by Walton McCarthy, Principle Engineer, NORAD Shelter Systems LLC® and author of Principles of Protection: US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards
Old Civil Defense Shelters Don’t Work to Protect from Nuclear War, but Modern Rated Underground Shelters Do
1962 U.S. Civil Defense Blast Shelter
The U.S. Department of Defense Office of Civil Defense proposed some uncomfortable and lethal nuclear shelter designs.
2017 NORAD Shelter Systems LLC® Blast Shelter
Old American civil defense shelters were not very useful, but modern shelter technology can protect thousands from nuclear blast and fallout, and provide life support for months in the aftermath of a nuclear detonation. The educated shelterists know that after 30 days, the fallout has decayed to safe levels.[i] The United States has had 214 above ground nuclear bomb tests since 1945[ii]. Yet we are all still here.
The civil defense shelter designs claimed to have a PF of 100 actually probably had a protection factor closer to 50 the shelter entranceways were unprotected. A PF of 50 with a 13,000 rem dose outside would expose the shelterist to 260 rems which is a 50% lethal radiation dose if medical help is available. Without medical help that dose is 100% lethal.
The Serious Flaws in the 1960s Civil Defense Shelters
Customers often ask me if it’s safe to use old civil defense shelters. The answer is a flat out NO! Most of these old civil defense FAMILY SHELTER DESIGNS shelters were designed to be used by people who were willing to live like cavemen, and for use 100 miles or more away from ground zero of a small kiloton nuclear weapon. These shelters were very poorly designed. With only 24 to 32 inches of earth over the ceiling, using sand bags for radiation shielding, and with no entranceway radiation shielding, the public civil defense shelters did not protect occupants from radiation unless the shelter was more than 100 miles away from ground zero.
If Family Shelter models PSD-F61-1 through PSD F61-5 were located 25 miles away or closer from a 100 KT surface burst, shelterists would have received radiation doses inside the so-called fallout shelters resulting in radiation sickness for 50% of the shelterists. These designs completely ignored that most of a nuclear bomb’s radiation comes in through the shelter entranceway. The Family Shelter Designs shelter entranceways let in sickly to lethal amounts of radiation. The protection factor stated in these manuals was only for overhead values and did not address or even consider radiation coming in through the entranceway.
Ten Times Ten is Four
The nuclear weapons today are 10 to 100 times larger than the ones of the 1950’s. However, a physical law needs to be understood. When a nuclear weapon increases in size by a factor of 10, the danger radius increases by only a factor of two, not ten. Many misinformed people have projected damage and death rates based on nuclear weapons that are 100 times larger than the one used at Hiroshima, but a bomb 100 times larger cannot produce 100 times the damage or 100 times the deaths, because the danger radius is only 4 times larger, not 100 times larger. The truth is bad enough, there is no need to exaggerate it
Civil Defense Shelter Radiation Poisoning
Radiation doses are measured in rems (Roentgen Equivalent Mammal). A relatively safe acute radiation dose within a 24 hour period is between 0 to 25 rems. Radiation sickness will occur at exposures starting at 60 rems. A 50% lethal radiation dose is between 200 and 450 rems. Half the people exposed to 200 to 450 rems will die of radiation poisoning if medical help is available.[iii] All will die if medical help is not available.
Earth Cover Provides Radiation Protection
Underground nuclear shelters without proper overhead earth cover cannot protect shelterists from gamma radiation. Sandbags stacked on top of each other is not the same radiation shielding as using solid earth. When sandbags are stacked on top of each other even when cross stacked, there are significant gaps between them large enough to let air through and some radiation comes through also. I built eleven of these in 1974 and 1975 and even after wetting the sandbags with water, the gaps between the bags did not close.
Ideally a nuclear shelter is under 71 inches of earth cover. View earth cover table at the Principles of Protectionwebsite.
Protection Factor from Earth Cover
The Protection Factor is the fraction of radiation received on the shielded side of the radiation barrier. A Protection Factor or PF of 100 would reduce or attenuate the radiation to 100th of the outside dose. The Department of Defense and Office of Civil Defense use the 1/10th value layer thickness method where 16 inches of earth provides a PF of 10 and 32 inches of earth provide a gamma PF of 100.[iv]
Ideally a nuclear shelter is under 71 inches of earth cover. View earth cover table at the Principles of Protectionwebsite.
