Cable for nuclear power station

Cables for nuclear power plant All kinds of wires and cables under special environment of nuclear power plant.

Types of cables for nuclear power plants

Nuclear power station cable refers to the raw materials used for the insulation and sheath of nuclear power station cable, including plastic, rubber and other varieties.  The type of cable is determined by the type of cable. There are two classification methods for cables in nuclear power plants: one is classified according to function, including measuring cables, communication cables, instrument cables, fireproof cables (silicon insulated cables), etc;  The other is that according to the safety level, the safety level of cables for nuclear power plants is IE, and they should have a service life of more than 4 years. The safety level of cables for IE nuclear power plants is divided into K1, K2 and K3,3.   The development process of cable products in nuclear power plants is essentially the upgrading of materials.

Characteristics of cables for nuclear power plants

1、 Low smoke performance:    the insulation and sheath materials of cables used in nuclear power plants must be low-smoke, non-toxic, non-corrosive halogen-free flame retardant cables, such as thermoplastic flame retardant halogen-free or cross-linked flame retardant halogen-free materials,  To meet special nuclear safety requirements. In case of fire, the amount of smoke released from the combustion of halogen-free cable is very low, without toxicity and corrosivity, and its flame retardant component can effectively play the role of flame retardant,  The cable will not become a channel for flame spread. The main technical characteristics of halogen-free flame-retardant cable include: (1) the total accumulated amount of cable smoke for nuclear power station Dm<150; (2) Non-toxicity and corrosivity,  That is, HCI and CO will not be released during cable combustion; (3) It has flame retardancy. The flame retardancy of the polymer is usually evaluated by the oxygen index (0I) method, with OI ≥ 28 generally.    2、 Environmental resistance:    Materials used for cables in nuclear power plants must have environmental resistance, namely heat resistance, radiation resistance and LOCA resistance.  (1) Heat-resistance Because nuclear power station cables often work in high temperature environment, high temperature cables. Therefore, they need to have long-term heat resistance performance. Polymers that meet the requirements of heat resistance should be selected, and the cable should have a service life of more than 40 years.  (2) Irradiation resistance (mild environment, harsh environment) When cables used in nuclear power plants are exposed to a large amount of radiation, the insulation and sheath materials will become brittle and the mechanical properties will become poor. Therefore, as the insulation and sheath materials for cables in nuclear power plants, they must have excellent radiation resistance. Different polymers have different irradiation resistance. People usually add anti-irradiation agent to the polymer to improve its anti-irradiation performance.  (3) In LOCA-resistant nuclear power plants, coolant loss accident (LOCA) and high energy line break (HELB) are generally referred to as LOCA. In case of LOCA/HELB, the cable will be impacted by high-temperature and high-pressure steam and corrosive chemicals, and will be exposed to higher dose of radiation than normal operation. Therefore, the cable of nuclear power plant shall have LOCA resistance.