SU1066373A1 - Device for measuring absolute power of nuclear reactor - Google Patents

Abstract

A DEVICE FOR MEASURING THE ABSOLUTE POWER OF 5CHARTER REACTOR, containing a detector, amplifier, divider and recorder, the detector connected to the input of the amplifier, and the output of the divider is connected to the recorder, so that, in order to expand the functionality of the device, a second detector is inserted into it, the second amplifier, the first and second frequency resonant filters, the first and second multiplication units and the averaging unit, the second detector being connected to the input of the second current amplifier, the output of which is connected to the input ohm the second frequency resonant filter and the second second multiplication unit, the first input of which is connected to the output of the first amplifier and the input of the first frequency resonance filter, the first and second inputs of the first multiplication unit are connected respectively to the outputs of the first Gb and second frequency resonant filters, the output of the first block is cut through the averaging unit is connected to the first input of the divider, the second input of which is connected to the output of the second multiplication unit, the frequency resonant filters IAJOIKC, fyd are tuned to the frequency CO g de (cc is the maximum constant for the decay of precursors of delayed neutrons j, and about the constant decay of instantaneous neutrons.

Description

The invention relates to the field of control reactors and can be used to measure the absolute power of zero-power nuclear reactors on the critical assemblies and critical tests, as well as for the absolute calibration of current and pulse power level monitoring systems.

A device is known for measuring the absolute power of neutron activation of a substance with a known absorption cross section. The known device has a number of serious drawbacks: it is laborious, requires the use of calibrated chambers, sources, the introduction of these chambers and sources inside the core, which is extremely undesirable when calibrating already assembled reactors

The closest to the proposed device is a device for measuring the absolute power of a nuclear reactor containing a neutron flux detector, current amplifier, divider, and a recorder, the neutron flux detector connected to the input of the current amplifier, the divider output connected to the C2J recorder.

A disadvantage of the known device is the limited field of application, due to the dependence of the dynamic sensitivity on frequency, which leads to an additional error of variation in reactors with intermediate and fast neutrons.

The aim of the invention is to expand the functionality of the device.

The goal is achieved in that a device for measuring the absolute power of a nuclear reactor, containing a neutron flux detector, current amplifier, divider and recorder, the neutron flux detector connected to the current amplifier input, the divider output connected to the recorder, introduced the second neutron flux detector , the second current amplifier 5 is the first and second frequency resonant filters, the first and second multiplication units and the averaging unit, with the second neutron flux detector connected to the input of the second amplifier, output coupled to an input of the second frequency of resonance of the filter

and the second input of the second multiplication unit, the first input of which is connected to the output of the first current amplifier and the input of the first frequency resonant filter, the first and second inputs of the first multiplication unit are connected respectively to the outputs of the first and second resonant frequency filters, the output of the first multiplication unit is connected to the first input of the divider, the second input of which is connected to the output of the second multiplication unit, the resonant filters are set to clock7 (.

f McG

d

totu

211

2Ti

Where

maximum constant NMC4KS on the decay of delayed neutron precursors,

d constant decay of instant neutrons. The drawing shows a block diagram of a device for measuring the absolute power of a nuclear reactor.

The device contains the first 1 and second 2 neutron flux detectors, the first 3 and second 4 current amplifiers, the first 5 and second 6 frequency resonant filters, the first 7 and second 8 multiplication blocks, averaging unit 9, divider 10, recorder 11.

The device works as follows. The ionization currents of the detectors are fed to the inputs of current amplifiers, which have conversion factors in general form as. and stars As a result, voltages appear on the output terminals of the amplifiers, consisting of constant values

and l

2 2 2

(eleven

and fluctuation components

one

,, (i) ()

zff 1

. (2)

2 de jt,

j currents average currents

slr (i) —fluctuations of nuclear reactor reactivity,, E, are the conversion factors;

and ,, and voltages at the output of the amplifiers; effective for dollars

slow neutrons; (t), —current fluctuations, (t) due to the statistics of the neutron registration process. These signals are fed to the inputs of frequency resonant filters, which have frequency characteristics, K, (jw and t (j. And () (the bandwidth of the amplifiers is narrow, it completely stacks in the range I. The iMOKc oL .iMeKcre is the maximum constant for the decay of delayed neutron precursors } oi is the constant of the decay of instantaneous neutrons. Then the signals at the filter outputs will be equal to r1 (, (x) Au (ih) x (-) J where, G (x),) the impulse response of the filters. which is obtained at the output of the averaging block, will be equal to (average product n The correlated jester MY registration will be equal to zero) y «), u, where A (0) is the spectral reactivity noise density with -, 1 G /, () (} the calibration coefficient constant with this filter design. The first signal is supplied to the first input, the second input of which is given a signal equal to the product of voltages U U. At the output of the divider, a signal is obtained that is proportional to Ci 5, ptO) Thus, the output voltage of the divider is accurate to and known coefficient equal to the absolute power of the nuclear reactor. The described device was manufactured and tested on various reactors. With a minimum factor E / / i §ff 0.1, where e is the detection efficiency of the detector, the measurement error did not exceed 7%. The measurement time required to isolate the correlated component of the signals did not exceed 1.5 hours.

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Claims (2)

DEVICE FOR MEASURING ABSOLUTE POWER OF A NUCLEAR REACTOR, comprising a detector, an amplifier, a divider and a recorder, the detector being connected to the input of the amplifier and the output of the divider connected to the register. a radiator, distinguishing with I in that, in order to expand the func- the device’s capabilities, a second detector, a second amplifier, a first and second frequency resonance filters, a first and a second frequency multiplier and an averaging block are inserted into it, the second detector being connected to the input of the second current amplifier, the output of which is connected to the input of the second frequency resonant filter by the second input of the second multiplication unit, the first input of which is connected to the output of the first amplifier and the input of the first frequency resonance filter, the first and second inputs of the first multiplication unit are connected respectively continuously the outputs of the first and second frequency resonant filters, the output of the first multiplier block through the block of averaging pervm input connected to the divider, a second input coupled to an output of the second multiplication block, frequency filters tuned to the resonant frequency 2ϊϊ where Д] _М0 (кс “is the maximum decay constant of delayed neutron precursors; оС is the decay constant of instant neutrons. S and, „. 1066373