SU1328848A1 - Measuring channel of intrareactor monitoring system - Google Patents

Abstract

The invention relates to the technical means of the intrareactor control system and can be used in experimental and. power water and boiling reactors. The aim of the invention is to increase the number of monitored parameters of the fuel cartridge in the active zone while simultaneously increasing (L-lg

Description

precision and reliability of control. The measuring channel of the intracontrol monitoring system contains an electrical connector I, which is rigidly connected to valve 2, inside which is a passive thermostat 3 with conductors 4 of the communication line of thermoelectric converters (TEC), cold CEP 5 connectors located outside the reactor with the ability to control them temperature A hermetic septum 9 separates the high pressure zone from the low pressure zone. In the channel sections at the inlet and outlet from the core, the hot junctions of 24, 25 and 11 TECs are located, the distance between which in the group located at the core entrance is not less than the product of the maximum possible coolant velocity for this group by inertia

The invention relates to the technical means of the in-reactor control system and can be used in experimental and power water and boiling reactors.

The aim of the invention is to increase the number of monitored parameters of the fuel cartridge in the active zone while at the same time increasing the accuracy and reliability of the control.

In the drawing, shows a diagram of the measuring channel.

The measuring channel contains an electrical connector 1, which is rigidly connected to the valve 2, inside which is a passive thermostat 3 with conductors 4 of the communication line of thermoelectric converters (TEC), cold joints 5 TEC, conductors 6 and 7, providing the emergence and transmission of thermo-EMF (e.g. chromel-alumel) and thermal resistance 8 (e.g. from Pt) for measuring the temperature of cold junctions 5. A hermetic septum .9 separates the high pressure zone from the low pressure zone and serves as a seal. One cable of this group is wound on a magnetically sensitive core 26, which is magnetically coupled to a rotating permanent magnet 30 fixed to the rotor axis of a turbine meter installed at the entrance to the core. The assembly of direct charge detectors located at given levels of the active zone contains detectors 13–16 with emitters having a predominant spectral sensitivity to epithermal. neutrons, and detectors 17-19 with emitters sensitive to thermal neutrons. The insulators and collectors of the direct charge detectors, the shells and the insulators of their cables have a total effective thickness of at least three thicknesses of the half-attenuation / -radiation layer of the emitters. 3 hp f-ly, 1 ill.

for 10 TEC cables and direct charge detectors (DPS). Hot junction 11 TEC serves to measure the temperature of the heat carrier at the fuel assembly exit,

those. above the upper boundary of the core 12. DIPs 13-16 serve to convert the flux density, mainly epithermal neutrons, into an electric current (emitter, for example,

from Rh), and DPS 17-19 to convert the thermal neutron flux density into electric current (emitter, for example, from V). A calibration channel 20, extending up to the lower boundary 21 of the active zone, allows graduation of DPS 13-19 by an activation method. The hermetic septum 22 is used in the hermetic embodiment of protective reinforcement 23.

Hot junctions 24 and 25 TECs, located below the active zone, serve as the measuring point for measuring the temperature of the coolant at the inlet to the fuel assembly and for measuring the local velocity of the coolant by the correlation thermal noise method.

The magnetic core 26 serves as the core of the electromagnetic coil 27, in which the conductors 28 are used.

and 29 cable TECs with a hot junction 25. Magnetic conductor 26 has the possibility of magnetic interaction with a permanent magnet 30 fixed on the axis of the impeller rotor with impeller 31. The arrow 32 indicates the direction of flow of the heat - exchange fluid interacting with the small knife 31 and the hot spas 11 , 24, 25 TEC.

The measuring channel works as follows.

Cold junctions 5 TECs are placed in a passive thermostat 3, equipped with a thermal resistance 8, which allows you to automatically continuously measure the temperature of cold junctions and determine the absolute temperature of the coolant in the hot junction area 11, 24 and 25. The velocity of the coolant at the entrance to the active zone is determined The frequency of rotation of the rhetor turbine flowmeter, with which the permanent magnet 30 rotates. Simultaneously with the rotation of the rotor in the electromagnetic coil 27, equipped with a magnetic core 26, an emf is induced. and through conductors 28 and 29 is transmitted to an information-measuring system. Conductors 28 and 29 simultaneously serve to convert the temperature of hot spa 25 into thermo-emf and transfer it to an information-measuring system.

The signal of the rotation frequency of the impeller rotor is highlighted against the background of the TEC signals by comparing the signals of TEC 24 (without winding the cable) and 25 (winding the cable). Hot junctions of TECs 24 and 25 placed in the coolant flow allow determination of the local velocity of the coolant by the correlation thermosum method. Having determined the transition coefficient from local speed to coolant flow through a cassette through a turbine meter, you can continuously measure the coolant flow through a cassette in the period after the turbine meter (which has a service life significantly shorter than the life time of the TEC).

A DPS 13–16 with an emitter from Rh converts the flows of mainly epithermal neutrons into electric current, which is transmitted through individual cables 10 to the out-of-reactor information-measuring system. A DPS 14, 16 and 18 with an emitter from V convert the flux of predominantly thermal neutrons into electric current, which is also transmitted via appropriate cables to the information-measuring system. The latter processes the DPZ signals and, with a given periodicity, provides the distribution of the energy gap and steam content along the height of the active zone. During the operation of the measuring channel, an uneven burning of the emitters material occurs.

