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Three-tier system guards Kalpakkam

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Nov 29, 2010
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Kalpakkam, according to India’s seismic zoning maps, is in zone 2, or prone--at worst-- to quakes of magnitude 5 on the Richter scale

Kalpakkam, Chennai: A three-tier system of sandbags, rocks and embankment put in place after the 2004 tsunami that lashed this southern Indian coastal town can nullify the impact of sea waves as large as the ones that disrupted nuclear power stations at Fukushima, Japan, last week and stoked fears of a radiation leak, scientists say.

Though the 220 megawatt (MW) reactors at the Indira Gandhi Centre for Atomic Research (IGCAR) are just two of India’s 20 commissioned nuclear power plants, they are the only ones in the direct line of a tsunami.

Most geologists say tsunami waves that can threaten India can only be generated by massive earthquakes at the volatile fault line that separates two tectonic plates, called the India and Burma plates, that are close to the Andaman islands.

“Rest assured, there’s nothing to be worried about,” said Prabhat Kumar, senior director at IGCAR. Kumar is in charge of constructing so-called fast breeder reactors, the next generation of reactors, which can produce about 500MW each. He is closely involved with the maintenance of existing reactors, which produce nearly one-tenth of India’s nuclear power.

The 11 March earthquake and tsunami in Japan killed thousands of people and caused explosions at three nuclear reactors. The catastrophe, which follows nuclear disasters at Three Mile Island, US, in 1979, and Chernobyl, Ukraine, in 1986, has triggered fears about the safety of India’s nuclear plants.

By 2020, India expects to generate at least 20 gigawatt of power from nuclear sources, an almost fourfold increase from current levels, by building more powerful reactors with the help of domestic and global private companies.

Kalpakkam, according to India’s seismic zoning maps, is in zone 2, or prone—at worst— to quakes of magnitude 5 on the Richter scale. In comparison, the 10 metre (m) high waves that lashed Japan were caused by a quake of magnitude 9.1 on the Richter scale just 130 kilometres off its coast.

Scientists at the Kalpakkam station, which is located 9.7m above the ocean’s surface, said attributes such as wave surge and impact were as important as the height of the waves to judge their destructive potential.

According to the region’s seismic zoning, the station is designed to withstand waves that are 5.2m high. In conjunction with the three-tier system that buffers the plant’s boundaries from the coast by nearly 500m, it is strong enough to withstand even 9m-high onslaughts.

V. Manoharan, an engineer at the plant who survived the 2004 Indian Ocean tsunami by clinging on to rafters at the church he was attending on 26 December, said waves of the height of Japan’s tsunami would send some water into the plant, but it would “gently recede away, like waves at the beach”.

The 2004 tsunami, which sent 6-7m high waves that swept the residential section of the research centre to the Tamil Nadu coast, killed five employees, who were among a total of 30 casualties reported from Kalpakkam. The tides forced one of the reactors at the Kalpakkam plant into “a safe shutdown mode”—which meant the plant was manually shut down as a precaution, though, according to officials, operations were back to normal within three days.

Apart from this first line of defence, officials at IGCAR said the power stations were connected to a series of diesel- and battery-powered backups that could power the station at full load continuously for seven days and were designed to immediately begin cooling down the reactors.

On Tuesday, India’s apex atomic energy regulator, the Atomic Energy Regulatory Board (AERB) said it will carry out a comprehensive reassessment of safety and emergency mitigation measures at all the Indian nuclear power plants in the light of the Japanese crisis.

Emergency-preparedness plans exist for all nuclear power plants in India, and they are periodically rehearsed, AERB said in a statement. “It is constantly monitoring the situation at Japan’s nuclear sites in the aftermath of unprecedented earthquake and tsunami,” it added.

In India, out of 20 reactors— 19 of which are in operation— only two units at Tarapur, Maharashtra, are boiling-water reactors similar to the ones at Fukushima.

All the reactors in India are designed to withstand the effects of earthquake and tsunami of specific magnitudes, which were decided based on conservative criteria.

