Kabushiki Kaisha Toshiba

Shigehiro Kono

Daijiro Ito

Makoto Tomitaka

Yutaka Tanaka

Atsushi Kimura

Norihiro Umemura

Tsuyoshi Kumagai

Masato Shibazaki

According to an embodiment, a neutron measurement apparatus has: a neutron detector; a preamplifier that amplifies an output signal of the neutron detector and outputs a neutron detection signal; a pulse counting unit that measures the neutron intensity by using pulse counting method by which the neutron detection signal is used to count the number of individual pulses; a Campbell measurement unit that measures the neutron intensity by using Campbell method by which a time average of squares of AC component of the neutron detection signal is calculated; a correction constant calculation unit that calculates a correction constant for correcting an output of the Campbell measurement unit by using an output of the pulse counting unit and an output of the Campbell measurement unit; and a correction value calculation unit that outputs, based on the output of the Campbell measurement unit, a corrected value by using the correction constant.

Neutron measurement apparatus and neutron measurement method

According to an embodiment, a neutron measurement apparatus has: a neutron detector; a gamma ray detector; a neutron detector signal processing unit which performs Fourier transform on the signals received for a prescribed period, generates neutron detector signal frequency data in a frequency domain, calculates the neutron-detection signal power spectrum and stores it; a gamma-ray detector signal processing unit which performs Fourier transform on the signals received for a prescribed period, generates gamma ray detector signal frequency data in a frequency domain, calculates gamma ray detector signal power spectrum and stores it; and a neutron calculation unit which generates a neutron signal by removing a part contributed by the gamma ray detector signal power spectrum from the neutron detector signal power spectrum.

Neutron measurement apparatus, neutron calculation apparatus, and neutron measurement method

A neutron measurement apparatus includes: an analog signal processor; a digitizing processor; an FFT calculation processor; and a signal processor. The analog signal processor amplifies alternating current components of detector output signals output from a neutron detector, and filters to remove high frequency components from the output signals, which the digitizing processor digitizes at a constant sampling period in a time series; the FFT calculation processor converts certain of the signals in a time domain from the digitizing processor into signals in a frequency domain, and filters the signals in the frequency domain; and the signal processor selects and extracts signals having required frequency components through the calculation processing on the FFT calculation processor, to calculate power spectral densities of the extracted signals, and to convert the calculated power spectral densities into a neutron measurement value.

Disclosed is a method of monitoring the neutron sensitivity of a neutron detector. Voltage having a predetermined potential difference is applied between an anode and a cathode without irradiating the neutron detector with neutrons to permit an &agr;-ray to be emitted from the nuclear fission substance. The &agr;-ray ionizes the ionizing gas to form an &agr;-ray current (I&agr;) flowing between the anode and the cathode. The current (I&agr;) thus formed is monitored. Also, with the monitoring region in which the applied voltage and the &agr;-ray current (I&agr;) bear a substantially proportional relationship, obtained is an extrapolated zero-volt &agr;-ray current (I&agr; ) at 0V of the applied voltage between the anode and the cathode from the proportional relationship by an extrapolating method, and the extrapolated zero-volt &agr;-ray current (I&agr; ) is correlated with the neutron sensitivity.

Method of monitoring neutron sensitivity of neutron detector

A power range monitor apparatus includes a plurality of average power range monitors for calculating/monitoring local power values, average reactor power values, and core flow rate values, a plurality of rod block monitors for monitoring the average values of local power values, and a plurality of flow rate signal converters for converting the signal form of recirculation rate detection signals. The flow rate signal converters concurrently transmit recirculation rate detection signals as digital signals to the average power range monitors. The average power range monitors obtain core flow rate signals from the respective recirculation rate detection signals, use them to monitor the average reactor power, and transmit them to the rod block monitors. The rod block monitors select optimal values from average reactor power values and core flow rate signals to perform a monitoring operation.

Growing community of inventors

Tama, Japan

Shigehiro Kono