Framatome Gmbh

Areva Np Gmbh

Jean-Lucien Mourlevat

Pierre Kockerols

Gilles Andre Poyaud

Bruno Julien

Gerard Montanari

Jean-Michel Bourin

Monique Lovedec

Gilbert Sengler

Norque Louedec

Olivier Pavageau

Annalisa L'Abbate

Anastasie Lefebvre De Rieux

A method involving periodic implementation, during the same operating cycle of the reactor, the method including following steps of: a) calculating, from measurements provided by sensors present in the reactor, the three-dimensional distribution of the local power in the core, b) simulating at least one accidental transient occurrence of power applied to the calculated three-dimensional distribution of local power, c) identifying, using thermomechanical calculations, at least one rod which is the most likely to be subject to a fracture of the cladding thereof during the simulated transient occurrence of power, and d) determining, using thermomechanical calculations on the rod identified, the value of the parameter which is representative of the operability of the reactor.

Method of determining the value of a parameter representative of the operability of a nuclear reactor, determining system, computer and corresponding medium

Neutron flux is measured using a subset of detectors ( ) selected from a set of detectors ( ) introduced into fuel assemblies ( ) of the core ( ) to obtain measurement signals, the number n of detectors ( ) of the subset being at most equal to 15% of the number of fuel assemblies ( ) in the core ( ), the measurement signals are processed and the instantaneous distribution of the neutron flux in the core ( ) is calculated allowing for the measurement signals. At least one operating parameter of the core is calculated from the instantaneous neutron flux distribution, and an alarm is triggered if at least one parameter is outside a fixed range. The operation of the core of the nuclear reactor can therefore be monitored virtually in real time. The neutron flux detectors ( ) introduced into the fuel assemblies of the core preferably include measuring probes consisting of collectrons.

Method and system for monitoring at least one operating parameter of the core of a nuclear reactor

During operation of the nuclear reactor, at specified time intervals, a neutron flux is measured using a set of neutron flux detectors which are fixed and arranged in the core ( ) of the nuclear reactor, the maximum number n of detectors ( ) being 15% of the number of fuel assemblies in the core. The measured signals are processed and the instantaneous distribution of neutron flux or of power throughout the entire core ( ) is calculated from the measured signals. At least one core operating parameter is calculated from the instantaneous neutron flux distribution and an alarm is raised if at least one parameter exceeds a set range.

Process and device for monitoring at least one operating parameter of the core of a nuclear reactor

A temperature regulation system of a pressurized water nuclear reactor is inhibited when a combination of the nuclear and the axial power difference exceeds a predetermined inhibit threshold.

Method and apparatus for protecting a nuclear reactor

An emergency stop of a pressurized water reactor to be protected is triggered when the nuclear power (ET) thereof reaches an emergency stop limit (LP). The value of this limit is lower with lower operating temperatures (ST) of the reactor.

Method of protecting a nuclear reactor in the event of a load increase

Protection against the consequences of a cluster of control rods falling accidentally is provided by four chains, each of which includes two neutron flux detectors (D1A, D1B), two primary treatment circuits (R1A, S1A and R1B, S1B) associated with said two detectors such that each provides a primary fall signal in the event of the flux measured by the corresponding detector decreasing rapidly, and an OR gate (P1) for providing an output fall signal from the chain in the event of at least one of said primary signals being present. The detectors (D1A, D4B, D3A, D1B, D2A, D3B, D4A and D2B) are angularly distributed around the vertical axis (A) of the core (2). A secondary treatment circuit (6) causes an emergency reactor stop to take place in the event that it receives fall signals at the outputs from at least two chains.

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Noisy le Roi, France

Jean-Lucien Mourlevat