CA1041776A - Turbine bypass control system and method for a nuclear power plant - Google Patents
Turbine bypass control system and method for a nuclear power plantInfo
- Publication number
- CA1041776A CA1041776A CA261,738A CA261738A CA1041776A CA 1041776 A CA1041776 A CA 1041776A CA 261738 A CA261738 A CA 261738A CA 1041776 A CA1041776 A CA 1041776A
- Authority
- CA
- Canada
- Prior art keywords
- turbine
- signal
- valve
- control valve
- bypass control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Control Of Turbines (AREA)
Abstract
TURBINE BYPASS CONTROL SYSTEM AND
METHOD FOR A NUCLEAR POWER PLANT
ABSTRACT OF THE DISCLOSURE
A turbine bypass control system for a nuclear power plant having a turbine bypass circuit connecting the steam outlet of a nuclear reactor to a condenser by bypassing a steam turbine and including at least one bypass control valve and at least one on-off valve connected in parallel with each other, and a turbine bypass control method of a nuclear power plant for effecting control of pressure in the reactor by using the bypass control valve and the on-off valve in combination at the time of load rejection and turbine trip. The bypass control valve is adapted to be actuated by a control signal for adjusting the degree of opening thereof and a rapidly opening signal for causing the same to be rapidly brought to an open position, while the on-off valve is adapted to be actuated by the rapidly opening signal.
METHOD FOR A NUCLEAR POWER PLANT
ABSTRACT OF THE DISCLOSURE
A turbine bypass control system for a nuclear power plant having a turbine bypass circuit connecting the steam outlet of a nuclear reactor to a condenser by bypassing a steam turbine and including at least one bypass control valve and at least one on-off valve connected in parallel with each other, and a turbine bypass control method of a nuclear power plant for effecting control of pressure in the reactor by using the bypass control valve and the on-off valve in combination at the time of load rejection and turbine trip. The bypass control valve is adapted to be actuated by a control signal for adjusting the degree of opening thereof and a rapidly opening signal for causing the same to be rapidly brought to an open position, while the on-off valve is adapted to be actuated by the rapidly opening signal.
Description
'76 1 This invention relates to a turbine bypass control system and method for a nuclear power plant having a nuclear reactor, particularly a boiling-water reactor. .
Heretofore, a turbine bypass circuit for a :~
nuclear power plant equipped with a boiling-water reactor is known which bypass circuit is provided with control valves having a total capacity to permit a rated steam volume to pass therethrough so that excess steam in the 10 nuclear reactor can be released therefrom without ::
scramming the nuclear reactor at -the time of load ~ ~ :
rejection or turbine trip. Another turbine bypass circuit is also known which is provided with control valves having a total capacity which is at a level below a rated steam volume for effecting control of pressure in the nuclear reactor in a stable manner in starting and shutting down the nuclear power plant. The prior art referred to above is described in detail in a paper ~ :
entitled "A Characteristic of Control System for Nuclear ~ .
Turbine1' of "Hi-tachi Hyoron", Vol. 53, No. 6, pp. 13 to 19, published in June, 1971.
The present tendency is that the latter turbine :
bypass system is further provided, as a safety device, with means for causing the relief valve of the nuclear reactor 25 to forcedly perform a steam releasing operation so as to :~
eliminate the need to scrarn the nuclear reactor at the -time of load rejection or other accident.
The abovementioned turbine bypass control systems of the prior art have the disadvantages of requiring a . -~0 control mechanism of a complex construction and being - 1 - ~ , . .
~ 43~7~6 1 high in co~t.
Accordingly, an object of this invention is to provide a turbine bypass control system which obviates the aforementioned disadvantages of the prior art and ., .
can be produced at low cost because its construction is relatively simple.
Another object of the invention is to provide a turbine bypass control system which enables control of -pressure in the nuclear reactor to be effected in a stable ;
manner when the nulcear reactor plant is started and shut down, and which eliminates the need to scram the nuclear reactor at the time of load rejection and turbine trip.
Still another object of the invention is to provide a turbine bypass control method for effecting control of pressure in the nuclear reactor without scramming the nuclear reactor at the time of load rejection and turbine trip.
In accordance with this invention, there is provided a turbine bypass control system for a nuclear !;;
power plant wherein a nuclear reactor, a steam control valve, a steam turbine and a condenser are connected `
together by conduits in the indicated order, such turbine bypass control system comprising a turbine bypass circuit `~
including at least one bypass control valve and at least 25 one on-off valve connected in parailel with one another .
and connecting the steam outlet of the nuclear reactor to . ;
the condenser, first signal supply means for supplying a `-"
control signal to the bypass control valve for adjusting `
the degree of opening of the bypass control valve so as to maintain the pressure in the nuclear reactor at a ' ' '
Heretofore, a turbine bypass circuit for a :~
nuclear power plant equipped with a boiling-water reactor is known which bypass circuit is provided with control valves having a total capacity to permit a rated steam volume to pass therethrough so that excess steam in the 10 nuclear reactor can be released therefrom without ::
scramming the nuclear reactor at -the time of load ~ ~ :
rejection or turbine trip. Another turbine bypass circuit is also known which is provided with control valves having a total capacity which is at a level below a rated steam volume for effecting control of pressure in the nuclear reactor in a stable manner in starting and shutting down the nuclear power plant. The prior art referred to above is described in detail in a paper ~ :
entitled "A Characteristic of Control System for Nuclear ~ .
Turbine1' of "Hi-tachi Hyoron", Vol. 53, No. 6, pp. 13 to 19, published in June, 1971.
The present tendency is that the latter turbine :
bypass system is further provided, as a safety device, with means for causing the relief valve of the nuclear reactor 25 to forcedly perform a steam releasing operation so as to :~
eliminate the need to scrarn the nuclear reactor at the -time of load rejection or other accident.
The abovementioned turbine bypass control systems of the prior art have the disadvantages of requiring a . -~0 control mechanism of a complex construction and being - 1 - ~ , . .
~ 43~7~6 1 high in co~t.
Accordingly, an object of this invention is to provide a turbine bypass control system which obviates the aforementioned disadvantages of the prior art and ., .
can be produced at low cost because its construction is relatively simple.
