செர்நொபிள், புகுஷிமா மாதிரிக் கோர அணு உலை விபத்துகளைத் தவிர்க்கும் உலகளந்த புதிய தடுப்பு அரண்கள்

சி. ஜெயபாரதன் B.E.(Hons) P.Eng (Nuclear) கனடா

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https://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/safety-of-nuclear-power-reactors.aspx

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Achieving safety: the reactor core

Concerning possible accidents, up to the early 1970s, some extreme assumptions were made about the possible chain of consequences. These gave rise to a genre of dramatic fiction (e.g. The China Syndrome) in the public domain and also some solid conservative engineering including containment structures in the industry itself. Licensing regulations were framed accordingly.

It was not until the late 1970s that detailed analyses and large-scale testing, followed by the 1979 meltdown of the Three Mile Island reactor, began to make clear that even the worst possible accident in a conventional western nuclear power plant or its fuel would not be likely to cause dramatic public harm. The industry still works hard to minimize the probability of a meltdown accident, but it is now clear that no-one need fear a potential public health catastrophe simply because a fuel meltdown happens.  Fukushima has made that clear, with a triple meltdown causing no fatalities or serious radiation doses to anyone, while over two hundred people continued working on the site to mitigate the accident’s effects.

The decades-long test and analysis program showed that less radioactivity escapes from molten fuel than initially assumed, and that most of this radioactive material is not readily mobilized beyond the immediate internal structure. Thus, even if the containment structure that surrounds all modern nuclear plants were ruptured, as it has been with at least one of the Fukushima reactors, it is still very effective in preventing escape of most radioactivity.

A mandated safety indicator is the calculated probable frequency of degraded core or core melt accidents. The US Nuclear Regulatory Commission (NRC) specifies that reactor designs must meet a 1 in 10,000 year core damage frequency, but modern designs exceed this. US utility requirements are 1 in 100,000 years, the best currently operating plants are about 1 in 1 million and those likely to be built in the next decade are almost 1 in 10 million. While this calculated core damage frequency has been one of the main metrics to assess reactor safety, European safety authorities prefer a deterministic approach, focusing on actual provision of back-up hardware, though they also undertake probabilistic safety analysis (PSA) for core damage frequency, and require a 1 in 1 million core damage frequency for new designs.

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Achieving optimum nuclear safety

A fundamental principle of nuclear power plant operation worldwide is that the operator is responsible for safety. The national regulator is responsible for ensuring the plants are operated safely by the licensee, and that the design is approved. A second important concept is that a regulator’s mission is to protect people and the environment.

Design certification of reactors is also the responsibility of national regulators. There is international collaboration among these to varying degrees, and there are a number of sets of mechanical codes and standards related to quality and safety.

With new reactor designs being established on a more international basis since the 1990s, both industry and regulators are seeking greater design standardisation and also regulatory harmonization. The role of the World Nuclear Association’s CORDEL Working Group and the OECD/NEA’s MDEP group are described in the Cooperation paper.

An OECD/NEA report in 2010 pointed out that the theoretically-calculated frequency for a large release of radioactivity from a severe nuclear power plant accident has reduced by a factor of 1600 between the early Generation I reactors as originally built and the Generation III/III+ plants being built today. Earlier designs however have been progressively upgraded through their operating lives.

It has long been asserted that nuclear reactor accidents are the epitome of low-probability but high-consequence risks. Understandably, with this in mind, some people were disinclined to accept the risk, however low the probability. However, the physics and chemistry of a reactor core, coupled with but not wholly depending on the engineering, mean that the consequences of an accident are likely in fact be much less severe than those from other industrial and energy sources. Experience, including Fukushima, bears this out.

A 2009 US Department of Energy (DOE) Human Performance Handbook notes: “The aviation industry, medical industry, commercial nuclear power industry, U.S. Navy, DOE and its contractors, and other high-risk, technologically complex organizations have adopted human performance principles, concepts, and practices to consciously reduce human error and bolster controls in order to reduce accidents and events.” “About 80 percent of all events are attributed to human error. In some industries, this number is closer to 90 percent. Roughly 20 percent of events involve equipment failures. When the 80 percent human error is broken down further, it reveals that the majority of errors associated with events stem from latent organizational weaknesses (perpetrated by humans in the past that lie dormant in the system), whereas about 30 percent are caused by the individual worker touching the equipment and systems in the facility. Clearly, focusing efforts on reducing human error will reduce the likelihood of events.” Following the Fukushima accident the focus has been on the organisational weaknesses which increase the likelihood of human error.

In passing, it is relevant to note that the safety record of the US nuclear navy from 1955 on is excellent, this being attributed to a high level of standardisation in over one hundred naval power plants and in their maintenance, and the high quality of the Navy’s training program. Until the 1980s, the Soviet naval record stood in marked contrast.

Defence in depth

To achieve optimum safety, nuclear plants in the western world operate using a ‘defence-in-depth’ approach, with multiple safety systems supplementing the natural features of the reactor core. Key aspects of the approach are:

  • high-quality design & construction,
  • equipment which prevents operational disturbances or human failures and errors developing into problems,
  • comprehensive monitoring and regular testing to detect equipment or operator failures,
  • redundant and diverse systems to control damage to the fuel and prevent significant radioactive releases,
  • provision to confine the effects of severe fuel damage (or any other problem) to the plant itself.

These can be summed up as: Prevention, Monitoring, and Action (to mitigate consequences of failures).

The safety provisions include a series of physical barriers between the radioactive reactor core and the environment, the provision of multiple safety systems, each with backup and designed to accommodate human error. Safety systems account for about one quarter of the capital cost of such reactors. As well as the physical aspects of safety, there are institutional aspects which are no less important – see following section on International Collaboration.

The barriers in a typical plant are: the fuel is in the form of solid ceramic (UO2) pellets, and radioactive fission products remain largely bound inside these pellets as the fuel is burned. The pellets are packed inside sealed zirconium alloy tubes to form fuel rods. These are confined inside a large steel pressure vessel with walls up to 30 cm thick – the associated primary water cooling pipework is also substantial. All this, in turn, is enclosed inside a robust reinforced concrete containment structure with walls at least one metre thick.  This amounts to three significant barriers around the fuel, which itself is stable up to very high temperatures.

These barriers are monitored continually. The fuel cladding is monitored by measuring the amount of radioactivity in the cooling water. The high pressure cooling system is monitored by the leak rate of water, and the containment structure by periodically measuring the leak rate of air at about five times atmospheric pressure.

Looked at functionally, the three basic safety functions in a nuclear reactor are:

  • to control reactivity,
  • to cool the fuel and
  • to contain radioactive substances.

The main safety features of most reactors are inherent – negative temperature coefficient and negative void coefficient. The first means that beyond an optimal level, as the temperature increases the efficiency of the reaction decreases (this in fact is used to control power levels in some new designs). The second means that if any steam has formed in the cooling water there is a decrease in moderating effect so that fewer neutrons are able to cause fission and the reaction slows down automatically.