“India has to have a variety of power sources at its command,” said Baldev Raj, director at IGCAR, “As far as we’re concerned, whatever known risks—cyclones, fires, tsunamis, earthquakes—have been accounted for in our designs. We’ll have to wait for more details from Japan to see what more can be incorporated in our designs to make them safer.”

Three-tier system guards Kalpakkam - Home - livemint.com
 
Kalpakkam, according to India’s seismic zoning maps, is in zone 2, or prone--at worst-- to quakes of magnitude 5 on the Richter scale

Kalpakkam, Chennai: A three-tier system of sandbags, rocks and embankment put in place after the 2004 tsunami that lashed this southern Indian coastal town can nullify the impact of sea waves as large as the ones that disrupted nuclear power stations at Fukushima, Japan, last week and stoked fears of a radiation leak, scientists say.

Though the 220 megawatt (MW) reactors at the Indira Gandhi Centre for Atomic Research (IGCAR) are just two of India’s 20 commissioned nuclear power plants, they are the only ones in the direct line of a tsunami.

Most geologists say tsunami waves that can threaten India can only be generated by massive earthquakes at the volatile fault line that separates two tectonic plates, called the India and Burma plates, that are close to the Andaman islands.

“Rest assured, there’s nothing to be worried about,” said Prabhat Kumar, senior director at IGCAR. Kumar is in charge of constructing so-called fast breeder reactors, the next generation of reactors, which can produce about 500MW each. He is closely involved with the maintenance of existing reactors, which produce nearly one-tenth of India’s nuclear power.

The 11 March earthquake and tsunami in Japan killed thousands of people and caused explosions at three nuclear reactors. The catastrophe, which follows nuclear disasters at Three Mile Island, US, in 1979, and Chernobyl, Ukraine, in 1986, has triggered fears about the safety of India’s nuclear plants.

By 2020, India expects to generate at least 20 gigawatt of power from nuclear sources, an almost fourfold increase from current levels, by building more powerful reactors with the help of domestic and global private companies.

Kalpakkam, according to India’s seismic zoning maps, is in zone 2, or prone—at worst— to quakes of magnitude 5 on the Richter scale. In comparison, the 10 metre (m) high waves that lashed Japan were caused by a quake of magnitude 9.1 on the Richter scale just 130 kilometres off its coast.

Scientists at the Kalpakkam station, which is located 9.7m above the ocean’s surface, said attributes such as wave surge and impact were as important as the height of the waves to judge their destructive potential.

According to the region’s seismic zoning, the station is designed to withstand waves that are 5.2m high. In conjunction with the three-tier system that buffers the plant’s boundaries from the coast by nearly 500m, it is strong enough to withstand even 9m-high onslaughts.

V. Manoharan, an engineer at the plant who survived the 2004 Indian Ocean tsunami by clinging on to rafters at the church he was attending on 26 December, said waves of the height of Japan’s tsunami would send some water into the plant, but it would “gently recede away, like waves at the beach”.

The 2004 tsunami, which sent 6-7m high waves that swept the residential section of the research centre to the Tamil Nadu coast, killed five employees, who were among a total of 30 casualties reported from Kalpakkam. The tides forced one of the reactors at the Kalpakkam plant into “a safe shutdown mode”—which meant the plant was manually shut down as a precaution, though, according to officials, operations were back to normal within three days.

Apart from this first line of defence, officials at IGCAR said the power stations were connected to a series of diesel- and battery-powered backups that could power the station at full load continuously for seven days and were designed to immediately begin cooling down the reactors.

On Tuesday, India’s apex atomic energy regulator, the Atomic Energy Regulatory Board (AERB) said it will carry out a comprehensive reassessment of safety and emergency mitigation measures at all the Indian nuclear power plants in the light of the Japanese crisis.

Emergency-preparedness plans exist for all nuclear power plants in India, and they are periodically rehearsed, AERB said in a statement. “It is constantly monitoring the situation at Japan’s nuclear sites in the aftermath of unprecedented earthquake and tsunami,” it added.

