Nuclear power plant cables

There are two classification methods for nuclear power plant cables: one is based on function, including measurement cables, communication cables, instrument cables, fire-resistant cables (silicon insulated cables), etc; Another approach is to classify based on security levels,Nuclear power plant cablesThe safety level belongs to IE level, and it should have a service life of more than 40 years. IE level nuclear power plant cables are divided into three safety levels: K1, K2, and K3. The development process of nuclear power plant cable products is essentially the upgrading of materials, the selection of cable types and raw materials.

Cable characteristics:

1. Low smoke performance

Nuclear power plant cablesThe insulation and sheath materials must be low smoke, non-toxic, and non corrosive halogen-free flame-retardant cables, such as thermoplastic flame-retardant halogen-free or cross-linked flame-retardant halogen-free materials, in order to meet special nuclear safety requirements. When halogen-free cables catch fire, the amount of smoke released during combustion is very low, and they are not toxic or corrosive. Their flame retardant components can effectively play a flame retardant role and will not make the cable a channel for flame spread. The main technical characteristics of halogen-free flame-retardant cables are: (1)Nuclear power plant cablesThe total cumulative amount of smoke Dm<150; (2) Non toxic and corrosive, that is, the cable does not release HCI and CO during combustion; (3) it has flame retardancy, and the flame retardancy of polymers is usually evaluated by the oxygen index (0I) method, generally OI ≥ 28.

2. Environmental resistance

The materials used for nuclear power plant cables must have environmental resistance, including heat resistance, radiation resistance, and LOCA resistance.
(1) Heat resistance is due to the fact that nuclear power plant cables often operate in high-temperature environments,High temperature cable.Therefore, they need to have long-term heat resistance performance, and polymers with heat resistance that meet the requirements should be selected, which can give the cable a service life of more than 40 years.
(2) Radiation resistance (mild environment, harsh environment)Nuclear power plant cablesWhen exposed to a large amount of radiation, insulation and sheath materials become brittle and their mechanical properties deteriorate. Therefore, as insulation and sheath materials for nuclear power plant cables, they must have excellent radiation resistance. Various high polymers have different radiation resistance properties. People usually add anti radiation agents to polymers to improve their radiation resistance.
(3) In LOCA resistant nuclear power plants, loss of coolant accidents (LOCA) and high-energy tube rupture accidents (HELB) are commonly referred to as LOCAs. When a LOCA/HELB occurs, the cable will be subjected to the impact of high-temperature and high-pressure steam and corrosive chemical agents, and will be subjected to higher doses of radiation than under normal operating conditions. Therefore, nuclear power plant cables should have resistance to LOCA.