In the 1950s and 1960s some experimental reactors in Idaho were deliberately tested to destruction to verify that large reactivity excursions were self-limiting and would automatically shut down the fission reaction. These tests verified that this was the case.

Beyond the control rods which are inserted to absorb neutrons and regulate the fission process, the main engineered safety provisions are the back-up emergency core cooling system (ECCS) to remove excess heat (though it is more to prevent damage to the plant than for public safety) and the containment.

Traditional reactor safety systems are ‘active’ in the sense that they involve electrical or mechanical operation on command. Some engineered systems operate passively, e.g. pressure relief valves. Both require parallel redundant systems. Inherent or full passive safety design depends only on physical phenomena such as convection, gravity or resistance to high temperatures, not on functioning of engineered components. All reactors have some elements of inherent safety as mentioned above, but in some recent designs the passive or inherent features substitute for active systems in cooling etc. Such a design would have averted the Fukushima accident, where loss of electrical power resulted is loss of cooling function.

The basis of design assumes a threat where due to accident or malign intent (e.g. terrorism) there is core melting and a breach of containment. This double possibility has been well studied and provides the basis of exclusion zones and contingency plans. Apparently during the Cold War neither Russia nor the USA targeted the other’s nuclear power plants because the likely damage would be modest.

Nuclear power plants are designed with sensors to shut them down automatically in an earthquake, and this is a vital consideration in many parts of the world. (See Nuclear Power Plants and Earthquakespaper)

The International Nuclear Event Scale
For prompt communication of safety significance

Level, DescriptorOff-Site Impact, release of radioactive materialsOn-Site ImpactDefence-in-Depth DegradationExamples
7
Major Accident
Major Release:
Widespread health and environmental effects
  Chernobyl, Ukraine, 1986 (fuel meltdown and fire); 
Fukushima Daiichi 1-3, 2011 (fuel damage, radiation release and evacuation)
6
Serious Accident
Significant Release:
Full implementation of local emergency plans
  Mayak at Ozersk, Russia, 1957 ‘Kyshtym’ (reprocessing plant criticality)
5
Accident with Off-Site Consequences
Limited Release:
Partial implementation of local emergency plans, or
Severe damage to reactor core or to radiological barriers Three Mile Island, USA, 1979 (fuel melting);
Windscale, UK, 1957 (military)
 
4
Accident Mainly in Installation, with local consequences.
either of:
Minor Release:
Public exposure of the order of prescribed limits, or
Significant damage to reactor core or to radiological barriers; worker fatality Saint-Laurent A1, France, 1969 (fuel rupture) & A2 1980 (graphite overheating);
Tokai-mura, Japan, 1999 (criticality in fuel plant for an experimental reactor).
3
Serious Incident
any of:
Very Small Release:
Public exposure at a fraction of prescribed limits, or
Major contamination; Acute health effects to a worker, orNear Accident:
Loss of Defence in Depth provisions – no safety layers remaining
Fukushima Daiichi 4, 2011 (fuel pond overheating);
Fukushima Daini 1, 2, 4, 2011 (interruption to cooling); 
Vandellos, Spain, 1989 (turbine fire); 
Davis-Besse, USA, 2002 (severe corrosion);
Paks, Hungary 2003 (fuel damage)
2
Incident
nilSignificant spread of contamination; Overexposure of worker, orIncidents with significant failures in safety provisions 
1
Anomaly
nilnilAnomaly beyond authorised operating regime 
0
Deviation
nilnilNo safety significance 
Below ScalenilnilNo safety relevance 
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Home / Information Library / Safety and Security / Safety of Plants / Safety of Nuclear Power Reactors

Safety of Nuclear Power Reactors

(Updated June 2019)

  • From the outset, there has been a strong awareness of the potential hazard of both nuclear criticality and release of radioactive materials from generating electricity with nuclear power. 
  • As in other industries, the design and operation of nuclear power plants aims to minimise the likelihood of accidents, and avoid major human consequences when they occur. 
  • There have been three major reactor accidents in the history of civil nuclear power – Three Mile IslandChernobyl and Fukushima. One was contained without harm to anyone, the next involved an intense fire without provision for containment, and the third severely tested the containment, allowing some release of radioactivity. 
  • These are the only major accidents to have occurred in over 17,000 cumulative reactor-years of commercial nuclear power operation in 33 countries. 
  • The evidence over six decades shows that nuclear power is a safe means of generating electricity. The risk of accidents in nuclear power plants is low and declining. The consequences of an accident or terrorist attack are minimal compared with other commonly accepted risks. Radiological effects on people of any radioactive releases can be avoided.

Context

In relation to nuclear power, safety is closely linked with security, and in the nuclear field also with safeguards. Some distinctions apply:

  • Safety focuses on unintended conditions or events leading to radiological releases from authorised activities. It relates mainly to intrinsic problems or hazards.
  • Security focuses on the intentional misuse of nuclear or other radioactive materials by non-state elements to cause harm. It relates mainly to external threats to materials or facilities.
  • Safeguards focus on restraining activities by states that could lead to acquisition or development of nuclear weapons. It concerns mainly materials and equipment in relation to rogue governments. (See also information paper on Safeguards.)

No industry is immune from accidents, but all industries learn from them. In civil aviation, there are accidents every year and each is meticulously analysed. The lessons from nearly one hundred years’ experience mean that reputable airlines are extremely safe. In the chemical industry and oil-gas industry, major accidents also lead to improved safety. There is wide public acceptance that the risks associated with these industries are an acceptable trade-off for our dependence on their products and services. With nuclear power, the high energy density makes the potential hazard obvious, and this has always been factored into the design of nuclear power plants. The few accidents have been spectacular and newsworthy, but of little consequence in terms of human fatalities. The novelty value and hence newsworthiness of nuclear power accidents remains high in contrast with other industrial accidents, which receive comparatively little news coverage.

Harnessing the world’s most concentrated energy source

In the 1950s attention turned to harnessing the power of the atom in a controlled way, as demonstrated at Chicago in 1942 and subsequently for military research, and applying the steady heat yield to generate electricity. This naturally gave rise to concerns about accidents and their possible effects. However, with nuclear power, safety depends on much the same factors as in any comparable industry: intelligent planning, proper design with conservative margins and back-up systems, high-quality components and a well-developed safety culture in operations. The operating lives of reactors depend on maintaining their safety margin.

A particular nuclear scenario was loss of cooling which resulted in melting of the nuclear reactor core, and this motivated studies on both the physical and chemical possibilities as well as the biological effects of any dispersed radioactivity.  Those responsible for nuclear power technology in the West devoted extraordinary effort to ensuring that a meltdown of the reactor core would not take place, since it was assumed that a meltdown of the core would create a major public hazard, and if uncontained, a tragic accident with likely multiple fatalities.