DPZ, therefore, the calibration coefficients of the DPD are periodically adjusted with the help of activation detectors introduced into the calibration channel 20.

In this metering channel, the turbine meter performs two functions:

means for directly measuring the flow of coolant through the fuel assembly during the initial period of operation of the reactor; and means for calibrating the correlation thermal noise flow meter under actual operating conditions. In the absence of a turbine meter

calibration of a correlation thermo-noise flow meter is not possible.

The combination of three functions performed by conductors 28 and 29 (transmission

signals of temperature, thermal noise and rotation frequency of the impeller), allows for the contactless transmission of the rotation frequency of the impeller, i.e. structurally separate the measuring channel from the impeller and at the same time reduce the number of cables inside the measuring channel, which is significant in conditions of a small internal diameter of the measuring channel.

The use of alternating emitters in the DPS assembly with preferential sensitivity to epi- or thermal neutrons makes it possible to measure two interrelated density distributions.

neutron flux, and by their ratio, determine the height distribution of the heat carrier vapor content.

Increasing the total effective thickness of the insulators and collectors of the DPS, as well as the shells and insulators of their cables to at least three times the thickness of the half-layer jS - radiation of emitters, eliminates 5, 1

read a shielding plate between the LPS and their cables, which provides an improvement in the permeability of the measuring channels through complex curved guide tubes; increase the mechanical strength and durability of the DPS; reduce the background component of the DPS signals induced by the j5-radiation of the emitter in the cables from the underlying DPS

Placing a passive thermostat inside the armature of the measuring channel improves the accuracy of temperature measurement by eliminating commonly used intermediate conductors and additional contacts between hot and cold TEC couplings. Formula I

The measuring channel of the in-core control system, containing an assembly of thermoelectric cable-type converters with grounded hot slots located in the coolant flow inside the reactor vessel, and cold joints located outside the reactor with the possibility of controlling their temperature and assembling direct charge detectors located at predetermined core levels and equipped with cams, both assemblies being combined with fittings having hermetic cable run from the high pressure zone to the low pressure and electric cable connector with communication lines of the information-measuring system, characterized in that, in order to increase the number of monitored parameters of the fuel cartridge in the active zone while simultaneously increasing the accuracy and

Editor N.Egorova Order 3491/52

Compiled by K. Kupalov Tehred A. Kravchuk

Corrector in

Circulation 394Subscribe

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35; Raushska nab ,, d. 4/5

Production and printing company, Uzhgorod, st. Project, 4

fO

five

288486

reliability of the control, in the channel sections at the inlet and outlet from the core is located along the group of hot junctions of thermoelectric converters, the distance between which in the group located at the entrance to the core is not less than the product of the maximum possible coolant velocity for a given groups on the inertia of thermoelectric converters, and at least one cable of this group is wound on a magnetically sensitive core that has a magnetic coupling with a rotating permanent magnet, mounted on the rotor axis of the turbine flow meter installed at the entrance to the active zone.

2. The measuring channel according to claim 1, characterized in that the assembly of direct charge detectors comprises alternating detectors with emitters having preferential spectral sensitivity to epithermal and thermal neutrons, respectively

3. Measuring channel according to claims 1 and 2, characterized in that the insulators and collectors of the direct charge detectors, the shells and the insulators of their cables have a total effective thickness of at least three thicknesses of the half-attenuation layer of the emitters.

4. Measuring channel according to claims 1-3, characterized in that all the cold junctions of thermoelectric converters and part of the thermal resistances that are part of the passive thermostat are located inside the extracavity part of the fitting between the sealed cable passage and the electrical connector.

20

25

thirty

35

40

Corrector v.But ha

Claims (4)

The claims <20 G. The measuring channel of the in-reactor monitoring system, comprising an assembly of cable-type thermoelectric converters with grounded 25 hot junctions placed in the heat carrier flow inside the reactor vessel and cold junctions located outside the reactor with the possibility of controlling their temperature and assembling direct detectors charging, located at predetermined core levels and equipped with cables, and both assemblies are combined using fittings having a tight cable routing from the zone you high pressure 35 to the low-pressure zone and an electric cable connector with communication lines of the information-measuring system, characterized in that, in order to increase the number of monitored parameters of the top beer cassette in the core while increasing the accuracy and reliability of control, in areas the channel at the entrance and exit from the active zone is located along the group of hot junctions of thermoelectric converters, the distance between which in the group located at the entrance to the active zone is not less than the product the maximum possible coolant speed for this group on the inertia of thermoelectric converters, and at least one cable of this group is wound on a magnetically sensitive core that is magnetically coupled to a rotating permanent magnet fixed to the axis of the rotor of the turbine flowmeter installed at the entrance to the active zone. 2. The measuring channel according to π.1, characterized in that the assembly of direct charging detectors contains alternating detectors with emitters having predominant spectral sensitivity to epithermal and thermal neutrons, respectively. 3. The measuring channel according to claims 1 and 2, characterized in that the insulators and collectors of the direct charging detectors, the sheaths and insulators of their cables have a total effective thickness of at least three thicknesses of the half attenuation layer of β-radiation of emitters. 4. The measuring channel according to claims 1 to 3, characterized in that all cold junctions of thermoelectric converters and part of the thermal resistance included in the passive thermostat are located inside the out-of-frame part of the valve between the hermetic cable penetration and the electrical connector.