|Year : 2010 | Volume
| Issue : 4 | Page : 171-173
Monitoring of gamma radiation levels around Kakrapar Atomic Power Station
S Venkataraman1, DP Nankar1, KS Pradeepkumar2, AG Hegde3, PK Sarkar3
1 Environmental Survey Laboratory, KAPS
2 RSSD, BARC, Mumbai, India
3 HPD, BARC, Mumbai, India
|Date of Web Publication||1-Dec-2011|
A G Hegde
HPD, BARC, Mumbai, India
Source of Support: None, Conflict of Interest: None
By installing a Gamma Tracer (Genitron make) outside of a mobile vehicle, gamma radiation levels around KAPS up to 30 km distance were measured for a period of one year. The hourly averaged gamma radiation levels in all the routes of mobile vehicle in many occasions varied from 56 to 112 nGyh -1 , with an average of 77 nGyh -1 . The hourly averaged gamma radiation levels in all TLD stations were also found to be within this range. Since this data is comparable to preoperational data, the impact of operation of KAPS on the environment is negligible.
Keywords: Gamma radiation, gamma tracer, KAPS environment
|How to cite this article:|
Venkataraman S, Nankar D P, Pradeepkumar K S, Hegde A G, Sarkar P K. Monitoring of gamma radiation levels around Kakrapar Atomic Power Station. Radiat Prot Environ 2010;33:171-3
|How to cite this URL:|
Venkataraman S, Nankar D P, Pradeepkumar K S, Hegde A G, Sarkar P K. Monitoring of gamma radiation levels around Kakrapar Atomic Power Station. Radiat Prot Environ [serial online] 2010 [cited 2020 Jun 6];33:171-3. Available from: http://www.rpe.org.in/text.asp?2010/33/4/171/90451
| 1. Introduction|| |
At Kakrapar Atomic Power Station (KAPS), two units of Pressurised Heavy Water Reactors with the installed capacity of 220 MWe each, are operating since 1994. During pre-operational time, the environmental gamma radiation levels around KAPS were measured using Thermo Luminescent Dosimeter (TLD) and documented as a baseline data. Also, during operational time, the environmental gamma radiation levels are being monitored using TLD on quarterly basis to study any possible variation in the baseline data, due to operation of KAPS. So far no significant variation of gamma radiation level was noticed around KAPS when compared to the baseline data. The data collected using TLD will give the gamma radiation level existing at the fixed location only.
To map the entire KAPS environment up to 30 km radius, TLD measurement will not be sufficient. For instantaneous mapping of gamma radiation levels from 1.6 km to 30 km radial zone around KAPS, an alternate monitoring system is prefered. For this purpose, state of the art instrument known as gamma tracer was used. The details of the gamma tracer used and the results obtained are described in this paper.
| 2. Materials and Methods|| |
2.1 Gamma Tracer
Gamma tracer (GT) (Genitron, Germany make) is commercially available portable instrument, which measures the dose rate and is widely used for environmental monitoring. It is an offline battery operated dose logging system. This instrument uses two small Geiger Muller (GM) detectors for covering a dose rate range of 20 nGyh -1 to 10 mGyh -1 . It is capable of storing 12800 data points in it's built-in memory along with the time information. The stored data can be downloaded to a Personal Computer (PC) using an infrared-based remote reader connected to a PC through Data gate embedded web server. The system can operate with it's internal battery for a period of 3 to 4 years.
During environmental radiation monitoring, a GT which is described above was installed on the front side of the Environmental Survey Laboratory (ESL) sampling vehicle. The GT was installed vertically with the detector facing the earth surface at a height of one meter.
Keeping KAPS stack as the centre, 30 km as radius and taking an angle of 22.5°, the circular area around KAPS was divided into 16 sectors for monitoring purpose. During regular environmental sampling ESL vehicle along with GT was made to move in the monitoring area such as, i) air moisture sampling locations, ii) water sampling locations along the aquatic system of KAPS, iii) TLD monitoring locations. The data obtained for 10 minutes were set to average as single data point and stored in the built-in memory of GT. After every two months the data collected in GT was retrieved using IR receiver. Thus, gamma radiation levels around KAPS environment up to 30 km radius were collected for the period October-2008 to September-2009. Six data points were averaged to give hourly data and analysed. The hourly averaged data points obtained for the above period are shown in [Figure 1] and given in [Table 1]. The data points collected for TLD locations are also given in [Table 2].
|Figure 1: Hourly averaged gamma radiation level data points from Oct.-08 to Sep.-09|
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|Table 1: Results of Gamma Radiation Level measurements using GT in 1.6 km to 30 km zone around KAPS in different months|
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| 3. Results and Discussion|| |
From the data points given in [Figure 1], the radiation level around KAPS environment was found to be uniform with the average dose rate of 77 nGyh -1 . The slightly enhanced radiation levels seen in the [Figure 1] for few hours, is due to the inadvertent exposure of GT in the laboratory during retrieval of the data. The number of data points collected, minimum, maximum and average radiation levels for each month are presented in [Table 1]. Radiation levels measured during operational period is in good agreement with that of the pre-operational period which was measured using TLD (Chougaonkar et al., 2004). From [Table 2] it is observed that the radiation levels measured in sampling locations are also in good agreement with that of the pre-operational period.
| 4. Conclusion|| |
Since the radiation levels measured during this period for all the sampling locations is comparable to the pre-operational data, these measurements can serve as a baseline data for this environment. This data can form basis for assessing the radiological impact assessment in the environment due to a nuclear/ radiological events. Also this study will be useful to locate the presence of orphan radioactive sources if any in the environment. This type of environmental monitoring using gamma tracer will serve to check the effectiveness of the mobile monitoring system in case of radiological / nuclear emergency. Gamma radiation levels in this environment are observed to be very low and uniform.
| 5. Acknowledgement|| |
The authors are grateful to Shri H.S.Kushwaha, Director, HS&E Group, BARC for his keen interest and constant encouragement. The help extended by Shri P.K. Dutta, Station Director, KAPS and Shri. Vinodkumar, Chief Superintendent, KAPS is gratefully acknowledged. Thanks are also due to all the ESL Staff for the help provided during this study.
| 6. Reference|| |
- Chougaonkar M.P., Shetty P.G., Mayya Y.S., Puranik V.D., Jha M.K., Jaison T.J. and Vyas P.V. (2004), BARC/2004/E/027.
[Table 1], [Table 2]