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美國紐約的一個放射塵避難所入口標誌

放射塵避難所是為保護人員免受核爆炸產生的放射性落下灰及其它放射性物質傷害的封閉空間。冷戰期間作為民事防護舉措,修建了大量放射塵避難所。

核爆炸時,地面物質因火球產生的高溫汽化,在吸收爆炸產生的中子後具有放射性。雨水和這類物質混合後形成了類似地面浮岩的輕質塵埃,即放射性落下灰。此類放射性物質落至地面並放出α粒子β粒子伽馬射線,造成顯著的放射性污染。放射塵避難所可以為人員提供庇護,以減少在放射性污染中的暴露程度,直到放射性程度下降到安全水平。

許多放射塵避難所留存至今,少數被闢為博物館

歷史

1957年左右的一個理想化的美國放射塵避難所

許多國家在冷戰期間為高級別政府官員和重要軍事設施修築放射塵避難所,例如美國的希臘島計劃英語Project Greek Island夏延山核戰碉堡加拿大緊急政府總部英語Emergency Government Headquarters。隨後制定了將現有建築物中地下室較堅固的改造成臨時放射塵避難所的計劃,並放置以黑黃相間三角形的避難所標誌。

美國在1956年建立了國家緊急警報中繼系統英語National Emergency Alarm Repeater(N.E.A.R.)以在核戰爭爆發時進行向公眾進行預警,並作為防空警報和無線電廣播的補充手段。在實際測試中這一系統並不實用,故在1966年被放棄。[1]

1961年9月,under the direction of Steuart L. Pittman英語Assistant Secretary of Defense for Homeland Defense and Americas' Security Affairs#Precedent, the federal government started the Community Fallout Shelter Program.[2][3] A letter from President Kennedy advising the use of fallout shelters appeared in the September 1961 issue of Life magazine.[4]

In November 1961 in Fortune magazine, an article by Gilbert Burck appeared that outlined the plans of 納爾遜·洛克菲勒, 愛德華·泰勒, Herman Kahn英語Herman Kahn, and Chet Holifield英語Chet Holifield for an enormous network of concrete lined underground fallout shelters throughout the 美國 sufficient to shelter millions of people to serve as a refuge in case of 核戰爭.[5]

American fallout shelters in the early 1960s were sometimes funded in conjunction with funding for other federal programs, such as 市區更新 projects of the Federal Housing Authority英語Federal Housing Authority, examples being Barrington Plaza英語Barrington Plaza, and other development projects of Los Angeles County Civil Defense and Disaster Commission英語Los Angeles County Civil Defense and Disaster Commissioner, Louis Lesser英語Louis Lesser, and were designed for large numbers of citizens.[6][7][8]

瑞士 built an extensive network of fallout shelters, not only through extra hardening of government buildings such as schools, but also through a building regulation that ensured that all residential building built after 1978 contained a nuclear shelter able to withstand a blast from a 12 megaton explosion at a distance of 700 metres.[9] In addition, the Swiss government maintains large communal shelters (including the Sonnenberg Tunnel英語Sonnenberg Tunnel) stocked with over four months of food and fuel.[9] The reference Nuclear War Survival Skills英語Nuclear War Survival Skills declared that, as of 1986, "Switzerland has the best civil defense system, one that already includes blast shelters for over 85 percent of all its citizens."[10]瑞士現今的居民避難所大多被改造成酒窖、溜冰室、體育館等其他用途,亦可作為其他自然災害的避難所。[9]

Similar projects have been undertaken in 芬蘭, which requires all buildings with area over 600 m² to have an NBC shelter, and 挪威, which requires all buildings with an area over 1000 m² to have a shelter.[11]

蘇聯東方集團國家則是將地鐵車站作為公共防空及放射塵避難所。

建築結構

Door to a light fallout shelter.

輻射防護

A basic fallout shelter consists of shields that reduce gamma ray exposure by a factor of 1000. The required shielding can be accomplished with 10 times the thickness英語Radiation protection#Shielding design of any quantity of material capable of cutting gamma ray exposure in half. Shields that reduce gamma ray intensity by 50% (1/2) include 1 cm (0.4 inch) of lead, 6 cm (2.4 inches) of concrete, 9 cm (3.6 inches) of packed earth or 150 m (500 ft) of air. When multiple thicknesses are built, the shielding multiplies. Thus, a practical fallout shield is ten halving-thicknesses of packed earth, reducing gamma rays by approximately 1024 times (210).[12]

Usually, an expedient purpose-built fallout shelter is a trench; with a strong roof buried by c. 1 m (3 ft) of earth. The two ends of the trench have ramps or entrances at right angles to the trench, so that gamma rays cannot enter (they can travel only in straight lines). To make the overburden waterproof (in case of rain), a plastic sheet may be buried a few inches below the surface and held down with rocks or bricks.[13]

