Thermal margin protection system for a nuclear reactor

Claim 2

In a thermal damage protection apparatus for a nuclear reactor system, said system including a reactor core having channels therein through which a coolant is circulated and means for monitoring and generating signals commensurate with the coolant temperature and core power, the improvement comprising: means responsive to a signal commensurate with core power for generating a signal which varies in proportion to core radal peaking factor; means responsive to said core power and peaking factor signals for generating a power signal compensated for peaking factor; and means responsive to said compensated power signal and to a signal commensurate with the coolant temperature upstream of the reactor core for generating a signal commensurate with the core thermal limit as a function of coolant pressure.

Claim 3

The apparatus of claim 1 further comprising: means for correcting the upstream coolant temperature signal to compensate for stratification effects before applying said temperature signal to said thermal limit signal generating means.

Claim 4

The apparatus of claim 2 wherein said correcting means comprises: means responsive to signals commensurate with coolant temperature upstream and downstream of the reactor core for generating a signal commensurate with core power as a function of thermal energy added to the coolant; means for multiplying said signal commensurate with power as a function of added thermal energy by a stratification constant to generate a stratification error signal; and means for summing said stratification error and upstream coolant temperature signals to provide a coolant temperature signal corrected for stratification effects.

Claim 5

The apparatus of claim 1 further comprising: means responsive to signals commensurate with coolant temperature upstream and downstream of the reactor core for generating a signal commensurate with core power as a function of thermal energy added to the coolant; and means responsive to said signal commensurate with core power as a function of added thermal energy and to a signal commensurate with core power as a function of measured neutron flux for selecting the signal commensurate with the highest power level for application to said peaking factor signal generating means.

Claim 6

The apparatus of claim 4 further comprising: means for correcting the upstream coolant temperature signal to compensate for stratification effects before applying said temperature signal to said thermal limit signal generating means.

Claim 7

The apparatus of claim 5 wherein said correcting means comprises: means for multiplying said signal commensurate with power as a function of added thermal energy by a stratification constant to generate a stratification error signal; and means for summing said stratification error and upstream coolant temperature signals to provide a coolant temperature signal corrected for stratification effects.

Claim 8

In a thermal damage protection apparatus for a nuclear reactor system, said system including a reactor core having channels therein through which a coolant is circulated and means for monitoring the coolant temperature and core power, as a function of measured neutron flux and for generating signals commensurate therewith, the improvement comprising: means responsive to signals commensurate with coolant temperature upstream and downstream of the reactor core for generating a signal commensurate with core power as a function of thermal energy added to the coolant; means responsive to said signal commensurate with core power as a function of added thermal energy and to a signal commensurate with core power as a function of measured neutron flux for selecting the signal commensurate with the highest power level; and means responsive to the power signal passed by said selecting means and to said signal commensurate with upstream coolant temperature for generating a signal commensurate with the core thermal limit as a function of coolant pressure.

Claim 9

In a thermal damage protection apparatus for a nuclear reactor system, said system including a reactor core having channels therein through which a coolant is circulated and means for monitoring the coolant temperature and core power, as a function of measured neutron flux and for generating signals commensurate therewith, the improvement comprising: means responsive to signals commensurate with coolant temperature upstream and downstream of the reactor core for generating a signal commensurate with core power as a function of thermal energy added to the coolant; means responsive to said signal commensurate with core power as a function of added thermal energy and to a signal commensurate with core power as a function of measured neutron flux for selecting the signal commensurate with the highest power level; and means responsive to the power signal passed by said selecting means and to said signal commensurate with upstream coolant temperature for generating a signal commensurate with the core thermal limit as a function of coolant pressure.

Claim 10

The apparatus of claim 7 further comprising: means responsive to the selected power signal for generating a signal which varies in proportion to core radial peaking factor; and means responsive to the selected power signal and to said peaking factor signal for generating a power signal compensated for peaking factor for application to said thermal limit signal generating means.

Claim 11

The apparatus of claim 7 further comprising: means for correcting the upstream coolant temperature signal to compensate for stratification effects before applying said temperature signal to said thermal limit signal generating means.

Claim 12

The apparatus of claim 9 wherein said correcting means comprises: means for multiplying said signal commensurate with power as a function of added thermal energy by a stratification constant to generate a stratification error signal; and means for summing said stratification error and upstream coolant temperature signals to provide a coolant temperature signal corrected for stratification effects.

