Tritium is a radioactive isotope of hydrogen with one proton and two neutrons that undergoes beta decay. Because tritium can form a gas or water just like normal hydrogen does, wherever water and air can go, tritium can go.
Globally, nature produces about 5 kilograms of tritium every year when cosmic rays hit the upper atmosphere, which then enters the global water cycle. The concern is that tritium is one of the few isotopes that are regularly released from nuclear power plants.
Each light water nuclear plant generates 1 or 2 grams of tritium annually. While the majority is trapped inside the nuclear fuel, planned releases of less than 0.1 gram are far below the EPA threshold of 20,000 pCi/L for tritium in drinking water. Radioactive decay and dilution in air or water will reduce the radioactivity prior to any release.
There have been unplanned releases that have surpassed EPA limits at a nuclear plant, but nearby public water sources and supplies were measured and found not to exceed EPA limits. Besides isolating groundwater or restricting flow, the NRC reports that tritium also rapidly disperses and dissipates in the environment.
The active monitoring and management of tritium are enhanced by its low radiological risk.
Tritium has one of the least energetic beta decays possible. Higher energy transfers are correlated with greater health impacts, and tritium decay only releases 18.6 keV. By comparison, the Cesium-137 decay releases a total energy of 1174 keV. As a result, skin is a suitable defense against tritium decay products.
Tritiated water that is ingested or inhaled does not stay in the body indefinitely. The biological half-life for tritium is 10 days largely due to how the body removes its water. This does not change much if 3% of the tritium is organically bound and stays for 40 days. Given the radiological half-life of 12.3 years, most tritium nuclei will exit the body before they decay.
Moreover, biology inhibits the delivery of large radiation doses from tritium. Trying to accumulate tritium by quickly drinking water will induce water poisoning before any radiological effects can occur.
I dont disagree with reducing radiological doses whenever possible. In fact, some reactor designs can produce less tritium. But powering data centers with fossil fuels instead of nuclear power will disperse much more naturally-occurring radioactivity than any regulated release of tritium.
One must work extremely hard to receive a radiation dose from tritium, so concerns over expanding nuclear power due to tritium are not supported by science. Ironically, fusion will require more tritium as fuel than what nature and nuclear power provide today. Instead of releasing tritium, nuclear facilities will actively produce tritium from lithium.
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