5.27) IMPACT ON LAND, AGRICULTURE, LIVE STOCK AND FOOD SECURITY.
Impact on Land:
Beneficial impacts would be felt on land use pattern and topographical features of the area due to greening of the area through plantation and green belt development. Under operating conditions, there will not be any impact on the land environment as discharges are insignificant as compared to the combined natural background parameters.
As of now, a total of 23890 plants and trees have been developed for green belting, at Kudankulam site (KKNPP). The area covered by lawns and gardens is 16419 Squaremeters. Hedges accounts for 2467 Running meters and this will help to improve the quality of environment around NPP. The green belt development will be continued in future which will attract more fauna specially avian species resulting in improvement in biodiversity as evident in other nuclear power station like Kaiga, Kalpakkam,Tarapur etc.
Impact on Agriculture, live stock and food security:
National Environmental Engineering Research Institute (NEERI) has prepared the Environmental Impact Assessment (EIA) report and had documented the land use classification in 30 Kms radius of the plant site based on satellite mapping.
The land use/ land cover classification indicates 8.73% area covered by vegetation, 8.73% are covered by Barren land, 23.39% area covered by scrubland, 8.52% area covered by sandy area, 0.08% built‐up area, 49.68% water body including sea, river/nala etc.
This is the baseline data. However data from the other nuclear power plants in the country indicate that operation of NPPs do not have any adverse impact on agriculture, live stock and food security.
5.28) IMPACT ON FLORA AND FAUNA
As such the land acquired has been dry and barren and hence there is no impact on the flora and fauna inside the plant area. NEERI has conducted the base line study of the biological environment in and around KK site and is well documented.
Also as on June 2011, a total of 23890 plants and trees have been developed for green belting, at KKNPP. The area covered by lawns and gardens is 16419 Square meters. Hedges accounts for 2467 running meters.
The Green Belt programme will be continued to develop a green belt in the vacant land, after assigning the plant structures of KKNPP 3 to 6.
Because of the green belt developed, the area around plant and township has become a hub for migratory birds.
5.29) COOLANT WATER DISPOSAL&THERMAL ECOLOGY
Already discussed at 5.26) above.
5.30) Seismology
Structures, systems and components (SSC) of Indian nuclear power plant (NPP) are designed for two levels of earthquakes which are estimated according to safety requirements laid down by the Atomic Energy Regulatory Board (AERB) which are in line with the IAEA (International Atomic Energy Agency) guidelines (IAEA Guide 50‐SG‐S1):
1) S1 level of ground motion or OBE (Operating Basis Earthquake).
2) S2 level of ground motion or SSE (Safe Shutdown Earthquake).
S1 level corresponds to the maximum ground motion which can be expected to be experienced at the Site during the life of the NPP i.e. once in a 100 years. All SSC necessary for power generation are designed for this level of ground motion.
S2 level corresponds to the conservatively estimated level of ground motion which can be expected to occur once in 10,000 years. All SSC important to safety are designed to remain functional during a S2 level earthquake.
SSE is derived on the basis of maximum earthquake potential associated with the tectonic structures and seismotectonic province in the region and takes into account,
I. The maximum earthquake potential inside the seismic tectonic province of the site associated with specific tectonic structures
II. The maximum earthquake potential inside the seismic province of the site not associated with specific tectonic structures
III. The maximum earthquake potential for the adjoining seismotectonic provinces associated with specific tectonic structures and
IV. the maximum earthquake potential for the adjoining seismotectonic provinces not associated with a specific tectonic structure.
Earthquake Design Basis for Kudankulam Nuclear Power Plant (KKNPP) ‐1 & 2
Kudankulam Nuclear Power Plant is located in Indian Seismic Zone II which is the least seismic potential region of our country. (ref. IS 1893). However, for designing of the Plant, detailed studies are conducted to conservatively estimate extent of ground motion applicable to the specific Site with reference to Seismotectonic and Geological conditions around it so that NPPs are designed for a SSE level earthquake which has a very low probability of being exceeded (return period of 1 in 10,000 years).
For Kudankulam NPP, the following tasks were undertaken for detailed evaluation of Site specific conditions as below:
a) Study of the seismotectonic and geological setup of the region.
b) Selection of a set of recorded accelerograms with source and site conditions resembling those at Site for computing response spectra.
c) Generation of response spectra of the selected time‐histories for various values of damping and statistical analysis of the ensemble of response spectra.
d) Collection of additional information on earthquakes, regional and local geology and tectonics pertinent to evaluating fault activity and design basis ground motion parameters.
e) Integration of the above information to arrive at the Earthquake Design Basis (EDB). This involves the generation of peak ground acceleration and response spectral shapes for various components of ground motion for both S1 and S2.
f) Generation of spectral compatible accelerograms.
All potential, active and non‐active faults, lineaments and seismic history within a radius 300 kms have been analyzed to arrive at the SSE and OBE levels of earthquake. As per above data, there are no faults / lineaments in the near vicinity of the site. The most intense earthquake experienced in this 300km region is the earthquake that occurred at Coimbatore (307 km) on 08/02/1900 which had an epicentral intensity of VII on the MMI scale (6.0 in the Richter scale).
Towards enhanced conservation, the high intensity earthquakes that occurred in this seismotectonic region have been assumed to act at the closest faults/ lineaments near the site in arriving at the SSE level. The Site specific response spectra for SSE at KKNPP has been derived from the envelope of these hypothetical events.
Considering the above events, a rock‐site‐specific formula for the maximum peak ground acceleration valid for the range of magnitude and distance of interest has been derived.
The peak ground accelerations thus evaluated for KKNPP are as follows.
Peak ground acceleration (g) |
Level | Horizontal | Vertical |
SSE | 0.15 | 0.11 |
OBE | 0.05 | 0.036 |
References:
i) Report on “Earthquake Design Basis for Kudankulam Site” prepared by Dr.A.K.Gosh, BARC & Shri D.C. Banerjee, AMD.
Conclusion: the seismic parameters for the design of SSC of KKNPP have been arrived at in a highly conservative manner following the AERB stipulations and thus the seismic safety of the plant is assured with a large safety margin.
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