Implementation method for reactor LPD and DNBR on-line protection and monitoring

Abstract

The invention discloses an implementation method for reactor LPD and DNBR on-line protection and monitoring. The method includes the steps that the measured current of self-powered detectors SPND andvarious measured operation parameters of a reactor main coolant system are collected; the collected data is transmitted to an upper calculation unit and a lower calculation unit; the upper calculationunit and the lower calculation unit perform LPD online calculation and DNBR online calculation, wherein the calculation accuracy of the upper calculation unit is higher than that of the lower calculation unit; based on the LDP and DNBR calculation results of the lower calculation unit, LPD and DNBR protection input signals are provided for a reactor protection system to achieve the LPD and DNBR protection function; based on the LDP and DNBR calculation results of the upper calculation unit, the reactor operation status is monitored. By means of the method, the LPD and DNBR distribution of axial sections of each fuel assembly of a reactor core is monitored on line; the LPD and DNBR protection input signals are provided for the reactor protection system, and thus the operation safety and economy of a nuclear power plant are improved.

Description

technical field [0001] The invention relates to the field of nuclear safety, in particular to an implementation method for on-line protection and monitoring of reactor LPD and DNBR. Background technique [0002] When the pressurized water reactor is in operation, the core is required to work in the mode of nucleate boiling heat transfer, and the heat transfer efficiency is the highest at this time. However, when some transient state causes the local heat flux density in the stack to increase to a certain extent, the bubbles generated on the cladding wall will be connected together before leaving the wall to form a vapor film, which will increase the thermal resistance and reduce the heat transfer coefficient. , causing the cladding temperature to rise sharply, and finally lead to the fuel temperature being too high to melt down. This situation is deviation from nucleate boiling (DNB). In order to ensure the safety of the reactor, the maximum heat flux on the surface of the ...

AI Technical Summary

Problems solved by technology

This method can reduce the error of the channel, but it has complex dynamic compensation, and it is necessary to convert the DNB safety limit function into the shutdown setting value of the protection system, and the process is relatively cumbersome.

At the same time, the online monitoring of neutron flux density parameters in the core is only completed by the nuclear instrumentation system outside the reactor, which cannot meet the requirements of reactor protection in terms of calculation accuracy and response time.

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