Reactor vessels are containers that are protective in nature and they surround the fission core in a nuclear reactor. The vessels are the central components of the reactor coolant systems. The reactor vessels mostly are made of stainless steel because steel provides the best reliability in terms of protection and preventing leakages. Steel further provides high strength and toughness with low porosity under neutron irradiation. When the material is in operation, neutron radiation from the reactor causes embrittlement of the reactor pressure making it less tough and capable of maintaining its identity and integrity structurally.

Special considerations have to be taken in to help reduce the embrittlement that could be experienced in the system. Embrittlement is experienced differently in different reactors. Pressurized water reactors are more susceptible than the boiling water reactors. This is because the boiling water reactors experiences less neutron radiations and therefore less embrittlement than in pressurised reactors. The design of the systems also speak a lot an help reduce the rate radiations. The design will reduce the number of neutrons that will reach the wall and hence minimize the current rate of embrittlement on the vessel.

Another factor of paramount importance is the kind of the steel in use. Steel is a metal that is made from the composition of different components of other metals. For instance, a higher proportion of copper and nickel will make the steel metal more susceptible to embrittlement than steel with less proportions of the same metals. Reactor vessels are also manufactured from carbon alloy steel to ensure strength is achieved. The sufficiency of the strength is necessary to keep and further maintain the pressure within without any defects in the system. The assurance of the strength and fracture toughness also helps maintain the structural integrity of the reactor vessels.