Yes, the Nuclear Regulatory commission is considering a repudiation of the Linear No-Threshold hypothesis. It is false to say that NRC is considering “replacing” it with any other hypothesis, certainly not that of radiation hormesis.
Radiation hormesis, if correct, must be established by long-term mechanistic laboratory research. The hormesis idea has arisen only anecdotally by observation of the health status of certain groups of people who seem, anecdotally, to have benefitted from low-dose exposure.
This article by Mr. Grossman is laden with unproved assertions presented as demonstrated scientific findings.
“ But as the years went by it became clear there was no threshold—that any amount of radiation could injure and kill, that there was no “safe” dose. “
That belief did not develop as the years went by. It was a sudden one-time assertion made by Herman Muller at his Nobel Prize acceptance speech in 1946.
It was a baseless assertion since Muller’s doses were unrelated to any amount that could be considered moderate or low or safe. They were massive. Furthermore, they were delivered by x-rays, a form of radiation not produced by nuclear fission.
The only observations Muller could make were of gross external abnormalities, mostly eye-color variations in his insect test-subjects. He was unable to visually inspect cell-molecular abnormalities because the electron microscope had not yet been invented during the 1920s when his research was performed. Likewise for measurement of variations in the mass in organic molecules; neither had the mass spectrometer yet been invented.
“ But, it was found, after a ‘latency’ or ‘incubation’ period of several years, the exposure could then result in illness and death. “
“ Moreover, because the effects of radiation are cumulative, the sum of several small exposures are considered to have the same effect as one larger exposure, something called ‘response linearity.’ “
The latency and response linearity (cumulative effects) hypotheses certainly have been proposed, but they have never been tested. To test them would involve decades-long research performed on long-lived animals, probably primates. Such research would require commitment of large amounts of laboratory space, manpower, and money. Those have never been forthcoming and the studies to test those hypotheses have not been performed.
“ BEIR VII found that ‘the balance of evidence from epidemiological, animal and mechanistic studies tend to favor a simple proportionate relationship at low doses between radiation dose and cancer risk.’ “
There exists no balance of evidence from epidemiological, animal and mechanistic studies. As stated above, mankind has performed no animal or mechanistic studies, only epidemiological studies. This has been the state of affairs until very recently.
“ Dr. Fairlie says ‘the scientific evidence for the LNT is plentiful, powerful and persuasive.’ He summarizes many studies done in Europe and the United States including BEIR VII. “
BEIR does not conduct studies. It is tasked with making recommendations, expected to be based on research study results presented to it. No such results, other than epidemiological, have been presented. It is characteristic of epidemiological studies that there is no clearly identifiable control group, and usually no reliable information about exposure rates for individual subjects.
Mankind has only recently begun to address our historic neglect of animal and mechanistic investigation of ionizing radiation. For example, see my blog post at http://tinyurl.com/lo5azxw , describing slight progress in those fields, in the following paragraphs:
Blog Entry: However, in 2012 there was a bare scratching of the surface of the type (2) class of study. That is, a laboratory experimental study measuring numeric values for breakage categories (A) and (B), using molecular mass spectrometry and optical microscopes, for an irradiated test group of animals, was compared to a non-irradiated control group.
It was performed at the Massachusetts Institute of Technology, funded by the US Department of Energy and the MIT Center for Environmental Health Sciences [National Institute of health]. It was published in the journal Environmental Health Perspectives under the auspices of the National Center for Biotechnology Information - NCBI. It is viewable at
and described in laymen's terms at