Radioactive effluent monitoring

After an atomic energy site begins operations involving the use of radioactive materials, meteorological services may be required under the following conditions (1) if there is a continuous or intermittent source of radioactive effluent present in the area, or if there is a source potentially present to the extent that an atomospheric monitoring program is required (2) if there is a daily or occasional requirement for weather forecasts, which may be required for the control of stack effluent (3)... 

Production, Use, Release, and Disposal. The production of radon occurs directly from a radium source either in the environment or in a laboratory environment. The disposal of gaseous radioactive effluents has been documented. Increased radon concentrations have been detected in waste generated by uranium and phosphate mining therefore, these sites should be monitored on a continual basis. Although there are regulations for disposal of radionuclides in general, there are none that specifically address disposal of radon contaminated materials. Further research on the disposal of radon attached to charcoal, which is used in radon monitoring indoors, would be beneficial. 

Concerning radiation protection outside the plant, a barrier concept with progressive rates of vacuum from inside (e.g., glove boxes) to the outer atmosphere in connection with the ventilation system and treatment of off-gas by HEPA filters will achieve protection of the population. Emission of airborne radioactivity is monitored and the radioactivity of liquid effluents is controlled. 

Continuous monitoring of all gaseous effluents released from the HCF to the environment is accomplished to measure expected releases of airborne radioactive isotopes that are routinely evolved as a normal consequence of isotope processing. These released effluents will principally consist of small quantities of noble gases and radioiodine. Additional information regarding the quantities and monitoring of liquid and gaseous radioactive effluents is contained in Chapter 9, Section 9.4. 

Radioactive effluent released from the stack are continuously monitored for inert gas activity, particulate activity, iodine and tritium, to ensure that releases are within stipulated limits. 

Liquid and gaseous effluent monitors measure radioactive materials discharged to the environs. 

This section outlines the measures that are proposed to control and monitor discharges to the environment of solid, liquid, and gaseous radioactive effluents. This includes ... 

Suitable means of measuring discharges to the environment, such as by sampling and monitoring of discharges of radioactive effluents, shall be provided in the design. 

Releases of radioactive effluents shall be monitored and the results recorded in order to verify compliance with the applicable regulatory requirements. They shall also be reported periodically to the regulatory body or another competent authority in accordance with its requirements. 

Plants are designed to accormnodate routine releases of radioactivity and to minimize releases resulting from abnormal conditions and accidents. However, as indicated in Figure 5.1-11, because an accident resulting in off-site early health effects (death and injuries) would have to be fast, direct, and unfiltered, such a release would most probably be via an unmonitored pathway to the atmosphere. The most important example is a release due to a major containment failure or major containment penetration failure. As a result, effluent-monitoring systems located in routinely monitored release pathways (e.g., stacks) would not be able to assess the extent and the characteristics of such a severe release. 

Gas ionization detectors are widely used in radiochemistry and X-ray spectrometry. They are simple and robust in construction and may be employed as static or flow detectors. Flow studies have received attention in the interfacing of radioactive detectors with gas chromatographs. A radio-gas chromatograph (Figure 10.9) uses a gas flow proportional counter to monitor the effluent from the gas chromatography column. To achieve... 

Separated components emerging in the column effluent can be monitored by means of a physical measurement, e.g. UV or visible absorbance, refractive index, conductivity or radioactivity. Alternatively, separate fractions can be collected automatically and subjected to further analysis. 

In the case of radioactive isotopes, however, the newcomer in the field is faced with a bewildering array of instruments and manufacturers. Developments in this field have been rapid and papers a few years old probably describe assay methods which are now out of date. Currently there is a vast choice amongst ion chambers, proportional counters, Geiger-Miiller counters, crystal scintillation counters, liquid scintillation counters and semi-conductor counters — all with admirable characteristics for particular purposes. If a worker s interests lie solely in gas chromatographic examination of products then he can obtain a counter specially designed to monitor column effluents. Similarly there are various scanners especially for paper chromatograms or thin layer plates. 

SC 64-22 Design of Effective Effluent and Environmental Monitoring Programs SC 64-23 Cesium in the Environment SC 72 Radiation Protection in Mammography SC 85 Risk of Lung Cancer from Radon SC 87 Radioactive and Mixed Waste... 

High-level waste reprocessing is the most hazardous operation in the nuclear industry. It is there that the largest quantities of fissionable and radioactive nuclides are handled in aqueous solution. These large-scale operations require both remote control and remote maintenance of the plant to protect the workers from radiation. In addition, the air and water effluents along with the solid refuse must be closely monitored to assure that the public is protected. Finally, the fissionable material requires strict accountability to ensure that it is not diverted to unauthorized uses. 

Finally, both dilution and dispersion of large volumes of air and water effluents containing very low quantities of radioactivity generally are necessary. The concentration of radioactivity in these effluents is controlled by federal and international regulations, and such effluents are continuously monitored before release to the environment from the waste treatment and other activities. In a particular operation, the regulations may be reflected by a set of actions that are triggered by successively higher levels of radioactivity. 

Reaction mixtures are chromatographed on a PolyHydroxyethyl Aspartam-ide column (4.6 mm X 100 mm) from Poly LC (Columbia, MD). Inorganic phosphate is not adsorbed to the column under the initial conditions (40 mM triethylamine-phosphoric acid, pH 2.8), while elution of ATP requires 800 mM triethylamine-phosphoric acid (pH 2.8). Initial conditions are maintained for 16 minutes and total run time was 30 minutes including reequilibration. Column effluent was monitored by a flow-through radioactivity monitor. 

During this period, many improvements have also been made in older traditional techniques. Noteworthy here is the positive impact HPLC had on conventional liquid chromatography regarding equipment and stationary phases and the significantly enhanced sensitivity of the radioactivity detectors for monitoring column effluents. 

Direct monitoring of radioactivity in GLC effluents is still under development (e.g., N3). Sensitivity is limited by the necessarily short period of counting which is possible. 

In the United States, commercial nuclear power plant operators are required to monitor and report any detectable quantities of radioactive materials released to the environment (NRC 1996). Table 6-1 summarizes releases of radiostrontium isotopes with half-lives >8 hours to the atmosphere and water for 1993 from PWR and BWR nuclear power plants. Nearly all of the radioactive material reported as released in effluents are from planned releases from normal plant operation or anticipated operational occurrences. The latter includes unplanned releases of radioactive materials from miscellaneous actions such as equipment failure, operator error, or procedure error, and are not of such consequence as to be considered an accident (NRC 1993b). 

---