Last week, just before the US Fourth of July holiday, the Nuclear Regulatory Commission (NRC) proposed a new rule this will change how it regulates radiation exposure. The Trump administration is trying to restart the construction of nuclear power plants in the United States, and many nuclear advocates have complained about existing U.S. regulations as a major obstacle to the industry’s prosperity. So there was likely to be major changes.
Instead, the NRC’s proposed new rules affirm the science behind its existing rules, suggesting that any problems stem mainly from the vagueness of the terminology it uses. So instead, it validates standards intended to do the same thing, but avoid using some of the languages it relies on. Perhaps the clearest indication of the evolutionary change is that the NRC estimates that the changing rules will save industry — not just energy, but also medical and research programs — a total of $9.5 million a year.
LNT and ALARA
At the heart of US nuclear regulations are two technical abbreviations. The first is LNT, which stands for “non-linear threshold”. This refers to the question of whether there is any level of radiation below which it no longer produces harmful biological effects – a “threshold” in LNT. “Unbounded” implies that it does not, and this is consistent with biology, which demonstrates that even single particles or photons of radiation can damage DNA, and that the mechanisms that cells have to repair this damage are inherently error-prone. The “linear” in LNT simply describes how the effect of radiation is measured directly by dose.
