Comparative analysis of estimates of neutron radiative capture cross sections for the most important fission products

Belanova, T. S.; Gorbacheva, L.V.; Grudzevich, O. T.; Ignatyuk, A. V.; Manturov, G. N.; Plyaskin, V. I.

doi:10.1007/bf01123639

Cited by 5 publications

(2 citation statements)

References 14 publications

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“…It is also known that elements which have sharply different radiative capture cross sections in the thermal and epithermal neutron ranges are used as emitters in direct-charge detectors. Specifically, for direct-charge detectors with a rhodium emitter the 103 Rh(n, γ) reaction cross section for thermal neutrons is 145 b, at the 1.253 eV resonance the value is 5100 b, and the resonance integral is 1100 b [23]. Consequently, for different fractions of the thermal and resonance neutrons in the spectra the results of the calibration of the in-reactor detectors in the GIDRA and other reactors will be substantially different.…”

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Research-reactor neutron fields for calibrating in-reactor detectors in nuclear power plants

et al. 2006

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The neutron spectra of research and power reactors are compared. The spectra were measured by the neutron-activation method and calculated using the KASKAD computer code. The a priori spectrum in the calculation was constructed as a superposition of physically validated spectra. A method of calibrating in-reactor detectors in nuclear power plants on the basis of the sensitivity to the 235 U fission rate in 1 g of uranium using the neutron fields of research reactors is proposed.The use of the neutron fields of research reactors for calibrating the detectors in the standard apparatus of high-power nuclear reactors has been described in [1]. As a rule, such detectors are calibrated according to the sensitivity to neutrons, which is insufficient for solving certain scientific-technical problems [2][3][4]. Specifically, to determine the power release in a reactor core it is necessary to calibrate in-reactor detectors, for example, direct-charge detectors [5], according to the sensitivity not only to neutrons but also to the fission rate of 235 U per 1 g U [6].The objective of the present work is to compare the 235 U fission rate in the neutron fields of research reactors and the RBMK-1000 power reactor and to investigate the dependence of this rate on the ratio of the thermal and epithermal neutrons in the spectra of the reactors studied. For this, the spectra of neutrons in the cores of seven research reactors and two RBMK-1000 channel reactors in the No. 2 unit of the Leningrad nuclear power plant were investigated.Neutron Field of the Kvant Critical Stand [2]. The 1410 mm in diameter and 500 mm high core in this stand consists of 175 fuel assemblies, placed in a water moderator. Ninety four compensation and absorbing rods are placed along the perimeter; a vertical IK-6 experimental channel with inner diameter 85 mm and wall thickness 3 mm is placed near the steel vessel of the stand. The neutron spectrum in the IK-6 channel was measured at the level of the center of the core of the critical stand at power 1 kW.Neutron Field of the F-1 Reactor [1, 3]. The spherical core of the F-1 graphite reator is 6 m in diameter and is surrounded by a 1 m thick graphite reflector. It is assembled from graphite blocks into which are inserted 35 mm in diameter and 100 mm high metal cylindrical blocks of natural uranium. The total uranium mass in the reactor is 48 tons and the graphite mass is 430 tons. The neutron spectrum was measured at core center in the horizontal central experimental channel at reactor power 24 kW.

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Research-reactor neutron fields for calibrating in-reactor detectors in nuclear power plants

et al. 2006

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“…The microscopic approach in the nuclear theory accounts for specificity of each nucleus through its single-particle and collective (phonon) spectra. Therefore, it allows "some irregular changes" obtained in the global phenomenological models for nuclear reactions data [3] to be seen and checked. Thus, for double-magic nuclei it is necessary to use the microscopic approaches for both PSF and NLD.…”

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Microscopic calculations of the characteristics of radiative nuclear reactions for double-magic nuclei

Achakovskiy

Kamerdzhiev

Tselyaev

et al. 2016

EPJ Web of Conferences

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Abstract. The neutron capture cross sections and average radiative widths Γ γ of neutron resonances for two double-magic nuclei 132 Sn and 208 Pb have been calculated using the microscopic photon strength functions (PSF), which were obtained within the microscopic self-consistent version of the extended theory of finite Fermi systems in the time blocking approximation. For the first time, the microscopic PSFs have been obtained within the fully self-consistent approach with exact accounting for the single particle continuum (for 208 Pb). The approach includes phonon coupling effects in addition to the standard RPA approach. The known Skyrme force has been used. The calculations of nuclear reaction characteristics have been performed with the EM-PIRE 3.1 nuclear reaction code. Here, three nuclear level density (NLD) models have been used: the so-called phenomenological GSM, the EMPIRE specific (or Enhanced GSM) and the microscopical combinatorial HFB NLD models. For both considered characteristics we found a significant disagreement between the results obtained with the GSM and HFB NLD models. For 208 Pb, a reasonable agreement has been found with systematics for the Γ γ values with HFB NLD and with the experimental data for the HFB NLD average resonance spacing D 0 , while for these two quantities the differences between the values obtained with GSM and HFB NLD are of several orders of magnitude. The discrepancies between the results with the phenomenological EGLO PSF and microscopic RPA or TBA are much less for the same NLD model.

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Introduction

Belanova¹,

Ignatyuk²,

Pashchenko³

et al.

Low Energy Neutrons and Their Interaction With Nuclei and Matter. Part 2

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Comparative analysis of estimates of neutron radiative capture cross sections for the most important fission products

Cited by 5 publications

References 14 publications

Research-reactor neutron fields for calibrating in-reactor detectors in nuclear power plants

Research-reactor neutron fields for calibrating in-reactor detectors in nuclear power plants

Microscopic calculations of the characteristics of radiative nuclear reactions for double-magic nuclei

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