In avoiding such accidents the industry has been very successful. In over 17,000 cumulative reactor-years of commercial operation in 33 countries, there have been only three major accidents to nuclear power plants – Three Mile Island, Chernobyl, and Fukushima – the second being of little relevance to reactor designs outside the old Soviet bloc.

The three significant accidents in the 50-year history of civil nuclear power generation are:

  • Three Mile Island (USA 1979) where the reactor was severely damaged but radiation was contained and there were no adverse health or environmental consequences.
  • Chernobyl (Ukraine 1986) where the destruction of the reactor by steam explosion and fire killed two people initially plus a further 28 from radiation poisoning within three months, and had significant health and environmental consequences.
  • Fukushima (Japan 2011) where three old reactors (together with a fourth) were written off after the effects of loss of cooling due to a huge tsunami were inadequately contained. There were no deaths or serious injuries due to radioactivity, though about 19,000 people were killed by the tsunami.

Appendix 1: The Hazards of Using Energy contains a table showing all reactor accidents and a table listing some energy-related accidents with multiple fatalities.

These three significant accidents occurred during more than 17,000 reactor-years of civil operation. Of all the accidents and incidents, only the Chernobyl and Fukushima accidents resulted in radiation doses to the public greater than those resulting from the exposure to natural sources. The Fukushima accident resulted in some radiation exposure of workers at the plant, but not such as to threaten their health, unlike Chernobyl.  Other incidents (and one ‘accident’) have been completely confined to the plant.

Apart from Chernobyl, no nuclear workers or members of the public have ever died as a result of exposure to radiation due to a commercial nuclear reactor incident. Most of the serious radiological injuries and deaths that occur each year (2-4 deaths and many more exposures above regulatory limits) are the result of large uncontrolled radiation sources, such as abandoned medical or industrial equipment. (There have also been a number of accidents in experimental reactors and in one military plutonium-producing pile – at Windscale, UK, in 1957 – but none of these resulted in loss of life outside the actual plant, or long-term environmental contamination.)  See also Table in Appendix 2: Serious Nuclear Reactor Accidents.

In the USA the Nuclear Regulatory Commission (NRC) in March 2012 made orders for immediate post-Fukushima safety enhancements, likely to cost about $100 million across the whole US fleet. The first order requires the addition of equipment at all plants to help respond to the loss of all electrical power and the loss of the ultimate heat sink for cooling, as well as maintaining containment integrity. Another requires improved water level and temperature instrumentation on used fuel ponds. The third order applies only to the 33 BWRs with early containment designs, and will require ‘reliable hardened containment vents’ which work under any circumstances. The industry association, NEI, told the NRC that licensees with these Mark I and Mark II containments “should have the capability to use various filtration strategies to mitigate radiological releases” during severe events, and that filtration “should be founded on scientific and factual analysis and should be performance-based to achieve the desired outcome.” All the measures are supported by the industry association, which has also proposed setting up about six regional emergency response centres under NRC oversight with additional portable equipment.

In Japan similar stress tests were carried out in 2011 under the previous safety regulator, but then reactor restarts were delayed until the newly constituted Nuclear Regulatory Authority devised and published new safety guidelines, then applied them progressively through the fleet.

Severe Accident Management

In addition to engineering and procedures which reduce the risk and severity of accidents, all plants have guidelines for Severe Accident Management or Mitigation (SAM). These conspicuously came into play after the Fukushima accident, where staff had immense challenges in the absence of power and with disabled cooling systems following damage done by the tsunami. The experience following that accident is being applied not only in design but also in such guidelines, and peer reviews on nuclear plants will focus more on these than previously.

In mid-2011 the IAEA Incident and Emergency Centre launched a new secure web-based communications platform to unify and simplify information exchange during nuclear or radiological emergencies. The Unified System for Information Exchange on Incidents and Emergencies (USIE) has been under development since 2009 but was actually launched during the emergency response to the accident at Fukushima.

Earthquakes and Volcanoes

The International Atomic Energy Agency (IAEA) has a Safety Guide on Seismic Risks for Nuclear Power Plants, and the matter is dealt with in the WNA paper on Earthquakes and Nuclear Power Plants. Volcanic hazards are minimal for practically all nuclear plants, but the IAEA has developed a new Safety Guide on the matter. The Bataan plant in Philippines which has never operated, and the Armenian plant at Metsamor are two known to be in proximity to potential volcanic activity.

Flooding – storms, tides and tsunamis

Nuclear plants are usually built close to water bodies, for the sake of cooling. The site licence takes account of worst case flooding scenarios as well as other possible natural disasters and, more recently, the possible effects of climate change. As a result, all the buildings with safety-related equipment are situated on high enough platforms so that they stand above submerged areas in case of flooding events. As an example, French Safety Rules criteria for river sites define the safe level as above a flood level likely to be reached with one chance in one thousand years, plus 15%, and similar regarding tides for coastal sites.

Occasionally in the past some buildings have been sited too low, so that they are vulnerable to flood or tidal and storm surge, so engineered countermeasures have been built. EDF’s Blayais nuclear plant in western France uses seawater for cooling and the plant itself is protected from storm surge by dykes. However, in 1999 a 2.5 m storm surge in the estuary overtopped the dykes – which were already identified as a weak point and scheduled for a later upgrade – and flooded one pumping station. For security reasons it was decided to shut down the three reactors then under power (the fourth was already stopped in the course of normal maintenance). This incident was rated 2 on the INES scale.

In 1994 the Kakrapar nuclear power plant near the west coast of India was flooded due to heavy rains together with failure of weir control for an adjoining water pond, inundating turbine building basement equipment. The back-up diesel generators on site enabled core cooling using fire water, a backup to process water, since the offsite power supply failed. Following this, multiple flood barriers were provided at all entry points, inlet openings below design flood level were sealed and emergency operating procedures were updated. In December 2004 the Madras NPP and Kalpakkam PFBR site on the east coast of India was flooded by a tsunami surge from Sumatra. Construction of the Kalpakkam plant was just beginning, but the Madras plant shut down safely and maintained cooling. However, recommendations including early warning system for tsunami and provision of additional cooling water sources for longer duration cooling were implemented.

In March 2011 the Fukushima Daiichi nuclear plant was affected seriously by a huge tsunami induced by the Great East Japan Earthquake. Three of the six reactors were operating at the time, and had shut down automatically due to the earthquake. The back-up diesel generators for those three units were then swamped by the tsunami. This cut power supply and led to weeks of drama and loss of the reactors. The design basis tsunami height was 5.7 m for Daiichi (and 5.2 m for adjacent Daini, which was actually set a bit higher above sea level). Tsunami heights coming ashore were about 14 metres for both plants. Unit 3 of Daini was undamaged and continued to cold shutdown status, but the other units suffered flooding to pump rooms where equipment transfers heat from the reactor circuit to the sea – the ultimate heat sink.

