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ARTICLE
Year : 2010  |  Volume : 33  |  Issue : 4  |  Page : 205-208  

Environmental radiation mapping of KAPS emergency planning zone using mobile monitoring techniques


1 Radiation Safety System Division, BARC, India
2 Health Physics Division, BARC, India

Date of Web Publication1-Dec-2011

Correspondence Address:
S S Patil
Radiation Safety System Division, BARC
India
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Source of Support: None, Conflict of Interest: None


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  Abstract 

The operation of Nuclear Power Plants results in generation of low level effluents, which are released in a controlled manner out of which atmospheric releases are carried out through the stack to reduce the radiation dose rate on ground by dispersion. In order to assess the radiological impact of routine and accidental releases from a nuclear installation, it is necessary to know the concentration of radionuclides and dose rate profile in the environment, which helps in the implementation of early countermeasures during a radiation emergency. The mobile radiation monitoring technique using various systems/radiation monitors installed on a mobile monitoring vehicle helps in quick assessment during any emergency. This methodology was tested on mobile platform at KAPS and it's surroundings by installing various state of the art systems like GRaMS, CARMS, AGSS, Gamma Tracer etc. which is discussed in this paper. The detailed radiation monitoring carried out in the Emergency Planning Zone of KAPS showed the radiation level in the range of 50-60 nGy.h -1.

Keywords: Emergency planning zone, KAPS, mobile radiation monitoring, NPP


How to cite this article:
Patil S S, Saindane S S, Jose R, Venkatraman S, Pradeepkumar K S. Environmental radiation mapping of KAPS emergency planning zone using mobile monitoring techniques. Radiat Prot Environ 2010;33:205-8

How to cite this URL:
Patil S S, Saindane S S, Jose R, Venkatraman S, Pradeepkumar K S. Environmental radiation mapping of KAPS emergency planning zone using mobile monitoring techniques. Radiat Prot Environ [serial online] 2010 [cited 2021 Aug 3];33:205-8. Available from: https://www.rpe.org.in/text.asp?2010/33/4/205/90471


  1. Introduction Top


Kakrapar Atomic Power Station (KAPS) is situated on the southern bank of Moticher Lake, which is about 85 km towards east of Surat City on Surat- Dhulia Road. Moticher lake is a shallow reservoir formed by constructing an earthen Dam across the Kakrapar left bank canal, an irrigation canal drawn out of Kakrapar weir which is about 30 km downstream of Ukai Dam built on River Tapi. The latitude and longitude of the site are 21 o 14' N and 73 o 21' E respectively. The site is in the southern region of Gujarat State in Tapi District Kakrapar Atomic Power Station comprises of two nuclear power reactors (PHWR type) of capacity 220 MW each. The effluents from nuclear power plants are treated adequately and then released in a controlled engineering manner under strict compliance of discharge criteria. Environmental radiation monitoring using state of the art monitoring system was carried out in the EPZ (15 km radius from plant) of KAPS. The study provides a reference dose rate data for a large number of villages in the EPZ of KAPS. This data can form basis for a radiological impact assessment in the environment in case of any nuclear/radiological accident or any suspected release of radioactivity to the atmosphere. During the radiological monitoring the samples were collected from the few locations and analysed for gross α and β and also gamma spectrometry is also done. The air sample is also taken at a downwind direction for 5 mins and counted for gross α and β. Aerial Gamma Spectrometry System (AGSS) were used for collecting the spectrum at every location.

The main objectives of this Mobile Radiation mapping were

  • To generate baseline dose rate data around the NPP sites
  • To demonstrate the capability of detecting any illicit trafficking of radioactive material
  • To detect presence of any orphan sources in public domain
  • To check the effectiveness of mobile radiation monitoring methodology in case of radiological/nuclear emergencies.
  • To assess the signal strength of GSM network in the EPZ for online data transfer during an emergency situation.


During the survey way points of various locations were noted and radiation measurement was carried out. The environmental dose rates data was transferred to various ERC (Emergency Response Centre) centres.


  2. Instruments Top


During the survey period both the online and offline instruments were used so that any elevated dose rates from the background radiation level can be monitored properly. The following instruments were used during the survey.

  1. AGSS (Aerial gamma spectrometry system)
  2. CARMS (Compact aerial radiation monitoring system)
  3. GRaMS (Global system for mobile based radiation monitoring system)
  4. Gamma Tracer
  5. Hand held survey meter (Bicron and identifinder)
  6. GPS (Global positioning system)


All the above instruments mentioned were portable and batteries operated, and were connected to the GPS.


