PEEK - Robust Enough for Nuclear Applications

Among the most rigours manmade environments ever created, the inside of a nuclear reactor would probably rate high on the list. The process that allows the reactor to generate the kind of energy we need is not only complex in theory but poses huge practical hurdles when it comes to containment and durability.

Apart from the energy release, nuclear reactions also give off radiation – most notably gamma radiation – which most standard materials are unable to withstand. Gamma radiation causes other materials to get ionised, which in turn makes them hazardous for human exposure. It also accelerates the degradation of materials, causing brittleness and fractures that can increase the likelihood of leaks and failures.

PEEK has long been known as a polymer with unparalleled strength. We have compared earlier the tensile strengths, tensile modulus, heat resistance and chemical resistance of PEEK. In addition to this, the material can reach strengths comparable with metals, when used with the right kinds of fillers. Adding to this list is the capability of PEEK to dwell within high-radiation environments without suffering any significant losses in properties.

Studies have shown that when exposed to the harsh environments seen within the nuclear reactor chamber, PEEK is able to survive over an extended period, where other materials would easily fail. Most notably, the effect of gamma radiation on PEEK is low, meaning that PEEK becomes the material of choice for a host of applications within the nuclear reactor.

1. PEEK Seals
   The performance of seals to contain liquids that flow within the reactor is of utmost importance. Most materials would suffer from brittleness and deformation when subjected to radiation and heat from this system. PEEK seals have been shown to hold their shape over time and tests show that the hardness and crystallinity of the material is not severely affected by the conditions.

2. PEEK linings
   Vats and chambers within the nuclear reactor have relied traditionally on using linings made from heavy metals such as lead and titanium. This is both expensive and makes the process of holding and disposing of nuclear waster very cumbersome. PEEK linings have been shown to be very effective in containing radiation. It is possible to make thinner walled tanks and have them lined or coated with a thin layer of PEEK.

3. PEEK Valves, Plates and Nozzles
   Given the quantum of fluids within the reactor, PEEK is now replacing many of the standard valves, plates and nozzles to ensure that key components within the system do not fail. PEEK is both highly machinable and injection mouldable. Further, PEEK can be 3D printed to create specialised shapes that fit perfectly within an existing system. This versatility lends itself both to precision components needed within the system during construction of the nuclear reactor as well as specialised parts that may be required for maintenance, reinforcement and/or damage control once the reactor is already operational.

As the field expands, new applications of PEEK within the nuclear space are constantly being discovered. Given we know that PEEK is able to survive within the environment without suffering adversely, it remains to be see where else this polymer will find uses.