National Report of The Slovak Republic, september 2001


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4.6.3 Monitoring of radiation situation by the operator


4.6.3.1 Radiation control at SE, a.s.´s nuclear installations

For the description, see National Report as of September 1998.

Fig. 4.6.3.1 shows the development of average collective effective dose per SE-EBO and SE-EMO unit for 1994 through 2000. In 2000, the collective effective dose per NPP V-1 unit was higher than the average CED value of 1130 man mSv achieved at PWR units in 1997-99 (according to WANO), due to the extensive scope of works during the completion of gradual upgrading. CED may be expected to drop in subsequent years to values achieved prior to the gradual upgrading. The values achieved at NPP B-2 and SE-EMO are rather low, and based on this parameter, these units are among the top 25% PWR units, since the value for these types of reactors was 720 man mSv in 1997-99.

There has been no case of irradiation limits being exceeded for any SE, a.s.´s employee or contractor for the said period. At SE, a.s.´s NI, CED values keep staying at a low average level, suggesting a rather good standard of its management through the application of the ALARA system.

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Fig. 4.6.3.1 Average collective effective dose per SE-EBO and SE-EMO unit

4.6.3.2 Air and water emission control 

Discharges into the air are continuously monitored using devices placed at ventilation stacks. These equipment continuously monitor the activity of gases, airborne particles and iodine. Moreover, samples of airborne particles are continuously taken for the determination of alpha nuclides and Sr 90.

Hydrosphere discharges are verified upon continuously to record deviations from normal conditions. For the purposes of accounting the control of activities in discharged waste waters is performed by measuring the activity of tritium and corrosion and fission products and of fission products of Strontium before the discharge of waste waters.

Limits of atmosphere and hydrosphere discharges of radioactive substances are given in the Annex - chapter 6.4.

The limits of atmospheric and hydrosphere discharges of radioactive substances for SE-EBO and SE-EMO set for 2000 are shown in Tables 4.6.3.2a.) and 4.6.3.2b.). It may be stated that in 2000 as well as in all the preceding years, the discharge limits for radioactive substances were not exceeded, with discharges of corrosion and fission products and atmospheric discharges deep below the authorized limits.

Atmospheric discharges in 2000

Facility

Discharge

Activity

Share on limit [%]

 

rare gases

9.29 TBq

0.,23

NPP V-1

aerosols

702.13 MBq

0.39

 

iodine 131

673.18 MBq

1.0

 

rare gases

5.36 TBq

0.13

NPP V-2

aerosols

 11.59 MBq

0.006

 

iodine 131

2.37 MBq

0.004

 

rare gases

14.41 TBq

0.35

NPP MOCHOVCE

aerosols

10.91 MBq

0,.06

 

iodine 131

56.53 MBq

0.08

ISFSF

b aerosols

25.3 MBq

8.44


Table 4.6.3.2.a

Hydrospheric discharges in 2000

Facility

Discharge

Activity

Share on limit [%]

Bohunice

Corrosion  & fission prod.

206.85 MBq

0.54

site

tritium

   13 421.55 GBq

30.71

NPP MOCHOVCE

Corrosion & fission prod.

58.40 MBq

5.31

 

tritium

10487.00 GBq

87.39


Table 4.6.3.2.b

4.6.3.3 Monitoring of environmental impacts 

Being part of the radiation control of nuclear installations, also environmental impacts of the operation of nuclear power plants are assessed. Environmental impact assessment of the operation of nuclear power plants commences by pre-operation monitoring of radioactivity at the site considered for the construction of the nuclear power plant and in its surroundings. The series of values obtained serves to realistically compare environmental impacts of the operation of the power plant.

Prior to commissioning NPP Mochovce, a survey and analysis of the site were performed with the results included in the epidemiological survey entitled „Health Condition of the Population in the Area of the Nuclear Power Plant Mochovce” (1999). The study summarized the results of a detailed survey and assessment of an area with a diameter or up to 20 km, based on health indicators. The report provided an exhaustive description of the health condition of the population in the area, before start up of the NPP Mochovce as a document for assessing its impact on the environment.

Environmental impacts of the power generating nuclear installation are monitored and documented by Laboratory of Environmental Radiation Control. The scope of the monitoring is set by a monitoring program that at the same time sets minimum numbers and types of the media to be monitored. The media that are monitored for potential impacts of the power generating nuclear facility include air, water, soil and agricultural products as part of the food chain acting upon human beings. More than 1,150 samples are taken from the environment every year.

