Semipalatinsk Revisited Radiological Evaluation of the Former Nuclear Test Site
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Doc-03.qxd 1/21/99 9:34 AM Page 12 SEMIPALATINSK REVISITED RADIOLOGICAL EVALUATION OF THE FORMER NUCLEAR TEST SITE BY PETER STEGNAR AND TONY WRIXON arious locations around the world are Vaffected by residual radioactive material. Some of them are the result of past peaceful activities, while others result from military programmes, including the testing of nuclear weapons. In the 1990s, there has been growing international cooperation in assessing the radiological effects of past military nuclear activities. In many countries, attention has turned to assessing and, where necessary, remediating areas 12 affected by residual radioactive materials from military steppes of Kazakhstan became explosions were conducted activities. The IAEA has been the first centre for nuclear underground. Thirteen of the leading this effort of assessing weapons testing within the underground tests resulted in former nuclear-weapon test Soviet Union. The release of radioactive gases to the sites. This article reports on Semipalatinsk test site is a atmosphere. (See table, page 14.) preliminary radiological 19,000 km2 zone in the north- The only on-site inhabitants evaluations of the east of the country, 800 km during the testing programme Semipalatinsk site in north of the capital Almaty. were in the town of Kurchatov Kazakhstan, where the former The zone lies southwest of the whose purpose was to service Soviet Union conducted more Irtysh River which flows into the site, and in the small than 400 nuclear tests over a Kazakhstan from China and settlements of Akzhar and forty year period. which, for a short distance, Moldari along the northern forms part of the nuclear test edge of the site. Recently there THE SITE site boundary. has been a limited amount of The Republic of Kazakhstan is During the period 1949-89 resettlement within the area, located immediately south of the former Soviet Union mostly by semi-nomadic Russia, and west of China. conducted about 460 nuclear farmers and herders. The bulk Following World War II, the weapons tests within the test of the local population is in site. They included explosions settlements just outside the site Photo: Lake Tel’kem-2 in that were conducted on the border. The total population of Kazakhstan, which resulted surface or in the atmosphere. from a crater caused by a Five of these surface tests were Mr. Stegnar is a staff members in nuclear test. The test used three not successful and resulted in the Waste Safety Section, and Mr. nuclear devices, each the the dispersion of plutonium in Wrixon is Head of the Radiation equivalent of 240 tonnes TNT. the environment. Starting in Safety Section, Division of IAEA BULLETIN, 40/4/1998 (Credit: IAEA mission/July 1994) 1961, more than 300 test Radiation and Waste Safety. Doc-03.qxd 1/21/99 9:34 AM Page 13 these settlements is estimated to be 30,000 to 40,000 people. IAEA MISSIONS In May 1993, representatives of the Kazakhstan Government informed the IAEA of their concern about the radiological situation in Semipalatinsk and western areas. Subsequently, the Government of Kazakhstan requested the IAEA to provide assistance regarding the former test areas of Semipalatinsk and western Kazakhstan. The IAEA agreed to organize a study of the radiological situation in Based on the results of this spectroscopy and these areas. This commitment first mission, IAEA officers met radiochemical analysis to resulted in a series of activities in March 1994 at Agency determine radionuclide to characterize and evaluate the headquarters in Vienna with a concentrations. Experts from radiological situation at the delegation from Kazakhstan. the team spent time talking to Semipalatinsk test site. At this meeting, one topic of inhabitants in the surrounding November 1993. The first discussion was the concern farms and settlements for the IAEA mission was performed about Semipalatinsk. In purpose of gaining information in November 1993. The response to this concern, the on the local diet and customs objectives were to become IAEA agreed to establish, relevant to the dose assessment. familiar with the test site and through its technical co- June 1998. A third mission 13 provide guidance on future operation programme, a was conducted in 1998 in actions. The team was also project to assist the Republic of compliance with a United asked to assist in strengthening Kazakhstan in the radiological Nations General Assembly the national infrastructure in assessment of the Resolution (52/169M). In this the area of radiation Semipalatinsk test site. mission an expert team protection, with emphasis on July 1994. A second IAEA intensively examined the environmental monitoring. mission to the test site was consequences and needs arising The team traveled to the conducted in July 1994. The from two generations of Semipalatinsk site and objectives were to collect nuclear testing in the territory identified the most likely areas additional