The phenomenal growth in the applications of radioisotopes and radiation technology has helped in improving the quality of life of the human race. India is also one amongst the seven declared nuclear weapon states, which uses nuclear technology for strategic purposes.
Nuclear plants, in general, adopt a defense- in-depth approach and multiple physical barriers to ensure that radioactivity is contained at all times. However, a finite number of very low probability events are postulated to occur, releasing radioactivity into the environment. Consequently, emergency preparedness and response plans are in place to cope with nuclear or radiological emergency scenarios ranging from minor incidents like a small spillage of radioactive material to a major nuclear accident releasing large-scale radioactivity (like Chernobyl) in the public domain.
Nuclear or radiological emergency disaster scenario
Any radiation incident resulting in, or having a potential to result in, exposure to and/or contamination of the workers or the public, in excess of the respective permissible limits can be termed as a nuclear/ radiological emergency.
These emergencies, which are usually well within the coping capability of the plant/facility authority (along with neighboring administrative agencies, if required) can be broadly classified in the following manner:
- An accident-taking place in any nuclear facility of the nuclear fuel cycle.
- A ‘criticality’ accident in a nuclear fuel cycle facility where an uncontrolled nuclear chain reaction takes place.
- An accident during the transportation of radioactive material.
- The malevolent use of radioactive material as Radiological Dispersal Device (RDD) by terrorists..
- A large-scale nuclear disaster resulting from a nuclear weapon attack (as had happened at Hiroshima and Nagasaki in Japan),
The International Atomic Energy Agency (IAEA) classifies the above emergency scenarios under two broad categories—nuclear and radiological:
- A nuclear emergency refers to an emergency situation in which there is, or is presumed to be, a hazard due to the release of energy along with radiation from a nuclear chain reaction.
- All other emergency situations, which have the potential hazard of radiation exposure due to decay of radioisotopes, are classified as radiological emergencies.
The Government of India has identified Department of Atomic Energy (DAE) as the nodal agency for providing the necessary technical inputs to the national or local authorities for responding to any nuclear or radiological emergency in the public domain.
The Ministry of Home Affairs (MHA) is the nodal ministry in such emergencies. For this purpose, a Crisis Management Group (CMG) has been functioning since 1987 at DAE.
In the event of any nuclear/radiological emergency in the public domain, CMG is immediately activated and it coordinates with the local authority in the affected area and all the concerning authorities at the centre (NCMC/ NEC/NDMA) to ensure that the necessary technical inputs are available to respond to the nuclear/radiological emergency.
Based on the radiological conditions and their consequences, emergencies at nuclear facilities are categorised as emergency standby, personnel emergency, plant emergency, on-site emergency and off-site emergency.
For the first three types of emergencies, in the order of severity, which are foreseen as possible, though with very low probability, detailed plant-specific emergency response plans are already in place. In all these situations, the consequences of the accident are expected to be limited to the plant only.
On-site emergency, where the consequences of an accident are not likely to cross the site boundary, a detailed response plan does exist. This emergency does not lead to any radiation release in the public domain.
The last type of emergency scenario (having the highest level of severity in the category of nuclear emergency in the nuclear facilities), even though with a very low possibility of radioactive releases in the public domain, is off-site emergency for which detailed response plans are put in place by the district magistrate/ collector of the area in coordination with the plant authorities.
Each nuclear power station of the present generation has
- An Exclusion Zone surrounding the power station in which no habitation is permitted and this area is under the administrative control of the plant authority. An area of larger radius outside the Exclusion Zone is declared as.
- The Sterilised Zone where growth and development is restricted.
- The Emergency Planning Zone (EPZ) which extends further beyond the Sterilised Zone.
The AERB has also laid down guidelines for the safe use of sources and safe operation of facilities which are to be adopted and followed by all the facilities using radioisotopes/radiation sources. These include safe design of the equipment used, its operation within the permissible range of parameters and availability of a suitably qualified Radiological Safety Officer (RSO) who is responsible for ensuring safe practices.
Emergency Plans to Respond to Transportation Accident
The AERB has laid down guidelines to be adopted for the transport of radioactive materials and emergency response plans for accidents during their transportation.
The consignor of the material is responsible for ensuring that the prescribed safety procedures are followed.
The SOPs also indicate what will be done in the event of any radiation emergency—the precautions to be taken, the agencies to be notified, etc.
Medical Preparedness for Nuclear Emergencies
In each constituent unit of DAE, a few doctors have been dedicated and given the necessary training in the medical management of radiation emergencies.
All nuclear power plants and the Bhabha Atomic Research Centre (BARC) are equipped with radiation monitoring instruments, have personnel decontamination centres and the necessary stock of antidote medicines and specific de-corporation agents for typical radioisotopes.
To educate the people about the beneficial aspects of nuclear radiation and to remove their misgivings about it, the authorities of nuclear fuel cycle facilities in general, and that of nuclear power stations in particular, are actively involved in carrying out regular public awareness programmes for people living in the vicinity of these facilities.
Mitigation and Preparation
- To reduce radiation-induced health effects by preventing.
