Waste Isolation in Cavities Produced by Nuclear Explosions
Scientific and Technical Substantiation and Development of the Concept of Radioactive Contamination Localization in Cavities Produced in Rock Salt Deposits during Underground Explosions for the Purposes of the National Economy
Tech Area / Field
- ENV-RED/Remediation and Decontamination/Environment
- ENV-RWT/Radioactive Waste Treatment/Environment
8 Project completed
Senior Project Manager
Tyurin I A
VNIPI Promtechnology, Russia, Moscow
- Institute of Dynamics of the Geosphere, Russia, Moscow
- Columbia University / Lamont-Doherty Earth Observatory, USA, NY, Palisades\nUS Geological Survey, USA, VA, Reston
Project summaryThe purpose of the present project is the scientific and technical substantiation and development of the concept of radioactive contamination localization in cavities produced in rock salt deposits during underground nuclear explosions (UNE) for the purposes of the national economy, that corresponds to the purposes of radiating safety maintenance and environment protection.
In 70-80 years in former USSR territory with the help of nuclear-explosions technology was prepared a park of 15 underground facilities (UF) on Astrakhan gas-condensate field (GCF).
At present only 9 UE from all park are in operation. Others were recognized as not suitable for commercial use and were transferred into the preservation mode.
After the ending of the operational terms it was provided to realize a complex of engineering measures for liquidation of explosive and technological chinks shafts and closing UF, ensuring the reliable, durable and controllable isolation of all kinds of radioactive contamination, connected with UNE realization, and harmful substances contained in the not taken leavings of a stored product, from human residing environment.
It is known, that the realization of any kinds of UNE means in essence the preparation of the "burial place" for the large group radio nuclides including strontium-90, cesium-137, uranium-234, uranium-236, plutonium-239 etc, in the bowels the earth. At UNE with capacity 10 Kt the radio-activity of products in one year makes 3.5×1015 Bq, and in 10 years – 1.6×1013 Bq.
The basic source of the radioactive contamination representing danger for the environment, is the pickle, collecting in UF during its construction and operation. Among the radio nuclides, contained in the pickle, from the point of ecology view the greatest danger represent the mobile (leached, outwashed by water) forms of cesium-137 and strontium-90. Tritium, represented in UF as molecules of water, completely passes in the pickle. Also radon and radium, contained in hydrocarbonaceous gas condensate layer are passing into the pickle.
The pickle in UF on its specific activity could be referred to a category with poor (below 1×10-5 Ci/l) and middle activity by the liquid Radio Active Leavings (from 1×10-5 Ci/l up to 1 Ci/l).
Besides it, with the complete basis, to a category of harmful substances subjected to the underground isolation, can be referred high toxic chemical components of the products stored in UF (hydrogen sulfide, methanol, sulfuric angidrit, hydrocarbonaceous gas, etil mercaptans, etc.), which remain in underground storage fasility after the ending of its operation.
The greatest danger to an environment is the penetration of harmful substances from UF onto a surface and into the above-placed water horizons. In the real conditions their migration depends on specific engineering-geological and hydro-geological conditions, which is presented on the each separate site of a underground storage. The most probable ways of carrying out of the radioactive and chemical pollution are the shafts of explosive and technological chinks, which estuary and underground equipment to the end of operation would be worn out due to the aggressive substances contained in a kept product, and also system of cracks, formed above the explosive cavity roof.
These circumstances are aggravated by presence of the superfluous pressure exceeding meanings stipulated by specifications, that is a consequence of underground developments volumes reduction caused by abnormal properties of the salt layers on separate sites of UF park. Due to this factor there can be a penetration of UF contents into human residing environment through on the above mentioned channels
The realization of the above mentioned complex of engineering measures for UF park closing, provides the inspecting of the place of UNE realization and drawing up of the ecological passports describing radiation conditions, usual in UNE zones and in adjoining to them territories, and also development of the long-term prognosis for radio nuclides and other harmful substances migration from closed UF and security of the ecological monitoring.
Despite of the social and ecological importance of the established purpose even minimally necessary volume of works on systematic inspection of the actual condition of UF park and adjoining to them territories after 1992 was sharply reduced and subsequently was limited to works on the program of radiating monitoring only on pre- estuary platforms UF and maintenance of a technical condition estuary of the equipment.
The special importance of duly realization of the present project on the Astrakhan GCF is determined by the progressing loss of the UF volumes, located in the stone salt layers in the Seitovsky hydrochloric raising, and connected with it danger of replacement of the harmful substances onto the surface and into water horizons on the area directly closed to territory National Biosphere Reservation in the delta of the river Volga.
The concept, developed within the framework of the present project, for isolation of the radioactive pollution and other harmful substances in worn out UF, and also in the capacities, prescheduled removing from the operation, would serve as a basic point for engineering of the subsequent systems of the underground burying. The specified systems are called not only to ensure a long-term stability of closed objects to the influence of the natural and technical factors, but also to exclude an opportunity of the non-authorized access to the closed underground storehouse.
The present concept would be based on the results of the available share and archival materials analysis, which have the organizations – participants and which include the information received by them at all stages of the UF park construction, since development of the technical project and preliminary researches down to last systematic inspections of a technical condition of the underground objects and adjoining to them territories.
First of all for the realization of this project will be used the equipment (geophysical, dosimetric, laboratory etc.), computer facilities and measuring equipment available at organizations – of the participants of the project.
The performance of the project will ensure two years alternative employment of the military-industrial complex experts, in due time accepting active participation in designing, preparation and realization UNE.
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