KR101548142B1 - Energy conversion cycle for the steam produced by a sodium-cooled fast neutron reactor - Google Patents

Abstract

The present invention is based on the idea that the first expansion of the vapor coming from the steam generator 2 associated with the neutron furnace 1 leads from the "fossil fuel cycle" initial state 21 to the temperature of the vapor corresponding to the " And a first stage in which the second expansion of the vapor from the intermediate state 22 is in the first wet state 23 under which the vapor saturation curve S is located, A third stage in which the steam is dried and overheated and a third stage in which the third expansion of the steam is performed from its superheated state (24) to the second wetted state (25) To the energy conversion cycle for the vapor produced by the fast neutron furnace.

Description

COOLED FAST NEUTRON REACTOR FOR ENERGY CONVERSION CYCLE FOR THE STEAM PRODUCED BY A SODIUM-COOLED FAST NEUTRON REACTOR BACKGROUND OF THE INVENTION [0001]

The present invention relates to an energy conversion cycle for converting energy supplied by a sodium cooled fast neutron (so-called sodium fast neutron flux - FNR).

The present invention relates to nuclear facilities including at least nuclear reactors, steam generators, steam turbines and dryers and / or superheaters.

The gas or liquid water circulates through the unit in the closed circuit and is subjected to temperature and pressure variations.

The term "cycle " refers to a change in the temperature and pressure of the gas or liquid water between the outlet of the steam generator and its return to the steam generator.

In order to obtain the best cycle efficiency, it is advantageous to use sodium-cooled fast neutrons.

However, at the outlet from the sodium cooled fast neutron furnace the temperature and pressure values are much higher than those normally encountered in the "nuclear cycle" and approach the things commonly encountered in "fossil fuel cycle".

"Nuclear cycle" corresponds to a change in temperature and pressure generally encountered in steam-operated nuclear plants, which generally come from the outlet of the steam generator, and the steam is close to the saturation curve.

The "fossil fuel cycle" uses a fossil fuel combustion boiler to respond to changes in temperature and pressure that are commonly encountered in a thermal power station.

The sodium cooled fast neutron furnace (FNR) of the French Pheonix power station allows operation with steam operating at temperatures and pressures close to those encountered in "fossil fuel cycles" Utilize a steam turbine technique that causes the steam to expand as it passes through the high-pressure turbine and the intermediate-pressure turbine.

The temperature and pressure conditions in the different components of the plant, i.e. turbine and superheater, should not be too high to have an operating life of around 60 years.

Low temperatures reduce the risk of creep in different components. EP 0 163 564 relates to a high-speed neutron furnace having a steam generator integrated with a reactor vessel.

In this regard, the gist of the present invention is an energy conversion cycle for the steam produced by the sodium-cooled fast neutron furnace which improves the service life of the equipment.

To do this, the energy conversion cycle for the vapor produced by the sodium cooled fast neutron furnace of the present invention is

A first expansion of the steam coming from the steam generator associated with the neutron source is performed to induce the steam from the initial state of "fossil fuel cycle" to the intermediate state of the temperature and pressure of the steam corresponding to the " stage,

A second stage in which a second expansion of the vapor from the intermediate state is carried out until a vapor of the first wet state located below the vapor saturation curve is obtained,

A third stage in which the steam is dried from its first wet state and overheated to induce the vapor in a dry and superheated state located above the saturation curve, and

Characterized in that the third expansion of the steam is carried out from its superheated state to a second wet state located below the vapor saturation curve and the steam is subsequently condensed and re-introduced into the steam generator.

The cycle to the sodium cooled fast neutron as claimed in the present invention is further placed in the zone of the saturated vapor than the cycle of the prior art sodium cooled fast neutron, operating at the same temperature and pressure conditions directly at the outlet of the steam generator, This condition is close to that encountered at the thermal power station.

The cycle as claimed in the present invention leads to an increase in efficiency as compared to that currently obtained with the French Sodium Fast Neutron (FNR) power station.

This cycle can be used for high power neutron furnaces up to a class of more than 1500 MWe.

The present invention allows the sodium cooled fast neutron furnace to be used with standard components currently used for fossil fuel or nuclear power stations.

Thus, the present invention makes it possible to avoid the implementation of superheaters such as those used for the French sodium-cooled fast neutron (FNR) power station, and these superheaters are difficult to design and expensive to manufacture.

