Of all types of radiation, gamma radiation is the most penetrating and energetic. It damages the body by breaking bonds in genetic material and other biological molecules. The body’s innate ability to repair such damage can be overwhelmed when exposed to either high doses or low doses over many years.
Thus the Nuclear Regulatory Commission (NRC) sets limits to the radiation doses to which individuals can be exposed during work. The annual radiation dose limit for the general public is 100 mrem.
Due to the special nature of work in nuclear plants, the annual dose limit for nuclear workers is 5,000 mrem (50 times higher than that of the general public) although the NRC expects licensees to maintain levels at about 2,000 mrem.
Whether working in close proximity to the steam generator, under the head of the nuclear reactor vessel or in the reactor vessel itself, nuclear workers operate in highly radioactive environments during maintenance activities and in-service inspections. They can find themselves hanging above the radiation source itself while performing their work.
Thus, this higher dose limit is needed – but comes with a caveat: Federal law requires that nuclear plants ensure that occupational doses are “as low as is reasonably achievable” (ALARA). In other words, 5,000 mrem is the annual maximum (barring emergency situations), but a plant should work to keep the doses much lower if this can be reasonably achieved.
Until now, wearable protection against gamma radiation damage was not feasible, since the amount of lead required for an effective full suit was too heavy to enable mobility. Yet StemRad’s unique selective shielding technology, which protects the most vulnerable cells of the body – the body’s stem cells – finally provides this much sought after level of protection.
To the resounding support of the scientific community, including three Nobel laureates and world renowned experts on radiation damage, StemRad’s radiation gear has been shown to reduce the probability of cancer due to protracted exposure to low doses of gamma radiation and to increase survival upon exposure to high doses (see figure be).
Stem cells are usually the first to suffer radiation damage, thereby starting a chain of events that can lead to a variety of diseases. By protecting specific tissues in the hip region, StemRad’s radiation protection equipment safeguards the body’s bone marrow, which holds the majority of the body’s stem cells.
Due to selective shielding, mobility is easily achieved (since other parts of the body remain exposed, radiation doses should still be kept as low as possible). Covering the whole body with lead is unreasonable, but safeguarding specific areas of the body is definitely reasonable, complying with the ALARA standard.
Nuclear workers now have a light, affordable option for protection against gamma radiation damage. StemRad’s radiation protection equipment has been deployed in multiple areas and is being adapted to protect astronauts from radiation in collaboration with Lockheed Martin.
Effect of StemRad’s Radiation Protection Equipment