In general, nuclear plants are heavily regulated in terms of how much radiation they are able to release.

Material Release

Materials used in nuclear plants (such as BWR reactorBWR reactorA boiling water reactor uses Light Water as both coolant and neutron moderator. The second most used reactor, next to the PWR reactors, there are approximately 75 plants in current operation. The efficiency of these reactors is about 46%, with 33-34% in practice. Enriched uranium is used as nuclear fuel, as light water absorbs too many neutrons to use Uranium that is natural. Light water is not as good of a moderator compared to Heavy Water or graphite, but it is good as in the event of a LOCA os) that are irradiated commonly throughout operation can include

• RPVRPVReactor Pressure Vessel - contains all of the reactor heat. In BWR reactors, the RPV contains the reactor core - basically the entirety of the main reactor assembly. The RPV is designed to withstand a very large amount of force considering that in a BWR it must withstand the pressure that both it operates at and at emergency designs -- this is due to the fact that in most designs, the RPV isn't considered to be at major risk: even during a major LOCA the RPV is considered to be at healthy condi
• Primary cooling system
• Containment BuildingContainment Buildingit is the reinforced steel/lead/concrete structure enclosing the nuclear reactor. It is designed to contain the escape of radioactive steam or gas between 275-550 kPa * It is the forth step in the nuclear reactor defense-in-depth design against radioactive release Either free standing or attached to a missile shield - must be strong enough to withstand a 9/11 attack Although it is made to withstand accidents, it is NOT meant to condense/contain steam - like in the 3 mile and fukushima accide
  • shouldn't normally experience radiation, but in the event of an accident, may experience it in general However, importantly, according to the NRCNRCThe NRC has a important role in that it regulates the operation and regulation of Nuclear Reactors in the USA. This regulation is done by many means, one of which is reporting of all reactor activities daily. The regulation is scrutinized due to the risk of radiation contamination and the possibility of attacks or the usage of enriched uranium for weapons. The NRC also manages (In conjunction with OSHA and DOL) the radiation standards and regulations of workers. The NRC does not only work with, "most of an operating nuclear plant's direct radiation is blocked by its steel and concrete structures." (See also: Containment BuildingContainment Buildingit is the reinforced steel/lead/concrete structure enclosing the nuclear reactor. It is designed to contain the escape of radioactive steam or gas between 275-550 kPa * It is the forth step in the nuclear reactor defense-in-depth design against radioactive release Either free standing or attached to a missile shield - must be strong enough to withstand a 9/11 attack Although it is made to withstand accidents, it is NOT meant to condense/contain steam - like in the 3 mile and fukushima accide) These materials shouldn't normally be included in such release. However, in the decommissioning of such plants, it is possible for these structures to become exposed, through natural disasters or other means. However, according to World Nuclear: Apart from some surface contamination of plant, the remaining radioactivity comes from "activation products" in steel which has long been exposed to neutron irradiation, notably the reactor pressure vessel. Stable atoms are changed into different isotopes such as iron-55, iron-59 and zinc-65. Several are highly radioactive, emitting gamma rays. However, their half life is such (2.7 years, 45 days, 5.3 years, 245 days respectively) after 50 years from closedown their radioactivity is much diminished and the occupational risk to workers largely gone.