Testing grounds Balapan and Sary-Uzen
Location of wells at the testing ground BalapanTesting ground Balapan is situated in the south-eastern part of the Site and occupies the area of 780 km2. The testing site was used for underground nuclear explosions in the holes and model experiments with the usage of conventional explosive substances.
On the whole, 105 nuclear explosions, as a rule, explosions of high yield up to 150 kg, were performed on the site. The first in the USSR excavation explosion with soil outburst in the framework of the experiment on creation of an artificial water reservoir (15.01.65) was also made on this site. In 4 test-holes (No. 1007, 1069, 1204, 1301) emergency situations caused considerable contamination of the surrounding area.
As compared with atmospheric tests radioactive contamination of the territory caused by underground nuclear explosions is much lower. The main fraction of radioactive products remains “buried” under the soil layer. During underground nuclear explosions in holes with normal radiation situation the main part of produced radioactivity remains in the epicenter of an explosion under the ground, only a small part permeates to the surface as inert gases.
Examination of the near-mounth areas showed that in most cases radiation parameters do not exceed background levels. Maximal concentrations of radionuclides are registered at the wellheads. At the same time, radioactive contamination of soil cover spreading at a distance of tens to hundreds of meters whose specific activity is comparable with that of radioactive wastes was recorded in the near-mouth areas of 10 wells (2 of them are wells with emergency situations – wells number No. 1301 and 1069). The following values of specific activity of radionuclides are registered in these areas: 241Am – 3*105, 137Cs – 2*106, 90Sr – 2*105, 152Eu – 5*102, 154Eu – 4*102, 239+240Pu – 2*106 Bq/kg.
Distribution of 137Cs surface contamination density for the well 1069, mCi/km2Presence of “kettle-shaped cavities” remained after underground nuclear explosions creates a real possibility of their spontaneous, not-forced collapse. The signs of burning processes under the ground create a real danger of unexpected outbursts of underground gas accompanied by inflammation. For example, 17 years after the nuclear test in the well “Glubokaya” there was an explosion which resulted in formation of a hole of over 100m in diameter and 30m in depth. Location of wells at the testing ground Sary Uzen In the period from 1965 to 1980 on the testing ground Sary-Uzen underground nuclear explosions were made in 24 wells. In close vicinity to the site Sary-Uzen, in the mountain range Murzhik, underground nuclear test “Lazurit” was made. The main contamination of the territory was caused by emergency radiation situations occurred during nuclear devices tests in the wells 101, 111, 215 and during excavation explosions in the wells 1003 and 125.
MED values for the well 101 Spatial distribution of radionuclides within near-mouth areas on the testing ground Sary-Uzen is identical to the spatial distribution of radionuclides on Balapan site. Radioactive contamination of the environment in the vicinity of wells where nuclear explosions were accompanied by soil outbursts spreads over hundreds of meters and trace of radioactive fallouts formed during tests in test hole 101 is recorded at a distance of several kilometers. Radiological examination of test holes of Sary-Uzen ground revealed 4 unknown wells, which were not identified. On one of the holes maximal MED values – 2.0 μSv/h and high concentration of artificial radionuclides 137Cs – 2*103, 90Sr – 4*103, 241Am – 2*104 Bq/kg in soil samples were recorded.By the present time practically all heads of wells on Balapan and Sary-Uzen sites have been dismantled.