The steam is at a pressure comprised between 150 and 200 bar and at a temperature comprised between 450 and 570 ° C in the initial "fossil fuel cycle" state.

The intermediate state is defined for the pressure contained in 30 to 50 bar and for the temperatures contained in 234 to 300 占 폚.

The vapor in the first wet state is at a temperature comprised between 152 and 188 ° C and a pressure comprised between 5 and 12 bar after the second expansion.

The steam in its dry and superheated state is at a temperature comprised between 215 and 255 ° C and a pressure comprised between 5 and 12 bar.

In its final state, the vapor condenses at temperatures dependent on the cooling source used.

The present invention also relates to a steam turbine installation comprising a sodium cooled fast neutron furnace, for the implementation of the cycle defined above,

At least one steam generator,

An ultra high pressure / high temperature turbine connected to the steam generator to the neutron, wherein the first expansion of the steam from the steam generator to the neutron is changed from the initial state of the "fossil fuel cycle" to the temperature and pressure of the steam corresponding to the "nuclear cycle" High temperature / high temperature turbine,

An intermediate turbine connected to an ultra-high pressure / high temperature turbine and partially operating with saturated steam, wherein a second expansion of the steam is performed from the intermediate state until a vapor of the first wet state located below the vapor saturation curve is obtained, turbine,

A dryer and a superheater connected to the intermediate turbine, wherein the steam is dried from its first wet state and then overheated to induce steam in a dry and superheated state located above the saturation curve, and

An outlet turbine connected to the dryer and the superheater, the third expansion of the steam being performed from its superheated state to the second wetted state, and the steam then being condensed and re-directed to the steam generator will be.

Advantageously, the pipe connecting the outlet from the superhigh pressure turbine and the superheater causes the heated steam to be discharged to the downstream side of the superhigh pressure turbine, and the steam is used by the superheater.

The intermediate turbine is a high pressure turbine, and the outlet turbines are medium and low pressure turbines or only low pressure turbines. The low pressure turbine is supplied in parallel.

The high pressure turbine and the intermediate pressure turbine (when this is present in the second embodiment) are arranged in a combined unit.

The ultra high pressure / high temperature turbine and the intermediate turbine are included at a temperature comprised between 152 and 188 ° C after the first expansion and the second expansion from the initial state of the fossil fuel cycle at a pressure comprised between 150 and 200 bar and a temperature comprised between 450 and 570 ° C And is arranged to inflate the vapor in a wet vapor state where the pressure is comprised between 5 and 12 bar.

The dryer and the superheater comprise a pressure from 5 to 12 bar from an initial wet vapor state in which the temperature is comprised between 152 and 188 ° C and the pressure is comprised between 5 and 12 bar after the second expansion and the temperature is between 215 and 255 ° C To allow the steam to pass through the drying and superheating conditions contained in the steam.

The ultra high / high temperature turbine, the intermediate turbine and the outlet turbine (without intermediate pressure turbine) rotates the alternator input shaft at a network frequency, for example at 3000 rpm, producing less than 1200 MWe of power.

The ultra-high / high temperature turbine, the intermediate turbine and the outlet turbine (with the intermediate pressure turbine) rotate the alternator input shaft, which generates power in excess of 1200 MWe, for example at 1500 rpm, at half the network frequency.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood and its advantages become more apparent by a reading of the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically depicts a first embodiment as claimed in the present invention of a sodium cooled fast neutron beam (FNR).
Figure 2 schematically depicts a second embodiment as claimed in the present invention of a sodium cooled fast neutron beam (FNR);
Figure 3 shows an example of a close proximity to the portion of the cycle used in the sodium-cooled fast neutron flank (FNR) of the French Phoenix Power Station in curve A, and of a cycle as claimed in the present invention used in the sodium cooled fast neutron furnace in curve B. Enthalpy diagram, also referred to as the Mollier diagram, showing an example of a portion of the enthalpy diagram.

The cycle as claimed in the present invention as shown in FIG. 3 is a sodium cooled fast neutron (1, 1 ') that causes energy to be released to generate steam in the steam generators 2, 2' Can be implemented by two different steam turbine plants each presenting turbines 3, 3 ', intermediate turbines 4, 3 "and outlet turbines 5, 4', 5 ', respectively, Is suitable for rotating the input shafts 6a, 6a 'of alternating current generators 6, 6'.

