Two AP1400 nuclear power reactors are powering up in Georgia, and several ventures are developing new generation reactors. The outlook for more nuclear power seems bright. But will there be some future failure that leaks radioactive material out? Yes, perfection is impossible; airplanes crash.
Will such a radiation event kill off nuclear power, as did the harmless Three Mile Island accident?
Yes, if we are guided by baseless fear. Regulators claim any radiation exposure is potentially harmful and so set unreasonably low limits. Media headlines frighten people about any radiation leaks, no matter how small. This article will contrast today’s regulatory limits with published, recommended protective actions to avoid harm to the public after a radiation release from a nuclear reactor accident.
Ionizing radiation harms by displacing electrons, breaking molecular bonds in cells. It is measured in Sieverts (Sv) or Grays, which are watt-seconds of energy absorbed, per kilogram of body weight. An intensive, brief 10 Sv dose is deadly, 1 Sv risks acute radiation sickness, and such a dose over 0.1 Sv can slightly increase future cancer risk.
U.S. regulations limit annual public radiation exposure from nuclear power to 0.001 Sv. The limit is 100X smaller than a brief, intensive dose that might cause cancer, and 1000X smaller than one requiring medical attention. This enormous safety margin was created politically by reducing limits in an attempt to reassure frightened people, but resulted in most people viewing 0.001 Sv as dangerous. Worse, regulators magnify fear with the ALARA rule (as low as reasonably achievable), claiming even lower exposures may cause cancer.
The regulators’ 0.001 Sv limit counts not just a single dose, but all radiation absorbed over an entire year, as if the harm were cumulative, without any biological repair during the year. In reality, repair takes place at DNA, cellular, and tissue levels in time scales of hours to days. DNA repair begins in seconds to minutes after exposure, and cellular repair within hours. How long does it take your cut finger to heal?
Radiation from the triple Fukushima nuclear reactor meltdown killed no public citizens, but Japan’s government killed over 1,600 people with unnecessary evacuations. To prevent such future mistakes, International Atomic Energy Agency (IAEA) published Actions to Protect the Public in an Emergency due to Severe Conditions at a Light Water Reactor to protect the public from physical radiation harm, avoiding harm from fear based on regulators’ limits. This IAEA documented advice is directed to accident site responders working to protect people’s lives and health, independent of radiation limits promulgated by bureaucrats.
Chart 1 helps guide the accident response team and the public. IAEA’s green SAFE FOR EVERYONE, year-long, dose rate is 25 microSv/hour. This radiation exposure dose rate over a whole year totals to 0.2 Sv, 200X the regulators limit of 0.001 Sv/year, but is safe because the body repairs damage much more rapidly than 25 microSv/hour damages it.
Jack Devanney’s substack article tabulates observed harms and radiation doses to actual people in many studies. He observes that dose rates under 0.01 Sv/day did not exhibit statistically significant, detectable harm. The body’s intrinsic repair rate exceeds the radiation damage rate. Using a 10:1 safety margin he suggests 0.001 Sv/day safety limit. This is 40 microSv/hour, close to the IAEA SAFE FOR EVERYONE rate of 25 microSv/hour.
CHERNOBYL. The Chernobyl accident was deadly; 30 onsite workers with intensive doses over 2 Sv died. Cleanup workers exposed up to 0.3 Sv or more had slightly higher rates of cancer. Radioactive iodine dispersed into the food chain caused over 1,400 thyroid cancers leading to the deaths of 15 children; no other increases in public cancer rates was observed. Perhaps 200,000 people were evacuated. Radiation rates in the Chernobyl exclusion zone are now under 10 microSv/hour, not harmful to the 1,000 stubborn babushkas and others who still live there.
FUKUSHIMA. Within the stricken Fukushima power plants site, radiation peaked at 10,000 microSv/hour, dropping 90% in 10 hours. Outside the plant IAEA reported peak measured radiation of 170 microSv/hour 30 km northwest of the site. By the next month radiation dropped to less than 91 microSv/hour everywhere, provisionally safe by Chart 1 except in spots where radiation may have still exceeded 25 microSv/hour. There was no need to evacuate 164,000 people, leading to the deaths of over 1,600 people, and there was certainly no need to do it hastily.
THREE MILE ISLAND. Around Three Mile Island reactor accident the cumulative dose averaged only 15 microSv (likely under 25 microSv/hour everywhere), so there was no need to evacuate anyone. Nevertheless the accident was a factor in ending nuclear power plants construction in the U.S.
NATURAL RADIATION. The back of Chart 1 states the average annual dose rate from natural sources of radiation exposure fluctuates around 0.2 microSv/hour, but in some locations it can be up to 15 microSv/hour.
It’s dose rate, not dose, that matters. Harm results when dose rate exceeds repair rate. Regulators and the multi billion dollar radiation protection industry overstate radiation harm by orders of magnitude:
100X: 0.001 Sv/year regulatory limit vs observed intensive 0.1 Sv cancer threshold.
52X: regulatory yearlong biological repair assumption vs typical healing time.
ALARA: unknown whim.
Regulators should abandon cumulative, yearlong dose limits, and instead set dose rate limits consistent with biological repair times. The ALARA rule should be dropped. What should be the limit?
IAEA’s Chart 1 shows a 25 microSv/hour dose rate limit. Jack Devanney’s article suggested 40 microSv/hour. In 1934, the NCRP (National Commission on Radiation Protection) advised 40 microSv/hour (0.1 R/day in old units). Nearly 50 years later, NCRP founder Lauriston Taylor wrote “No one has been identifiably injured by radiation while working within the first numerical standards set by the NCRP and the ICRP in 1934.”
Nuclear power growth will end with the next radiation release unless we replace regulators with people who observe facts and consequences. The near century of concessions changing 1934 radiation limits from 40 microSv/hour to 0.001 Sv/year has not reduced harm one bit, but has increased public fear because the more restrictive limits have no evidential justification. Fear of nuclear power has killed many more people than radiation.
Nuclear power will be cheaper, ample, and less feared if regulators issue fact-based limits instead of conceding to protesters.
Dr. Hargraves teaches energy policy at Dartmouth’s Osher Lifelong Learning Institute and is a co-founder of a nuclear engineering company.