Axial power distribution monitor and display using outputs from ex-core detectors and thermocouples

Claim 1

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor in a manner to representively reconstruct the relative power distribution shape along the given axis which comprises the steps of : monitoring peripheral flux emanating from a core guadrant and from the core periphery at positions exterior of the core with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring the temperasture of reactor coolant flowing into the core and the temperature of the reactor coolant exiting the core at a location approximately corresponding to the source monitored flux; determining the power distribution in response to the peripheral flux measurements and the temperature measurements; and displaying the power distribution.

Claim 2

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor in a manner to representively reconstruct the relative power distribution shape along the given axis which comprises the steps of : monitoring peripheral flux emanating from a core guadrant and from the core periphery at positions exterior of the core with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring the temperasture of reactor coolant flowing into the core and the temperature of the reactor coolant exiting the core at a location approximately corresponding to the source monitored flux; determining the power distribution in response to the peripheral flux measurements and the temperature measurements; and displaying the power distribution.

Claim 15

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor which comprises the steps of: monitoring peripheral flux emanating from the core periphery with at least two detectors at positions exterior of the core, each detecting flux from a core quadrant and each of which detectors is located substantially along an axis substantially parallel to the given axis with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring the temperature of reactor coolant flowing into the core, the temperature of the reactor coolant exiting the core in the core periphery from which a substantial portion of the detected peripheral flux emanates, and the coolant pressure of the reactor coolant system; determining the peripheral power distribution in the core periphery according to: ##EQU6## where p j is the power distribution in the core periphery at a pre-selected elevation value j along the given axis; f(T exit , T ent , pressure) is a function of T ent , the temperature of the reactor coolant entering the core periphery, T exit , the temperature of the reactor coolant exiting the core periphery, and pressure, the rector system coolant pressure; and A 1j , A 2j , and A nj are predetermined constants; determining the axial power distribution in the core from the peripheral power distribution; determining the axial offset defined as: AO=(P.sub.t -P.sub.b)/(P.sub.t +P.sub.b) from the axial power distribution, where P t and P b are the fraction of power generated in the top and bottom half of the core, respectively; and displaying the axial offset.

Claim 16

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor which comprises the steps of: monitoring peripheral flux emanating from the core periphery with at least two detectors at positions exterior of the core, each detecting flux from a core quadrant and each of which detectors is located substantially along an axis substantially parallel to the given axis with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring the temperature of reactor coolant flowing into the core, the temperature of the reactor coolant exiting the core in the core periphery from which a substantial portion of the detected peripheral flux emanates, and the coolant pressure of the reactor coolant system; determining the peripheral power distribution in the core periphery according to: ##EQU6## where p j is the power distribution in the core periphery at a pre-selected elevation value j along the given axis; f(T exit , T ent , pressure) is a function of T ent , the temperature of the reactor coolant entering the core periphery, T exit , the temperature of the reactor coolant exiting the core periphery, and pressure, the rector system coolant pressure; and A 1j , A 2j , and A nj are predetermined constants; determining the axial power distribution in the core from the peripheral power distribution; determining the axial offset defined as: AO=(P.sub.t -P.sub.b)/(P.sub.t +P.sub.b) from the axial power distribution, where P t and P b are the fraction of power generated in the top and bottom half of the core, respectively; and displaying the axial offset.

Claim 26

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor in a manner to representatively reconstruct the relative power distribution shape along the given axis which comprises the steps of: monitoring peripheral flux emanating from the core periphery at positions exterior of the core with at least two detectors, each detector detecting flux from a core quadrant and each of which detectors is located substantially along an axis substantially parallel to the given axis with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring a signal proportional to the core peripheral thermal power in the core periphery from which a substantial portion of the monitored flux emanates; determining the peripheral power distribution in the core periphery, responsive to the peripheral flux measurements and the signal, from a linear relation among the responses of the peripheral flux measurements and the signal; determining the power distribution in the core from the peripheral power distribution; and presenting the power distribution.