In India, out of 20 reactors— 19 of which are in operation— only two units at Tarapur, Maharashtra, are boiling-water reactors similar to the ones at Fukushima.

All the reactors in India are designed to withstand the effects of earthquake and tsunami of specific magnitudes, which were decided based on conservative criteria.

“India has to have a variety of power sources at its command,” said Baldev Raj, director at IGCAR, “As far as we’re concerned, whatever known risks—cyclones, fires, tsunamis, earthquakes—have been accounted for in our designs. We’ll have to wait for more details from Japan to see what more can be incorporated in our designs to make them safer.”

Three-tier system guards Kalpakkam - Home - livemint.com

indian scientists are among brilliants in the world
 
Cool!!! They have taken appropriate measures against all possible threats. Specially protection against Tsunami is excellent.
 
Safety in nuclear power plants in India
R. Deolalikar

Safety in nuclear power plants (NPPs) in India is a very important topic and it is necessary to dissipate correct information to all the readers and the public at large. In this article, I have briefly described how the safety in our NPPs is maintained. Safety is accorded overriding priority in all the activities. NPPs in India are not only safe but are also well regulated, have proper radiological protection of workers and the public, regular surveillance, dosimetry, approved standard operating and maintenance procedures, a well-defined waste management methodology, proper well documented and periodically rehearsed emergency preparedness and disaster management plans. The NPPs have occupational health policies covering periodic medical examinations, dosimetry and bioassay and are backed-up by fully equipped Personnel Decontamination Centers manned by doctors qualified in Occupational and Industrial Health. All the operating plants are ISO 14001 and IS 18001 certified plants. The Nuclear Power Corporation of India Limited today has 17 operating plants and five plants under construction, and our scientists and engineers are fully geared to take up many more in order to meet the national requirements.

Safety in NPPs in India is a very vast subject and would need reams of papers to cover it aptly.
All nuclear facilities are sited, designed, constructed, commissioned and operated in accordance with strict quality and safety standards. Principles of defense in depth, redundancy and diversity are followed in the design of all nuclear facilities and their systems/components. The regulatory framework in the country is robust, with the independent Atomic Energy Regulatory Board (AERB) having powers to frame the policies, laying down safety standards and requirements and monitoring and enforcing all the safety provisions. The AERB exercises the regulatory control through a stage-wise system of licensing. As a result, India's safety record has been excellent in over 277 reactor years of operation of power reactors.

The design considerations that have a bearing on radiation protection in NPPs include:

Proper design, plant layout and adequate shielding:
Design values are prescribed for the radiation level at a specified distance from the equipment/components as well as for the general radiation fields in different areas of the plant. The plant layout is such that the areas are segregated according to their radiation levels and contamination potential. The design, layout of areas and equipment, maintenance approach and shielding, etc. are made such that the collective dose to the station personnel would be “as low as reasonably achievable” (ALARA) and meet the specified regulation on collective dose.
Limits of air contamination levels in different zones of the plant:
Provision of ventilation is made such that in full-time occupancy areas of the plant, the airborne contamination are maintained below 1/10 Derived Air Concentration.
Source control by proper selection of materials/components:
Materials used in plant systems are selected in such a way that the activation products arising from the base material or the impurity content do not significantly contribute to radiation exposures.
Design limit for collective dose:
 
EMERGENCY PREPAREDNESS

General
NPPs are designed, constructed, commissioned and operated in conformity with existing stringent nuclear safety standards. These standards ensure an adequate margin of safety so that NPPs can be operated without undue radiological risks to the plant personnel and members of the public. Notwithstanding these safety standards, it is necessary to develop, as a measure of abundant caution and in conformity with international practices, emergency response plans so that any eventuality, howsoever unlikely, with a potential to result in undue radiological risk to plant personnel and public, is handled effectively. The preparedness and response to emergencies are important responsibilities of the operating organization. All NPPs have established and documented emergency procedures by having an on-site emergency preparedness plan. Similarly, the plan with respect to off-site emergency is made available with the district authority. The role, responsibilities and action plans for various agencies required to act during an emergency are detailed in these plans.