The maximum amplitude of this tsunami was 23 metres at point of origin, about 160 km from Fukushima. In the last century there had been eight tsunamis in the Japan region with maximum amplitudes above 10 metres (some much more), these having arisen from earthquakes of magnitude 7.7 to 8.4, on average one every 12 years. Those in 1983 and in 1993 were the most recent affecting Japan, with maximum heights 14.5 metres and 31 metres respectively, both induced by magnitude 7.7 earthquakes. This 2011 earthquake was magnitude 9.

For low-lying sites, civil engineering and other measures are normally taken to make nuclear plants resistant to flooding. Lessons from Blayais have fed into regulatory criteria since 2000, and those from Fukushima will certainly do so. Sea walls are being built or increased at Hamaoka, Shimane, Mihama, Ohi, Takahama, Onagawa, and Higashidori plants. However, few parts of the world have the same tsunami potential as Japan, and for the Atlantic and Mediterranean coasts of Europe the maximum amplitude is much less than Japan.

Hydrogen

In any light-water nuclear power reactor, hydrogen is formed by radiolytic decomposition of water. This needs to be dealt with to avoid the potential for explosion with oxygen present, and many reactors have been retrofitted with passive autocatalytic hydrogen recombiners in their containment, replacing external recombiners that needed to be connected and powered, isolated behind radiological barriers. Also in some kinds of reactors, particularly early boiling water types, the containment is rendered inert by injection of nitrogen. It was reported that WANO may require all operators to have hydrogen recombiners in PWRs. As of early 2012, a few in Spain and Japan did not have them.

In an accident situation such as at Fukushima where the fuel became very hot, a lot of hydrogen is formed by the oxidation of zirconium fuel cladding in steam at about 1300°C. This is beyond the capability of the normal hydrogen recombiners to deal with, and operators must rely on venting to atmosphere or inerting the containment with nitrogen.

International collaboration to improve safety

There is a lot of international collaboration, but it has evolved from the bottom, and only in 1990s has there been any real top-down initiative. In the aviation industry the Chicago Convention in the late 1940s initiated an international approach which brought about a high degree of design collaboration between countries, and the rapid universal uptake of lessons from accidents. There are cultural and political reasons for this which mean that even the much higher international safety collaboration since the 1990s is still less than in aviation. See also: paper on Cooperation in Nuclear Power Industry, especially for fuller description of WANO, focused on operation.

World Association of Nuclear Operators

There is a great deal of international cooperation on nuclear safety issues, in particular the exchange of operating experience under the auspices of the World Association of Nuclear Operators (WANO) which was set up in 1989.  In practical terms this is the most effective international means of achieving very high levels of safety through its four major programs: peer reviews; operating experience; technical support and exchange; and professional and technical development. WANO peer reviews are the main proactive way of sharing experience and expertise, and by the end of 2009 every one of the world’s commercial nuclear power plants had been peer-reviewed at least once.  Following the Fukushima accident these have been stepped up to one every four years at each plant, with follow-up visits in between, and the scope extended from operational safety to include plant design upgrades. Pre-startup reviews of new plants are being increased.

IAEA Convention on Nuclear Safety

The IAEA Convention on Nuclear Safety (CNS) was drawn up during a series of expert level meetings from 1992 to 1994 and was the result of considerable work by Governments, national nuclear safety authorities and the IAEA Secretariat. Its aim is to legally commit participating States operating land-based nuclear power plants to maintain a high level of safety by setting international benchmarks to which States would subscribe.

The obligations of the Parties are based to a large extent on the principles contained in the IAEA Safety Fundamentals document The Safety of Nuclear Installations. These obligations cover for instance, siting, design, construction, operation, the availability of adequate financial and human resources, the assessment and verification of safety, quality assurance and emergency preparedness.

The Convention is an incentive instrument. It is not designed to ensure fulfilment of obligations by Parties through control and sanction, but is based on their common interest to achieve higher levels of safety. These levels are defined by international benchmarks developed and promoted through regular meetings of the Parties. The Convention obliges Parties to report on the implementation of their obligations for international peer review. This mechanism is the main innovative and dynamic element of the Convention.  Under the Operational Safety Review Team (OSART) program dating from 1982 international teams of experts conduct in-depth reviews of operational safety performance at a nuclear power plant. They review emergency planning, safety culture, radiation protection, and other areas. OSART missions are on request from the government, and involve staff from regulators, in these respects differing from WANO peer reviews.

The Convention entered into force in October 1996. As of September 2009, there were 79 signatories to the Convention, 66 of which are contracting parties, including all countries with operating nuclear power plants.

The IAEA General Conference in September 2011 unanimously endorsed the Action Plan on Nuclear Safety that Ministers requested in June. The plan arose from intensive consultations with Member States but not with industry, and was described as both a rallying point and a blueprint for strengthening nuclear safety worldwide. It contains suggestions to make nuclear safety more robust and effective than before, without removing the responsibility from national bodies and governments. It aims to ensure “adequate responses based on scientific knowledge and full transparency”. Apart from strengthened and more frequent IAEA peer reviews (including those of regulatory systems), most of the 12 recommended actions are to be undertaken by individual countries and are likely to be well in hand already.

Following this, an extraordinary general meeting of 64 of the CNS parties in September 2012 gave a strong push to international collaboration in improving safety. National reports at future three-yearly CNS review meetings will cover a list of specific design, operational and organizational issues stemming from Fukushima lessons. They include further design features to avoid long-term offsite contamination and enhancement of emergency preparedness and response measures, including better definition of national responsibilities and improved international cooperation. Parties should also report on measures to “ensure the effective independence of the regulatory body from undue influence.”

In February 2015 diplomats from 72 countries unanimously adopted the Vienna Declaration of Nuclear Safety, setting out “principles to guide them, as appropriate, in the implementation of the objective of the CNS to prevent accidents with radiological consequences and mitigate such consequences should they occur” but rejected Swiss amendments to the CNS as impractical. However, in line with Swiss and EU intentions, “comprehensive and systematic safety assessments are to be carried out periodically and regularly for existing installations throughout their lifetime in order to identify safety improvements… Reasonably practicable or achievable safety improvements are to be implemented in a timely manner.”

IAEA Design Safety Reviews and Generic Reactor Safety Reviews

An IAEA Design Safety Review (DSR) is performed at the request of a member state organization to evaluate the completeness and comprehensiveness of a reactor’s safety documentation by an international team of senior experts. It is based on IAEA published safety requirements. If the DSR is for a vendor’s design at the pre-licensing stage, it is done using the Generic Reactor Safety Review (GRSR) module. IAEA Safety Standards applied in the DSR and GRSR at the fundamental and requirements level, are generic and apply to all nuclear installations. Therefore, it is neither intended nor possible to cover or substitute licensing activity, or to constitute any kind of design certification.

