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Title: Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant

Abstract

A rare signal was detected at 23:53 Moscow time on April 27, 1986 with the LSD low-background scintillation detector located under Mont Blanc at a distance of 1820 km from Chernobyl. To reveal the origin of this signal, we discuss the results obtained with other instruments operating within a similar program, as well as analyze the characteristics of the pulses of the signal and facts referring to the explosion of the Chernobyl reactor. A hypothesis based on detection with the LSD of gamma-quanta from {beta} decays of {sup 135}I nuclei ejected into atmosphere by the reactor explosion and carried in the underground detector camera with air of positive ventilation is considered. The explosion origin of the LSD signal indicates a new technogenic source of the background in the search for neutrino bursts from cores of collapsing stars.

Authors:
;  [1];  [2]
  1. Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)
  2. Istituto Nazionale di Fisica Nucleare, and Osservatorio Astrofisico di Torino, Istituto di Fisica dello Spazio Interplanetario (Italy)
Publication Date:
OSTI Identifier:
22210514
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Experimental and Theoretical Physics; Journal Volume: 117; Journal Issue: 2; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATMOSPHERES; BETA DECAY; CAMERAS; CHERNOBYLSK-4 REACTOR; DETECTION; EXPLOSIONS; IODINE 135; NEUTRINOS; NUCLEAR POWER PLANTS; RADIATION ACCIDENTS; SCINTILLATION COUNTERS; SIGNALS; UNDERGROUND