The high pressure / high temperature turbines 3, 3 'are connected to one or more steam generators 2, 2' of the neutron reactors 1, 1 'by one or more pipes, From the initial state of the "fossil fuel cycle" at the outlet from the steam generator 2, 2 'of the neutron furnace 1, 1' to the intermediate state of the temperature and pressure of the steam, .

The valves V, V 'allow the flow rate of the steam coming from the steam generator (s) 2, 2' to be adjusted.

In the first embodiment shown in Fig. 1, the intermediate turbine is a high-pressure turbine 4 connected to an ultra-high pressure / high temperature turbine 3, which mainly operates with saturated steam by a pipe.

The high pressure turbine 4 allows the second expansion of the vapor to be performed from the intermediate state corresponding to the "nuclear cycle" initial state until the steam is obtained in the first wet state below the saturation curve S.

The drying and superheating of the steam is carried out by successively passing into the dryer 7 which physically separates the liquid water and the steam and then into the superheater 8 which are connected to the high pressure turbine 4 and the low pressure turbine 5 Is located within the pipe (12).

The discharge of the steam exiting the superheater 8 and the ultra high pressure / high temperature turbine 3 located downstream of the dryer 7 and the upstream side of the low pressure turbine 5 causes superheat of the steam, Lt; / RTI > The pipe 13 connecting the outlet from the superhigh-pressure turbine 3 and the superheater 8 causes the heated steam used by the superheater 8 on the downstream side of the superhigh-pressure turbine 3 to be exhausted.

The two low pressure turbines 5 fed in parallel and connected to the dryer 7 and the superheater 8 by the pipe 12 cause the third expansion of the vapor to take place from its superheated state to its final state. More than two low pressure turbines 5 may be used to perform this third expansion.

The water recovered from the dryer (7) and from the superheater (8) is again circulated by the pipe (11).

The systems 9, 10 of the condenser, reheater and pump are used to direct the condensed steam into the steam generator 2, but are not described here and known from the prior art.

This facility produces power in the order of 600 to 1200 MWe.

In the second embodiment shown in Fig. 2, the intermediate turbine is a high pressure turbine 3 "connected to an ultra high pressure / high temperature turbine 3 '

The high pressure turbine 3 "enables the second expansion of the vapor from the intermediate state corresponding to the" nuclear cycle "initial state until the steam is obtained in the first wet state below the saturation curve S.

The drying and superheating of the steam is carried out by successively passing into the dryer 7 which physically separates the liquid water and steam and then into the superheater 8 which are connected to the high pressure turbine 3 '' and the intermediate pressure turbine 4 ' As shown in Fig.

The discharge of steam exiting the superheater 8 'and the ultra high pressure / high temperature turbine 3' located downstream of the dryer 7 'and upstream of the intermediate pressure turbine 4' causes the steam to overheat, S). ≪ / RTI >

The pipe 13 'connecting the outlet from the superhigh pressure turbine 3' and the superheater 8 'causes the heated steam on the downstream side of the superhigh-pressure turbine 3' used by the superheater 8 'to be exhausted .

The high pressure turbine 3 "and the intermediate pressure turbine 4 ' are shown in FIG. 2 as being arranged in a single combined unit.

The intermediate pressure turbine 4 'and the two low pressure turbines 5', which are fed in parallel and connected to the intermediate pressure turbine 4 'by a pipe 12', have a third expansion of the steam from its superheated state to its final state . More than two low pressure turbines 5 'may be used to perform this third expansion.

At the level of the dryer 7 ', the water recovered from the superheater 8' is again circulated by the pipe 11 '.

The systems 9 ', 10' of the condenser, reheater and pump are used to direct the condensed steam into the steam generator 2 ', but are not described here and known from the prior art.

As shown in FIG. 3, the Mollier diagram expresses the entropy on the horizontal axis and the enthalpy of the fluid on the vertical axis.

In particular, this allows the fluid to change state as a function of temperature and pressure.

Here, the fluid is water, and the saturation curve S of water is shown in this diagram.

The saturation curve S corresponds to the limit between the two areas and for a given entropy the water is in the form of dry vapor over an enthalpy greater than the enthalpy of the saturation curve S and below the enthalpy of the saturation curve S, Takes the form of saturated steam (or wet steam) for low enthalpy. The name of the dry saturated steam is provided in the state of water just above the saturation curve (S). The water content of the wet steam increases as the enthalpy decreases until the water content of 1 is achieved when all vapor conditions condense to the liquid state.