DSRs have been undertaken in Pakistan, Ukraine, Bulgaria and Armenia. GRSRs have been done on AP1000 (USA & UK), Atmea1, APR1400, ACPR-1000+, ACP1000, and AES-2006 and VVER-TOI.

Eastern Europe from 1980s

In relation to Eastern Europe particularly, since the late 1980s a major international program of assistance was carried out by the OECD, IAEA and Commission of the European Communities to bring early Soviet-designed reactors up to near western safety standards, or at least to effect significant improvements to the plants and their operation. The European Union also brought pressure to bear, particularly in countries which aspired to EU membership.

Modifications were made to overcome deficiencies in the 11 RBMK reactors still operating at the time in Russia. Among other things, these removed the danger of a positive void coefficient response. Automated inspection equipment has also been installed in these reactors.

The other class of reactors which has been the focus of international attention for safety upgrades is the first-generation of pressurised water VVER-440 reactors. The V-230 model was designed before formal safety standards were issued in the Soviet Union and they lack many basic safety features. Four are still operating in Russia and one in Armenia, under close inspection.

Later Soviet-designed reactors are very much safer and have Western control systems or the equivalent, along with containment structures.

Source: International Atomic Energy Agency

Three simple sets of figures are quoted in the Tables below and that in the appendix.  A major reason for coal’s unfavourable showing is the huge amount which must be mined and transported to supply even a single large power station. Mining and multiple handling of so much material of any kind involves hazards, and these are reflected in the statistics.

Summary of severe* accidents in energy chains for electricity 1969-2000

 OECDNon-OECD 
Energy chainFatalitiesFatalities/TWyFatalitiesFatalities/ TWy
Coal 225915718,000597
Natural gas1043851000111
Hydro14330,00010,285
Nuclear003148
Data from Paul Scherrer Institut, in OECD 2010. * severe = more than five fatalities
Comparison of accident statistics in primary energy production
(Electricity generation accounts for about 40% of total primary energy)

Data from Paul Scherrer Institut, in OECD 2010. * severe = more than five fatalities

Comparison of accident statistics in primary energy production
(Electricity generation accounts for about 40% of total primary energy)

FuelImmediate fatalities
1970-92
Who?Normalised to deaths
per TWy* electricity
Coal6400workers342
Natural gas1200workers & public85
Hydro4000public883
Nuclear31workers8
* Basis: per million MWe operating for one year, not including plant construction, based on historic data which is unlikely to represent current safety levels in any of the industries concerned.
Sources: Sources: Ball, Roberts & Simpson, 1994; Hirschberg et al, Paul Scherrer Institut 1996, in: IAEA 1997; Paul Scherrer Institut, 2001.

* Basis: per million MWe operating for one year, not including plant construction, based on historic data which is unlikely to represent current safety levels in any of the industries concerned.
Sources: Sources: Ball, Roberts & Simpson, 1994; Hirschberg et al, Paul Scherrer Institut 1996, in: IAEA 1997; Paul Scherrer Institut, 2001.

ஐரோப்பிய நாடுகளில் மாவட்டக் கணப்பளிக்க 300 MWe தொழிற்கூடக் கட்டமைப்பு சிற்றணுவுலை நிலையம் நிறுவத் திட்டங்கள்

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ஜெனரல் எலெக்டிரிக் 300 MWe தொழிற்கூடக் கட்டமைப்பு சிற்றணுவுலை நிலையம்

GE Small Modular Reactor (SMR)

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சி. ஜெயபாரதன் B.E.(Hons) P.Eng (Nuclear) கனடா

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துருவப் பகுதி பணிகளுக்கு, சுவைநீர் உற்பத்திக்கு, வீட்டுக் கணப்புக்குப் புதிய சிற்றணுவுலை நிலையங்கள் அமைப்பு

2020 ஆண்டில் இப்போது 30 நாடுகளில் சுமார் 100 மெகாவாட் முதல் 1600 மெகாவாட் திறத்தில் இயங்கி வரும் 460 அணுமின் நிலையங்கள் மின்சாரம் உற்பத்தி செய்து, மின்வடங்களில் பரிமாறி வருகின்றன  இதுவரை உலகில் முப்பெரும் அணுவுலை விபத்துகள் [அமெரிக்காவில் திரிமைல் ஐலண்டு விபத்து, சோவித் ரஷ்யாவில் செர்நோபிள் விபத்து, ஜப்பானில் புகுஷிமா விபத்து]  நேர்ந்து பொதுமக்கள் பலரைப் புலப்பெயர்ச்சி செய்தும், பலருக்குக் கதிரடிக் கொடுத்தும், பேரிடர் அளித்தும்  அச்சமூட்டி வந்துள்ளன.  இந்த விபத்துகளால், பொதுநபர் இடரோடு, அணுவுலை இயக்க அமைப்பாளருக்குப் பெருத்த நிதி இழப்பும் ஏற்பட்டுள்ளன.  மேலும் உலகில் புதிய அணுமின் உலைகள் கட்டுவது நிறுத்தப் பட்டோ, தாமதிக்கப் பட்டோ, பழைய அணுவுலைகள் மூடப்பட்டோ, அல்லது செம்மை செய்யப்பட்டோ, புதிய அமைப்பு முறைகள், கட்டுப்பாட்டு விதிகள் மாற்றப் பட்டோ செலவுகள் எல்லைக்கு மீறி விட்டன.  ஆகவே அவற்றைப் பாதுகாப்புடன் இயக்க விட்டுப் புதிய சுற்றுச் சூழல் மாசில்லா முறைகளில் சூரிய மின்சார உற்பத்தி, காற்றாலை மின்சார உற்பத்தி செய்ய நாடுகள் துவங்கி விட்டன.

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Concept Drawing of GE High Temperature Gas Cooled Reactor.

Image courtesy of World Nuclear Association

ஆனால் நிலக்கரி, இயல்வாயு எரிசக்தி மின்சாரம், அணுசக்தி  மின்சாரம்  போன்று தொடர்ந்து பேரளவு அடிப்பளுத் திற மின்சாரம் [Baseload Power] பரிமாற சூரியசக்தியோ, காற்றாலை சக்தியோ ஈடு செய்ய முடியவில்லை. மேலும் சூரிய சக்தியை இரவில் பரிமாறச் சேமித்து வைக்க முடியவில்லை.  காற்றில்லா சமையங்களில் மின்சாரப் பரிமாற்றம் முற்றிலும் நிறுத்தம் அடைகிறது. அடுத்து அணுப்பிணைவு சக்தி [Nuclear Fusion Energy] வாணிப ரீதியாக, மக்களுக்கு வசதிப்படும் வரை, இப்போதுள்ள அணுப்பிளவு சக்தி [Nuclear Fission Power] நிலையங்கள் தொடர்ந்து இயங்கி வரவேண்டும். கதிரியக்கம் இல்லாத, கதிரியக்க மாசுக்கள் சேராத, புதிய அணுப்பிணைவு நிலையங்கள் வாணிப உலகில் வருவதற்கு 10 அல்லது 15 ஆண்டுகள் ஆகலாம்.

