CS252269B1 - The method of blocking the emergency protection of the first type from the failure of the last operating turbine generator - Google Patents

Abstract

The method of blocking the first type of emergency protection from the failure of the last operating turbine is intended for nuclear power plants with WER type reactors with flywheel main circulation pumps. Its essence lies in blocking this protection up to the power level at which the steam produced in the steam generators can be reliably discharged without the risk of increasing the pressure in them to the level of action of the steam generator safety valves, or without the risk of increasing the pressure in the primary circuit to the level of action of its safety valves. This will reduce temperature shocks, especially on the fuel, unnecessary losses in electricity production and disruption of continuity and time losses during start-up work.

Description

The present invention relates to a method of blocking emergency protection of the first kind from the failure of the last operating turbine generator in reactor blocks with flywheel main circulating pumps and solves the minimization of its intervention.

The known method of blocking emergency protection from the failure of the last turbogenerator counts on the necessity to block this protection during the beginnings of reactor power up to the phasing of the turbogenerator and increasing their output to the level of the unit's own consumption. the protection unlocks, so that the failure of turbine generators means shutdown of the reactor by emergency protection of the first kind, ie not by the fastest way of shutdown.

Any impact of the first type of emergency protection leads to rapid temperature changes in the fuel and the main technological components of the nuclear power plant, and thus to their considerable stress and reduction of their service life.

Failure of the last working turbogenerator is one of the causes of false action of emergency type I protection. Since the outages of the turbine generators themselves are largely due to missing signals or quickly remedies, the first type of emergency response from this cause, in addition to thermal shocks, causes unnecessary losses in power generation and disturbances in continuity and time during start-up work.

The aforementioned drawbacks are substantially mitigated by the method of blocking the reactor emergency protection from failure of the last operating turbine generator, in nuclear power plants with flywheel main circulation pumps (in which the run-off is always ensured even without turbine generator operation), according to the invention.

Its essence consists in blocking the emergency protection from the failure of the last operating turbine generator up to the power level at which the steam produced in steam generators can be reliably removed without the risk of pressure increase in the steam generators safety valves or safety valves.

252 269

According to the invention, at any time during operation, the sum of the ingestion of all operable transfer stations is determined, the readiness of the circuits capable of reducing the reactor power as a function of the increased steam pressure upstream of the turbine is evaluated. 'Reactor power at which the protection can still be blocked under the above conditions.

In this way, the permissible power limit is shifted to higher power levels.

Example /

For a nuclear power plant in working order, if the reactor power reduction circuit is capable of halving the power within 30 seconds by increasing the steam pressure upstream of the turbine and the releasing station to an atmosphere of 15% of nominal steam production, it is possible to keep this protection blocked up to 58% of the nominal reactor power, if a maximum excess pressure of 1 MPa is acceptable.

Thus, if there are two turbine generators in such a unit, this protection can be kept locked whenever only one turbine generator is operating.

If releasing stations for turbine condensers with a total capacity of 50 -t 60% of the nominal steam are reliably prepared for operation, this protection can be kept blocked even at 100% of the reactor power and can be unlocked (not allowed to act) only if operation of the transfer station to the condenser became inoperable.

This type of blocking can be implemented manually or automatically.

In the case of sufficient overflow of the transfer stations into the atmosphere, the operability of which depends only on the operable state of their control circuit, it is even possible to dispense (blocked permanently) without the above protection.

Claims (2)

SUBJECT OF THE INVENTION 252 269 1. A method of blocking the first type of emergency protection from failure of the last operating turbine generator in nuclear power reactors with flywheel main circulating pumps, characterized in that the power level to which it is. the total mass of operable transfer stations and the capability of the circuits capable of reducing the reactor power as a function of the steam pressure upstream of the turbine shall be determined. 2. The method according to claim 1 _, characterized in that the monitoring of the instantaneous ingestion of ready-made transfer stations is carried out automatically by means of logic circuits.