Shelters with 61 inches of earth overhead have a PF of 2,048. Along with good entranceway geometry shielding a 61 inch overhead earth shelter can be as close as 0.9 miles from a 100 KT surface burst and allow not more than 25 rems inside the shelter over the 30 day duration known as “the fallout period.” NORAD shelters have a gamma (fallout) protection factor of 8,192 and therefore allow only 1.6 rems to enter the shelter from overhead with a 13,000 gamma rem dose outside.
Earth Cover Protection Requirements
A nuclear bomb blast radiation dose table can be found at PrinciplesofProtection.net. The details of the earth cover a shelter must have to protect occupants from radiation poisoning for “Gamma and Neutron Radiation Doses in rems inside a Shelter Based on Earth Cover 100 KT Surface Burst” is re-printed from PRINCIPLES OF PROTECTION, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design.
Civil Defense Actual Protection: Lethal
According to this reference based on the DELFIC Radiation Fallout Model from actual nuclear weapons tests, a 100 KT nuclear surface burst will produce 0 psi overpressure, 0 initial gamma radiation rems, 3,800 fallout gamma rems and 0 neutron rems at 25 miles from ground zero.[v]
Old civil defense fallout shelters had about 27-32 inches of earth cover and they are supposed to have had a Protection Factor of 100[vi], exposing the shelter occupants to 38 rems inside the shelter. This is just the radiation from overhead. The radiation dose entering the shelter from the entranceway of these shelters would be about the same dose as overhead[vii] so the total radiation dose even at 25 miles away would be 76 rems resulting in radiation sickness for 50% of the shelterists. This is assuming that there is really a PF of 100. The civil defense family shelters of the 1960’s were designed for people who were willing to live like cavemen. Many do not even allow a person to stand up, do not work, and few people would comfortable living even for a few minutes in this type of protection.
|Old Civil Defense Radiation “Protection” in Relation to Current Protection Standards|
|Earth Cover||32 inches|
|Weapon Size||100 KT|
|Miles from GZ||25|
|Initial Gamma Radiation rems||0|
|Fallout gamma rems||3,800|
|Stated Protection Factor||100|
|Implied Exposure rems||38|
|Entranceway Exposure rems||unstated|
|Entranceway Actual Exposure rems||38|
|Actual Exposure rems||76|
|Shelter Duration Required||30 Days|
|Actual Shelter Duration||A few hours to a day|
Civil Defense Air Filtration: Lethal
Another problem is that these old shelters had no air filtration system so shelterists would receive an additional dose coming into the shelter by breathing unfiltered air which is the worst type of radioactive contamination.
Civil Defense Shelter Life Support: Non-Existent
Finally these shelters were never designed for the 30 day duration which is the time it takes for the radiation level to decay to normal. After 30 days, 99% of the total or lifetime radiation dose will have decayed[viii]. For this reason, 30 days has been established as the required shelter duration time for a nuclear weapon. None of the old civil defense shelters have any type of life support system to allow people to survive off-grid for 30 days. The goal of a fallout shelter is to reduce the level inside the shelter to a level less than 25 total rems from all sources during the first 30 days and to provide life support for 30 days. There is not enough room in these civil defense shelters for a 30 day water and food supply. People need 30 days of food, water, toilet paper, and light as well as a decent toilet.
Modern Shelter “Total Rems in Shelter”
These old shelters meet absolutely none of the modern day standards. A good modern underground shelter will not allow more than 5 rems inside the shelter from all sources, and not allow more than 25 total rems in the first 30 days. The Total Rems in Shelter (TRS) of zero is possible but would be very expensive and not a worthwhile goal.