Another object of the invention is to provide a turbine bypass control system which enables control of -pressure in the nuclear reactor to be effected in a stable ;
manner when the nulcear reactor plant is started and shut down, and which eliminates the need to scram the nuclear reactor at the time of load rejection and turbine trip.
Still another object of the invention is to provide a turbine bypass control method for effecting control of pressure in the nuclear reactor without scramming the nuclear reactor at the time of load rejection and turbine trip.
In accordance with this invention, there is provided a turbine bypass control system for a nuclear !;;
power plant wherein a nuclear reactor, a steam control valve, a steam turbine and a condenser are connected `
together by conduits in the indicated order, such turbine bypass control system comprising a turbine bypass circuit `~
including at least one bypass control valve and at least 25 one on-off valve connected in parailel with one another .
and connecting the steam outlet of the nuclear reactor to . ;
the condenser, first signal supply means for supplying a `-"
control signal to the bypass control valve for adjusting `
the degree of opening of the bypass control valve so as to maintain the pressure in the nuclear reactor at a ' ' '
- 2 - ;
.-. .. :
':
~./a 4~L7t~
1 set leve], and a second signal supply means for supplying a rapidly opening signal to the bypass control valve and the on-off valve for rapidly bringing them to open positions at the time of load rejection and turbine trip.
In accordance with the invention, there is also provided a turbine bypass control method of a nuclear power plant for effecting control of pressure in the nuclear reactor by releasing excess steam therefrom through a turbine bypass circuit at the time of load rejection and turbine trip, such turbine bypass control method comprising the steps of providing in the turbine bypass circuit at least one bypass control valve and at least one on-off valve connected in parallel with each other in the bypass circuit, sensing the occurrence of load rejection and turbine trip and rapidly opening the bypass control valve and the on-off valve, gradually ~-closing the bypass control valve in accordance with a decrease in the pressure in the nuclear reactor, and 20 bringing the on-off valve to a fully closéd position when `
the bypass control valve has been brought to a fully closed position and then bringing the bypass control valve to an open position again whereby the bypass control valve can be rendered operative to effect control. i-Fig. 1 is a systematic view of the turbine -bypass control system comprising one embodiment of the invention;
Flg. 2 is a time chart showing the process for controlling pressure in the nuclear reactor by using the ~`~
bypass control valves and the on-off valves of the turbine :. .. : . . . ~ . . . ~
~,~4~q6 1 bypass circuit shown in Fig. l; and ~ ig. 3 is a sequence circuit diagram showing the manner in which the bypass control valves and the on-off valves of the turbine bypass circuit are actuated in interlocking relationship in the nuclear reactor power control process shown in ~ig. 2.
A preferred embodiment of the invention will now be described with reference to the accompanying drawings. Generally denoted by the numeral 1 is a nuclear power plant which comprises a boiling-water reactor 2 including a steam outlet 3 connected to a steam turbine 9 through a conduit 4, a main stop valve 5, a conduit 6, a steam control valve 7 and a conduit 8. ~he turbine 9 has a generator 10 directly connected thereto 15 and includes a steam outle-t ll connected to a condenser -13 through a conduit 12. The condensate from the condenser 13 is returned to the nuclear reactor through a conduit 16 by means of a pump 15 connected to the condenser 13 through a conduit 14.
- There is provided, between the conduit 4 connected to the nuclear reactor steam outlet 3 and the .
condenser 13, a turbine bypass circuit generally designated 9 by the numeral 17 for providing an auxiliary steam passage which bypasses the turbine 9. The turbine bypass circuit ;'-17 includes a plurality of turbine bypass valves (eight in number in the embodiment shown in Fig. 1) connected in parallel with one another in the turbine bypass circuit 17 and having a total capacity which is equal to a 100%
rated steam volume of the nuclear power plant. ~he 30 turbine bypass valves comprise at least one bypass `
1q~4~!7t76 1 control valve or two bypass control valves 18 and 19 in - :
the embodiment shown, and at least one on-off valve or six on-of~ valves 20, 21, 22, 23, 24 and 25 in the embodiment shown, ~he bypass control valves and on-off valves 18 to 25 are in closed positions when a control signal or a rapidly opening signal, subsequen-tly to be described, is not supplied thereto.
First signal supply means comprises a low value gate 26 for supplying control signals 27 and 28 to the steam control valve 7 and the b~pass control valves 18 and 19 of the turbine bypass circuit 17, respec-tively, for adjusting the degree of opening of these valves.
A speed error signal 31 obtained by deducting a turbine .- , speed signal 30 representing the actual turbine speed ~ .
from a speed-load setting signal 29 which determines the speed of the turbine 9 is inputed to the low value gate 26. At the same time, a pressure error signal 34 :~
obtained by deducting a pressure setting signal 33 for determining the steam pressure in the nuclear reactor 2 20 from a main steam pressure signal 32 representing the ~:
actual steam pressure in the nuclear reactor 2 is also inputed to the low value gate 26. Of the speed error signal 31 and the pressure error signal 34. inputed to the low value gate 26, the signal of the lower value is 25 outputed from the low value gate 26 as the control signal :
27 for adjusting the degree of opening of the steam control valve 7. The control signal 28 supplied to the bypass control valves 18 and 19 for adjusting the degree ~:~
of opening thereof is obtained by deducting the control signal 27 from the pr ssure error signal 34.
-- 5 -- , .
~)4i7t76 1When the nuclear power plant 1 is at normal operating level, the pressure error signal 34 is smaller in value than the speed error signal 31. In such case, the pressure error signal 34 is used as the control signal 27 for adjusting the degree of opening of the steam control valve 7, and the control signal 28 for adjusting the degree of opening of the bypass control valves 18 -and 19 is cancelled and becomes zero. Accordingly, although the degree of opening of the steam control valve 7 is adjusted, the bypass control valves 18 and 19 are inoperative or closed. On the other hand, when control of pressure in the reactor 2 is effected in starting or shutting down the nuclear power plant 1 or after load rejection has occurred, the speed error signal 31 is 15 smaller in values than the pressure error signai 34~`~
In such case, the speed error signal 31 is used as the control signal 27 for adjusting the degree of opening of the steam control valve 7~ and the control signal 28 for adjusting the degree of opening of the bypass control 20 valves 18 and 19 is also generated. Thus both the steam control valve 7 and the bypass control valves 18 and 19 .;,. . .
have their degree of opening adjusted. --Second signal supply means comprises a power load unbalance relay 35 for supplying a rapidly closing 25 signal 36 for rapidly closing the steam control valve 7 and a rapidly opening signal 37 for rapidly opening the turbine bypass valves 18, 19, 20 9 21 ~ 22 ~ 23 ~ 24 and 25 to the steam control valve 7 and the turbine bypass valves 18 to 25 J respectively, at the time of loadr~
~O rejection. A first stage pressure signal 38 representing . .
