HTGR power plant hot reheat steam pressure control system

Claim 3

A control system according to claim 1 wherein the control means include, means to generate a fourth signal having a predetermined proportionality with the difference between the second and third signals, means to generate a fifth signal having a predetermined proportionality with the first signal, means to generate a sixth signal representative of the fourth signal diminished by the fifth signal, and means to position the valve means in accordance with the sixth signal.

Claim 4

A control system according to claim 2 wherein the means to generate the fourth signal comprise, a comparator to generate an output signal representative of the difference between the second signal and the third signal, and a proportional controller responsive to the output signal of the comparator to generate the fourth signal, said fourth signal having a predetermined proportionality with the comparator output signal.

Claim 5

A control system according to claim 1 wherein the valve means is characterized by a linear relationship between steam flow through the valve means and position of the valve means at constant inlet pressure to the valve means, and wherein the associated positioning means positions the valve means at a position which is linearly related to the sixth signal.

Claim 6

A control system according to claim 2 wherein the control means further include means to generate a bias signal, and wherein the sixth signal represents the sum of the bias signal with the fourth signal, diminished by the fifth signal.

Claim 7

A control system according to claim 5 wherein the valve means is characterized by a linear relationship between steam flow through the valve means and position of the valve means at constant inlet pressure to the valve means, and wherein the associated positioning means positions the valve means at a position which is linearly related to the sixth signal.

Claim 10

A control system according to claim 7 wherein the control means includes means to generate a signal representative of a limit value of steam flow through the condenser bypass line, and wherein the second valve means is positioned to regulate the condenser bypass line flow at the limit value, the steam flow through the alternate bypass line being varied to reduce said pressure difference at times when the condenser bypass line flow is so regulated.

Claim 11

A control system according to claim 8, wherein the flow limit signal is generated in accordance with the second signal, and the value of the limit signal varies inversely with the detected value of steam pressure in the hot reheat header.

Claim 12

A control system according to claim 9 wherein the means for generating the limit signal is a function generator, said function generator having the second signal as an input signal and generating the limit signal as an output signal.

Claim 13

A control system according to claim 7 wherein the control means include, means to generate a fourth signal in accordance with the difference between the second and third signals, means to generate a fifth signal having a predetermined proportionality with the first signal, means to generate a bias signal, means to generate a sixth signal representative of the sum of the bias signal with the fourth signal diminished by the fifth signal, means to generate a signal representative of a limit valve of steam flow through the condenser bypass line, and means to position the first and second valve means in response to the sixth signal and the limit signal.

Claim 14

A control system according to claim 11 wherein the fourth signal has a preDetermined proportionality with the difference between the second and third signals.

Claim 15

A control system according to claim 11 wherein the means to position the first and second valve means include, selection means responsive to the sixth signal and to the flow limit signal to select the lower of said signals and transmit the selected signal to a means for positioning the first valve means and to a comparator, means to position the first valve means in accordance with the selected signal, a comparator to generate an output signal representative of the difference between the sixth signal and the selected signal, and means to position the second valve means in accordance with the output signal of the comparator.

Claim 16

A control system according to claim 13 wherein the second valve means is closed at times when the sixth signal is lower than the limit signal.

Claim 17

A control system according to claim 14 wherein the first valve means is closed when the sixth signal is zero.

Claim 18

A control system according to claim 13 wherein each of said first and second valve means is characterized by a linear relationship between steam flow through the valve means and position of the valve means at constant differential pressure across the valve means, and wherein the associated positioning means positions the valve means at a position which is linearly related to the signal to which the positioning means is responsive.

Claim 21

A control system according to claim 17 wherein the control means includes, means to generate a first bias signal, and means to generate a second bias signal, and wherein the first valve means is positioned in accordance with the difference between the first bias signal and the first desired steam flow signal and the second valve means is positioned in accordance with the difference between the second bias signal and the second desired steam flow signal, at times when the detected and desired steam pressure values are equal.

Claim 22

A control system according to claim 17 wherein the control means includes, means to generate a first feedback signal in accordance with the difference between the detected and desired pressure signals, and means to generate a second feedback signal in accordance with the difference between the detected and desired pressure signals, and wherein the steam flow through the first bypass line is varied in accordance with the first feedback signal, and the steam flow through the second bypass line is varied in accordance with the second feedback signal.

Claim 23

A control system according to claim 19 wherein the first feedback signal has a first predetermined proportionality with the difference between the detected and desired pressure signals and the second feedback signal has a second predetermined proportionality with said difference.

Claim 24

A control system according to claim 20 wherein said first and second predetermined proportionalities are equal.