- To limit, to the extent practicable, the occurrence of stochastic effects in the population.
Domain of Action
The response actions within the site boundary of the nuclear facility are the responsibility of the management of the nuclear facility whereas the implementation of the emergency response plans in the public domain (beyond the site boundary) is the responsibility of the concerned district authority.
In the event of an off-site emergency having the potential for trans-boundary effects, necessary action is taken by DAE in accordance with the country’s international obligations.
Capacity building for nuclear and radiological emergencies
Handling Plant Emergency
Nuclear facilities in the country are equipped for the detection, classification, notification and mitigation of any emergency situation. They are capable of the following:
- Emergency operating procedures for the assessment of an emergency condition and its mitigation.
- Pre-identification of any facility-specific, abnormality.
- Facility-specific approved nuclear emergency response plans specifying the jobs.
- Alerting the plant personnel by sounding the emergency siren and making an emergency announcement.
- Adequate means for communicating a notification to the emergency response organisations.
- Identified assembly locations for plant personnel and casual visitors.
- Formation of rescue teams and activation of a treatment area and decontamination centre.
- Radiation survey around the plant and outside the plant and site boundaries.
- Assessment of wind speed, wind direction and the affected sector around the nuclear facility.
- Whenever required, the nuclear facility is able to mobilise the services of the ambulance and paramedical staff at its site.
- Equipment and materials for handling a nuclear emergency are kept at a designated place of the nuclear facility and ERC.
Handling On-site Emergency
In addition to all the provisions applicable in a plant emergency, the following additional provisions are ensured:
- Extensive radiological survey for an assessment of the radiological conditions within the site boundary.
- Suitable prophylaxis to be made available at all assembly areas.
- Identification of temporary shelters within the facility/site for shifting plant personnel.
- Provision of a fleet of vehicles for evacuation of plant personnel.
- Provision of fixed and portable contamination monitors to check contaminated personnel/vehicles leaving the site.
- The concerned district authorities are alerted to be on standby for emergency operations in the public domain.
- Radiological monitoring of the environment in the EPZ (16 km radius around the plant).
Handling Off-site Emergency
In addition to all the provisions applicable in plant emergency and on-site emergency, the following additional provisions are to be ensured for handling a nuclear emergency in the public domain:
- Pre-identification of plant conditions.
- An assessment of the radiological status at the site boundary and in the public domain.
Specialised Response Teams
Four battalions of National Disaster Response Force (NDRF) are being specially trained by NDMA with assistance from DAE/DRDO (for detecting and monitoring radiation, for their own protection during response actions, decontamination and triage operation, etc.) to provide specialised response during a nuclear/radiological emergency/disaster.
Role of Civil Defense
Selected civil defence personnel will be trained extensively in the subjects of radiation, radioactivity, radiation protection, use of monitoring instruments, use of protective gear, shielding, decontamination, waste disposal, etc.
Role of Armed Forces
The armed forces will also gear up their nuclear disaster preparedness so that they can be inducted in the event of nuclear disasters.
Periodic Exercises and Mock Drills
It focuses on roles and responsibilities, resource identification, use of equipment, understanding the effects of radiation on human beings, animals and the environment.
The evaluation of an exercise will identify areas of emergency plans and preparedness that may need to be improved or enhanced. It will be the responsibility of the nuclear facility and the district authority to review the evaluation report and ensure implementation of the corrective measures recommended by the evaluators.
Emergency Response Centres (ERCs)
ERCs will be set up at all levels (i.e., state capitals and major cities) with the necessary manpower, instruments and equipment. Depending upon the location and assigned functions, these ERCs will also be maintained in a ready state to quickly respond to any nuclear/ radiological emergency.
Radiation Detection, Monitoring Instruments and Protective Gear
In case of any nuclear/radiological emergency, the first need is the availability of instruments for detecting and monitoring the radiation. An inventory of radiation monitoring instruments and protective gear will be built up by all the SDMAs and DDMAs in consultation with DAE.
Real Time Monitoring Systems
A network of simple environmental monitors, the IERMON has been established by BARC. These monitors work on a 24 x 7 basis
The specific requirements of a nuclear emergency communication system include:
- Civil defence communication (siren/signals) to communicate stay-in and evacuation warnings in the event of an off-site emergency or a large-scale nuclear disaster.
- Reliable and diverse communication systems will be ensured for communication among national, state and district headquarters through Emergency Operations Centres (EOCs) as envisaged in the NDCN of NDMA.
- All possible communication channels will be explored, including ham radio operators, as per the vulnerability profile of the state/district.
- SOPs will be laid down for effective communication during a nuclear emergency/disaster.
- Mock drills will be periodically carried out to test the communication links.
- A nodal officer (District Information Officer) will be identified for briefing the media.
Identifying and ensuring the availability of access routes and transportation vehicles for evacuation of the affected population are to be ensured as part of the preparedness programme in an all- hazards approach, in consultation with all thestakeholders including DAE.
Some places like schools, colleges, community centres, marriage halls, religious places, etc., can be easily converted into shelters in the event of a radiological/nuclear emergency without too much investment.