''`' ., ' ' 7~76 1 the turbine power and a signal 39 representing the power output of the generator 10 are inputed to the power load unbalance relay 35, which is adapted to produce the rapidly closing signal 36 to be supplied to the steam control valve 7 and the rapidly opening signal 37 to be supplied to the turbine bypass valves 18 to 25 when a difference in value is suddenly produced between the first stage pressure signal 38 and the signal 39 representing the power output of the generator 10. The rapidly opening signal 37 for the turbine bypass valves 18 to 25 is supplied to all the turbine bypass valves 18 to 25, in the event that lOO~o load rejection occurs when the nuclear power plant 1 is operating at lOO~o rated load.
However, in the event that all the load is rejected when the nuclear power plant 1 is operating at 70~o load, the rapidly opening signal 37 is only supplied to the turbine bypass valves of the minimum number or six valves `
which are sufficient to cause steam of a volume corresponding to the level of load rejection to pass through the turbine bypass circuit 17. Attention is directed to the fact that, in the latter case, the bypass control valves 18 and 19 are included at all times in the six turbine bypass valves to which the rapidly opening signal 37 is supplied.
~here is also provided a known mechanism (not ~-shown) which is adapted to rapidly close the main stop ;
valve 5 and to rapidly open the turbine bypass valves 18 to 25 at the time of turbine trip.
~he bypass control valves 18 and 19 and the on-off valves 20 to 25 o-f the turbine bypass circuit 17, - . ., ~ ~ ; , .~ . . . .
7~
1 which are closed at the time of load rejection or turbine trip, are successively closed in a specifically interlocking relationship subsequently to be described, ;;
since the volume of steam passing through the turbine bypass circuit 17 decreases as the reactor power of the nuclear reactor 2 is subsequently reduced.
The steam generated in the nuclear reactor 2 has its flow rate adjusted by the steam control valve 7 and is introduced into the turbine 9 to rotate the same.
Rotation of the turbine 9 runs the generator 10 to generate electric power. Meanwhile the steam 9 that has performed the function of rotating the turbine is passed -on to the condenser 13 where the steam is changed into water. The condensate is returned by means of the feed ~ .
,!; : . .
water pump 15 to the nuclear reactor 2. The volume of .;.. . . .
steam generated in the nuclear reactor 2 is larger than the volume of steam consumed by the turbine 9 when, for example, the nuclear power plant 1 is started in a normal fashion. In such case, excess steam is directly passed on to the condenser 13 through the turbine bypass circuit 17 by bypassing the turbine 9.
More specifically, the common practice is to `
generate a greater volume of steam in the nuclear reactor 2 than is required by the turbine 9 when the nuolear power plant 1 is started in a normal fashion, in order that control of the plant may be carried out in a stable manner when the plant is started. Thus the speed error signal 31 which represents the difference between the speed-load setting signal 29 and the turbine speed signal ~0 30 becomes smaller in value than the pressure error .. ,` ' ', .
~ L~7~7~
1 signal 34 which represents the difference between the main steam pressure signal 32 and the pressure setting signal 33. Accordingly, the speed error signal 31 passes -through the low value gate 26 and is used as the control 5 signal 27 for aajusting the degree of opening of the steam control valve 7.
Meanwhile a signal corresponding to the value obtained by deducting the speed error signal 31 from the pressure error signal 34 is supplied to the bypass control valves 18 and 19 as the control signal 28 therefor, with the result that the bypass control valves are brought to open positions and their degree of opening is adjusted. ' This causes excess steam in the nuclear reactor 2 to be directly passed on to the condenser 13 through the bypass control valves 18 and 19 of the turbine bypass circuit 17.
In shutting down the nuclear power plant 1, the steam is controlled in a manner to pass through the turbine bypass circuit 17 as described with reference to the operation for starting the same.
In the event that load rejection occurs, a difference is produced suddenly in value between the first stage pressure signal 38 representing the power of the turbine 9 and the signal 39 representing the power output of the generator 10, and the difference is 25 detected by the power load unbalance relay 35.
Accordingly the power load unbalance relay 35 produces `~
the rapidly closing signal 36 for the steam control valve 7 and the rapidly opening signal 37 for the turbine bypass valves 18 to 25. The steam control valve 7 is rapidly 30 closed by the rapidly closing signal 36, thereby avoiding _ 9 _ 7~
1 running of the turbine 9 at overspeed. The rapidly opening signal 37 rapidly opens the turbine bypass valves 18 to 25 in a minimum number essential to let pass, through the bypass circuit 17, a~ excess steam volume which corresponds to the level of load rejection and which is prevented from passing through the steam control valve 7. If turbine trip occurs, then the main stop valve 5 is fully closed as aforementioned. In such case, ;
the turbine bypass valves 18 to 25 are also rapidly , closed in essential minimum number.
~ et us assume that all the load is rejected when the nuclear power plant 1 is operating at 70~0 load.
The operation of the turbine bypass control system according to the invention in case of such emergency will now be described with reference to Fig. 2 and Fig.
.-. .. :
':
~./a 4~L7t~
1 set leve], and a second signal supply means for supplying a rapidly opening signal to the bypass control valve and the on-off valve for rapidly bringing them to open positions at the time of load rejection and turbine trip.