To improve the monitoring of impacts of nuclear installations on their immediate surroundings, a teledosimetric system was set up in the vicinity of NPP Bohunice. The teledosimetric system is computer controlled and allows samples of airborne particles, radio iodine to be taken, to determine the dose equivalent rates around the site, and meteorological data. Selected teledosimetric system-obtained data are on-line transmitted to ERC ÚJD.

Since the amounts of discharges into the air and water streams are small, to assess impacts of NPP Bohunice and NPP Mochovce upon the population in the area, dose burden to which the population is exposed is analyzed based on real discharges of radioactive substances in the respective years, accounting for the meteorological situation as monitored by SHMÚ meteorological station at Jaslovské Bohunice and Mochovce.

The analysis uses standardized software RDEBO and/or RDEMO that computes individual dose equivalents (IDE). The calculations suggest that the area with the highest level of effective dose equivalents spreads along the prevailing direction of winds. For Bohunice, it is direction S and SS at 3 - 5 km (the village of Malženice), and the critical age group are the 7 - 12-year-olds. For NPP Mochovce, the direction is SSE at 3 - 5 km (the village of Nový Tekov). The critical age group are infants.

These IDE values are considerably lower than those received by the population from the natural background. The individual dose equivalent from the natural background around NPP Bohunice and NPP Mochovce is 100 - 10 000 times higher than the values shown in the tables. IDE calculations are characterized by principal conservatism, being thus markedly overestimated as compared to the actual situation, since estimates of input data, in particular of the consumption of food harvested within the region and of water, their effects on the result of the calculation of the radiological impact is complex.

The results of the calculations for the three most burdened population groups for both areas are shown in Tables 4.6.3.3a.) a 4.6.3.3b.)

In addition to the monitoring of the very nuclear installations, environmental impact assessment of the operation of nuclear installations is also taken care of by the regulatory bodies (SHI).

 

Year

IDE [Sv]

 

infants

7-12 years

adults

1998

1.64E-7

1.11E-7

6.61E-8

1999

6.63E-8

8.67E-8

8.29E-8

2000

1.49E-7

2.05E-7

1.92E-7


Table 4.6.3.3a.) IDE calculated for population groups in the environment of NPP Bohunice

Year

IDE [Sv] NPP Mochovce

 

infants

2-7 years

adults

1998

1.00E-7

8.60E-8

6.80E-8

1999

3.77E-7

2.79E-7

2.09E-7

2000

6.67E-7

4.85E-7

3.59E-7


Table 4.6.3.3b.) IDE calculated for population groups in the environment of NPP Mochovce

The Center for Health Protection against Radiation performs monitoring of integral doses within the system of monitoring points in the environment of the NI using thermoluminescence dosimeters; it measures discontinued dose rates in the system of monitoring points in the NI environment, it monitors activities of corrosion and fission products in fallouts, airborne particles, drinking, surface and ground waters, in soil, sediments, agricultural products and food components produced in the environment of the nuclear facility, it makes random parallel analyses of airborne particles in exhalations and samples from wastewater collection tanks prior to their being discharged.

Slovak Radiation Monitoring Network Center (SÚRMS) is a standing executive component of KRH that takes care of methodological support of monitoring network components and their uniform proceeding in monitoring radiation situation.

SÚRMS is established at Institute of Preventive and Clinical Medicine in Bratislava as part of the latter. SÚRMS head is appointed by KRH Chairman at the suggestion of Minister of Health.

In times where there is no radiation accident, SÚRMS directly reports to the Minister of Health.

SÚRMS is comprised of the following units that take part in the monitoring of radiation situation in Slovakia:
 

  • Slovak Institute of Hydrometeorology’s monitoring system,
  • monitoring system of the Army of the Slovak Republic,
  • monitoring system of MV SAR - Office of CP,
  • monitoring system of MZ SAR,
  • monitoring systems of NPPs.

Results of direct measurements at constant monitoring stations, results of evaluation of samples from the environment and computed values from analyses of the impact on the population of discharges of radioactive substances suggest that although measurable, the impacts of the operation of reactors at NPP Bohunice and NPP Mochovce on the population and the environment are but negligible.

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