இப்போது  மேலும் ஒரு பிரச்சனை  உண்டாகி விட்டது.  துருவப் பிரதேசங்களில் ஆயில் கிணறுகள் தோண்டவும்,  வட அமெரிக்க, ஐரோப்பிய வடக்குக் குளிர்ப் பகுதி வீடுகளுக்கு கணப்பு சக்தி, மின்சாரம் அனுப்பவும், கடலிருந்து சுவைநீர் எடுக்கவும், உள்நாட்டில் சிறு நகரங்களுக்கு அடிப்பளு மின்சாரம் பரிமாறவும் சிற்றணுவுலை தேவைப்படுகிறது.  இந்த தேவை கனடா, அமெரிக்கா, ரஷ்யா, ஃபின்லாந்து, ஜப்பான், சைனா, இந்தியா போன்ற நாடுகள் 200 MWe முதல் 300 MWe மின்திறம் உடைய பற்பல தொழிற்கூட கட்டமைப்புச் சிற்றணுவுலை நிலையங்கள்  [Small Modular Reactor] (SMR-200 MWe, SMR-300 MWe) நிறுவத் திட்ட மிட்டுள்ளார்.  இச்சிறு அணுமின் உலை உறுப்புகள் தொழிற்கூடத்திலே சேர்ப்பாகித்  தயாராகிக் குறிப்பிட்ட கட்டு மான இடத்துக்கு முழுமையாக வந்து சேரும்.

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https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/small-nuclear-power-reactors.aspxGE-Hitachi to Offer 300 MW SMR

https://en.wikipedia.org/wiki/World_Association_of_Nuclear_Operators

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தொழிற்கூடக் கட்டுமான சிற்றணுவுலைச் சிறப்புகள், தயாரிப்பு நிறைபாடுகள் 

  1.  கட்டுமானம்,. சோதிப்பு, சீர்ப்படுத்து போக்குவரத்து செலவுகள் குறைவு.
  2. கட்டுமான எளிமை, மாற்றுதல் எளிமை, சோதிப்பு எளிமை.
  3. மாநிலத்தில் உள்ள நடுத்தர மின்வடங்கள் ஏந்திச் செல்ல வசதி
  4. சிற்றணுவுலை தயாரிக்கும், இயக்கும் காலம்  குறைவு
  5. யந்திர சாதன இணைப்பு, அடுக்கு எளிது.
  6. விபத்து நேர்ந்தால் விளையும் கதிரியக்க மாசுகள் குறைவு.
  7. அணு உலை மாற்றம் செய்வது, சோதனை செய்வது எளிது.
  8. தூர இடங்களுக்கு, துருவப் பகுதி இடங்களுக்கு தூக்கிச் செல்வது எளிது.

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Because of radiation given off in the fission reactions, the reactor core is completely contained and separate from the electric generation part of the plant.

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வெஸ்டிங்ஹவுஸ் AP-1000 MWe அணுமின்சக்தி நிலையம்

https://www.reuters.com/article/us-india-usa-trump-westinghouse-exclusiv/exclusive-westinghouse-set-to-sign-pact-with-indian-firm-for-nuclear-reactors-during-trump-visit-idUSKBN20E1PM

https://timesofindia.indiatimes.com/india/US-based-Westinghouse-to-build-6-nuclear-power-plants-in-India/articleshow/52644065.cms

https://en.wikipedia.org/wiki/AP1000

Obama, Modi Kick Start the Westinghouse Nuclear Deal

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அமெரிக்கா இந்தியாவில் கட்டும் ஆறு 1000 MWe அணுமின்சக்தி நிலையங்கள் 

2020 பிப்ரவரி 20 ஆம் தேதி இந்திய வெளிநாட்டு அமைச்சு செயலாளர் விஜய்  கோகலேயும் அமெரிக்க  அகில் நாட்டுப் பாதுகாப்பு, ஆயுதக் கட்டுப்பாடு துணைச் செயலாளர் ஆன்டியா தாம்ஸன் ஆகியோர் கலந்துரையாடலில் வெளியான செய்தி இது.  பொதுநல அணுசக்திப் பயன்பாட்டில் இருநாட்டுக் கூட்டுறவு உடன்பாட்டின்படி, ஆறு 1000 மெகாவாட் அணுமின்சக்தி நிலையங்களை, அமெரிக்காவின் வெஸ்டிங்ஹவுஸ் நிறுவகம் கட்ட வாஷிங்டன் D.C. இல் ஒப்பந்தம் செய்யப் பட்டுள்ளது.  கடந்த பத்தாண்டுகளாக, அணுமின் உலை விபத்து இழப்பு நிதி [Indian Liability Rules] யார் அளிப்பது ?  அணு உலை இயக்கும் இந்தியாவா ?  அல்லது அணு உலை கட்டிய வெஸ்டிங்ஹவுஸா ?  [இது போன்று முன்பு போபால் நச்சு வாயுக் கசிவு விபத்தில் துயருற்ற லட்சக் கணக்கான இந்தியருக்கு விபத்து இழப்பு நிதி அளிப்பதில் தர்க்கம் ஏற்பட்டு நோயாளிகள் பெருந்துயர் உற்றார்.]  இந்த ஆறு அணு மின்சக்தி நிலையங்கள் ஆந்திராவில் நிறுவகம் ஆகும். இந்தியா 2031 ஆண்டுக்குள் 22,480 மெகாவாட் உற்பத்தி செய்யத் திட்டமிட்டு உள்ளது.  2019 ஆண்டு  அணுமின்சார உற்பத்தி அளவு ; 6780 மெகாவாட்.

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2008 ஆம் ஆண்டில் அமெரிக்க அதிபர் ஓபாமா உள்ள போது இரண்டு நாடுகளும் ஆரம்ப ஒப்பந்தம் செய்து கொண்டாலும், இப்போது டிரம்ப் காலத்தில்தான் அத்திட்டம் உறுதி செய்யப்பட்டது.  “அமெரிக்கர் சாதனத்தை விற்பனை செய்” என்ற டிரம்ப் சுலோகத்தில் முடிவானது இந்த திட்டம்.  இந்தியா 2024 ஆண்டுக்குள் மின்சக்தி உற்பத்தியை மும்மடங்கு பெருக்க [தற்போது 6700 மெகாவாட்]  முனைந்துள்ளது.  அமெரிக்கன் 1000 மெகாவாட் ஒரு நிலையம் நிறுவ, குறைந்தது 3 ஆண்டுகள் ஆகலாம். சென்ற ஆண்டில் இந்தியாவும், ரஷ்யாவும் மேலும் ஆறு 1000 மெகாவாட் கூடங்குள மாடல் அணு மின்சக்தி நிலையங்கள் கட்ட ஒப்பந்தம் செய்து கொண்டன.  நொடித்துப் போன வெஸ்டிங்ஹவுஸ்  நிறுவனத்தைக் கைதூக்க அதிபர் டிரம்ப் இந்தியாவுக்கு பிப்ரவரியில் போகும் போது, இந்த திட்டம் உறுதி ஆகும்.  ஆயினும் விபத்து இழப்பு நிதி கொடுக்கும் பொறுப்பு யாருடையது என்பது முடிவு செய்யப் படவில்லை.