In accordance with the invention, there is also provided a turbine bypass control method of a nuclear power plant for effecting control of pressure in the nuclear reactor by releasing excess steam therefrom through a turbine bypass circuit at the time of load rejection and turbine trip, such turbine bypass control method comprising the steps of providing in the turbine bypass circuit at least one bypass control valve and at least one on-off valve connected in parallel with each other in the bypass circuit, sensing the occurrence of load rejection and turbine trip and rapidly opening the bypass control valve and the on-off valve, gradually ~-closing the bypass control valve in accordance with a decrease in the pressure in the nuclear reactor, and 20 bringing the on-off valve to a fully closéd position when `
the bypass control valve has been brought to a fully closed position and then bringing the bypass control valve to an open position again whereby the bypass control valve can be rendered operative to effect control. i-Fig. 1 is a systematic view of the turbine -bypass control system comprising one embodiment of the invention;
Flg. 2 is a time chart showing the process for controlling pressure in the nuclear reactor by using the ~`~
bypass control valves and the on-off valves of the turbine :. .. : . . . ~ . . . ~
~,~4~q6 1 bypass circuit shown in Fig. l; and ~ ig. 3 is a sequence circuit diagram showing the manner in which the bypass control valves and the on-off valves of the turbine bypass circuit are actuated in interlocking relationship in the nuclear reactor power control process shown in ~ig. 2.
A preferred embodiment of the invention will now be described with reference to the accompanying drawings. Generally denoted by the numeral 1 is a nuclear power plant which comprises a boiling-water reactor 2 including a steam outlet 3 connected to a steam turbine 9 through a conduit 4, a main stop valve 5, a conduit 6, a steam control valve 7 and a conduit 8. ~he turbine 9 has a generator 10 directly connected thereto 15 and includes a steam outle-t ll connected to a condenser -13 through a conduit 12. The condensate from the condenser 13 is returned to the nuclear reactor through a conduit 16 by means of a pump 15 connected to the condenser 13 through a conduit 14.
- There is provided, between the conduit 4 connected to the nuclear reactor steam outlet 3 and the .
condenser 13, a turbine bypass circuit generally designated 9 by the numeral 17 for providing an auxiliary steam passage which bypasses the turbine 9. The turbine bypass circuit ;'-17 includes a plurality of turbine bypass valves (eight in number in the embodiment shown in Fig. 1) connected in parallel with one another in the turbine bypass circuit 17 and having a total capacity which is equal to a 100%
rated steam volume of the nuclear power plant. ~he 30 turbine bypass valves comprise at least one bypass `
1q~4~!7t76 1 control valve or two bypass control valves 18 and 19 in - :
the embodiment shown, and at least one on-off valve or six on-of~ valves 20, 21, 22, 23, 24 and 25 in the embodiment shown, ~he bypass control valves and on-off valves 18 to 25 are in closed positions when a control signal or a rapidly opening signal, subsequen-tly to be described, is not supplied thereto.
First signal supply means comprises a low value gate 26 for supplying control signals 27 and 28 to the steam control valve 7 and the b~pass control valves 18 and 19 of the turbine bypass circuit 17, respec-tively, for adjusting the degree of opening of these valves.
A speed error signal 31 obtained by deducting a turbine .- , speed signal 30 representing the actual turbine speed ~ .
from a speed-load setting signal 29 which determines the speed of the turbine 9 is inputed to the low value gate 26. At the same time, a pressure error signal 34 :~
obtained by deducting a pressure setting signal 33 for determining the steam pressure in the nuclear reactor 2 20 from a main steam pressure signal 32 representing the ~:
actual steam pressure in the nuclear reactor 2 is also inputed to the low value gate 26. Of the speed error signal 31 and the pressure error signal 34. inputed to the low value gate 26, the signal of the lower value is 25 outputed from the low value gate 26 as the control signal :
27 for adjusting the degree of opening of the steam control valve 7. The control signal 28 supplied to the bypass control valves 18 and 19 for adjusting the degree ~:~
of opening thereof is obtained by deducting the control signal 27 from the pr ssure error signal 34.
-- 5 -- , .
~)4i7t76 1When the nuclear power plant 1 is at normal operating level, the pressure error signal 34 is smaller in value than the speed error signal 31. In such case, the pressure error signal 34 is used as the control signal 27 for adjusting the degree of opening of the steam control valve 7, and the control signal 28 for adjusting the degree of opening of the bypass control valves 18 -and 19 is cancelled and becomes zero. Accordingly, although the degree of opening of the steam control valve 7 is adjusted, the bypass control valves 18 and 19 are inoperative or closed. On the other hand, when control of pressure in the reactor 2 is effected in starting or shutting down the nuclear power plant 1 or after load rejection has occurred, the speed error signal 31 is 15 smaller in values than the pressure error signai 34~`~
In such case, the speed error signal 31 is used as the control signal 27 for adjusting the degree of opening of the steam control valve 7~ and the control signal 28 for adjusting the degree of opening of the bypass control 20 valves 18 and 19 is also generated. Thus both the steam control valve 7 and the bypass control valves 18 and 19 .;,. . .
have their degree of opening adjusted. --Second signal supply means comprises a power load unbalance relay 35 for supplying a rapidly closing 25 signal 36 for rapidly closing the steam control valve 7 and a rapidly opening signal 37 for rapidly opening the turbine bypass valves 18, 19, 20 9 21 ~ 22 ~ 23 ~ 24 and 25 to the steam control valve 7 and the turbine bypass valves 18 to 25 J respectively, at the time of loadr~
~O rejection. A first stage pressure signal 38 representing . .
''`' ., ' ' 7~76 1 the turbine power and a signal 39 representing the power output of the generator 10 are inputed to the power load unbalance relay 35, which is adapted to produce the rapidly closing signal 36 to be supplied to the steam control valve 7 and the rapidly opening signal 37 to be supplied to the turbine bypass valves 18 to 25 when a difference in value is suddenly produced between the first stage pressure signal 38 and the signal 39 representing the power output of the generator 10. The rapidly opening signal 37 for the turbine bypass valves 18 to 25 is supplied to all the turbine bypass valves 18 to 25, in the event that lOO~o load rejection occurs when the nuclear power plant 1 is operating at lOO~o rated load.
However, in the event that all the load is rejected when the nuclear power plant 1 is operating at 70~o load, the rapidly opening signal 37 is only supplied to the turbine bypass valves of the minimum number or six valves `
which are sufficient to cause steam of a volume corresponding to the level of load rejection to pass through the turbine bypass circuit 17. Attention is directed to the fact that, in the latter case, the bypass control valves 18 and 19 are included at all times in the six turbine bypass valves to which the rapidly opening signal 37 is supplied.
