The first question that comes to mind when it comes to nuclear power plants in geographies such as Turkey. Nuclear plants are designed, built and supervised according to the stricter and uncompromising mistic safety standards than traditional housings, bridges or industrial factories.
According to the international Atomic Energy Agency (IAEA) norms, a nuclear reactor is subject to engineering accounts in order to withstand the most severe space movement, even beyond the largest earthquake recorded in the region.
How to design nuclear power plants as seismic?
The philosophy of seismic design of nuclear power plants is based on two main earthquake levels:
- Operating Basic Earthquake - OBE: The earthquake size, which is likely to occur throughout the life of the plant and can continue to produce electricity safely without any damage to the plant.
- Safe Shutdown Earthquake - SSE: It is the most severe possible earthquake that may occur as a result of geological and sismological research in the region. The power generation in a yellowish at this level stops immediately; but the functions of safe closure of the reactor heart, uninterruptedly maintain cooling and radioactivity in the reactor container work complete.
| Parameter | Standard Housing / Industrial Structure | Nuclear Power Plant |
|---|---|---|
| Design Earthquake Period | Usually 475 - 2.475 years | 10,000 years and uniform Home |
| Targeted Status | Providing the safety of the can (conceptable) | Protection of zero radioactive leakage and critical cooling |
| Basic Design | Surfaceal or pile base | Several meters thick solid reinforced concrete radiant plate |
| Automatic Closure | No | SCRAM in milliseconds with precision seismic accelerations |
| Spare Cooling Systems | No | 4 times independent, physically separate emergency line |
What happens in the reactor instantly on Earthquake? Automatic SCRAM system
When the seismic acceleration threshold set in a nuclear power plant field is exceeded, automatic protection systems are activated without the need for human intervention:
- Cystic Sensors Detect: Multi-point mistmic sensors on the field instantly analyze the floor movement.
- SCRAM (Fast Shut Off) Trigger: Reactor control bars (neutron hysterone boron or cadmium alloy rods) in seconds with the help of gravity and pneumatic pushers in the reactor heart.
- Fision Stops: Chaining filament response ends completely in 2-3 seconds.
- Now Heat Relief Heads: If the chain reaction stops, the "waste heat" caused by radioactive degradation is safely removed through passive cooling pools that work with diesel generators or gravitation.
How long is Akkuyu NGS earthquake resistant?
Akkuyu Nuclear Power Plant is built in Mersin Gulnar region on the Mediterranean coast, where the most safe and fay density of Turkey is lowest.
- Field Selection: The site is located in the historical center of Anatolia and North Anatolia.
- Floor Fire Design: The design of Akkuyu NGS is made by adding at least two times of the maximum earthquake acceleration (PGA) which can take place in the field of 10.000 years (0.4g design acceleration).
- Double Layer Protection Shell (Containment): The reactor building is surrounded by 1.2 meters and 1.5 meters thickness two separate front-stressed concrete protection shells against aircraft crash, tsunami and severe shakes that may arise from outside.
- 6 February 2023 Earthquake Experience: The central base has been recorded in 7.7 and 7.6-sized earthquakes that are Kahramanmaraş and affect 11-based earthquakes, an approximately 3-sized light wind was recorded; the facility has been confirmed by independent audits in no construction and equipment.
Seismic defense depth in nuclear security
No system will rely on a single barrier by the principle of "Savunma Depth" (Defence in Depth) applied in nuclear engineering:
- First Barrier: The own physical structure of ceramic fuel pellets.
- Second Barrier: Zirconia alloy sealed fuel case (cladding) without pilling fuel pellets.
- Third Barrier: thick high strength steel reactor pressure container from 20 centimeters.
- Fourth Barrier: Double layer reactor protection shell consisting of meters thickness steel and concrete.
- Fifth Barrier: Located under the reactor, cor holder (Core Catcher) from aggressive heart pilling in extreme cases.
All of these physical barriers are calculated in the limits of flexibility and strength that will dampen severe seismic shock waves.
Frequently asked questions
How to chill the reactor if the earthquake is cut into electricity instantly?
Modern 3+ Generation (Gen-III+) has Passive Security Systems in reactors. Even if electrical, pump or operator intervention is completely disabled, water pools that work with gravitational, natural convection and evaporation principles can cool the reactor without interruption for at least 72 hours.
How to protect nuclear power plants from tsunamiye?
The maximum wave height, which can create possible submarine earthquakes and halves in the plants built on the coast. The resort area is installed on a high jeans from sea level and built seismic waves along the beach.
Can a nuclear power plant explode due to earthquake?
Nuclear reactors can not explode as nuclear bombs due to physical properties. The biggest risk that may occur due to earthquake is insufficient; multi-layer passive cooling and hydrogen eliminators in today’s reactors minimize this risk.
Resources
- IAEA, Site Review for Nuclear Installations (Specific Safety Guide No. SSG-9 Rev. 1).
- Nuclear Regulation Authority (NDK), Akkuyu Nuclear Power Plant Security Evaluation Reports.
- World Nuclear Association (WNA), Power Plants and Earthquakes: https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/nuclear-power-plants-and-earthquakes.aspx