Blast doors are designed to absorb the shock wave of a nuclear blast, bending and then returning to their original shape.[14]

氣候控制

Dry earth is a reasonably good thermal insulator, and over several weeks of habitation, a shelter will become dangerously hot.[15] The simplest form of effective fan to cool a shelter is a wide, heavy frame with flaps that swing in the shelter's doorway and can be swung from hinges on the ceiling. The flaps open in one direction and close in the other, pumping air. (This is a Kearny Air Pump英語Kearny Air Pump, or KAP, named after the inventor, Cresson Kearny英語Cresson Kearny)

Unfiltered air is safe, since the most dangerous fallout has the consistency of sand or finely ground pumice.[15] Such large particles are not easily ingested into the soft tissues of the body, so extensive filters are not required. Any exposure to fine dust is far less hazardous than exposure to the fallout outside the shelter. Dust fine enough to pass the entrance will probably pass through the shelter.[15] Some shelters, however, incorporate NBC英語Chemical, biological, radiological, and nuclear-filters for additional protection.

選址

Effective public shelters can be the middle floors of some tall buildings or parking structures, or below ground level in most buildings with more than 10 floors. The thickness of the upper floors must form an effective shield, and the windows of the sheltered area must not view fallout-covered ground that is closer than 1.5 km (1 mi). One of Switzerland's solutions is to utilise road tunnels passing through the mountains; with some of these shelters英語Sonnenberg Tunnel being able to protect tens of thousands.[16]

Fallout shelters are not always underground. Above ground buildings with walls and roofs dense enough to afford a meaningful protection factor英語Radiation protection#Shielding design can be used as a fallout shelter.[17]

設施

A battery-powered radio may be helpful to get reports of fallout patterns and clearance. However, radio and other electronic equipment may be disabled by 電磁脈衝. For example, even at the height of the cold war, EMP protection had been completed for only 125 of the approximately 2,771 radio stations in the United States 緊急廣播系統. Also, only 110 of 3,000 existing Emergency Operating Centers had been protected against EMP effects.[18] The 緊急廣播系統 has since been supplanted in the United States by the 緊急報警系統.

The reference Nuclear War Survival Skills英語Nuclear War Survival Skills includes the following supplies in a list of "Minimum Pre-Crisis Preparations": one or more shovels, a pick, a bow-saw with an extra blade, a hammer, and 4-mil polyethylene film (also any necessary nails, wire, etc.); a homemade shelter-ventilating pump (a KAP英語Kearny Air Pump); large containers for water; a plastic bottle of sodium hypochlorite bleach; one or two KFM英語Kearny Fallout Meters and the knowledge to operate them; at least a 2-week supply of compact, nonperishable food; an efficient portable stove; wooden matches in a waterproof container; essential containers and utensils for storing, transporting, and cooking food; a hose-vented 5-gallon can, with heavy plastic bags for liners, for use as a toilet; tampons; insect screen and fly bait; any special medications needed by family members; Pure 碘化鉀, a 2-oz bottle, and a medicine- dropper; A first-aid kit and a tube of antibiotic ointment; long-burning candles (with small wicks) sufficient for at least 14 nights; an oil lamp英語Nuclear War Survival Skills#Light; a flashlight and extra batteries; and a transistor radio with extra batteries and a metal box to protect it from EMP.[19]

Inhabitants should have water on hand, 1-2 gallons per person per day. Water stored in bulk containers requires less space than water stored in smaller bottles.[20]

Commercially made 蓋革計數器 are expensive and require frequent calibration. It is possible to construct an electrometer-type radiation meter called the Kearny Fallout Meter英語Kearny Fallout Meter, which does not require batteries or professional calibration, from properly-scaled plans with just a coffee can or pail, gypsum board, monofilament fishing line英語monofilament line, and aluminum foil.[21] Plans are freely available in the public domain in the reference Nuclear War Survival Skills英語Nuclear War Survival Skills by Cresson Kearny英語Cresson Kearny.[22]

使用

Inhabitants should plan to remain sheltered for at least two weeks (with an hour out at the end of the first week – see Swiss Civil Defense guidelines (which was once part of Swiss Zivilschutz)), then work outside for gradually increasing amounts of time, to four hours a day at three weeks. The normal work is to sweep or wash fallout into shallow trenches to decontaminate the area. They should sleep in a shelter for several months. Evacuation at three weeks is recommended by official authorities.[來源請求]

If available, inhabitants may take 碘化鉀 at the rate of 130 mg/day per adult (65 mg/day per child) as an additional measure to protect the thyroid gland from the uptake of dangerous radioactive iodine, a component of most fallout and reactor waste.[23]