Claim 25

A control system according to claim 18 wherein the first valve means position is linearly related to the difference between the first bias signal and the first desired steam flow signal, and the second valve means position is linearly related to the difference between the second bias signal and the second desired steam flow signal at times when the detected and desired pressure values are equal, each of said first and second valve means having a linear relationship between steam flow through the valve means and position of the valve means at constant inlet pressure to the valve means.

Claim 26

A control system according to claim 22 wherein each of said first and second valve means is closed at times when its respective difference signal is zero.

Claim 27

A control system according to claim 17, wherein each of said first and second valve means is positioned to cause a steam flow through its respective bypass line equal to one-half the predetermined minimum steam flow at times when the respective desired steam flow signal is zero and the desired and detected steam pressue values are equal to a predetermined low load pressure value.

Claim 30

A control system according to claim 25 wherein the control means include, means to generate a first limit signal representative of a limit value of steam flow through the first condenser bypass line, and means to generate a second limit signal representative of a limit value of steam flow through the second condenser bypass line, and wherein the first alternate bypass valve means is closed at times when the steam flow through the first condenser bypass line is less than the value represented by the first limit signal, and the second alternate bypass valve means is closed at times when the steam flow through the second condenser bypass line is less than the valve represented by the second limit signal.

Claim 31

A control system according to claim 26 wherein the first and second limit signals are generated by first and second function generators, each of said function generators being responsive to the detected pressure signal to generate a limit signal of value inversely proportional to the value of the detected pressure signal.

Claim 32

A control system according to claim 26 wherein control means further include, means to generate a first bias signal, means to generate a first feedback signal in accordance with the difference between the detected and desired pressure signals, means to generate a second bias signal, and means to generate a second feedback signal in accordance with the difference between the detected and desired pressure signals, and wherein the first condenser bypass valve means is positioned in accordance with a first flow demand signal representative of the sum of the first bias signal with the first feedback signal diminished by the first desired steam flow signal at times when the first flow demand signal is less than the first limit signal, and wherein the second condenser bypass valve means is positioned in accordance with a second flow demand signal representative of the sum of the second bias signal with the second feedback signal diminished by the second desired steam flow signal at times when the second flow demand signal is less than the second flow limit signal.

Claim 33

A control system according to claim 28 wherein each of said first and second feedback signals has a predetermined proportionality with the difference between the detected and desired pressure signals.

Claim 34

A control system according to claim 28 wherein the first condenser bypass valve means is positioned in accordance with the first limit signal and the first alternate bypass valve means is positioned in accordance with the difference between the first flow demand signal and the first limit signal at times when the first flow demand signal exceeds the first flow limit signal, and wherein the second condenser bypass valve means is positioned in accordance with the second limit signal and the second alternate bypass valve means is positioned in accordance with the difference between the second flow demand signal and the second limit signal at times when the second flow demand signal exceeds the second limit signal.

Claim 35

A control system according to claim 30 wherein each of said first and second feedback signals has a predetermined proportionality with the difference between the detected and desIred pressure signals

Claim 36

A power plant wherein a steam source derives heat from a reactor coolant gas that is circulated through the steam source and a high temperature nuclear reactor, said power plant comprising, electric generating means, a steam turbine, said turbine at least including a high pressure turbine element and a lower pressure turbine element, each turbine element having a steam inlet and a steam exhaust, said turbine being rotatably connected to the electric generating means, a steam source connected to supply superheated steam to the steam inlet of the high pressure turbine element, said steam source including means to reheat a flow of steam through reheating section connected between a steam inlet and the steam outlet, means to conduct steam from the high pressure turbine steam exhaust to the steam inlet of the reheating section, said means including an auxiliary steam turbine means connected to pass at least a portion of the steam flow to the inlet of the reheating section, said auxiliary steam turbine means being rotatably connected to a means for circulating the reactor coolant gas, a hot reheat header connected to the steam outlet of the reheating section to receive reheated steam and connected to supply reheated steam to the steam inlet of the lower pressure turbine element, a condensing means connected to the steam exhaust of the lower pressure turbine element to condense steam discharged therefrom, a bypass line connected to conduct steam from the hot reheat header to the condensing means, valve means connected to govern the flow of steam through the bypass line, means to generate a first signal representative of a desired steam flow through the lower pressure turbine element, means to generate a second signal representative of a detected pressure value of steam in the hot reheat header, means to generate a third signal representative of a desired pressure value of steam in the hot reheat header, and control means responsive to the first signal to position the valve means to govern the steam flow through the bypass line to maintain a steam flow through the reheating section that is equal to a predetermined minimum flow at times when the hot reheat header steam pressure is at a predetermined low load pressure value and the desired steam flow through the lower pressure turbine element is less than the predetermined minimum flow, and responsive to the second and third signals at times when the second and third signals differ to vary the steam flow through the bypass line to reduce the difference.