~here is also provided a known mechanism (not ~-shown) which is adapted to rapidly close the main stop ;
valve 5 and to rapidly open the turbine bypass valves 18 to 25 at the time of turbine trip.
~he bypass control valves 18 and 19 and the on-off valves 20 to 25 o-f the turbine bypass circuit 17, - . ., ~ ~ ; , .~ . . . .
7~
1 which are closed at the time of load rejection or turbine trip, are successively closed in a specifically interlocking relationship subsequently to be described, ;;
since the volume of steam passing through the turbine bypass circuit 17 decreases as the reactor power of the nuclear reactor 2 is subsequently reduced.
The steam generated in the nuclear reactor 2 has its flow rate adjusted by the steam control valve 7 and is introduced into the turbine 9 to rotate the same.
Rotation of the turbine 9 runs the generator 10 to generate electric power. Meanwhile the steam 9 that has performed the function of rotating the turbine is passed -on to the condenser 13 where the steam is changed into water. The condensate is returned by means of the feed ~ .
,!; : . .
water pump 15 to the nuclear reactor 2. The volume of .;.. . . .
steam generated in the nuclear reactor 2 is larger than the volume of steam consumed by the turbine 9 when, for example, the nuclear power plant 1 is started in a normal fashion. In such case, excess steam is directly passed on to the condenser 13 through the turbine bypass circuit 17 by bypassing the turbine 9.
More specifically, the common practice is to `
generate a greater volume of steam in the nuclear reactor 2 than is required by the turbine 9 when the nuolear power plant 1 is started in a normal fashion, in order that control of the plant may be carried out in a stable manner when the plant is started. Thus the speed error signal 31 which represents the difference between the speed-load setting signal 29 and the turbine speed signal ~0 30 becomes smaller in value than the pressure error .. ,` ' ', .
~ L~7~7~
1 signal 34 which represents the difference between the main steam pressure signal 32 and the pressure setting signal 33. Accordingly, the speed error signal 31 passes -through the low value gate 26 and is used as the control 5 signal 27 for aajusting the degree of opening of the steam control valve 7.
Meanwhile a signal corresponding to the value obtained by deducting the speed error signal 31 from the pressure error signal 34 is supplied to the bypass control valves 18 and 19 as the control signal 28 therefor, with the result that the bypass control valves are brought to open positions and their degree of opening is adjusted. ' This causes excess steam in the nuclear reactor 2 to be directly passed on to the condenser 13 through the bypass control valves 18 and 19 of the turbine bypass circuit 17.
In shutting down the nuclear power plant 1, the steam is controlled in a manner to pass through the turbine bypass circuit 17 as described with reference to the operation for starting the same.
In the event that load rejection occurs, a difference is produced suddenly in value between the first stage pressure signal 38 representing the power of the turbine 9 and the signal 39 representing the power output of the generator 10, and the difference is 25 detected by the power load unbalance relay 35.
Accordingly the power load unbalance relay 35 produces `~
the rapidly closing signal 36 for the steam control valve 7 and the rapidly opening signal 37 for the turbine bypass valves 18 to 25. The steam control valve 7 is rapidly 30 closed by the rapidly closing signal 36, thereby avoiding _ 9 _ 7~
1 running of the turbine 9 at overspeed. The rapidly opening signal 37 rapidly opens the turbine bypass valves 18 to 25 in a minimum number essential to let pass, through the bypass circuit 17, a~ excess steam volume which corresponds to the level of load rejection and which is prevented from passing through the steam control valve 7. If turbine trip occurs, then the main stop valve 5 is fully closed as aforementioned. In such case, ;
the turbine bypass valves 18 to 25 are also rapidly , closed in essential minimum number.
~ et us assume that all the load is rejected when the nuclear power plant 1 is operating at 70~0 load.
The operation of the turbine bypass control system according to the invention in case of such emergency will now be described with reference to Fig. 2 and Fig.
3. The total capacity of the turbine bypass valves 18 to 25 corresponds to the volume of stea~ produced when the plant is operating at 100% rated load. Thus it will be seen that the capacity of one turbine bypass valve `
corresponds to 12.5% of the rated steam v~lume.
If load rejection occurs when the plant 1 is operating at 70~0 load, then the minimum number of turbine bypass valves necessary for passing excess steam corresponding in volume to the load rejection level through the turbine bypass circuit 17 is six. ~hus the rapidly opening signal 37 for the turbine bypass valves ';
is only supplied to the bypass valves 18 and 19 and the ;!~
., . .
on-off valves 20 to 23, so that the aforementioned valves are rapidly opened (time t1). Since the bypass control valve 19 and the on-off valves 20 to 23 have a - 10 ~
7~
1 total capacity which corresponds to 62.5% of -the excess steam volume, the degree of opening of the bypass control valve 18 is adjusted such that the capacity of this valve corresponds to the rest or 7.5~ of the exce$s steam volume (time t2). ~his control is effected by the control signal 28 in the same manner as described with reference to the operation -for starting of the nuclear power plant 1. Thereafter the reactor power of the nuclear reactor 2 begins to decrease (time t3). With the decrease in reactor power, the bypass control valve 18 is gradually brought to its closed position by the control signal 28. If the reactor power is reduced to 62.5%, then the bypass control valve 18 is fully closed ttime t4). ~ull closure of the bypass control valve 18 brings the on-off valve 23 to a fully closed position (time t5) by an interlocking mechanism for the bypass control valves 18, 19 and the on-off valves 20 to 25 subsequently to be described. When the on-off valve 23 is in the process of closing, the bypass control valve 20 18 begins to open again to compensate for the volume of -~
steam which passes through the on-off valve 23, un-til the degree of opening of the bypass control valve 18 reaches a level which is equal to the degree of its full opening minus the degree of its opening corresponding to the reduction of reactor power from 62.5% to a reaction power level when the on~off valve 23 is fully closed.
~ ig. 2 is a time chart showing that the reactor power is kept constant after the operation load is reduced to 60%. Immediately after time t5 or following the lapse of an arbitrarily selected time after time .
.. . ,! ~ i ~ L7~
1 t5 during which time the reactor power is kept constant, the reactor power may be further reduced. If this is the case, the bypass control valve 18 is gradually brought to its closed position in the same manner as described above, and actuated in interlocking relationship with the predetermined on-off valve 22.
