Surveying radioactive contamination

For the monitoring of personnel radiation exposures, measurement of radioactive contamination and surveying of laboratories and equipment, and for the detection of radionuclides incorporated in the human body, various detectors and instruments are used. The principles of operation of these detectors have been discussed in the previous sections of this chapter. 

Several methods have been described in the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM 2000) for the survey and investigation of sites contaminated with radioactive materials. At the... 

Calibration of Survey Instruments Used in Radiation Protection for the Assessment of Ionizing Radiation Fields and Radioactive Surface Contamination (1991)... 

Though neither information survey nor research survey are capable of providing sufficient information to generate the entire radioecological picture of the studied territory/water area, they are quite sufficient for discovering eventual radioactive contamination issuing from the surveyed objects. 

Since 1990 extended radioecological monitoring based on radiation mapping has been implemented into the radioecological survey practice [2]. Completeness of the environmental contamination information has been attained through generation of radiation field maps with simultaneous indication of source-term location areas, boundaries of radioactive substance spreading, identification of radiation-hazardous zones with indication of the most probable man-caused radionuclide transfer paths. 

One of the most common topics asked of those who work with the actinides relates to handling procedures. The radioactive nature of these elements does require the use of special facilities, processes, and precautions. However, working with radioactive elements in subcritical quantities is as safe, if not safer, than handling many of the toxic chemicals found in a typical synthetic laboratory. The primary advantage in handling radioactive material is the ease with which these elements can be detected. Unlike other toxic chemicals, for example, lead, thallium, arsenic, and so on, a simple survey (seconds) with a radiation detector will show if containment of the material has been lost, where it is, and approximately how much is present. With appropriate monitoring, virtually no uptake of radioactive material occurs, and if any personnel contamination does occur, it is quickly detected and treated. 

NCRP. 1991. National Council on Radiation Protection and Measurements. Calibration of survey instruments used in radiation protection for the assessment of ionizing radiation fields and radioactive surface contamination. NCRP Report No. 112. Bethesda MD. 

The evolution of environmental radioactivity and radiation measurements in Japan originated essentially in the survey of widespread radioactivity contamination due to the nuclear explosion tests at Bikini atoll on 1st March, 1954. Today, environmental radiation monitoring in the vicinity of nuclear power facilities has become more important than radioactive fallout surveillance, since 38 nuclear power plants are already in operation or under construction in Japan. 

The governmental inspection of imported foods was taken by food sanitation inspectors at seaports and airports in Japan by a first screening test with a simple scintillation survey meter and also by a minute analysis of Ge detector at four major sea ports (Tokyo, Yokohama, Osaka, Kobe), one major airport (Narita) and in the National Institute of Hygienic Sciences, Tokyo. At the same time, trade companies were requested voluntarily to check imported foods for radioactive contamination under the above Japanese interim standard of 370 Bq/kg at the laboratories designated by the Ministry of Health and Welfare of Japan (Washima and Ohkubo, 1987). 

There are also several methods to determine patterns of fate and transport of pollutants in the environment. In some cases, microcosms and me-socosms are used to study fate, biodegradability, bioavailability, and transport within compartments. Field surveys may also be used to study fate and transport of pollutants in contaminated environments. Such studies involve collection and analysis of biota, water, air, soil, or sediment. In some cases, radioactively labeled contaminants ( tracers ) may be introduced in mesocosms or noncontaminated environments in order to determine their fate and patterns of transport. Finally, mathematical models are often used to produce computer simulations to... 

E. Detection of Suspected NBC Agents. It is not always evident when biological, chemical, or radiological weapons have been used. For example, several days will pass between the release of anthrax and the appearance of the first symptom. One method to detect the use of NBC agents before the appearance of symptoms is to sample the environment and troops. Personnel monitoring using radiation survey instruments should be done if radioactive contamination is... 

C. The principle objective in an area survey is to establish the location and radiation levels associated with one or more isodose rate lines. An isodose rate line is a plotted contour line that depicts the location of some uniform level of radiation or radioactive contamination. 

Third, atomic bomb tests in the west may have contaminated areas later used as ranges for conventional ordnance. Radioactive elements in the early atom bombs have a half-life of 12,000 years. Thus, these areas are just about as radioactive now as they were 60 years ago. Ranges in suspected atomic bomb test plumes should be surveyed prior to ordnance recovery work. Radio assay of groundwater or drinking water also requires substantial expertise. 

Submit a radiation survey documenting the absence of radioactive contamination, or the levels of residual contamination. In the latter case, an effort wUl be required to eliminate the contamination. 

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