Claim 37

A power plant wherein a steam source derives heat from a reactor coolant gas that is circulated through the steam source and a high temperature nuclear reactor, said power plant comprising, electric generating means, a steam turbine, said turbine at least including a high pressure turbine element and a lower pressure turbine element, each turbine element having a steam inlet and a steam exhaust, said turbine being rotatably connected to the electric generating means, a steam source connected to supply superheated steam to the steam inlet of the high pressure turbine element, said steam source including means to reheat a flow of steam through reheating section connected between a steam inlet and the steam outlet, means to conduct steam from the high pressure turbine steam exhaust to the steam inlet of the reheating section, said means including an auxiliary steam turbine means connected to pass at least a portion of the steam flow to the inlet of the reheating section, said auxiliary steam turbine means being rotatably connected to a means for circulating the reactor coolant gas, a hot reheat header connected to the steam outlet of the reheating section to receive reheated steam and connected to supply reheated steam to the steam inlet of the lower pressure turbine element, a condensing means connected to the steam exhaust of the lower pressure turbine element to condense steam discharged therefrom, a bypass line connected to conduct steam from the hot reheat header to the condensing means, valve means connected to govern the flow of steam through the bypass line, means to generate a first signal representative of a desired steam flow through the lower pressure turbine element, means to generate a second signal representative of a detected pressure value of steam in the hot reheat header, means to generate a third signal representative of a desired pressure value of steam in the hot reheat header, and control means responsive to the first signal to position the valve means to govern the steam flow through the bypass line to maintain a steam flow through the reheating section that is equal to a predetermined minimum flow at times when the hot reheat header steam pressure is at a predetermined low load pressure value and the desired steam flow through the lower pressure turbine element is less than the predetermined minimum flow, and responsive to the second and third signals at times when the second and third signals differ to vary the steam flow through the bypass line to reduce the difference.

Claim 38

A power plant according to claim 32 wherein the control means include, means to generate a fourth signal having a predetermined proportionality with the first signal, means to generate a bias signal, means responsive to the second and third signals to generate a fifth signal in accordance with the difference between the second and third signals, means to generate a sixth signal representative of the sum of the fifth signal with the bias signal diminished by the fourth signal, and means to position the valve means in accordance with the sixth signal.

Claim 39

A power plant according to claim 33 wherein the fifth signal has a predetermined proportionality with the difference between the second and third signals.

Claim 40

A power plant according to claim 33 wherein the valve means is characterized by a linear relationship between steam flow through the valve means and position of the valve means at constant inlet pressure to the valve means, and the positioning means positions the valve means at a position which is linearly related to the sixth signal.

Claim 41

A power plant wherein a steam source derives heat from a reactor coolant gas that is circulated through the steam source and a high temperature nuclear reactor, said power plant comprising, electric generating means, a steam turbine, said turbine at least including a high pressure turbine element and a lower Pressure turbine element, each turbine element having a steam inlet and a steam exhaust, said turbine being rotatably connected to the electric generating means, a steam source connected to supply superheated steam to the steam inlet of the high pressure turbine element, said steam source including means to reheat a flow of steam through a reheating section connected between a steam inlet and a steam oulet, means to conduct steam from the high pressure turbine element exhaust to the steam inlet of the reheating section, said means including an auxiliary steam turbine means connected to pass at least a portion of the steam flow to the inlet of the reheating section, said auxiliary steam turbine means being rotatably connected to a means for circulating the reactor coolant gas, a hot reheat header connected to the steam outlet of the reheating section and connected to supply reheated steam to the steam inlet of the lower pressure turbine element, a condensing means connected to the steam exhaust of the lower pressure turbine element to condense steam discharged therefrom, a condenser bypass line connected to conduct steam from the hot reheat header to the condensing means, first valve means connected to govern the flow of steam through the condenser bypass line, an alternate bypass line connected to conduct steam from the hot reheat header to an alternate steam discharge means, second valve means connected to govern the flow of steam through the alternate bypass line, means to generate a first signal representative of a desired steam flow through the lower pressure turbine element, means to generate a second signal representative of a detected pressure value of steam in the hot reheat header, means to generate a third signal representative of a desired pressure value of steam in the hot reheat header, and control means responsive to the first signal to position the first and second valve means to govern the steam flows through the bypass lines to maintain a steam flow through the reheating section that is equal to a predetermined minimum flow at times when the hot reheat header is at a predetermined low load pressure value and the desired steam flow through the lower pressure turbine element is less than the predetermined minimum flow, and responsive to the second and third signals at times when the second and third signals differ to vary the steam flow through one of the bypass lines to reduce the difference.

