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Cables in radioactive environments
Requirements, materials and resistance
Cables in radioactive environments must withstand extreme loads. In addition to classic influences such as temperature and chemicals, ionising radiation also affects materials. For operators of systems – for example, in nuclear technology, medical technology or research – selecting suitable cables is essential for safety, service life and operating costs.
What is radioactive radiation?
Radiation is the propagation of energy in the form of particles or electromagnetic waves. In technical applications, a distinction is mainly made between three types of radiation:
- Alpha radiation
- Beta radiation
- Gamma radiation
The radiation dose is crucial for assessing the load on the material. It describes the energy absorbed per unit mass and is specified in the following units:
- Gray (Gy) – physical dose
- Sievert (Sv) – biological effect
- Rad (Rd) – obsolete unit
The higher the dose and the longer the exposure time, the greater the effect on materials such as cable jackets and core insulation.
Open CT scanner in which cables are lightly exposed to radioactive radiation.
Requirements for cables in radioactive areas
In radioactive environments, particularly high demands are placed on electrical cables:
- High radiation resistance
- Defined, long service life
- Mechanical stability despite radiation exposure
- Minimising maintenance intervals
Premature cable failure can not only cause production downtime but also necessitate dangerous maintenance work in loaded areas. That's why durable, reliable cable solutions are essential.
Practical tests show that cables can be specially designed for defined radiation doses. Different materials were investigated in a test with a load of 10⁶ Gray. It turned out that both the jacket material and the core insulation are crucial for overall performance.
How does radiation affect cables and plastic?
Radioactive radiation mainly affects plastic, which is used in cables as a jacket or insulation material.
Typical effects:
- Break-up of molecular chains
- Material hardening
- Embrittlement
- Pore formation
- Crack formation up to jacket damage
Over the long term, these changes lead to malfunctions and can shut down entire systems.
Basic rule:
The more stable and longer the molecular chains of a plastic, the better its resistance to radioactive radiation.
Comparing radiation-resistant cable materials
Choosing the right material is crucial for successful use in nuclear or radiation-exposed areas.
Overview of radiation resistance:
| Material | Radiation resistance | Suitability |
|---|---|---|
| PVC | approx. 10 Mrad | Low |
| TPE | approx. 15 Mrad | Restricted |
| PUR | approx. 100 Mrad | Very high |