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ஜப்பான் புகுஷிமா அணு உலை விபத்துக்குப் பிறகு உலக அணு மின்சார நிலையங்களின் எதிர்கால இயக்கம் பற்றித் தீர்மானங்கள் -1

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  1. http://afterfukushima.com/tableofcontents
  2. http://afterfukushima.com/book-excerpt
  3. https://youtu.be/YBNFvZ6Vr2U
  4. https://youtu.be/HtwNyUZJgw8
  5. https://youtu.be/UFoVUNApOg8
  6. http://www.cornell.edu/video/five-years-after-fukushima-lessons-learned-nuclear-accidents
  7. https://youtu.be/_-dVCIUc25o
  8. https://youtu.be/kBmc8SQMBj8
  9. https://www.statista.com/topics/1087/nuclear-power/
  10. https://www.statista.com/statistics/238610/projected-world-electricity-generation-by-energy-source/
  11. https://youtu.be/ZjRXDp1ubps
  12. https://www.thinkingpower.ca/PDFs/NuclearPower/NP_3_2_Crawford.pdf

முன்னுரை: 2011 மார்ச்சு மாதம் 11 ஆம் தேதி ஜப்பான் கிழக்குப் பகுதியைத் தாக்கிய 9 ரிக்டர் அளவு அசுர நிலநடுக்கத்தில் கடல் நடுவே 50 அடி (14 மீடர்) உயரச் சுனாமி எழுந்து நாடு, நகரம், வீடுகள், தொழிற்துறைகள் தகர்ந்து போயின.  சுமார் 10,000 பேர் உயிரிழந்தனர்.  மேலும் 17,000 பேர் இன்னும் காணப்பட வில்லை.  சுமார் 80,000 பேர் புலப்பெயர்ச்சி செய்யப் பட்டுள்ளார். புகுஷிமா வின் நான்கு அணுமின் உலைகளின் எரிக்கோல்கள் வெப்பத் தணிப்பு நீரின்றி, பேரளவு சிதைந்து, ஹைடிரஜன் வாயு சேமிப்பாகி வெளியேறி மேற்தளக் கட்டங்கள் வெடித்தன.  அத்துடன் ஒன்று அல்லது இரண்டு அணு உலைக் கோட்டை அரணில் பிளவு ஏற்பட்டுக் கதிரியக்கப் பிளவுத் துணுக்குகள் (Radioactive Fission Products) சூழ்வெளியிலும், கடல் நீரிலும் கலந்தன.  அந்தப் பேரிழப்பால் பல்லாயிரம் பேர் உயிரிழந்தும் பிழைத்துக் கொண்டோர் வீடிழந்தும், தமது உடமை இழந்தும், சிலர் கதிரியக்கத்தாலும் தாக்கப்பட்டார்.  நான்கு  அணுமின் உலை களில் பெருஞ் சேதம் ஏற்பட்டதால் ஜப்பான் நாட்டில் 2720 மெகா வாட் அணு மின்சக்தி (MWe) உற்பத்தி குன்றி அண்டை நகரங்களில் பேரளவு மின்வெட்டுப் பாதிப்புகள் நேர்ந்துள்ளன.

உலக நாடுகள் 21 ஆம் நூற்றாண்டில் அணுமின் நிலையங்களை ஒரு தேவையான தீங்கு எரிசக்திக் கூடங்கள் என்று கருதியே இயக்கி வருகின்றன.  ஐயமின்றிப் பேரளவு மின்சாரத்தைச் சிறிய இடத்தில் உற்பத்தி செய்ய அணுசக்திக்குப் போட்டியான, நிகரான ஓர் எரிசக்தி தற்போதில்லை.  ஒரு மோட்டார் காரை உற்பத்தி செய்ய சுமார் 10,000 யந்திரச் சாதனங்கள், உபகரணங் கள் தேவைப்படு கின்றன.  அதுபோல் ஓர் அணுமின்சக்தி நிலையத்தை அமைத்து இயக்க மில்லியன் கணக்கில் யந்திரச் சாதனங்கள், உபகரணங்கள் அவசியம் தயாரிக்கப்பட வேண்டும்.  மின்சாரத்தைப் பரிமாறுவதோடு இந்த யந்திர யுகத்தில் பாதுகாப்பாய் இயங்கி வரும் பல்வேறு அணுமின் நிலையங்களால் மில்லியன் கணக்கில் பலருக்கு வேலையும், ஊதியமும், நல்வாழ்வும் கிடைத்து வருகின்றன.

கட்டுரை ஆசிரியர்

தற்போது முப்பதுக்கு மேற்பட்ட உலக நாடுகளில் 447 அணுமின் நிலையங்கள் [அமெரிக்காவில் திரி மைல் தீவு, ரஷ்யாவில் செர்நோபில் நிலையம், ஜப்பானில் புகுஷிமாவின் நான்கு அணுமின் உலைகள் ஆகியவற்றைத் தவிர] பாதுகாப்பாக இயங்கி சுமார் 370,000 MWe (16%) மின்சார ஆற்றலைப் பரிமாறி வருகின்றன.  மேலும் 56 நாடுகளில் 284 அணு ஆராய்ச்சி உலைகள் அமைப்பாகி ஆய்வுகள் நடத்தப் பட்டு வருகின்றன.  அணு மின்சக்தி நிலையங்கள் 1950 ஆண்டு முதல் தோன்றி மின்சாரம் அனுப்பத் துவங்கிய பிறகு தொடர்ந்த 60 ஆண்டு களில் ஆறு பெரிய கதிரியக்க விபத்துகள் நிகழ்ந்துள்ளன.  2011 ஆண்டு மார்ச்சு வரை உலக அணு உலைகளில் சராசரி 10 ஆண்டுக்கு ஒருமுறை ஒரு பெரு விபத்து நேர்ந்திருக்கிறது !  ஜப்பான் புகுஷிமா அணு உலைகள் விபத்துக்குப் பிறகு எதிர்கால அணுமின்சக்திக்கு உலக நாடுகள் இன்னும் ஆதரவு அளிக்கின்றனவா அல்லது எதிர்ப்பு அறிவிக்கின்றனவா என்பதை விளக்கமாய் ஆராய்வதே இந்தக் கட்டுரையின் குறிக்கோள்.