Citation Formats

Agafonova, N. Yu., E-mail: natagafonova@gmail.com, Malgin, A. S., E-mail: malgin@lngs.infn.it, and Fulgione, W. Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant. United States: N. p., 2013. Web. doi:10.1134/S1063776113100087.
Agafonova, N. Yu., E-mail: natagafonova@gmail.com, Malgin, A. S., E-mail: malgin@lngs.infn.it, & Fulgione, W. Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant. United States. doi:10.1134/S1063776113100087.
Agafonova, N. Yu., E-mail: natagafonova@gmail.com, Malgin, A. S., E-mail: malgin@lngs.infn.it, and Fulgione, W. Thu . "Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant". United States. doi:10.1134/S1063776113100087.
@article{osti_22210514,
title = {Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant},
author = {Agafonova, N. Yu., E-mail: natagafonova@gmail.com and Malgin, A. S., E-mail: malgin@lngs.infn.it and Fulgione, W.},
abstractNote = {A rare signal was detected at 23:53 Moscow time on April 27, 1986 with the LSD low-background scintillation detector located under Mont Blanc at a distance of 1820 km from Chernobyl. To reveal the origin of this signal, we discuss the results obtained with other instruments operating within a similar program, as well as analyze the characteristics of the pulses of the signal and facts referring to the explosion of the Chernobyl reactor. A hypothesis based on detection with the LSD of gamma-quanta from {beta} decays of {sup 135}I nuclei ejected into atmosphere by the reactor explosion and carried in the underground detector camera with air of positive ventilation is considered. The explosion origin of the LSD signal indicates a new technogenic source of the background in the search for neutrino bursts from cores of collapsing stars.},
doi = {10.1134/S1063776113100087},
journal = {Journal of Experimental and Theoretical Physics},
number = 2,
volume = 117,
place = {United States},
year = {Thu Aug 15 00:00:00 EDT 2013},
month = {Thu Aug 15 00:00:00 EDT 2013}
}
  • Radioactive waste management is an important component of the Chernobyl Nuclear Power Plant accident mitigation and remediation activities of the so-called Chernobyl Exclusion Zone. This article describes the localization and characteristics of the radioactive waste present in the Chernobyl Exclusion Zone and summarizes the pathways and strategy for handling the radioactive waste related problems in Ukraine and the Chernobyl Exclusion Zone, and in particular, the pathways and strategies stipulated by the National Radioactive Waste Management Program. The brief overview of the radioactive waste issues in the ChEZ presented in this article demonstrates that management of radioactive waste resulting from amore » beyond-designbasis accident at a nuclear power plant becomes the most challenging and the costliest effort during the mitigation and remediation activities. The costs of these activities are so high that the provision of radioactive waste final disposal facilities compliant with existing radiation safety requirements becomes an intolerable burden for the current generation of a single country, Ukraine. The nuclear accident at the Fukushima-1 NPP strongly indicates that accidents at nuclear sites may occur in any, even in a most technologically advanced country, and the Chernobyl experience shows that the scope of the radioactive waste management activities associated with the mitigation of such accidents may exceed the capabilities of a single country. Development of a special international program for broad international cooperation in accident related radioactive waste management activities is required to handle these issues. It would also be reasonable to consider establishment of a dedicated international fund for mitigation of accidents at nuclear sites, specifically, for handling radioactive waste problems in the ChEZ. The experience of handling Chernobyl radioactive waste management issues, including large volumes of radioactive soils and complex structures of fuel containing materials can be fairly useful for the entire world's nuclear community and can help make nuclear energy safer.« less
  • During the accident in the fourth power-generating unit of the Chernobyl nuclear power plant complicated spatially distributed processes (neutron-physical, thermohydrodynamic, chemical, and thermomechanical) were focused and became intertwined. This has made it difficult to model the accident numberically and it has made international collaboration in this field urgent. As a result, specialists in three different countries performed a series of methodological investigations of the effect of different factors on the positive reactive arising as a result of the insertion of the safety and control rods. These works confirmed that the positive reactivity is highly sensitive to the state of themore » core prior to the accident and they substantiated the need for reproducing in detail the preliminary initial conditions during computational modeling of the first phase of the accident. The first stage of a combined comprehensive computational analysis of the Chernobyl accident were quasistatic estimates of the positive reactivity according the DINA and CITATION codes. The results of the reconstruction of the three-dimensional neutron fields on the basis of information recorded approximately 2 minute prior to the accident by the SKALA system were used as the initial information for constructing the preaccident state of the reactor.« less
  • Immediately after the first information about the accident at the Chernobyl nuclear power plant was received, three groups of experts were formed at the I.V. Kurchatov Institute of Atomic Energy. The purpose of these groups was to analyze the accident. Later they were given official status by a special decree of the President of the Academy of Sciences of the USSR. The group of which the authors of the present report as well as O. Ya. Shakh were members was charged with estimating the activity, composition, and dynamics of the emission of radioactive substances from the damaged power-generating unit onmore » the basis of computational, experimental, and field data. All estimates presented below were obtained in May-June 1986. An objective estimate of the parameters of the emission of fission products and fuel from the damaged reactor can be made only if the following parameters are known: activity of radionuclides accumulated in the core; character and dynamics of accident development; state of the fuel and reactor as a whole; and, region (zone) of propagation and composition of the radioactive fallout. The situation was especially difficult because there was very little initial information. Only computational data on the activity of the radionuclides accumulated in the RBMK reactor during normal operation were available. The primary information received about the real radiation conditions and the composition of the samples was sporadic and random. This, together with the lack of practical experience in estimating the consequences of serious radiation accidents, made it impossible to formulate unequivocal conclusions and often resulted in divergent points of view. For this reason, the working documents on the assessment of the emission contained some contradictions. Ultimately, the collective work of the experts and fruitful discussions led to the development of a base estimate of the composition, activity, and dynamics of emission.« less
  • The accident in the second power-generating unit of the Chernobyl nuclear power plant on October 11, 1991 was the result of unauthorized connection of the TG-4 turbogenerator, which was shut down for repairs, into the grid (in the off-design asynchronous engine mode), and this resulted in a serious fire in the machine room and subsequent failure of systems which are important for safety and which ensure the design mode of reactor cooling: These were primarily failures of the feed and emergency feed pumps and failure of the BRU-B control valve, which regulates steam release during cooling.
  • The main difficulty in making a retrospective assessment of the collective indicators of the degree of irradiation of personnel at the Chernobyl nuclear power plant in 1986 is that complete data on the individual dose load are not available. However, information obtained thus far makes it possible to estimate, to a first approximation, the collective irradiation dose to personnel. The data on which the calculation is based were obtained by a detailed reconstruction of the individual routes under accident and post-accident radiation conditions. This reconstruction was made possible by working directly with eye witnesses and witnesses to the events ofmore » 1986, the participation of experts, and the use of data from the teams and archives of the accountants at the plant, and many other auxiliary organizations. From the standpoint of mathematical statistics, the actual individual irradiation does to personnel in 1986 consists of a universe of data and the part that is constructed at a given time---the sample. The universe of data is not known but can be adequately determined only after the dose reconstruction work has been completed. In this paper, we estimate the collective irradiation dose to personnel as a parameter of an unknown universe of data on the basis of a sample of the individual irradiation doses identified at a given time.« less