Zoning concept and emergency planning

In India, a NPP is generally sited in a relatively low-population zone, with the basic objective of limiting the dose-received members of the public and population as a whole under normal and accident conditions to ALARA levels. In order to achieve the above objective, the area around the NPP is divided into the following zones:
Exclusion zone
An exclusion zone of 1.5 km radius around the plant is established, which is under the exclusive control of the operating organization, and no public habitation is permitted in the area. The dose limits to a member of the public, under normal operating conditions and under design basis accident conditions specified, are applied at the boundary of this exclusion zone.
Sterilized zone
With the help of administrative measures, efforts are made to establish a sterilized zone up to a 5-km radius around the plant. This is the annulus around the exclusion zone, which has the potential for extensive contamination in case of a severe accident. Development activities within this area are controlled so as to check an uncontrolled increase in the population. In this area, only natural growth of the population is permitted.
Emergency planning zone (EPZ)
This is the zone defined around the plant up to a 16-km radius and provides for the basic geographical framework for decision making on implementing measures as part of a graded response in the event of an off-site emergency. The EPZ is examined in great detail while drawing up an offsite emergency plan and arranging logistics for the same. The entire EPZ is divided into 16 equal sectors. The objective is to optimize the emergency response mechanism and to provide the maximum attention and relief to the regions most affected during an offsite emergency.

Emergency measures

The emergency measures consist of emergency actions in respect of notification, alerting personnel, assessment of situation, corrective actions, mitigation, protection and control of contamination. These are detailed in the emergency response manual.
Notification
Any emergency situation will be promptly notified to the concerned personnel as per the notification plan. The message conveyed in the notification is required to be clear and concise.
Assessment action during emergency
Indicating, recording and annunciating instruments provided in the main control room, radiation surveys, environmental surveys, meteorological data and status of plant are utilized to assess the situation and to predict the projected doses. These assessment actions enable planning timely corrective and protective actions.
Corrective actions
These actions are taken to correct plant abnormal situations and to bring the plant under control. The types of corrective actions are decided by the situations prevailing at that point of time.
Protective measures (countermeasures)
These actions are taken to mitigate the consequences of a radiological event and to protect site personnel, members of the public and livestock from radiation. These include sheltering, administration of prophylactics, control on consumption of contaminated foodstuff and, finally, evacuation. It is essential to ensure that the response measures would reduce the overall impact to the public to a level significantly lower than what they would be in the absence of such measures. The emergency response manual gives details of the protective measures and the intervention levels approved by the AERB for initiating protective measures to limit radiation exposures. Evacuation is a very effective countermeasure but is very carefully considered before a decision to implement is taken. The benefits and risks of this countermeasure are carefully assessed in terms of averted dose. If radiation levels in the affected zone continue to exist beyond acceptable levels, then relocating the affected population is resorted to.
Contamination control measures
Contamination control measures are meant to check the spread of radioactive contamination. These actions include segregation of highly contaminated persons and decontaminating them, decontamination of vehicles, regulating the traffic, access control to prevent unauthorized entry to keep traffic routes open solely from the emergency response point of view, confiscation of contaminated food stuff and substituting fresh uncontaminated food in its place, banning fishing in contaminated sea/river water, banning the consumption of contaminated water and its replacement with contamination-free water, identification of contaminated areas requiring excavation and disposal of contaminated soil, decontamination of contaminated dwellings or their disposal and destroying the contaminated crops and grass.
I hope that this comprehensive piece of information would go a long way in making the reader understand how meticulously our NPPs operate and how much of efforts, infrastructure and man power are directed solely in catering to the safety of the personnel and the public. All the operating plants are ISO 14001 and IS 18001 certified plants.
Before I end, I would assure all the readers that the NPPs in India are very much in safe hands. The NPCIL today has 17 operating plants and five plants under construction, and our scientists and engineers are fully geared to take up many more in order to meet the national requirements.
 
I am very skeptical about what govt says about safety. Industrial accidents are not uncommon in India, and most of them are found to be human error and negligence.
 

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