Fig. 3 shows one form of sequence circuit where in bypass control valves 18 and 19 and the on-off valves 20 to 25 of the turbine bypass circuit 17 are made to operate in interlocking relationship. In the interest of brevity, the circuit diagram only shows the interlocking operation of -~he bypass control valve 18 with the on-off valves 22, 23 and 24. It is to be ;
';?
understood, however, that the other bypass control valve i 15 19 can be also made to operate in interlocking -~
relationship with the on-off valves 20, 21 and 25 in~ ;~
like manner. If the rapidly opening signal 37 is supplied -to the turbine bypass valves 18 to 23 as described with t reference to Fig. 2, then a contact 50 for the bypass control valve 19 and contacts 51 and 52 for the on-off valves 22 and 23 are closed. This energizes rapidly opening electromagnetic valves Sl, S5 and S6 for the bypass control ~alve 18 and on-off valves 22 and 23 respectively, so that the valves 18, 22 and 23 are rapidly opened. Although the rapidly opening signal 37 disappears quickly, contacts 53, 54 and 55 for the valves 18, 22 and 23 respectively are closed, because closure of the contacts 50, 51 and 52 energizes self-holdlng relays Yl, Y5 and Y6. Thus the electromagnetic valves Sl, S5 and S6 are self held.
`,~, . .... . .
~ 7~
1 Since the rapidly opening signal 37 is not supplied to the on-off valve 24, a contact 56 remains open. Thus a rapidly opening electromagnetic valve S7 and a self-holding relay Y7 are in inoperative positions, and 5 a contact 57 remains open.
At this time, the on-off valves 20 and 21 are also rapidly opened in the same sequence of operations.
Upon the on-off valves 20 to 23 being brought to fully open positions, fully open signal contacts 58, 59, 60 and 61 for these valves are closed. Since the on-off valves 24 and 25 remain closed, fully open signal contacts 62 and 63 for these valves remain open. Relays W3, W4, W5, W6, W7 and W8 are connected in series with the fully open signal contacts 58, 59, 60, 61, 62 and 15 63 respectively. ~nergization of the relay W3 closes an `~
interlocking operation contact (not shown) for the on-off valve 20. ~nergization of the relay W4 opens a contact 64 and closes an interlocking operation contact (not sho~m) for the on-off valve 21. Energization of the relay W5 ;
20 opens contacts 65 and 66 and closes an interlocking operation contact 67 for the on-off valve 22. ~ikewise, energiza-tion of the relay W6 opens contacts 68, 69 and -70 and closes a contact 71; energization of the relay W7 opens contacts 72, 73, 74 and 75 and closes a contact 25 76; and energization of the relay W8 opens contacts 77, 78, 79, 80 and 81 and closes an interlocking operation contact (no-t shown) for the on-off valve 25. Thus, if the fully open signal contacts 58 to 61 are closed as aforesaid, -then only the relay W6 out of all the relays `
W3 to W8 is energized and the interlocking operation - 13 ~
~4~ 76 1 eontact 71 for the on-off valve 22 is closed.
Also, if the bypass control valve 18 is fully open, then a contact 82 is closed and a relay ~ is energized, so that a contact 83 of the relay B is opened.
This de-energizes the rapidly opening electromagnetic valve S1, so that the bypass control valve 18 is thereafter controlled by a servo valve (not shown).
Meanwhile, a gradual reduction in reactor power will cause a gradual reduction in pressure in the nuclear reactor 2. If this is the casej then the bypass control valve 18 gradually closes in accordance with the rate of decrease in pressure in the nuclear reactor 2. Upon the bypass control valve 18 being brought to a fully closed position, a fully closed signal contact 84 therefor is closed and a relay A is energized. This closes contac-ts 85, ~6 and 87 of the relay A. On the other hand, since only the contact 67 out of the contacts 67, 71 and 76 ; ;
is elosed as aforesaid, only a relay Z6 out of relays Z6' Z7 and Z8 is energized. This opens a contact 88 for the relay Z6' and contacts 89 and 90 for the relays Z5 and Z7 respectively remain closed. This de-energizes `~
the rapidly opening electromagnetic valve S6 for the on-off valve 23, so that the on-off valve 23 is closed.
When the on-off valve 23 lS fully closed, the steam pressure in the nuclear reactor 2 rises. However, the eontrol signal 28 is supplied to the bypass control ';
valve 18 to re open the same in accordance with a rise in the steam pressure in the reactor. Control of the pressure in the nuelear reactor is effected in this way.
`,.~' ,''.
, :' '
corresponds to 12.5% of the rated steam v~lume.
If load rejection occurs when the plant 1 is operating at 70~0 load, then the minimum number of turbine bypass valves necessary for passing excess steam corresponding in volume to the load rejection level through the turbine bypass circuit 17 is six. ~hus the rapidly opening signal 37 for the turbine bypass valves ';
is only supplied to the bypass valves 18 and 19 and the ;!~
., . .
on-off valves 20 to 23, so that the aforementioned valves are rapidly opened (time t1). Since the bypass control valve 19 and the on-off valves 20 to 23 have a - 10 ~
7~
1 total capacity which corresponds to 62.5% of -the excess steam volume, the degree of opening of the bypass control valve 18 is adjusted such that the capacity of this valve corresponds to the rest or 7.5~ of the exce$s steam volume (time t2). ~his control is effected by the control signal 28 in the same manner as described with reference to the operation -for starting of the nuclear power plant 1. Thereafter the reactor power of the nuclear reactor 2 begins to decrease (time t3). With the decrease in reactor power, the bypass control valve 18 is gradually brought to its closed position by the control signal 28. If the reactor power is reduced to 62.5%, then the bypass control valve 18 is fully closed ttime t4). ~ull closure of the bypass control valve 18 brings the on-off valve 23 to a fully closed position (time t5) by an interlocking mechanism for the bypass control valves 18, 19 and the on-off valves 20 to 25 subsequently to be described. When the on-off valve 23 is in the process of closing, the bypass control valve 20 18 begins to open again to compensate for the volume of -~
steam which passes through the on-off valve 23, un-til the degree of opening of the bypass control valve 18 reaches a level which is equal to the degree of its full opening minus the degree of its opening corresponding to the reduction of reactor power from 62.5% to a reaction power level when the on~off valve 23 is fully closed.