Claim 13

The apparatus of claim 10 further comprising: means responsive to the selected power signal for generating a signal which varies in proportion to core radial peaking factor; and means responsive to the selected power signal and to said peaking factor signal for generating a power signal compensated for peaking factor for application to said thermal limit signal generating means.

Claim 14

The apparatus of claim 7 wherein said reactor system includes a plurality of coolant circulator pumps and wherein said improved protection apparatus further comprises: means for varying the signal commensurate with core power as a function of added thermal energy in accordance with the circulator pump operating configuration prior to application to said selecting means.

Claim 15

The apparatus of claim 12 wherein said thermal limit signal generating means comprises: means for modifying said signal commensurate with upstream coolant temperature in accordance with a constant which changes with the circulator pump configuration; means for modifying said selected power signal in accordance with a constant which changes with the circulator pump configuration; means for combining said modified temperature and power signals to generate said thermal limit signal; and switch means operatively connected to said added thermal energy power signal varying means for selecting temperature and power signals commensurate with the pump configuration for application to said signal combining means.

Claim 16

The apparatus of claim 13 further comprising: means responsive to the power signal passed by said selecting means for generating a signal which varies in proportion to core radial peaking factor; means responsive to said selected core power and peaking factor signals for generating a power signal compensated for peaking factor; and means delivering said compensated power signal to said means for modifying the power signal in addition to said selected power signal whereby said switch means will select a modified peaking factor compensated power signal when in the position commensurate with operation of all available circulator pumps.

Claim 17

The apparatus of claim 14 further comprising: means for correcting the upstream coolant temperature signal to compensate for stratification effects before applying said temperature signal to said thermal limit signal generating means.

Claim 18

The apparatus of claim 15 wherein said correcting means comprises: means for multiplying said signal commensurate with power as a function of added thermal energy by a stratification constant to generate a stratification error signal; ane means for summing said stratification error and upstream coolant temperature signals to provide a coolant temperature signal corrected for stratification effects.

Claim 19

The apparatus of claim 12 further comprising: means for generating a plurality of coolant low flow set point signals; and means operatively connected to said added thermal energy power varying means for selecting a low flow set point signal commensurate with the circulator pump configuration.

Claim 20

The apparatus of claim 16 further comprising: means for generating a plurality of coolant low flow set point signals; and means operatively connected to said added thermal energy power varying means for selecting a low flow set point signal commensurate with the circulator pump configuration.

Claim 21

A thermal margin protection system for a nuclear power plant, said plant including a reactor core having channels therein for the circulation of a coolant and a plurality of coolant circulator pumps, said reactor also being provided with sensors for producing core inlet and outlet coolant temperature signals and a core power signal said protection system comprising: means responsive to a signal commensurate with coolant inlet temperature for generating a plurality of temperature signals commensurate with the possible circulator pump configurations; means responsive to a signal commensurate with core power for generating a plurality of power signals commensurate with the possible circulator pump configurations; summing means for combining applied core power and coolant inlet temperature signals to generate a thermal limit signal commensurate with coolant pressure; first switch means for selecting one of said coolant temperature signals and a corresponding core power signal for application to said summing means, said switch means being positioned in accordance with the pump operating configuration; means for generating a plurality of low flow trip set point signals commensurate with the possible circulator pump configurations; and second switch means operatively connected to said first switch means for selecting a low flow set point signal commensurate with the positioning of said first switch means.

Claim 22

A thermal margin protection system for a nuclear power plant, said plant including a reactor core having channels therein for the circulation of a coolant and a plurality of coolant circulator pumps, said reactor also being provided with sensors for producing core inlet and outlet coolant temperature signals and a core power signal said protection system comprising: means responsive to a signal commensurate with coolant inlet temperature for generating a plurality of temperature signals commensurate with the possible circulator pump configurations; means responsive to a signal commensurate with core power for generating a plurality of power signals commensurate with the possible circulator pump configurations; summing means for combining applied core power and coolant inlet temperature signals to generate a thermal limit signal commensurate with coolant pressure; first switch means for selecting one of said coolant temperature signals and a corresponding core power signal for application to said summing means, said switch means being positioned in accordance with the pump operating configuration; means for generating a plurality of low flow trip set point signals commensurate with the possible circulator pump configurations; and second switch means operatively connected to said first switch means for selecting a low flow set point signal commensurate with the positioning of said first switch means.