உலக அணு மின்சக்தி இயக்கக் கண்காணிப்புக் கூட்டுப் பேரவை [ WANO -World Association of Nuclear Operators ] விதித்த மேம்பாடு நெறி முறைகள்

2011 புகுஷிமா பெரு விபத்துக்குப் பிறகு, பாடங்கள் கற்று நான்கில் ஒரு தலையகமாக இருக்கும் இங்கிலாந்து லண்டன்  வானோ பேரவையில் வடிக்கப்பட்ட மேம்பாட்டு நெறிப்பாடுகள் கீழே தரப்பட்டுள்ளன.  அவை சிக்கலானவை, சிரமமானவை, சவாலானவை.  அவற்றை நிறைவேற்ற மிக்க நிதிச் செலவும், நேரச் செலவும் ஏற்படும். அவற்றுக்கு மெய் வருந்திய உழைப்பும், குறிப்பணியும் அவசியம் என்று, அவற்றை வெளியிட்ட வானோ ஆளுநர், பீட்டர் புரோசெஸ்கி சொல்கிறார்.

  1.  புகுஷிமா விபத்தில் கற்றுக் கொண்ட பாதுகாப்புப் பாடப் பணிகள் உலக முழுமையாக சுமார் 6000.
  2. அவற்றுள் முக்கியமானவை :  அபாய நிகழ்ச்சி காப்பு வினைகள்,  அபாய நிகழ்ச்சி உதவிகள், அபாய நிகழ்ச்சி பராமறிப்பு வினைகள், அபாய நிகழ்ச்சி அறிவிப்பு முறைகள், கதிரியக்க திரவம் சேமிப்புக் கலன்கள், பயிற்சி பெற்ற ஏராளமான பணியாளர், தோழ நாடுகள் முதல் உளவு, அடுத்த உளவு, முழு உளவு, ஆய்வு அறிக்கை வெளியீடு. வானோ உலக நாட்டு உளவு & அறிக்கை வெளியீடு.

As of November 28, 2016 in 31 countries 450 nuclear power plant units with an installed electric net capacity of about 392 GW are in operation and 60 plants with an installed capacity of 60 GW are in 16 countries under construction.

Country
IN OPERATIONUNDER CONSTRUCTION
NumberElectr. net output
MW
NumberElectr. net output
MW
Argentina31.632125
Armenia1375
Belarus22.218
Belgium75.913
Brazil21.88411.245
Bulgaria21.926
Canada1913.524
China3631.4022020.500
Czech Republic63.930
Finland42.75211.600
France5863.13011.630
Germany810.799
Hungary41.889
India226.22552.990
Iran1915
Japan4340.29022.650
Korea, Republic2523.13334.020
Mexico21.440
Netherlands1482
Pakistan41.00532.343
Romania21.300
Russian Federation3626.55775.468
Slovakian Republic41.8142880
Slovenia1688
South Africa21.860
Spain77.121
Sweden109.651
Switzerland53.333
Taiwan, China65.05222.600
Ukraine1513.10721.900
United Arab Emirates45.380
United Kingdom158.918
USA9998.86844.468
Total450391.9156059.917

Nuclear power plants world-wide, in operation and under construction, IAEA as of 27 November 2016

அணுமின் உலைகள் எதிர்காலம் பற்றி அகில நாடுகளின் தீர்மானங்கள்

புகுஷிமா அணுமின் உலைகளில் நேர்ந்த வெடிப்பு நிகழ்ச்சிகளை நேரடியாகக் கண்டு பயந்து போன ஆயிரம் ஆயிரம் பொது மக்களின் வெறுப்பும், எதிர்ப்பும் வேறு.  அணுசக்தி உற்பத்தி மீது அகில நாட்டு அரசுகளின் ஆதரவும், முடிவும் வேறு !  பொது மக்கள் பல்லாண்டுகள் ஒரு மனதாய் அவற்றை எதிர்த்தாலும் இப்போது உலக நாடுகளில் இயங்கிக் கொண்டிருக்கும் 440 அணுமின் நிலையங்கள் உடனே நிறுத்தம் அடையப் போவ தில்லை.  இப்போது (ஜூன் 14, 2011) கட்டப்பட்டு வரும் அணுமின் உலைகளின் எண்ணிக்கை : 60.  அடுத்துத் திட்டமிடப் பட்டவை : 155.  எதிர்கால எதிர்ப்பார்ப்பு அணுமின் உலைகள் : 338.  புகிஷிமா அணு உலை விபத்தில் கற்றுக் கொள்ளும் முதற்பாடம் : 1960 ஆண்டுகளில் டிசைன் செய்யப் பட்ட முதல் வகுப்புப் பிற்போக்கு அணுமின் உலைகள் விரைவில் நிச்சயம் மூடப்படும் நிரந்தரமாய்.  முப்பது வருடமாய் இயங்கி வரும் அணுமின் உலைகள் சில மீளாய்வு செய்யப் பட்டுப் பழைய சாதனங்கள் புதுப்பிக்கப் பட்டு ஆயுட் காலம் இன்னும் 5 அல்லது 10 ஆண்டுகள் நீடிக்கப் படலாம் அல்லது அதற்கு நிதியின்றேல் நிரந்தரமாய் நிறுத்தம் அடையலாம்.

  1. https://youtu.be/CPeN7GhTpz4
  2. https://www.thegreenage.co.uk/cos/nuclear-power-in-france/
  3. https://youtu.be/4YgmCu7dfS4
  4. https://www.dw.com/en/france-sticking-with-nuclear-power/av-38397323
  5. https://www.businessinsider.com/countries-generating-the-most-nuclear-energy-2014-3
  6. https://www.youtube.com/watch?v=TZV2HRKNvao
  7. https://www.youtube.com/watch?v=HMrQJoN-Ks4
  8. https://www.youtube.com/watch?v=kr4mFLws3BM
  9. https://www.youtube.com/watch?v=YfulqRdDbsg
  10. https://www.youtube.com/watch?v=Hn-P3qnlB10
  11. https://www.world-nuclear.org/information-library/safety-and-security/safety-of-plants/safety-of-nuclear-power-reactors.aspx
  12. https://www.eurekalert.org/pub_releases/2019-11/pp-nrw112519.php
  13. http://theconversation.com/nuclear-power-is-set-to-get-a-lot-safer-and-cheaper-heres-why-62207
  14. http://nuclearsafety.gc.ca/eng/reactors/power-plants/nuclear-power-plant-safety-systems/index.cfm
  15. https://alternativeenergy.procon.org/questions/is-nuclear-power-safe-for-humans-and-the-environment/
  16. https://en.wikipedia.org/wiki/Environmental_impact_of_nuclear_power

++++++++++++++++++++++++

S. Jayabarathan [jayabarathan.wordpress.com/ March 15, 2020 [R-4]

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