of radionuclides that formed a fallout trace, such as occurred following the two botched explosions Kraton-3 and Globus-1. The radiation consequences of these explosions were determined by the channels by which the blast products reached the surface, the time it took for this to occur, and the gas content in the rock at the point where the nuclear device was placed. At the Kraton-3 site, explosion products began erupting through the loading-hole shaft 5 seconds after the explosion and lasted for about 10 minutes. During this explosion in the carbonate reservoir rock, in addition to fission fragment radionuclides, alpha-emitters were also discharged, yielding a fallout trace (based on a commitment dose of 5 mSv) reaching about 30 km in length. At the Globus-1 site, radionuclides began to be discharged 17 minutes after the explosion. Because of the high fume characteristics of the rock (limestone), site contamination with fission-fragment radionuclides along the trace did not exceed several hundred meters despite the long duration of gaseous product (carbon dioxide) outflow (more than 10 days). Radionuclides were discharged through the casing space of the loading hole as a gas-water gryphon, which partially cleansed the gas of nonvolatile radionuclides. A pressure-induced gas eruption from the explosion zone also occurred at the Globus-3 site. In the latter case, the gas eruption began about 12 minutes after the explosion and lasted for 7 hours. This time, the gas flow rate and site contamination level were considerably lower than at the Globus-1 site, since the Globus-3 nuclear device had been placed in clay rock with sandstone layers.
Sites contaminated as a result of hole boring in the central explosion zone, particularly in connection with loading-hole recovery. Recovery of loading holes in rock salt resulted in the controlled emission of various forms of tritium and inert radioactive gases, which did not lead to any long-term site contamination. The boring of holes in a water-bearing horizon leading to the central explosion zone resulted in contamination of the immediate site grounds with cesium-137, strontium-90, and tritium entrained in drilling fluid and sludge, as well as stratal water extraction from the explosion zone during hydrodynamic survey works. This was the case with the Globus-1, Globus-2, Kama-1, and Kama-2 sites. At the Kama-1 site, the primary cause of site contamination was the unplanned discharge of carbon dioxide and radioactive water from the loading hole during its recovery. The contaminated zone exceeded 30,000 m2 in area. It should be noted that the cesium-137 and strontium-90 contamination of the Globus-1 site was mainly caused by hole boring in the explosion zone.
Sites where technogenic radionuclides were released to the earth’s surface and distributed in the soil as a result of violations of technical procedures. The most typical example in this category is the Grifon site. At this site, a product (crude oil) was extracted from the explosion zone along with radioactive water, which after being separated from the oil was used for repressuring. Leakages in the injection wellheads resulted in the contamination of dozens of wellhead zones with cesium-137, strontium-90, and tritium, while accidental pipe ruptures contaminated areas beyond the immediate drilling sites.