CA1041776A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Turbine bypass control system and method for a nuclear power plant
Assignee: Hitachi Ltd
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Filing: 1976-09-21
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Granted: 1978-11-07
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Expires: 1996-09-21
Abstract
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.
Inventors
- 👤 Yoshimi Koide
- 👤 Katsuto Kashiwahara
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-03 13:47
CPC Classifications
Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
158 words
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.
Claim 2
Dependent Claim
158 words
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.
Claim 3
Dependent Claim
99 words
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.
Claim 4
Dependent Claim
31 words
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.
Claim 5
Dependent Claim
200 words
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.
Claim 6
Dependent Claim
103 words
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.
Claim 7
Dependent Claim
18 words
A turbine bypass control system as claimed in Claim 5, wherein said interlocking mechanism comprises a sequence circuit.
Claim 8
Dependent Claim
170 words
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.
Claim 9
Dependent Claim
170 words
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.
Claim 10
Dependent Claim
44 words
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.
Claim 11
Dependent Claim
68 words
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.
Claim 12
Dependent Claim
35 words
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.
References Cited (Backward Citations)
No citation records indexed.
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