mm 5. Cross-section of the shell space, m 2 6. Surface of heat exchange by external diameter, m 2 7. Pipe cross-section, m 2 8. Volume of sodium, m 3 9. Volume of water (steam), m Weight in drained state, t 16x x x

22 Basic formulas for thermal calculations in PGN-200M Q isp D 1 c p1 t' 1 t'' 1 D 2 i' 2 i 2pv D 2 r 2 D 2 i 2pp i'' 2 D f F isp 1 Q isp F isp k isp.sr s.g t log.isp.sr t b t m t log.sr 2.3 log t b t m

23 Basic formulas for thermal calculations PGN-200M 5. k 1 1 s ok ok 1 s tr tr Nu 1 d ekv 7. d ekv 4 F P

24 TQ - diagram of the evaporation module Na Water

25 Na-Na heat exchangers for NPPs with BN reactors In addition, in PGN-200M steam generators at NPPs with fast neutron reactors, the key element of the 3rd heat circuit is a Na-Na heat exchanger. The Na- Na heat exchanger is an integral part of the fast neutron reactor with the sodium coolant of the nuclear steam generating unit and is designed to transfer heat from the circulating heat transfer medium (sodium) of the primary circuit circulating in the intertube space to the heat medium (sodium) of the second (intermediate) circuit, circulating inside the pipes.

26 Intermediate HE Type of heat exchanger - vertical, shell-and-tube, with coaxial supply and removal of coolant of the second circuit, counter-flow. The heat exchanger consists of a pipe system, pressure and discharge chambers, a central pipe, a protection unit, a safety hood and fixation items.

27 Intermediate HE The pipe system consists of 2 tube boards, upper and lower, connecting and profiling shells, heat exchanging pipes and rods with spacer parts. The heat exchanger, as an intermediate one, ensures reliability of operation, radiation safety, excludes the entry of radioactive components of the coolant into the turbine.

28 Intermediate HE The heat exchanger successfully fulfilled the assigned service life as a part of the Beloyarsk NPP reactor facility. Based on the results of the technical condition survey, the life of the heat exchanger has been extended for another 5 years. Work is being conducted to extend the life of the heat exchanger to 40 years.

29 Technical parameters of Na-Na HE 1st circuit 2nd circuit Thermal power, MW 350 Coolant flow rate, kg/s Rated pressure, MPa 0,05 0,85 Nominal temperature of coolant C: at the inlet at the outlet Heat transfer surface, m Heat exchanger weight including mounting parts, t

30 Steam boilers Steam boilers are specialized boiler plants designed for the production of saturated or superheated steam. They can use the energy of fuel burned in their furnaces, electric energy (electric steam boiler) or utilize the heat released in other units (waste heat boilers). Classification according to purpose: Energy steam boilers are designed for steam production used in steam turbines. Industrial steam boilers - produce steam for technological needs, they are so-called "industrial steam generators". Steam heat recovery boilers - for the production of steam use secondary energy resources heat of hot gases formed in the technological cycle. Energy recovery boilers in the steam generators make use of the heat of the gas turbine exhaust gases.