~ ig. 2 is a time chart showing that the reactor power is kept constant after the operation load is reduced to 60%. Immediately after time t5 or following the lapse of an arbitrarily selected time after time .
.. . ,! ~ i ~ L7~
1 t5 during which time the reactor power is kept constant, the reactor power may be further reduced. If this is the case, the bypass control valve 18 is gradually brought to its closed position in the same manner as described above, and actuated in interlocking relationship with the predetermined on-off valve 22.
Fig. 3 shows one form of sequence circuit where in bypass control valves 18 and 19 and the on-off valves 20 to 25 of the turbine bypass circuit 17 are made to operate in interlocking relationship. In the interest of brevity, the circuit diagram only shows the interlocking operation of -~he bypass control valve 18 with the on-off valves 22, 23 and 24. It is to be ;
';?
understood, however, that the other bypass control valve i 15 19 can be also made to operate in interlocking -~
relationship with the on-off valves 20, 21 and 25 in~ ;~
like manner. If the rapidly opening signal 37 is supplied -to the turbine bypass valves 18 to 23 as described with t reference to Fig. 2, then a contact 50 for the bypass control valve 19 and contacts 51 and 52 for the on-off valves 22 and 23 are closed. This energizes rapidly opening electromagnetic valves Sl, S5 and S6 for the bypass control ~alve 18 and on-off valves 22 and 23 respectively, so that the valves 18, 22 and 23 are rapidly opened. Although the rapidly opening signal 37 disappears quickly, contacts 53, 54 and 55 for the valves 18, 22 and 23 respectively are closed, because closure of the contacts 50, 51 and 52 energizes self-holdlng relays Yl, Y5 and Y6. Thus the electromagnetic valves Sl, S5 and S6 are self held.
`,~, . .... . .
~ 7~
1 Since the rapidly opening signal 37 is not supplied to the on-off valve 24, a contact 56 remains open. Thus a rapidly opening electromagnetic valve S7 and a self-holding relay Y7 are in inoperative positions, and 5 a contact 57 remains open.
At this time, the on-off valves 20 and 21 are also rapidly opened in the same sequence of operations.
Upon the on-off valves 20 to 23 being brought to fully open positions, fully open signal contacts 58, 59, 60 and 61 for these valves are closed. Since the on-off valves 24 and 25 remain closed, fully open signal contacts 62 and 63 for these valves remain open. Relays W3, W4, W5, W6, W7 and W8 are connected in series with the fully open signal contacts 58, 59, 60, 61, 62 and 15 63 respectively. ~nergization of the relay W3 closes an `~
interlocking operation contact (not shown) for the on-off valve 20. ~nergization of the relay W4 opens a contact 64 and closes an interlocking operation contact (not sho~m) for the on-off valve 21. Energization of the relay W5 ;
20 opens contacts 65 and 66 and closes an interlocking operation contact 67 for the on-off valve 22. ~ikewise, energiza-tion of the relay W6 opens contacts 68, 69 and -70 and closes a contact 71; energization of the relay W7 opens contacts 72, 73, 74 and 75 and closes a contact 25 76; and energization of the relay W8 opens contacts 77, 78, 79, 80 and 81 and closes an interlocking operation contact (no-t shown) for the on-off valve 25. Thus, if the fully open signal contacts 58 to 61 are closed as aforesaid, -then only the relay W6 out of all the relays `
W3 to W8 is energized and the interlocking operation - 13 ~
~4~ 76 1 eontact 71 for the on-off valve 22 is closed.
Also, if the bypass control valve 18 is fully open, then a contact 82 is closed and a relay ~ is energized, so that a contact 83 of the relay B is opened.
This de-energizes the rapidly opening electromagnetic valve S1, so that the bypass control valve 18 is thereafter controlled by a servo valve (not shown).
Meanwhile, a gradual reduction in reactor power will cause a gradual reduction in pressure in the nuclear reactor 2. If this is the casej then the bypass control valve 18 gradually closes in accordance with the rate of decrease in pressure in the nuclear reactor 2. Upon the bypass control valve 18 being brought to a fully closed position, a fully closed signal contact 84 therefor is closed and a relay A is energized. This closes contac-ts 85, ~6 and 87 of the relay A. On the other hand, since only the contact 67 out of the contacts 67, 71 and 76 ; ;
is elosed as aforesaid, only a relay Z6 out of relays Z6' Z7 and Z8 is energized. This opens a contact 88 for the relay Z6' and contacts 89 and 90 for the relays Z5 and Z7 respectively remain closed. This de-energizes `~
the rapidly opening electromagnetic valve S6 for the on-off valve 23, so that the on-off valve 23 is closed.
When the on-off valve 23 lS fully closed, the steam pressure in the nuclear reactor 2 rises. However, the eontrol signal 28 is supplied to the bypass control ';
valve 18 to re open the same in accordance with a rise in the steam pressure in the reactor. Control of the pressure in the nuelear reactor is effected in this way.
`,.~' ,''.
, :' '
Claims (10)
1. A turbine bypass control system for a nuclear power plant wherein a nuclear reactor, a steam control valve, a steam turbine and a condenser are connected together in the indicated order by conduits, said turbine bypass control system comprising:
a. a turbine bypass circuit connecting a steam outlet of said nuclear reactor to said condenser by bypassing said steam turbine, said turbine bypass circuit including at least one bypass control valve and at least one on-off valve connected in parallel with one another;
b. first signal supply means for supplying a control signal to said bypass control valve to adjust the degree of opening thereof so as to maintain pressure in said nuclear reactor at a set level; and c. second signal supply means for supplying a rapidly opening signal to said bypass control valve and on-off valve at the time of load rejection and turbine trip so as to rapidly open said control valve and on-off valve.
a. a turbine bypass circuit connecting a steam outlet of said nuclear reactor to said condenser by bypassing said steam turbine, said turbine bypass circuit including at least one bypass control valve and at least one on-off valve connected in parallel with one another;
b. first signal supply means for supplying a control signal to said bypass control valve to adjust the degree of opening thereof so as to maintain pressure in said nuclear reactor at a set level; and c. second signal supply means for supplying a rapidly opening signal to said bypass control valve and on-off valve at the time of load rejection and turbine trip so as to rapidly open said control valve and on-off valve.
