DD273512A1 - CIRCUIT ARRANGEMENT FOR TIMELINE NEUTRON FLOW DENSITY MEASUREMENT IN A CORE REACTOR BY MEANS OF RHODIUM INCORE DETECTORS - Google Patents

Abstract

Circuit arrangement for timely neutron flux density measurement. With this circuit arrangement, the correction of the output signal of built-in the gap zone of a nuclear reactor, time-delayed electron emission detectors with rhodium emitter to be gewaehrleistet. The circuit arrangement can also be used for power density determination in nuclear reactors. The invention includes that only an inverting operational amplifier is used, to which an adjustable resistor R0 and two Verzogegerungsglieder are connected in parallel, each Verzoegerungsglied consists of a series connection of two resistors R1 whose connection point is connected via a capacitor C1 to ground.

Description

R ₀ = (32,3 ... 5,7) -K; R ₁ = 0.548-K; R ₂ = 5.74 K; _r 121.2s

^C 'T-

_ 761.6 s .

~ R ₂ '

Uao

K = (1.05 ... 1, H) p-,

 Mon.

where i _{mo is} the constant detector current and U _ao the required output voltage at i _mo .

For this 1 page drawing

Field of application of the invention

The invention relates to an analog circuit arrangement for timely neutron fluence measurement. With this circuit arrangement, the correction of the output signal of built-in switching zone of a nuclear reactor, time-delayed electron emission detectors are to be ensured with rhodium emitter. The circuit arrangement can also be used for power density determination in nuclear reactors.

Characteristic of the known state of the art It is already well known to use incore detectors for neutron flux density measurements in nuclear reactors. In particular for the registration of reactor transients such as load changes, shutdowns, failure of the reactor or of Power plant components are aimed at using promptly responding detectors (Jaschik, W. et al., Nucl. Set. Engng.

53 (1974) p.61).

Due to low current efficiency and insufficient robustness to radiation exposure, these become However, detectors used only in a few cases. On the other hand, the delayed-acting rhodium incore detectors (Zimbalov, S.A., et al., Report IAE-3050, Moscow,

1978; Stein, H., et al., Nuclear Energy 23 (19PO] p.226).

its delay must be compensated by time correction of the detector output signal. For this purpose is the

Use of digital computers known (Kantrowitz, M.L., IEEE Trans, on NS 34 [1987]). The use of a digital computer for this purpose is unreasonably expensive. Because of its many active components, a digital computer is in principle less reliable than a simple analog

Circuit.

As a problem, the digitization of the detector output signal must be estimated, because this considerable Signal distortions may arise. Furthermore, an analog correction circuit with at least six operational amplifiers and appropriate shading

with passive components known (Buttler, E., Liewers, P., ZfK work report RPD-3/82, Rossendorf, 1982). With noisy

However, this correction circuit is prone to overdrive and instability. Object of the invention

The aim of the invention is a simple structure; Stnhil working rhodium detector correction circuit for generating true neutron flux density signals.

Explanation of the nature of the invention

The invention has the object of using the Inveraen detector kinetics from the output current of the rhodium detector to generate a neutron flux density proportional voltage.

According to the invention the object is achieved in that only one Ii vertierender operational amplifier is used, to which an adjustable resistor R ₀ and two Verzörgorungsgliedor are connected in parallel, wobol each delay element bosteht from a series connection of two resistors Ri, the Vorbindungspunkt each via a capacitor Ci to ground is switched.

It is advantageous if the resistors of a delay element are the same size. The sizes of the passive components are determined according to the formulas

R ₀ = (32.3 ... 5.7) K; R, = 0.540 K; R ₂ = 5.74 K; ^ _ 121.2s.

C ₂ =

Ri 761.6s R ₂

 Mon.

where Lo is the constant detector current and U _{10 is} the required steady state output voltage at Lo. In this case, the words for the variable resistor R _{0 are determined} as a function of the current component of the instantaneous current component to be set for the respective detector on the detector overall signal. The size K is used for a coarse adjustment of the proportion of the prompt signal component.

embodiment The invention will be explained in more detail using an exemplary embodiment. The accompanying drawing shows the circuit arrangement according to the invention. The circuit arrangement consists of an inverting operational amplifier, to which an adjustable resistor R ₀ and

two delay elements are connected in parallel, each delay element of a series connection zweior

Resistors R ₁ is the Vorbindungspunkt each connected via a capacitor C to ground. According to the formulas given in the solution, under the conditions which can be freely chosen at will, it follows that the

stationary detoctor current i _mo = 2 uA and is to be converted to the desired voltage U ₁₀ = 1V at a

Value of 7.5% of the steady-state prompt current component on the total detector signal following values for the passive components:

K = 0.541 mO R ₀ = 6.67 Ω R, = 0.296 Ω R ₂ = 3.1OmQ C, = 409mF C ₂ = 246 mF

The voltage meter to be attached to the output of the circuit arrangement according to the invention can be calibrated by known methods for displaying the neutron flux or power density.

Claims (3)

1. Circuit arrangement for timely Neutronenflußdlchtemessung in a nuclear reactor by means of rhodium incore detectors, wherein operational amplifier and passive components are used, characterized in that only one inverting operational amplifier is used, to dom an adjustable resistor Ro and two delay elements are connected in parallel, each Delay element consists of a series connection of two resistors Ri whose Vorbindungspunkt is connected in each case via a capacitor C ₁ to ground. 2. Circuit arrangement according to claim 1, characterized in that the resistors of a delay element are the same size. 3. Circuit arrangement according to claim 1, characterized in that the passive components are determined according to the formulas