Claim 27

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor in a manner to representatively reconstruct the relative power distribution shape along the given axis which comprises the steps of: monitoring peripheral flux emanating from the core periphery at positions exterior of the core with at least two detectors, each detector detecting flux from a core quadrant and each of which detectors is located substantially along an axis substantially parallel to the given axis with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring a signal proportional to the core peripheral thermal power in the core periphery from which a substantial portion of the monitored flux emanates; determining the peripheral power distribution in the core periphery, responsive to the peripheral flux measurements and the signal, from a linear relation among the responses of the peripheral flux measurements and the signal; determining the power distribution in the core from the peripheral power distribution; and presenting the power distribution.

Claim 31

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor in a manner to representatively reconstruct the relative radially peaked power distribution shape along the given axis which comprises the steps of: monitoring peripheral flux emanating form the core periphery at positions exterior of the core with at least two detectors, each detector detecting flux from a core quadrant and each of which detectors is located substantially along an axis substantially parallel to the given axis with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring a signal proportional to the core peripheral thermal power in the core periphery from which a substantial portion of the monitored flux emanates; determining peripheral power distribution in the core periphery, responsive to the peripheral flux measurements and the signal, from a linear relation among the responses of the peripheral flux measurements and the signal; determining axial power distribution in the core form the peripheral power distribution; determining the radially peaked power distribution; and displaying the radially peaked power distribution.

Claim 32

A method of monitoring the power distribution along a given axis of a core of a nuclear reactor in a manner to representatively reconstruct the relative radially peaked power distribution shape along the given axis which comprises the steps of: monitoring peripheral flux emanating form the core periphery at positions exterior of the core with at least two detectors, each detector detecting flux from a core quadrant and each of which detectors is located substantially along an axis substantially parallel to the given axis with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; monitoring a signal proportional to the core peripheral thermal power in the core periphery from which a substantial portion of the monitored flux emanates; determining peripheral power distribution in the core periphery, responsive to the peripheral flux measurements and the signal, from a linear relation among the responses of the peripheral flux measurements and the signal; determining axial power distribution in the core form the peripheral power distribution; determining the radially peaked power distribution; and displaying the radially peaked power distribution.

Claim 34

A method of determining axial power distribution in a reactor core, comprising: measuring peripheral core flux in the core periphery at two locations with the core periphery comprising no more than about two fuel assembly widths from an edge of the core within a core quadrant; measuring core coolant inlet temperature; measuring core coolant exit temperature of the coolant exiting fuel rod assemblies in the core periphery; determining enthalpy change in the core periphery from the inlet temperature and the exit temperature; and determining core peripheral axial power distribution from the enthalpy change and the peripheral core flux.

Claim 35

A method of determining axial power distribution in a reactor core, comprising: measuring peripheral core flux in the core periphery at two locations with the core periphery comprising no more than about two fuel assembly widths from an edge of the core within a core quadrant; measuring core coolant inlet temperature; measuring core coolant exit temperature of the coolant exiting fuel rod assemblies in the core periphery; determining enthalpy change in the core periphery from the inlet temperature and the exit temperature; and determining core peripheral axial power distribution from the enthalpy change and the peripheral core flux.

Claim 36

An apparatus for determining axial power distribution in a reactor core, comprising: at least two neutron detectors located at different axial positions and measuring flux in acore quadrant in the core periphery with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; an inlet temperature sensor measuring coolant inlet temperature as it enters the reactor; core exit temperature sensors positioned at coolant outlets of reactor assemblies in the core periphery and measuring coolant exit temperatures; and distribution means for producing local peripheral axial power distribution from the measured flux, the inlet temperature and the exit temperatures.

Claim 37

An apparatus for determining axial power distribution in a reactor core, comprising: at least two neutron detectors located at different axial positions and measuring flux in acore quadrant in the core periphery with the core periphery comprising no more than about two fuel assembly widths from an edge of the core; an inlet temperature sensor measuring coolant inlet temperature as it enters the reactor; core exit temperature sensors positioned at coolant outlets of reactor assemblies in the core periphery and measuring coolant exit temperatures; and distribution means for producing local peripheral axial power distribution from the measured flux, the inlet temperature and the exit temperatures.