SafetySafety is the top priority throughout the NPP life cycle — from siting and design to operation and decommissioning.
Defence in depthIAEA standardsIndependent state oversight
How NPP safety is ensured
NPP safety rests on two pillars: the responsibility of the operator who designs, builds and operates the plant, and independent state control that verifies every decision.
“1+2” marks topics that concern both the plant and the regulator: each has two separate texts — what the plant does and what the state verifies.
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What the operator (KNPP) does
Defence in depth
Several independent levels of protection: if one fails, the next one takes over.
Defence in depth is the foundation of safety at every modern NPP. It combines physical barriers and organisational measures.
Physical barriers against radioactive substances:
1. The fuel pellet retains most fission products.
2. The sealed fuel rod cladding.
3. The reactor vessel and the primary coolant circuit.
4. The containment — a reinforced concrete building designed for internal pressure and external impacts.
Levels of protection:
• preventing deviations from normal operation;
• detecting and correcting deviations;
• controlling design-basis accidents;
• managing beyond-design-basis accidents and mitigating their consequences;
• protecting the public outside the site.
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What the operator (KNPP) does
Emergency cooling systems
Active and passive systems remove heat from the reactor even during a total loss of power.
After shutdown the fuel keeps producing decay heat, so it must be reliably cooled.
• Active systems — emergency cooling pumps with independent trains and back-up diesel generators.
• Passive systems — hydro-accumulators, passive heat removal via steam generators and the containment; they rely on physics (gravity, natural circulation) with no operator action or external power.
• Core catcher — a device under the reactor that retains and cools molten core material in a severe accident.
In Generation III+ reactors this combination provides up to 72 hours of autonomous cooling without operator intervention.
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What the operator (KNPP) does
Physical protection
Multi-layer protection of the site, nuclear materials and information systems.
Physical protection prevents unauthorised access, theft of nuclear material and sabotage.
• A guarded perimeter with access zones and engineered barriers.
• Access control, screening and monitoring of personnel and cargo movement.
• CCTV and intrusion alarms with round-the-clock monitoring.
• Cyber security of control systems: isolation of critical networks.
• Nuclear material accounting and control under IAEA safeguards.
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What the operator (KNPP) does
Seismic safety
The plant is designed with a safety margin against the maximum credible earthquake for the site.
Seismic safety starts with site selection: tectonic faults, earthquake history and soil properties are studied.
• A maximum design earthquake is defined for the site and all safety-related structures are designed for it with a margin.
• Seismic sensors on site automatically shut down the reactor if ground motion exceeds a set level.
• Equipment undergoes seismic qualification — tests and calculations of vibration resistance.
• Seismic monitoring of the area is carried out before construction and throughout operation.
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What the operator (KNPP) does
Protection against external hazards
Natural and man-made hazards are considered — from hurricanes and floods to an aircraft crash.
NPP buildings and systems are designed for the external hazards typical of the site area:
• extreme temperatures, hurricane winds, tornadoes, snow loads;
• flooding and water-level changes;
• aircraft crash, external explosions and fires;
• loss of off-site power and cooling water.
The Generation III+ containment is designed to withstand the crash of a large aircraft. Back-up power and water sources are provided for each hazard.
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Emergency planning
Readiness for any emergency is the plant’s duty; verifying that readiness is the state’s task.
What the plant (KNPP) does
• An on-site plan to protect personnel and accident response procedures.
• The plant emergency centre and protected control points.
• Regular emergency drills for shift crews and exercises with external services.
• Stocks of personal protective equipment and mobile equipment to supply water and power.
• Prompt notification of authorities and the public.
What the regulator verifies
• The regulator approves the plant’s emergency plans and reviews them during licensing.
• State bodies (Ministry of Emergency Situations, local authorities) prepare public protection plans for the planning zone.
• Joint exercises of the plant, regulator and response services are held and their results published.
• Kazakhstan is party to the IAEA conventions on early notification and assistance in the event of a nuclear accident.
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Radiation monitoring
The radiation situation is monitored twice: by the plant itself and by an independent state monitoring system.
What the plant (KNPP) does
• An automated radiation monitoring system on site, in the sanitary protection zone and the surveillance zone.
• Control of airborne and liquid discharges; individual dosimetry for personnel.
• Sampling of air, water, soil and food around the plant.
• Real-time data is planned to be published on the website.
What the regulator verifies
• Independent state radiation monitoring is carried out by authorised bodies that do not depend on the plant operator.
• The regulator sets permissible discharge limits and checks compliance.
• State monitoring results are published and can be compared with the plant’s data.
• Data is shared with IAEA international information exchange systems.
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What the state and the regulator control
International standards
Compliance with IAEA standards is confirmed by independent review and state licensing — not by the operator’s own statement.
The design and operation of NPPs in Kazakhstan must comply with national law and IAEA safety standards.
• Licensing: the regulator issues separate licences for siting, construction and operation — after document review and inspections.
• IAEA missions: independent international peer-review missions (e.g. SEED for site evaluation, INIR for infrastructure, OSART for operational safety).
• Conventions: Kazakhstan is party to the Convention on Nuclear Safety and the Joint Convention on the Safety of Spent Fuel and Radioactive Waste Management.
• Reporting: results of inspections and missions are published.
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This section was moved from
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About KNPP
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Safety
NPP Safety
About the safety of modern nuclear reactors: Modern reactor plant designs use defense in depth to prevent the release of radioactive materials into the environment. Defense in depth is achieved by combining multiple sequential and independent layers of protection that must fail before radiation can cause harm to the public or the environment. The design of such nuclear reactor systems incorporates a series of physical barriers and a combination of active, passive, and inherent safety features to ensure that the physical barriers to nuclear material proliferation are effective. Thanks to the combination of active and passive safety systems, generation III and III+ reactors can achieve emergency autonomy of up to 72 hours. In other words, in the event of a major accident, the reactor can cool down within 3 days without the intervention of operating personnel. In addition, when developing modern reactors, the probabilities of beyond design basis accidents are analyzed. For example, some reactor buildings can be designed to withstand Category 3 hurricanes.
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This section was moved from
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Nuclear Energy
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Safety of Modern NPPs: Nuclear, Radiation and Physical Protection
Modern nuclear power plants are high-tech facilities where safety is a priority principle of design, construction and operation.The risk of an accident does not exceed 1:10 million per year. The resilience of modern designs can withstand earthquakes up to magnitude 9.According to IAEA data, the risk of serious accidents at modern reactors is extremely low and continues to decrease thanks to strict regulation and innovation.
Nuclear safety is aimed at preventing accidents and controlling the chain reaction. Modern reactors have up to four protection barriers: fuel matrix, fuel cladding, hermetic reactor vessel and protective shell.
Radiation safety is aimed at minimizing radiation doses for workers, the public and the environment.
The effective dose for NPP personnel does not exceed 20 mSv per year, and for the public — less than 1 mSv/year above natural background.
Globally, according to the World Nuclear Association, the radiation background from NPPs is comparable to natural background from space and soil.
Nuclear physical security covers measures against terrorism, theft of nuclear materials and unauthorized access to them. Unlike nuclear safety (accident prevention), it is focused on threats related to human activities.
Modern nuclear power plants demonstrate a high level of safety due to multi-level systems, strict regulation and continuous improvement. NPP safety is a combination of national norms, technologies, human factors and international standards, providing reliable protection without compromise for human health and the environment.