Claim 23

The apparatus of claim 19 further comprising: means responsive to signals commensurate with coolant inlet and outlet temperature for generating a signal commensurate with core power as a function of thermal energy added to the coolant; and means operatively connected to said first switch means for varying said signal commensurate with core power as a function of added thermal energy in accordance with the pump operating configuration.

Claim 24

The apparatus of claim 20 wherein said reactor core also has means for generating a core power signal a a function of measured neutron flux associated therewith and wherein said protection system further comprises: comparing means responsive to said signals commensurate with core power as a function of flux and coolant thermal energy increase for selecting the signal representative of the highest power level application to said means for generating a plurality of power signals.

Claim 25

The apparatus of claim 21 further comprising: means responsive to the selected power signal for generating a signal which varies in proportion to core radial peaking factor; and means responsive to the selected power signal and to said peaking factor signal for generating a power signal compensated for peaking factor for application to said means for generating a plurality of power signals whereby said first switch will select a power signal compensated for peaking factor only when in the position commensurate with operation of all the circulator pumps.

Claim 26

The apparatus of claim 22 further comprising: means for correcting the coolant inlEt temperature signal to compensate for stratification effects before applying said temperature signal to said means for generating a plurality of temperature signals.

Claim 27

The apparatus of claim 23 wherein said correcting means comprises: means for multiplying said signal commensurate with power as a function of added thermal energy by a stratification constant to generate a stratification error signal; and means for summing said stratification error and coolant inlet temperature signals to provide a coolant temperature signal corrected for stratification effects.

Claim 28

Apparatus for generating a signal commensurate with total core power produced by a nuclear reactor, said reactor including a core and a coolant circuit through said core, said reactor further including plurality of independently operable coolant circulator pumps and means for selecting the pumps to be operated, said coolant circuit having a hot side at the outlet from the reactor core and a cold side at the inlet to the reactor core and including means for providing signals commensurate with measured coolant temperature at the hot and cold sides of the core, said power signal generating apparatus comprising: means responsive to said hot and cold side temperature signals for generating a signal commensurate with core power as a function of thermal energy added to the circulating coolant; a plurality of separately adjusted attenuator devices, each of said attenuator devices being preset in accordance with a coolant mass flow rate; means applying said core power sgnal to said attenuator devices to generate a plurality of power signals respectively commensurate with said mass flow rates; switch means for selecting one of said mass flow rate compensated power signals; and means for coupling said switch means to the means for selecting the reactor circulator pump operating configuration whereby said switch means will be positioned in accordance with the number of coolant circulator pumps in operation and the selected power signal will be commensurate with the mass flow rate corresponding to the number of operating circulator pumps.

Claim 29

Apparatus for generating a signal commensurate with total core power produced by a nuclear reactor, said reactor including a core and a coolant circuit through said core, said reactor further including plurality of independently operable coolant circulator pumps and means for selecting the pumps to be operated, said coolant circuit having a hot side at the outlet from the reactor core and a cold side at the inlet to the reactor core and including means for providing signals commensurate with measured coolant temperature at the hot and cold sides of the core, said power signal generating apparatus comprising: means responsive to said hot and cold side temperature signals for generating a signal commensurate with core power as a function of thermal energy added to the circulating coolant; a plurality of separately adjusted attenuator devices, each of said attenuator devices being preset in accordance with a coolant mass flow rate; means applying said core power sgnal to said attenuator devices to generate a plurality of power signals respectively commensurate with said mass flow rates; switch means for selecting one of said mass flow rate compensated power signals; and means for coupling said switch means to the means for selecting the reactor circulator pump operating configuration whereby said switch means will be positioned in accordance with the number of coolant circulator pumps in operation and the selected power signal will be commensurate with the mass flow rate corresponding to the number of operating circulator pumps.

Claim 30

The apparatus of claim 25 wherein said power signal generating means comprises: means responsive to the hot and cold side temperature signals for providing an output signal which varies as the sum of K Alpha Delta T + K gamma Delta T2 + K Beta Delta T (TC) + d/dt (a Delta T + TC) where: K Alpha , K Beta , K gamma and a are gain constants Delta T is the difference between the hot and cold side temperatures TC is the cold side temperature.