In other words, the saturation curve S bounds the region of the saturated wet vapor S2 over the gas region of the dry superheated vapor S1.

Curve A represents a cycle similar to that used for the Fast Phoenix Neutron (FNR) of the French Phoenix Power Station.

Curve B represents the cycle used for the sodium cooled fast neutron beam (FNR) as claimed in the present invention.

In the cycle of curve A of the prior art, the vapor coming from one or more steam generators to the neutron is at a temperature of about 500 캜 and a pressure of about 180 bar.

After the first expansion in the super-high pressure turbine between points 11 and 12, the steam is at a temperature of about 250 DEG C and a pressure of the order of 30 bar.

The steam is then superheated to point 13. Between points 12 and 13, the temperature increases from 250 ° C to 380 ° C, while the pressure remains constant throughout, to about 30 bar.

The steam is then expanded to point 14 by an intermediate pressure turbine. Between points 13 and 14, the pressure decreases from 30 bar to 5 bar and the temperature decreases from 380 ° C to 180 ° C.

The steam is then expanded to the point 15 by the low pressure turbine.

The system of condensers and heat exchangers and pumps allows the condensed vapor to be re-injected into the vapor generators or generators to the neutrons.

In the cycle as claimed in the present invention, the steam coming from the steam generators or generators 2, 2 'of the neutron furnace 1, 1' has a temperature of about 500 ° C and a temperature of about 180 bar, and this initial state is shown by point 21 which coincides with point 11.

However, in the "nuclear cycle ", the initial point generally approximates the saturation curve S.

Thus, the first expansion leads to a vapor at a temperature of 500 DEG C at point 21 and a pressure of 180 bar into an intermediate state having a temperature and pressure corresponding to point 22, which is a property close to the initial point of the "conventional nuclear cycle ".

Thus, the first expansion leads the vapor to a point 22 corresponding to the "nuclear cycle" initial state located above the saturation curve S from point 21.

At point 22, the vapor is at a temperature of substantially 280 ° C and a pressure of 40 bar in FIG.

The vapor expands between point 22 and point 23 in the first wet state.

At point 23, the vapor is at a temperature of substantially 170 DEG C and a pressure of 7 bar.

The steam is dried at point 23 from its first wet state to the first dry heated state represented by point 24, and is superheated, and the pressure remains substantially constant.

At point 24, the steam is at a temperature of substantially 240 DEG C and a pressure of 7 bar.

The vapor is then expanded between point 24 and end point 25.

At point 25, the steam is at a temperature of substantially 35 ° C and a pressure of 60 mbar.

These values are provided by way of example only and depend on the heat source at point 21 and the vapor conditions provided to the cooling source at point 25.

For point 21, the steam may be arranged to be at a temperature comprised between 450 and 570 캜 and at a pressure comprised between 150 and 200 bar in the "fossil fuel cycle"

For point 22, the vapor may be arranged to be at a temperature comprised between 234 and 300 ° C and a pressure comprised between 30 and 50 bar after the second expansion.

For point 23, the vapor may be arranged to be in a first wet state, at a temperature comprised between 152 and 188 ° C after the second expansion and at a pressure comprised between 5 and 12 bar.

For point 24, after drying and superheating, the vapor may be arranged to be at a temperature comprised between 215 and 255 ° C and at a pressure comprised between 5 and 12 bar.

For point 25, the vapor is condensed in a second wet state, at a temperature dependent on the cooling source used for the neutron furnace after the third expansion.

Claims (15)

