Nuclear detonation detection system

A nuclear detonation detection system (NDDS) is a device or a series of devices that are able to tell when a nuclear explosion has occurred as well as the direction of the explosion. The main purpose of these devices or systems was to verify compliance of countries that signed nuclear treaties such as the Partial Test Ban treaty of 1963 (PTBT) and the Treaty of Tlatelolco.

There are many different ways to detect a nuclear detonation, these include seismic, hydroacoustic, and infrasound detection, air sampling, and satellites. Each have been used separately but at present the best results occur when data is used in tandem, since the energy caused by an explosion will transfer over to different mediums.[1]

The Partial Test Ban Treaty banned nuclear testing in the atmosphere, underwater, and in outer space. The U.S. developed many different devices to ensure the Soviet Union was upholding its part of the treaty. The PTBT aimed to ban underground testing as well but at the time the technology could not detect detonations very well with seismographs let alone differentiate them from earthquakes[2] making them more difficult to identify than atmospheric detonations or underwater. Larger yields could be differentiated but the smaller ones could not be. Even then larger explosions could be dampened by having a larger cavity in the ground.[3] With the threat of the Soviet Union conducting underground detonations the U.S. pumped money into seismology research. A major accomplishment was made by Sheridan Speeth by changing the seismographs into audible files one could differentiate between earthquakes and nuclear explosions just by listening to the difference.[4] However, due to his political beliefs his work was ignored.[citation needed] The main system for detecting underground detonations remained to have large numbers of monitoring stations but due to the difficulty in creating technology and the number of stations needed the treaty allowed underground testing.[citation needed]

Another way of detecting a nuclear detonation is through air sampling; in nuclear explosions there are radioactive isotopes that get released into the air which can be collected by plane. Radionuclides include Americium-241, Iodine-131, caesium-137, krypton-85, strontium-90, plutonium - 239, tritium, and xenon.[5] By sending planes over an area equipped with sensors they could reveal if there was a nuclear detonation, but most air samples are taken at one of many radionuclide stations set throughout the world. Even underground detonations will eventually release radioactive gases (most notably xenon) to be detected. One weakness of this method is that air currents could move the gases or radionuclides in another direction, depending on where the explosion was and the weather conditions at the time.[1] The process involves taking in air samples with a filter paper and the radioactive material is counted by a machine and analyzed by a computer. If there is outside “noise” (other forms of radiation like some released from factories or nuclear plants) it can throw off the results.[6] One example of air currents moving radioactive particles is the Chernobyl disaster. As the reactor started failing a large amount of radionuclides were released into the air which were then spread by air currents; leading to radiation that could be detected all the way in Sweden and other countries hundreds of miles away within a few days.[7] The same occurred at the Fukushima Daiichi disaster. The spread of radioxenon gas, iodine-131, and caesium-137 could be detected at different continents many miles away[8]

Satellites were also implemented during the cold war era to ensure no nuclear testing was going on. They relied on sensors that picked up radiation from nuclear detonations. Nuclear detonations always produced gamma rays, x-rays, and neutrons.[2] A notable U.S. satellite nuclear detection system was the VELA hotel project. The project consisted of 12 satellites, each equipped with x-ray, neutron, and gamma ray detectors.[9] Satellites are now also equipped with cameras that are able to capture above ground explosions.[citation needed] With the advent of Global Position System (GPS) satellites have become an important method of detonation detection.[10] A minor drawback to the satellite detection method is that there are some cosmic rays that emit neutrons could give false signals to the sensor [11]

There are 11 hydroacoustic stations that are set up to monitor any activity in the oceans. They were developed to ensure the ban on underwater testing, and because of water’s ability to carry sound they are very efficient.[12] However, hydroacoustics have difficulties pinpointing the location of an explosion or event, so they must be used with another method of detection (such as the ones previously mentioned).[13] Other problems that hydroacoustics faces are the difficulties caused by the structure of the sea floor, as well as islands that can block sound; sound travels the best through deep ocean meaning events near shallow water will not be detected as well.[14]

Infrasound works by having multiple stations that use microbarometers listen for infrasonic waves caused by explosions, volcanoes or other natural occurring events.[15] As with other detection methods, infrasound was developed during the cold war.[16] These stations were designed to detect explosions with forces as low as 1 kiloton. But after the PTBT, atmospheric detonation detection was left to satellites.[17] Although infrasound waves could travel across the earth multiple times they are very prone to being influenced by the wind and by temperature variations.[18] Long range infrasonic waves are difficult to differentiate (e.g. chemical explosion and a nuclear explosion).[citation needed]