Blast and Radiation Protection Required
An underground shelter with 48 inches of earth and 12 inches of concrete would allow 5 rems to enter the shelter from overhead in the 10 psi range from a 100 KT Surface Burst. Most of the shelters on the market today have no geometry entranceway shielding and allow and additional 25-50 rems to enter the shelter through the entranceway. While these new shelters are still a tremendous improvement from the old civil defense shelters, beware of any shelter manufacturer than claims that their shelters allow no radiation to enter the shelter. One should always ask “What is the design radiation dose for the shelter for Overhead Radiation and Entranceway Radiation?” and what is the source of their claims.
Modern Nuclear Shelter Standards
Because scientists can’t predict the weapon package for a specific target, protection values are stated for both a 500 KT air burst and a 100 KT surface burst at a the10 psi over pressure distance. Radiation doses and pressure ratings are inseparable and must be stated together. At 10 psi for a given size weapon there will be a certain radiation dose. See weapons effects tables to see the progression of radiation exposure based on earth cover and distance from ground zero.
NORAD Shelters “Design Radiation Dose”
The design radiation dose for overhead shielding for NORAD Shelters is based on a 100 KT surface burst producing 1,200 rems Initial Gamma, 9,554 rems of fallout gamma radiation, and 4,000 rems of neutron radiation. The Design Radiation Dose for the Entranceway is based on 3,250 rems of initial gamma, 12,000 rems for gamma, and 9000 rems of neutron, based on the standard 500 KT Air Burst. This is the radiation dose the shelter is designed for based on POP. Under these weapon effects, the NORAD Shelters will not allow more than 4 rems to enter the shelter from all sources.
Sagan’s Nuclear Winter Myth Debunked
According to the “ANNOUNCED U.S. ABOVE GROUND NUCLEAR WEAPONS TESTS PRIOR TO THE 1963 NUCLEAR TEST BAN TREATY” US Department of Energy NVO-209-Rev. 2, there were 74 nuclear weapons tested above ground in the Nevada test site and of these, 29 were larger than the 13 KT nuclear weapon used on Hiroshima. After 74 nuclear explosions in the U.S., we are all still here. The truth about nuclear weapons is bad enough, it does not have to be exaggerated.
Nuclear war is survivable. 29 bombs larger than Hiroshima were tested in the United States above ground prior to the nuclear test ban of 1963 and no nuclear winter appeared. It’s about time we learned to protect ourselves.
Carl Sagan created the myth of nuclear winter. It demoralized the U.S. from defending itself from a winnable war. Eventually Sagan admitted that nuclear winter could not happen, but by then the U.S. was traumatized by unscientific documentaries proving that nuclear war defense was hopeless.
Our enemies don’t need to use propaganda to demoralize us. While a core group of educated citizens know that the nuclear fallout danger period is only 30 days long, many believe that nuclear war is the equivalent to the end of the world. Just stay underground in a well-designed, properly installed shelter with Nuclear, Biological, Chemical and EMP protection measures, just for 30 days to wait for the fallout radiation level to decay. But Americans believed the documentaries based on faulty science. We abandoned our civil defense shelter program when properly designed and equipped modern shelter technology could save millions of lives. Our enemies couldn’t have created a more demoralizing propaganda campaign.
The modern underground shelter is EMP shielded and designed to survive a minimum 90 day duration off-grid which is the time period where most of the population will die out from lack of water, food, exposure, or medical supplies in the aftermath of a nuclear weapon detonation or EMP event. If we lose 80% of the population, it brings us back to the population of 1900[ix], which is not the end of the world. During this first 90 days, people will be desperate and shelterists should remain in the shelter during this time period. After this first 90 days, shelterists will be going in and out of the shelter for perhaps one to two years as the country rebuilds.
Sagan’s nuclear analysis group called themselves TTAPS: “Turco, Toon, Ackerman, Pollack, and Sagan.” In 1983 TTAPS analyzed the consequences of a full scale nuclear war. This report was the first in defining the theory of Nuclear Winter. It was scientifically later recognized in 1986 that the TTAPS report and its conclusion of Nuclear Winter had serious scientific flaws and was therefore never considered to be scientifically valid[x]. The TTAPS report was based on a single dimension model which neglected some rather serious aspects. The TTAPS report did not take into account the seasons, wind to dissipate the smoke, geography, or washout from rain. It assumed the spread of smoke to be instantaneous. It was based on a starting temperature 20oF below the average seasonal temperature, and finally, it did not account for the temperature moderating effects of the mass of the oceans which cover most of the planet surface.