Claim 42

A power plant wherein a steam source derives heat from a reactor coolant gas that is circulated through the steam source and a high temperature nuclear reactor, said power plant comprising, electric generating means, a steam turbine, said turbine at least including a high pressure turbine element and a lower Pressure turbine element, each turbine element having a steam inlet and a steam exhaust, said turbine being rotatably connected to the electric generating means, a steam source connected to supply superheated steam to the steam inlet of the high pressure turbine element, said steam source including means to reheat a flow of steam through a reheating section connected between a steam inlet and a steam oulet, means to conduct steam from the high pressure turbine element exhaust to the steam inlet of the reheating section, said means including an auxiliary steam turbine means connected to pass at least a portion of the steam flow to the inlet of the reheating section, said auxiliary steam turbine means being rotatably connected to a means for circulating the reactor coolant gas, a hot reheat header connected to the steam outlet of the reheating section and connected to supply reheated steam to the steam inlet of the lower pressure turbine element, a condensing means connected to the steam exhaust of the lower pressure turbine element to condense steam discharged therefrom, a condenser bypass line connected to conduct steam from the hot reheat header to the condensing means, first valve means connected to govern the flow of steam through the condenser bypass line, an alternate bypass line connected to conduct steam from the hot reheat header to an alternate steam discharge means, second valve means connected to govern the flow of steam through the alternate bypass line, means to generate a first signal representative of a desired steam flow through the lower pressure turbine element, means to generate a second signal representative of a detected pressure value of steam in the hot reheat header, means to generate a third signal representative of a desired pressure value of steam in the hot reheat header, and control means responsive to the first signal to position the first and second valve means to govern the steam flows through the bypass lines to maintain a steam flow through the reheating section that is equal to a predetermined minimum flow at times when the hot reheat header is at a predetermined low load pressure value and the desired steam flow through the lower pressure turbine element is less than the predetermined minimum flow, and responsive to the second and third signals at times when the second and third signals differ to vary the steam flow through one of the bypass lines to reduce the difference.

Claim 43

A power plant according to claim 36 wherein the steam flow through one of the bypass lines is varied in accordance with the difference between the detected and desired steam pressure values.

Claim 44

A power plant, according to claim 36 wherein the control means include means to generate a signal representative of a limit value of steam flow through the condenser bypass line, and the second valve means is closed at times when the steam flow through the condenser bypass line is less than the limit value.

Claim 45

A power plant according to claim 38 wherein the control means further include, means to generate a bias signal, means to generate a feedback signal in accordance with the difference between the second and third signals, and means to generate a flow demand signal representative of the sum of the bias signal with the feedback signal diminished by the first signal, and wherein the first valve means is positioned in accordance with the flow demand signal at times when the flow demand signal is less than the limit signal.

Claim 46

A power plant according to claim 39 wherein the first valve means is positioned in accordance with the limit signal and the second valve means is positioned in accordance with the difference between the flow demand signal and the limit signal at times when the flow demand signal exceeds the limit signal.

Claim 47

A power plant according to claim 40 wherein the feedback signal has a predetermined proportionality with the difference between the second and third signals.

Claim 48

A power plant wherein a steam source derives heat from a reactor coolant gas that is circulated through the steam source and a high temperature nuclear reactor, said steam source being connected to supply superheated and reheated steam to first and second turbine-generators, said power plant comprising, electric generating means, first and second steam turbines, each of said first and second steam turbines including at least a high pressure turbine element and a lower pressure turbine element, each turbine element having a steam inlet and a steam exhaust, said steam turbines being rotatably connected to the electric generating means, a steam source connected to supply superheated steam to the steam inlets of the high pressure turbine elements, said steam source including means to reheat a flow of steam through a reheating section connected between a steam inlet and a steam outlet, means to conduct steam from the high pressure turbine element steam exhausts to the steam inlet of the reheating section, said means including an auxiliary steam turbine means connected to pass at least a portion of the steam flow to the inlet of the reheating section, said auxiliary steam turbine means being rotatably connected to a means for circulating the reactor coolant gas, a hot reheat header connected to the steam outlet of the reheating section and connected to supply reheated steam to the steam inlets of the lower pressure turbine elements, condensing means connected to the steam exhausts of the lower pressure turbine elements to condense steam discharged therefrom, first and second bypass lines connected to conduct steam from the hot reheat header to the condensing means, first and second valve means connected to govern the steam flows through the respective first and second bypass lines, means to generate a first signal representative of a desired steam flow through the first lower pressure turbine element, means to generate a second signal representative of a desired steam flow through the second lower pressure turbine element, means to generate a third signal representative of a detected pressure value of steam in the hot reheat header, means to generate a fourth signal representative of a desired pressure value of steam in the hot reheat header, and control means responsive to the first and second signals to position the first and second valve means to govern the steam flows through the first and second bypass lines to maintain a steam flow through the reheating section that is equal to a predetermined minimum flow at times when the hot reheat header steam pressure is at a predetermined low load pressure value and the total desired steam flow through the first and second lower pressure turbine elements is less than the predetermined minimum flow, and responsive to the third and fourth signals when the third and fourth signals differ to vary the total steam flow through the first and second bypass lines to reduce the difference.

