New energy cable (Usually refers to special cables with high and low temperature resistance, radiation resistance, high insulation, low smoke and halogen-free characteristics) The application in the nuclear energy field is mainly focused on Power transmission, signal control and equipment connection of nuclear power plant And other key links, especially in the scenario of the integration of new energy and nuclear power (such as the new energy power station supporting the nuclear power plant, the power system of nuclear powered ships/devices). Its application needs to meet the stringent safety standards in the nuclear field (such as radiation resistance, high temperature resistance, fire and explosion protection). The specific application scenarios and characteristics are as follows: The nuclear island is the core area of the nuclear power plant (including reactors, pressure vessels, etc.), and the environment has Strong radiation, high temperature, high humidity And potential chemical corrosion (such as boric acid solution), which requires extremely high radiation resistance and insulation stability of cables:
Reactor cooling system : in new energy cables Radiation resistant cross-linked polyethylene (XLPE) cable or EPR cable The power transmission used to connect main pumps, valves and other equipment shall withstand γ - ray radiation dose ≥ 500kGy (about 10-20 times that of conventional cables), and operate stably for a long time at 120-150 ℃ (to avoid insulation aging).
Control loop inside containment : Adopted LSZH cable It is used for signal transmission of reactor emergency shutdown system and safety injection system. Even in case of fire (temperature ≥ 900 ℃), it can still maintain the circuit integrity for 1-3 hours (in accordance with IEC 60331 standard), and does not release toxic gas (to protect personnel and equipment) during combustion.
The environment of conventional island (steam turbine, generator and other equipment areas) is relatively mild, but it needs to meet the requirements of high power transmission and fire prevention:
Connection between generator and transformer : Using High voltage new energy cable (such as 110kV and above cross-linked polyethylene cables), with low loss and high current carrying characteristics, it is suitable for large capacity power output of nuclear power plants (the power of a single unit can reach more than 1000MW).
Auxiliary building power cable : Adopted Flame retardant PVC or cross-linked polyolefin cable It is used for power supply of auxiliary equipment such as water pump and fan, meeting the requirements of general fire protection (flame retardant class C and above) and temperature resistance (90-105 ℃), and its cost is lower than that of special cable for nuclear island.
With the promotion of the integration mode of "nuclear+new energy" (such as photovoltaic and energy storage power plants supporting nuclear power plants), new energy cables play a key role in cross system connection:
The supporting photovoltaic power stations and wind farms around the nuclear power plant need to connect the power to the nuclear power plant grid or public grid through cables, and at this time, it is necessary to use Weather resistant new energy cable (e.g Overhead insulated cable Or armored cable), which is resistant to outdoor ultraviolet radiation, high and low temperature cycles (- 40 ℃ to 70 ℃) and wind and sand erosion, and has lightning strike resistance and corrosion resistance (coastal nuclear power plants need salt spray protection).
In order to stabilize the output fluctuation of the nuclear power plant, the supporting energy storage plant (such as lithium battery energy storage and flywheel energy storage) needs to be connected to the power distribution system of the nuclear power plant through cables Flexible new energy cable (such as silicone rubber cable), which is suitable for frequent charging and discharging cycles of energy storage equipment, and has the characteristics of vibration resistance and chemical corrosion resistance (battery electrolyte).
In mobile or special environments such as nuclear powered ships (such as nuclear powered aircraft carriers and nuclear submarines), deep-sea nuclear power platforms, new energy cables have more advantages in lightweight, vibration resistance and impact resistance:
Nuclear ship power system : Adopted Thin wall insulated new energy cable (The thickness of insulation layer is 30% - 50% less than that of conventional cables), realizing high power transmission in limited space, and withstanding continuous vibration (vibration frequency 10-1000Hz) and seawater immersion (waterproof grade IP68) during ship navigation.
Deep sea nuclear power platform : The cable needs to withstand deep sea high pressure (for example, the water depth of 1000m corresponds to 10MPa pressure) and low temperature (0-10 ℃) Armored reinforced new energy cable (The outer layer is wrapped with stainless steel or titanium alloy armor) to prevent mechanical damage, and the insulation materials (such as PTFE) still maintain insulation performance under high voltage.
The performance requirements for cables in the nuclear field are far higher than those in ordinary industrial scenarios, and the core indicators include:
Radiation resistance : γ ray radiation dose tolerance ≥ 250kGy (nuclear island), ≥ 50kGy (conventional island), to avoid the degradation of insulation materials caused by radiation (such as polymer molecular chain breakage).
High temperature resistance and fire prevention : The nuclear island cable shall be able to withstand the high temperature above 120 ℃ for a long time, 900-1200 ℃ for a short time (fire), and meet the requirements of "circuit integrity" (GB/T 19216).
Low smoke, halogen-free and environmental protection : Cables in the nuclear island and control area shall meet the low smoke zero halogen standard (smoke density ≤ 75%, halogen acid gas release ≤ 0.5%) to avoid secondary pollution in case of accidents.
mechanical strength : Anti vibration and anti impact (for example, nuclear ship cables need to pass the 1000g acceleration impact test), and armored cables need to withstand mechanical rolling and abrasion.
prospect : With the growth of the global nuclear power installation (it is estimated that the global nuclear power will account for more than 15% in 2030) and the promotion of the "nuclear+new energy" model, the demand for new energy cables in the nuclear field will continue to increase, especially in the third-generation/fourth generation nuclear power plants (such as AP1000, HPR1000), the demand for high reliability, long-life (design life of more than 60 years) cables is more urgent.
Challenge : It is necessary to break through the material technology in extreme environments (such as insulation materials resistant to 1000kGy radiation), reduce the manufacturing cost of long-life cables, and meet the differentiated requirements of national nuclear power safety standards (such as the NRC of the United States and EURATOM of the European Union).
The application of new energy cables in the field of nuclear energy Nuclear island key system, conventional island power transmission, new energy coordination system As the core, its core value is to meet the requirements of "high safety, high reliability and strong tolerance" of nuclear energy environment. With technological progress, the new new energy cable with ultra-high temperature resistance, ultra strong radiation resistance and long life will further promote the deep integration of nuclear energy and new energy, and become the key component to ensure the safe and stable operation of nuclear energy system.