Authors Cautioned Model Was Weak
It was not surprising that the authors of the TTAPS model cautioned that the model had significant weaknesses which would have to be addressed before the model was to be treated as conclusive for any war scenario. The current scientific analysis from the National Center for Atmospheric Research (NCAR) indicates a temporary weather change similar to a Nuclear Fall. It also states “A major conclusion of the current work on the vulnerability of human and natural systems is that the mechanism most likely to lead to the greatest consequences to humans from a nuclear war is not the blast wave, not the thermal pulse, not direct radiation, or even fallout; rather it is mass starvation.[xi] The NCAR report was considered conclusive and no further research was warranted.
Radiation Doses and Cancer Rates
What about Hiroshima and Nagasaki? Weren’t those cities destroyed? The people at Hiroshima and Nagasaki who were exposed to the most severe weapon effects such as thermal burns, blast, and massive doses of radiation and who were malnourished still have a lower cancer rate than smokers in the United States[xii]. Adequate shelter will prevent shelterists from receiving more than 25 rems for the first 30 days, which will allow people to survive in good physical and mental health with no risk of contracting cancer above the present rates. More than half a century after the atomic bombing, the survivors, called hibakusha in Japanese, are becoming quite elderly. Their average age as of March 2010, is over 76.73 years old.[xiii]
Walton McCarthy M.E.
Today’s underground shelters are based onPrinciples of Protection, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards, Walton McCarthy M.E. Brown Books, 6th edition, 2013. (PrinciplesofProtection. net).
McCarthy’s book was written with a committee of experts from the US Department of Energy, US Department of Defense, Strategic Applications International, Nuclear Engineering Laboratory from the University of Illinois, Oak Ridge National Laboratories, Chemical Division of Edgewood Arsenal, Brookhaven National Laboratory, US Defense Nuclear Agency and the US National Bureau of Standards. It is available on Amazon and has been used by architects and engineers around the world since 1991. There are numerous other standards listed in the book for buoyancy, seismic joints, shelter duration, air manifolds, and many more. The website for the book has Nuclear Weapon Effects Tables based on actual nuclear tests, Radiation Shielding tables and a really cool Entranceway Radiation Calculator so people can determine how much radiation can be expected to enter their shelter through the entranceway.
[i] These values were developed by Dr. Joseph McGahan of the Scientific Applications International Corporation. These values are not theoretical. They were derived from the DELFIC model, which is based on actual radioactivity measurements made on site of the nuclear surface burst tests conducted in the United States prior to the Nuclear Test Ban Treaty of 1964. This reference is from page 670 Appendix A in Principles of Protection, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards, 2013, 6th Edition, Brown Books.
[ii] ANNOUNCED US ABOVE GROUND NUCLEAR WEAPONS TESTS PRIOR TO 1963 NUCLEAR TEST BAN TREATY, US Department of Energy, NVO-209 rev. 2. This reference is from page 2 of Principles of Protection, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards, 2013, 6th Edition, Brown Books.
[iii] NUCLEAR ATTACK PLANNING BASE 1990,Federal Emergency Management Agency, Final Project Report (NAPB-90).
[iv] THE EFFECTS OF NUCLEAR WEAPONS, Department of Defense and Energy Research and Development Administration, 1977, 3rd edition. Table 8.41 page 337.
[v] These values were developed by Dr. Joseph McGahan of the Scientific Applications International Corporation. These values are not theoretical. They were derived from the DELFIC model, which is based on actual radioactivity measurements made on site of the nuclear surface burst tests conducted in the United States prior to the Nuclear Test Ban Treaty of 1964. This reference is from page 670 Appendix A in Principles of Protection, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards, 2013, 6th Edition, Brown Books.