Claim 49

A power plant wherein a steam source derives heat from a reactor coolant gas that is circulated through the steam source and a high temperature nuclear reactor, said steam source being connected to supply superheated and reheated steam to first and second turbine-generators, said power plant comprising, electric generating means, first and second steam turbines, each of said first and second steam turbines including at least a high pressure turbine element and a lower pressure turbine element, each turbine element having a steam inlet and a steam exhaust, said steam turbines being rotatably connected to the electric generating means, a steam source connected to supply superheated steam to the steam inlets of the high pressure turbine elements, said steam source including means to reheat a flow of steam through a reheating section connected between a steam inlet and a steam outlet, means to conduct steam from the high pressure turbine element steam exhausts to the steam inlet of the reheating section, said means including an auxiliary steam turbine means connected to pass at least a portion of the steam flow to the inlet of the reheating section, said auxiliary steam turbine means being rotatably connected to a means for circulating the reactor coolant gas, a hot reheat header connected to the steam outlet of the reheating section and connected to supply reheated steam to the steam inlets of the lower pressure turbine elements, condensing means connected to the steam exhausts of the lower pressure turbine elements to condense steam discharged therefrom, first and second bypass lines connected to conduct steam from the hot reheat header to the condensing means, first and second valve means connected to govern the steam flows through the respective first and second bypass lines, means to generate a first signal representative of a desired steam flow through the first lower pressure turbine element, means to generate a second signal representative of a desired steam flow through the second lower pressure turbine element, means to generate a third signal representative of a detected pressure value of steam in the hot reheat header, means to generate a fourth signal representative of a desired pressure value of steam in the hot reheat header, and control means responsive to the first and second signals to position the first and second valve means to govern the steam flows through the first and second bypass lines to maintain a steam flow through the reheating section that is equal to a predetermined minimum flow at times when the hot reheat header steam pressure is at a predetermined low load pressure value and the total desired steam flow through the first and second lower pressure turbine elements is less than the predetermined minimum flow, and responsive to the third and fourth signals when the third and fourth signals differ to vary the total steam flow through the first and second bypass lines to reduce the difference.

Claim 50

A power plant according to claim 42 wherein the total steam flow through the first and second bypass lines is varied in accordance with the difference between the third and fourth signals.

Claim 51

A power plant according to claim 43 wherein the total steam flow through the first and second bypass lines is varied in predetermined proportionality with the difference between the third and fourth signals.

Claim 52

A power plant according to claim 42 wherein the control means include, means to generate a first bias signal, means to generate a second bias signal, means to generate a first feedback signal having a predetermined proportionality with the difference between the third and fourth signals, means to generate a second feedback signal having a predetermined proportionality with the difference between the third and fourth signals, means to position the first valve means in accordance with the sum of the first bias signal with the first feedback signal diminisheD by the first desired steam flow signal, and means to position the second valve means in accordance with the sum of the second bias signal with the second feedback signal diminished by the second desired steam flow signal.

Claim 53

A power plant according to claim 45 wherein each of said first and second valve means is characterized by a linear relationship between steam flow through the valve means and position of the valve means at constant inlet pressure to the valve means, and wherein the position of each of said valve means is linearly related to the sum of the respective bias signal with the respective feedback signal, diminished by the respective desired steam flow signal.

Claim 56

A method according to claim 47 wherein the position of the bypass valve means in the bypass line associated with the tripped turbine is varied in accordance with the difference between the first and second signals.

Claim 57

A method according to claim 48 wherein the bypass valve means position is varied in predetermined proportion to the difference between the first and second signals.