The Comprehensive Nuclear Test Ban Treaty (CTBT) banned all forms of nuclear testing in an attempt to disarm and move away from nuclear weapons, but with it came old challenges, such as how to ensure members would not cheat the treaty. To that end the International monitoring system (IMS) was born, having 321 stations, which use all of the sensor types previously described. Using collected data from each source to calculate detonations, the IMS brings hydroacoustic, infrasound, and seismic wave detection systems, as well as air samplers for radionuclides. All of this information is collected by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) which is stationed in Vienna, Austria.[19]

EffectivenessEdit

One of the first uses of the CTBTO and its detection systems showed itself effective when it was able to identify nuclear testing by India and Pakistan in May 1998.[20]

Another notable example is the detection of North Korean testing. As most countries have given up nuclear detonation tests, North Korea has attempted to create a powerful nuclear warhead.[21] Due to North Korea’s secrecy it is up to IMS to give researchers the information needed to evaluate North Korea’s threats. Even their low yield (0.6 Kiloton) first attempt at a nuclear weapon was picked up and isolated in 2006.[22]

ReferencesEdit

  1. ^ a b "3 Monitoring Technologies: Research Priorities - Research Required to Support Comprehensive Nuclear Test Ban Treaty Monitoring - The National Academies Press". doi:10.17226/5875. Retrieved 20 April 2017.
  2. ^ a b "Radiation - Nuclear Radiation - Ionizing Radiation - Health Effects - World Nuclear Association". Retrieved 20 April 2017.
  3. ^ Latter, A. L.; LeLevier, R. E.; Martinelli, E. A.; McMillan, W. G. (March 1961). "A method of concealing underground nuclear explosions". Journal of Geophysical Research. 66 (3): 943–946. doi:10.1029/JZ066i003p00943.
  4. ^ Volmar, Axel (January 2013). "Listening to the Cold War: The Nuclear Test Ban Negotiations, Seismology, and Psychoacoustics, 1958–1963". Osiris. 28 (1): 80–102. doi:10.1086/671364.
  5. ^ "General overview of the effects of nuclear testing: CTBTO Preparatory Commission". Retrieved 20 April 2017.
  6. ^ "Radionuclide data processing and analysis: CTBTO Preparatory Commission". Retrieved 20 April 2017.
  7. ^ "Chernobyl's Accident: Path and extension of the radioactive cloud". Retrieved 20 April 2017.
  8. ^ https://www.ctbto.org/fileadmin/user_upload/pdf/Spectrum/2013/Spectrum20_p27.pdf
  9. ^ "The Vela 5A satellite". Retrieved 20 April 2017.
  10. ^ "Looking from space for nuclear detonations". Retrieved 20 April 2017.
  11. ^ Medalia, Jonathan. Detection Of Nuclear Weapons And Materials. 1st ed. Washington, D.C: Congressional Research Service, Library of Congress, 2010. Print.
  12. ^ "Hydroacoustic monitoring: CTBTO Preparatory Commission". Retrieved 20 April 2017.
  13. ^ "3 Monitoring Technologies: Research Priorities - Research Required to Support Comprehensive Nuclear Test Ban Treaty Monitoring - The National Academies Press". doi:10.17226/5875. Retrieved 20 April 2017.
  14. ^ "3 Monitoring Technologies: Research Priorities - Research Required to Support Comprehensive Nuclear Test Ban Treaty Monitoring - The National Academies Press". doi:10.17226/5875. Retrieved 20 April 2017.
  15. ^ "Infrasound monitoring: CTBTO Preparatory Commission". Retrieved 20 April 2017.
  16. ^ https://www.esrl.noaa.gov/psd/programs/infrasound/atmospheric_infrasound.pdf
  17. ^ Medalia, Jonathan. Detection Of Nuclear Weapons And Materials. 1st ed. Washington, D.C: Congressional Research Service, Library of Congress, 2010. Print
  18. ^ "3 Monitoring Technologies: Research Priorities - Research Required to Support Comprehensive Nuclear Test Ban Treaty Monitoring - The National Academies Press". doi:10.17226/5875. Retrieved 20 April 2017.
  19. ^ "History of the International Data Centre". ctbto.org.
  20. ^ Barker, B., Clark, M., Davis, P., Fisk, M., Hedlin, M., Israelsson, H., . . . Wallace, T. (1998). Monitoring Nuclear Tests. Science, 281(5385), 1967-1968. Retrieved from https://www.jstor.org/stable/2895717
  21. ^ Davis, William J. Broad, Kenan; Patel, Jugal K. (12 April 2017). "North Korea May Be Preparing Its 6th Nuclear Test". Retrieved 20 April 2017 – via NYTimes.com.
  22. ^ "The Comprehensive Test Ban Treaty: Effectively Verifiable - Arms Control Association". Retrieved 20 April 2017.