[vi] FAMILY SHELTER DESIGNS, H-7 DEPARTMENT OF DEFENSE, OFFICE OF CIVIL DEFENSE, January 1962, designs PSD F-61-1 through PSD F-61-8, page 5.
[vii] See appendix D of Principles of Protection, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards, 2013, 6th Edition, Brown Books. This formula was developed specifically for personal blast shelters by Dr. Arthur B. Chilton. In developing this formula, he used the following books as references. Numbers were rounded using normal rounding procedures.
Diaz, J. and A.B. Chilton, MODELING RELATIONSHIPS for RADIATION TRANSPORT within DUCTS and OTHER CAVITIES in SHIELDS, Nucl. Sci., and Eng. 35,283, 1969.
Jaeger, R.G. ed., ENGINEERING COMPENDIUM on RADIATION SHIELDING FUNDAMENTALS and METHODS, New York, Springer- Verlag, 1968.
Kimel, H.R.ed., RADIATION SHIELDING ANALYSIS and DESIGN PRINCIPLES as APPLIED to NUCLEAR DEFENSE PLANNING, TR- 40, OCD/KSU, Report Supt. of Documents, U.S. Government Printing Office, Washington, D.C., 1966.
Maeker,R.E. and F.J. Muckenthaler, NEUTRON FLUXES in CONCRETE DUCTS ARISING from INCIDENT EPICADMIUM NEUTRONS: CALCULATIONS and EXPERIMENTS, Nucl. Sci., and Eng. 35,283, 1969.
NEWMARK, N.M., DESIGN of OPENINGS for BURIED SHELTERS, Contract Report 2-67, U.S. Army Engineer Waterways Experiment Station, July 1963.
Ritchie, R.H. and G.S. Hurst, “Penetration of Weapons Radiation: Application to the Hiroshima-Nagasaki Studies.”, HEALTH PHYSICS 1,390, 1959.
STRUCTURES SHIELDING against FALLOUT GAMMA RAYS from NUCLEAR DETONATIONS, NBC SPECIAL PUBLICATION 570, Washington, D.C., U.S. Government Printing Office, 1980.
U.S. Department of Defense and Energy Research and Development Administration. EFFECTS of NUCLEAR WEAPONS. Compiled by Samuel Glasstone and P.J. Dolan. Washington, D.C., 1977.
U.S. Department of Defense: Office of Civil Defense, SHELTER DESIGN and ANALYSIS-FALLOUT RADIATION SHIELDING, TR-20. Vol. 1 as amended, Washington, D.C., July 1967.
[viii] These values were developed by Dr. Joseph McGahan of the Scientific Applications International Corporation. These values are not theoretical. They were derived from the DELFIC model, which is based on actual radioactivity measurements made on site of the nuclear surface burst tests conducted in the United States prior to the Nuclear Test Ban Treaty of 1964. This reference is from page 670 Appendix A in Principles of Protection, The US Handbook of NBC Weapon Fundamentals and Shelter Engineering Design Standards, 2013, 6th Edition, Brown Books.
[ix] US Census for 2014 at 319 million and US Census for 1900 at 76 million people.
[x] Thompson Starley L., NUCLEAR WINTER REAPPRAISED, Foreign Affairs Volume 64, No. 5, Council on Foreign Relations, p. 993.
[xi] SCOPE 28 ENVIRONMENTAL CONSEQUENCES OF NUCLEAR WAR, Volume II, Ecological and Agricultural Effects, Mark A Harwell and Thomas C. Hutchinson, 1985, John Wiley and Sons, page xxxiv.
[xii] Committee for the Compilation of Materials on Damage Caused by the Atomic Bombs in Hiroshima and Nagasaki, HIROSHIMA and NAGASAKI, New York: Basic Books Inc., 1979, p.268. Average over all age groups is approximately 50 cases/100,00 of leukemia. American Cancer Society, CANCER FACTS and FIGURES, New York, 1987, p. 13. Smoker cancer rate of 68 per 100,000.
[xiii] Sakiko Masuda, Hiroshima Peace Media Center, based on Japan Ministry of Health, Labour, and Welfare based on A-bomb survivors who hold A-Bomb Survivor Certificates.