2. A turbine bypass control system as claimed in Claim 1, wherein said first signal supply means is adapted to supply another control signal to said steam control valve to control the degree of opening thereof simultaneously as the first mentioned control signal is supplied to said bypass control valve of said turbine bypass circuit, and said second signal supply means is adapted to supply a rapidly closing signal to said steam control valve to rapidly close the same simultaneously as the rapidly opening signal is supplied to said bypass control valve and on-off valve of said turbine bypass circuit.
3. A turbine bypass control system as claimed in Claim 2, wherein said turbine bypass control circuit includes two bypass control valves and six on-off valves connected in parallel with one another.
4. A turbine bypass control system as claimed in Claim 2, wherein said first signal supply means comprises a low value gate adapted to receive as its inputs a speed error signal obtained by deducting a turbine speed signal from a speed-load setting signal for the steam turbine and a pressure error signal obtained by deducting a pressure setting signal for the nuclear reactor from a main steam pressure signal of the nuclear reactor, said low value gate supplying the signal of the lower value of the speed error signal and the pressure error signal to said steam control valve as the last mentioned control signal therefor, a signal obtained by deducting the signal of the lower value from the pressure error signal being used as the first mentioned control signal for said bypass control valve, and wherein said second signal supply means comprises a power load unbalance relay adapted to receive as its inputs a first stage pressure signal representing the turbine power and a signal representing the power output of a generator connected to the steam turbine and to produce said rapidly opening signal and said rapidly closing signal when a difference is abruptly produced between the two inputs.
5. A turbine bypass control system as claimed in Claim 1, further comprising an interlocking mechanism adapted to cause said bypass control valve and said on-off valve to operate in interlocking relationship such that said on-off valve is fully closed when said bypass control valve is fully closed after being gradually closed in accordance with a reduction in the reactor power of the nuclear reactor after load rejection or turbine trip has occurred, said bypass control valve being opened again thereafter whereby said bypass control valve can be brought to a position in which it is capable of controlling pressure in the nuclear reactor.
6. A turbine bypass control system as claimed in Claim 5, wherein said interlocking mechanism comprises a sequence circuit.
7. A turbine bypass control method for a nuclear power plant comprising a nuclear reactor, a steam control valve, a steam turbine, a condenser and a turbine bypass circuit, such method being adapted to release excess steam from the nuclear reactor through the turbine bypass circuit at the time of load rejection and turbine trip so as to control pressure in the nuclear reactor and comprising the steps of:
a. providing in said turbine bypass circuit at least one bypass control valve and at least one on-off valve connected in parallel with one another;
b. sensing the occurrence of load rejection and turbine trip and rapidly opening said bypass control valve and on-off valve;
c. gradually closing said bypass control valve in accordance with a decrease in pressure in said nuclear reactor; and d. fully closing said on-off valve when said bypass control valve is fully closed, and then opening said control valve again whereby said control valve can be brought again to a position in which it can effect control.
a. providing in said turbine bypass circuit at least one bypass control valve and at least one on-off valve connected in parallel with one another;
b. sensing the occurrence of load rejection and turbine trip and rapidly opening said bypass control valve and on-off valve;
c. gradually closing said bypass control valve in accordance with a decrease in pressure in said nuclear reactor; and d. fully closing said on-off valve when said bypass control valve is fully closed, and then opening said control valve again whereby said control valve can be brought again to a position in which it can effect control.
8. A turbine bypass control method as claimed in Claim 7, wherein said steam control valve is rapidly closed simultaneously as said bypass control valve and on-off valve of the turbine bypass circuit are rapidly opened at the time of load rejection or turbine trip.
9. A turbine bypass control method as claimed in Claim 8, wherein at the time of load rejection the bypass control valves and the on-off valves of the turbine bypass circuit are rapidly opened in a minimum number essential to let pass through the turbine bypass circuit excess steam which corresponds in volume to the level of load rejection and is kept from passing through the steam control valve.
10. A turbine bypass control method as claimed in Claim 7, wherein the interlocked operation of said bypass control valve and on-off valve of the turbine bypass circuit is performed by means of a sequence circuit.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP50113744A JPS5239097A (en) | 1975-09-22 | 1975-09-22 | Control device for a turbine bypass of a nuclear energy turbine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041776A true CA1041776A (en) | 1978-11-07 |
Family
ID=14620013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA261,738A Expired CA1041776A (en) | 1975-09-22 | 1976-09-21 | Turbine bypass control system and method for a nuclear power plant |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5239097A (en) |
| CA (1) | CA1041776A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4472345A (en) * | 1980-07-25 | 1984-09-18 | Hitachi, Ltd. | Load control system for nuclear power plant |
| US8822963B2 (en) | 2011-12-29 | 2014-09-02 | Ge-Hitachi Nuclear Energy Americas Llc | Vapor forming apparatus, system and method for producing vapor from radioactive decay material |
| EP2960443A4 (en) * | 2013-02-19 | 2016-11-09 | Toshiba Kk | Valve control device for steam turbine and valve control method therefor |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58142909A (en) * | 1982-02-19 | 1983-08-25 | Teijin Ltd | Preparation of polyester elastomer |
-
1975
- 1975-09-22 JP JP50113744A patent/JPS5239097A/en active Granted
-
1976
- 1976-09-21 CA CA261,738A patent/CA1041776A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4472345A (en) * | 1980-07-25 | 1984-09-18 | Hitachi, Ltd. | Load control system for nuclear power plant |
| US8822963B2 (en) | 2011-12-29 | 2014-09-02 | Ge-Hitachi Nuclear Energy Americas Llc | Vapor forming apparatus, system and method for producing vapor from radioactive decay material |
| EP2960443A4 (en) * | 2013-02-19 | 2016-11-09 | Toshiba Kk | Valve control device for steam turbine and valve control method therefor |
| US10037042B2 (en) | 2013-02-19 | 2018-07-31 | Kabushiki Kaisha Toshiba | Valve control system and valve control method for steam turbine |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5423074B2 (en) | 1979-08-10 |
| JPS5239097A (en) | 1977-03-26 |
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