Method and a device for thermal monitoring of a nuclear reactor core
AssigneeCommissariat a l'Energie Atomique
InventorGeorges Barbier
Life of this patent
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Abstract
Thermal monitoring of a reactor core is carried out by utilizng coolant temperatures detected at the outlets of a plurality of fuel assemblies. The mean value of the "hot" and "cold" core outlet temperatures and the difference between these latter are established at each instant. An analog signal corresponding to the temperature difference between the coolant temperature at the outlet of said assembly and the mean core outlet temperature is delivered in respect of each fuel assembly. The signal is processed in order to initiate the appropriate safety actions.
Claims6
A method of thermal monitoring of a nuclear reactor core having fuel assemblies at temperatures T.sub.1 and T.sub.2 utilizing coolant temperatures detected at the outlets of a plurality of said fuel assemblies comprising the steps of
- establishing at each instant the mean core outlet temperature by forming the half-sum of the mean T.sub.1 and T.sub.2 core outlet temperatures corresponding respectively to the mean value of the coolant temperatures at the outlet of at least part of the fuel assemblies at temperatures T.sub.1 and to the mean value of the coolant temperatures at the outlet of at least part of the fueld assemblies at temperatures T.sub.2 and the difference between said core outlet temperatures T.sub.1 and T.sub.2,
- producing for each fuel assembly an analog signal corresponding to the temperature difference between the coolant temperature at the outlet of said fuel assembly and the mean core outlet temperature as initially increased or decreased by a predetermined fraction of the difference between the mean core outlet temperatures T.sub.1 and T.sub.2 to define a state of equilibrium at which said temperature difference is equal to zero, and
- processing said signal to initiate appropriate safety actions by overstepping of threshold values corresponding to temperature variations permitted on each side of the equilibrium zero.
An electric device for the thermal monitoring of a nuclear reactor core comprising
- N thermocouples which are equal in number to the number N of reactor core fuel assemblies at temperatures T.sub.1 and T.sub.2 ,
- N measuring channels connected individually to each of the N thermocouples and each comprising in series:
- at least one amplifier for the signal detected by the thermocouple,
- a summing amplifier at the output of the preceding amplifier and also at the output of two analog circuits supplied by at least a certain number of the N measuring channels and each comprising means enabling one circuit to deliver a signal corresponding to a value of opposite sign value of the mean core outlet temperature and enabling the other circuit to deliver a signal corresponding to a fraction of the difference between the mean core outlet temperatures T.sub.1 and T.sub.2,
- at the output of said summing amplifier, devices comprising different thresholds for pre-alarm, emergency shutdown and/or control rod drop, each device aforesaid delivering command signals for appropriate orders by at least one regrouping OR-circuit in the event of overstepping of the corresponding threshold value.
Dependencies are inferred from the claim text.