A method of energy conversion for a vapor produced by a sodium cooled fast neutron furnace,
The first expansion of the vapor coming from the steam generator 2 associated with the neutron furnace 1 is shifted from the "fossil fuel cycle" initial state 21 to the middle of the temperature and pressure of the vapor corresponding to the " A first stage, which is performed to induce the steam into a state (22)
- a second stage in which a second expansion of the vapor from the intermediate state (22) is carried out until the vapor of the first wet state (23) located below the vapor saturation curve (S)
- a third stage in which the steam is dried from the first wet state (23) and superheated to induce the vapor to a dry and overheated state (24) located above the saturation curve (S)
- a third expansion of the steam is carried out from the superheated state (24) to a second wetted state (25) located below the vapor saturation curve (S), the steam being condensed and re-introduced into the steam generator 4 stages,
In the "fossil fuel cycle" initial state 21, the steam is at a pressure comprised between 150 and 200 bar and at a temperature comprised between 450 and 570 ° C,
Wherein said intermediate state (22) is defined for a pressure comprised between 30 and 50 bar and a temperature comprised between 234 and 300 ° C. delete delete The method of claim 1, wherein the vapor in the first wet state (23) is at a temperature comprised between 152 and 188 ° C and a pressure comprised between 5 and 12 bar after the second expansion. The method of claim 1, wherein said steam in said drying and superheating state (24) is at a temperature comprised between 215 and 255 ° C and a pressure comprised between 5 and 12 bar. The method of claim 1, wherein in said second wet state (25) said vapor is condensed at a temperature dependent on the cooling source used. A steam turbine installation comprising a sodium-cooled fast neutron furnace (1, 1 '), said steam turbine installation comprising, for implementation of the energy conversion method according to claim 1,
- at least one steam generator (2, 2 '),
- an ultra high pressure / high temperature turbine (3, 3 ') connected to said steam generator (2, 2') of said neutron furnace (1, 1 '), said steam generator (2, 2' ) Is performed to derive the vapor from the "fossil fuel cycle" initial state (21) to the intermediate state (22) of the temperature and pressure of the vapor corresponding to the "nuclear cycle" initial state , The ultra-high-pressure / high-temperature turbine (3, 3 '),
- an intermediate turbine (4, 3 '') connected to said ultra-high / high temperature turbine (3, 3 ') and partially operating with saturated steam, said second expansion of said steam being located below said vapor saturation curve Is carried out from the intermediate state (22) until the steam of the first wet state (23) is obtained, the intermediate turbine (4, 3 "
- a dryer (7, 7 ') and a superheater (8, 8') connected to said intermediate turbine (4, 3 "), said steam being dried from its first wet state (23) (7, 7 ') and the superheater (8, 8'), which direct the steam to a dry and superheated state (24)
- an outlet turbine (5, 4 ', 5') connected to said dryer (7, 7 ') and said superheater (8, 8'), said third expansion of said vapor from an overheated state (24) Is carried out up to a state 25 and the steam is condensed and is led to the steam generator 2, 2 'again, comprising the outlet turbines 5, 4', 5 '
In the "fossil fuel cycle" initial state 21, the steam is at a pressure comprised between 150 and 200 bar and at a temperature comprised between 450 and 570 ° C,
Wherein the intermediate state (22) is defined for a pressure comprised between 30 and 50 bar and a temperature comprised between 234 and 300 占 폚. The steam turbine according to claim 7, wherein pipes (13, 13 ') connecting the outlet of the super high pressure turbine (3, 3') and the superheater (8, 8 ' , And said steam is used by said superheater (8, 8 '). 8. The steam turbine installation according to claim 7, wherein the intermediate turbine is a high pressure turbine (4) and the outlet turbines are low pressure turbines (5) supplied in parallel. 8. A steam turbine installation according to claim 7, wherein the intermediate turbine is a high pressure turbine (3 ") and the outlet turbines are an intermediate pressure turbine (4 ') and low pressure turbines (5') supplied in parallel. 11. The steam turbine installation according to claim 10, wherein the high pressure turbine (3 '') and the intermediate pressure turbine (4 ') are arranged in a combined unit. The turbine of claim 7, wherein the ultra-high pressure / high temperature turbine (3, 3 ') and the intermediate turbine (4, 3 ") have a pressure comprised between 150 and 200 bar after the first expansion and the second expansion, (21) at a temperature comprised within the temperature range of 152 to 188 DEG C and the pressure is in the range of 5 to 12 bar so as to expand the steam to a wet steam state (23) Steam turbine equipment. 8. A method according to claim 7, characterized in that the dryer (7, 7 ') and the superheater (8, 8') are arranged such that the temperature after the second expansion is between 152 and 188 < Wherein the steam is passed from the wet steam state (23) to a dry and superheated state (24) in which the pressure is comprised between 5 and 12 bar and the temperature is comprised between 215 and 255 ° C. 8. A method as claimed in claim 7, characterized in that the high pressure / high temperature turbine (3), the intermediate turbine (4) and the outlet turbines (5) Steam turbine installations. 8. The turbine of claim 7, wherein the high pressure / high temperature turbine (3 '), the intermediate turbine (3' ') and the outlet turbines (4', 5 ') generate power in excess of 1200 MWe A steam turbine arrangement for rotating an alternator input shaft (6 ').

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