radiological data of what has been the Republic of radioactive contamination from in and around the site, of Kazakhstan since 1991. The on the test site as well as off- collect and review existing data mission was composed of site. It also performed limited provided by Russian and specialists from organizations radiation measurements and Kazakh sources relevant to the and agencies of the United collected environmental radiological situation at the test Nations including the IAEA, samples at identified locations site, and to perform a the Government of to assist in further defining the prreliminary assessment of the Kazakhstan, and other concerns and provide present and potential future technical experts from the information as to future doses to residents in the international community. The actions. The team also visited Semipalatinsk area. mission was deployed from 15 governmental laboratories to The goal was to determine determine their capabilities for whether further radiological Photo: Specialists conduct in- cooperative efforts and to evaluation and assessment were situ gamma spectrometric locate existing radiological warranted. Soil, vegetable and measurements at Semipalatinsk assessment data. milk samples were collected during the IAEA mission in July and analyzed by gamma 1994. (Credit: IAEA mission/July 1994) IAEA BULLETIN, 40/4/1998 Doc-03.qxd 1/21/99 9:34 AM Page 14 to 30 June 1998 to carry out NUCLEAR TESTING AT SEMIPALATINSK the needs assessment of the humanitarian situation in the Duration Test Zone Number Semipalatinsk Test Site of testing Geology of tests Territory of Kazakhstan, as stipulated in the UN 1949-62 Sandstone Surface: 26 resolution. Air: 87 1961-89 Granite, quartz-porphyry, FINDINGS OF syenite rock mountain massif In mine galleries: 215 THE MISSIONS Based on information collected 1965-80 Alevrolite, porphyry, sandstones In boreholes: 24 during the missions and subse- quent research, there is suffi- 1968 Argyllite In boreholes: 2 cient evidence to indicate that most of the area has little or no 1965-89 Alevrolite, sandstones, residual radioactivity directly conglomerate In boreholes: 107 attributed to nuclear tests in Kazakhstan. There are a few areas that have elevated resid- ual radioactivity levels within external exposure. If these areas showed no elevated levels of the test site where the surface were permanently settled in the artificial radionuclides, tests were performed and future, estimated exposures sampling was not where a few underground tests could be up to 140 mSv per comprehensive. As such it is vented to the atmosphere. year. This annual exposure is difficult to draw general Preliminary surveys of these above the action level at which conclusions about the entire areas indicated that the conta- intervention is expected to be water supply. In addition the 14 mination is relatively localized. undertaken. Remedial action results do not provide any Due to the limited amount is, therefore, considered guarantee about the future of survey data that was necessary for these localized security of the water supply. collected during the missions, elevated areas. However, due to External dose rates. The the existence of actinide budgetary and other external radiation dose rates residues from the failed nuclear constraints, the most and soil activity outside the test tests could not be appropriate remedial action at site are the same, or close to, corroborated. Descriptions of this time may be to restrict typical levels in other regions the nature of the failed tests, access to these areas. and countries where no the prevailing conditions and The measurements made by nuclear-weapons testing had any supporting data would be the IAEA experts corroborate, been carried out. Some areas needed before further to a reasonable degree, the show small increases but these investigations are considered. more extensive surveys carried are not significant in terms of Currently there are no out by different organizations the exposure to the local restrictions of access to the from Kazakhstan and the population. nuclear test site and limited former Soviet Union. The One village had a higher reoccupation has already combined results are plutonium deposition level begun. An assessment of the considered sufficient to form than the other settlements and exposure of persons who, on a the basis of a preliminary has been the subject of more daily base, visit the areas where assessment of the radiological comprehensive soil sampling. the surface tests and vented situation of the area around the However, estimated annual underground explosions has Semipalatinsk test site. doses still remain low. been undertaken. The one exception to the Intervention to reduce the Initial findings of this above conclusion is the radiation exposure of people assessment indicate annual drinking water supply. While outside the Semipalatinsk test exposures in the region of 10 samples of drinking water site is not considered to be IAEA BULLETIN, 40/4/1998 mSv, predominantly due to taken during the missions justified. ❐.