  3. Monitoring Methodology Top


The instruments in the vehicle were kept such a way that the detector part of the instrument will get maximum exposure in the environment. The antenna of GPS was mounted on top side of vehicle to get maximum coverage of the satellite. The AGSS and CARMS were connected to 12 Volt battery for continuous acquisition of the spectrum (AGSS) and dose rate (CARMS). The vehicle speed during the monitoring period was 30-40 km.h -1 and acquisition time of the AGSS, CARMS and GRaMS kept at 5 sec. Gamma Tracer was also used for the survey and was mounted outside of the vehicle and the acquisition time of the Gamma Tracer was kept at one minute interval. Another GPS was used to record the positional coordinates of the important locations. The GRaMS system was connected to a 9V battery. The dose rate readings mentioned in [Table 1] was noted for every location and 5 observations were taken for a location. The AGSS, CARMS and GRaMS store the data into it's internal memory. The GRaMS system has also an additional capability of transferring the data to the remote/nodal ERC through GSM modem.
Table 1: Dose rate (nGy.h-1) measured by the different instruments during EPZ survey of Kakrapar

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  4. Data Analysis Top


The CARMS, GRaMS and Gamma Tracer dose rate data retrieved from the memory module and portable instrument's data was noted manually with time. After retrieval the data from CARMS and GRaMS, which were having 5 sec acquisition time converted into minute average. The minute average, standard deviation, maximum and minimum is calculated by using data set point of that minute which is shown in [Table 1]. The analysis of the dose rate data recorded by hand held instruments was carried out by taking an average of 5 readings noted manually for each location. The [Table 1] shows the dose rate data recoded at every location during the survey. The analysis of data shows the Gamma Tracer dose rate data shows slightly higher than the other instruments as shown in the [Figure 1]. At one location a higher dose rate was observed. It's spectrum analysis confirms the presence of the naturally occurring K-40.
Figure 1: Graphical presentation of dose rate nGy.h-1 recorded by various mobile monitoring instruments during the KAPS EPZ survey

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The soil, grass samples collected from the cultivated land and from villages which counted for gross α and β and gamma spectrometry was also done. The air sample collected from the different locations preferably downwind direction for 5 mins is also counted for gross β.

The external gamma dose rate due to stack release is computed in the downwind direction by using the Gaussian dispersion plume model (Patil et al. 2008). The dose rate computation is done by using the stack release rate, wind speed, wind direction and stability class during the survey period.


  5. Results and Discussion Top


The data given in [Table 1] gives the overall dose profile of the KAPS EPZ, which shows that gamma radiation field is varying between the 50-60 nGy.h -1 . As seen from in the [Figure 1] the dose rate response of the gamma tracer is slightly higher compare to other instruments. This may be due to the position of the gamma tracer which was kept outside the vehicle which minimises the shielding factor due to the vehicle. The analysis of these samples shows the BDL (Below Detection Level) values for radionuclides ( 137 Cs and 90 Sr) which we are more concerned. The air samples analysis results also shows BDL values as given in [Table 2].
Table 2: Sample analysis data collected during the survey period

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From the analysis of results of [Table 1] and [Table 2] the present dose rate data is comparable to pre-operational survey data. Thus it shows that the impact due of NPP operation in Kakrapar is insignificant. The EPZ of KAPS does not show any elevated radiation level and this is also confirmed from the spectrometry analysis. The slight variation in the dose rate reading was mainly due to the 40 K and natural U and Th decay series present in the earth crust (Saindane et al. 2007). The computed external gamma dose rate [Table 3] due to stack release does not show any increase in the radiation level in the down wind direction.
Table 3: Computed dose rate (nGy.h-1) using the meteorological data

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  6. Conclusion Top


The dose rate mapping in and around the KAPS and Emergency Planning Zone of KAPS does not show any significant increase with average of dose rate varying between 50-60 nGy.h -1 . The analysis of the grass and soil samples also shows below the BDL values for 137 Cs and 90 Sr. The overall analysis of the data acquired during the monitoring programme shows results comparable to the pre-operational values. This confirms that there is no radiological impact after NPP commissioning and operation at Kakrapar. The mobile radiation monitoring methodology and real time data transfer mechanism used will be highly useful in effective planning, execution and mitigating the consequences in case of any Nuclear or Radiological emergencies in public domain.


  7. Acknowledgement Top


The authors are grateful to Shri H.S. Kushwaha, Director, HS and EG, BARC. The authors are also grateful to Dr. D.N.Sharma, Associate Director HS&EG and Head RSSD BARC for continuous encouragement and for providing useful guidance. We also express our gratitude to E.S.Lab. Staff at KAPS, for providing necessary support during the survey.


  8. References Top


  1. Patil S.S. et al. (2008), Mobile Radiological Monitoring around Nuclear Power Plant Site at Tarapur, IARPNC-2008.
  2. Saindane, S.S. et al. (2007), A report on radiation mapping of Mumbai to Bangalore by railway route, Bangalore city, Karnataka and Kaiga emergency planning zone (EPZ) by road routes. BARC Report no: BARC/2007/R/001.



    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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  In this article
Abstract
1. Introduction
2. Instruments
3. Monitoring Me...
4. Data Analysis
5. Results and D...
6. Conclusion
7. Acknowledgement
8. References
Article Figures
Article Tables

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