Relative abilities of three different types of 游離輻射 to penetrate solid matter.
The protection factor provided by 10 cm of concrete shielding where the source is the idealised Chernobyl fallout.[24]
The protection factor provided by 20 cm of concrete shielding where the source is the idealised Chernobyl fallout.[24]
The protection factor provided by 30 cm of concrete shielding where the source is the idealised Chernobyl fallout.[24]
Calculated relative gamma dose rates from atomic bomb and chernobyl fallout

放射性落塵阻擋效果

α粒子

In the vast majority of accidents, and in all 核武器 blasts, the threat due to beta and gamma emitters is greater than that posed by the alpha emitters in the fallout. Alpha particles are identical to a helium-4 nucleus (two protons and two neutrons), and travel at speeds in excess of 5% of the speed of light. Alpha particles have little penetrating power; most cannot penetrate through human skin. Avoiding direct exposure with fallout particles will prevent injury from alpha radiation.[25]

β粒子

Beta radiation consists of particles (high-speed electrons) given off by some fallout. Most beta particles cannot penetrate more than about 10 feet (3 m) of air or about 18 inch (3 mm) of water, wood, or human body tissue; or a sheet of aluminum foil. Avoiding direct exposure with fallout particles will prevent most injuries from beta radiation.[26]

The primary dangers associated with beta radiation are internal exposure from ingested fallout particles and beta burns from fallout particles no more than a few days old. Beta burn英語Beta burns can result from contact with highly radioactive particles on bare skin; ordinary clothing separating fresh fallout particles from the skin can provide significant shielding.[26]

γ射線

Gamma radiation penetrates further through matter than alpha or beta radiation. Most of the design of a typical fallout shelter is intended to protect against gamma rays. Gamma rays are better absorbed by materials with high atomic numbers and high density, although neither effect is important compared to the total mass per area in the path of the gamma ray. Thus, lead is only modestly better as a gamma shield than an equal mass of another shielding material such as aluminum, concrete, water or soil.

Some gamma radiation from fallout will penetrate into even the best shelters. However, the radiation dose received while inside a shelter can be significantly reduced with proper shielding. Ten halving thicknesses英語Radiation protection#Shielding design of a given material can reduce gamma exposure to less than 11000 of unshielded exposure.[27]

核武器防護

The bulk of the 放射性 in nuclear accident fallout is more long-lived than that in weapons fallout. A good table of the 核素s, such as that provided by the Korean Atomic Energy Research Institute英語Korean Atomic Energy Research Institute, includes the fission yields of the different nuclides. From this data it is possible to calculate the isotopic mixture in the fallout (due to 核分裂產物 in bomb fallout).[來源請求]

Measures to lower the beta dose

The main threat of beta radiation exposure comes from hot particle英語hot particles in contact with or close to the skin of a person. Also, swallowed or inhaled hot particles could cause beta burn英語beta burns. As it is important to avoid bringing hot particles into the shelter, one option is to remove one's outer clothing, or follow other decontamination procedures英語human decontamination, on entry. Fallout particles will cease to be radioactive enough to cause beta burns within a few days following a nuclear explosion. The danger of gamma radiation will persist for far longer than the threat of beta burns in areas with heavy fallout exposure.[28]

Measures to lower the gamma dose rate

The gamma dose rate due to the contamination brought into the shelter on the clothing of a person is likely to be small (by wartime standards) compared to gamma radiation that penetrates through the walls of the shelter.[28] The following measures can be taken to reduce the amount of gamma radiation entering the shelter:

  • Roofs and gutters can be cleaned to lower the dose rate in the house.
  • The top inch of soil in the area near the house can be either removed or dug up and mixed with the 底土. This reduces the dose rate as the gamma rays have to pass through the topsoil before they can irradiate anything above.
  • Nearby roads can be rinsed and washed down to remove dust and debris; the 放射性落下灰 would collect in the sewers and gutters for easier disposal. In 基輔 after the 車諾比核事故 a program of road washing was used to control the spread of radioactivity.
  • Windows can be bricked up, or the sill raised to reduce the hole in the shielding formed by the wall.
  • Gaps in the shielding can be blocked using containers of water. While water has a much lower density than that of lead, it is still able to shield some gamma rays.
  • Earth (or other dense material) can be heaped up against the exposed walls of the building; this forces the gamma rays to pass through a thicker layer of shielding before entering the house.
  • Nearby trees can be removed to reduce the dose due to fallout which is on the branches and leaves. It has been suggested by the US government that a fallout shelter should not be dug close to trees for this reason.[29]

流行文化

美國的放射塵避難所標誌

Fallout shelters feature prominently in the 羅伯特·海萊因 novel Farnham's Freehold英語Farnham's Freehold (Heinlein built a fairly extensive shelter near his home in Colorado Springs in 1963),[30] Pulling Through by Dean Ing, 萊博維茲的讚歌 by 小沃爾特·M·米勒 and Earth英語Earth (Brin novel) by 大衛·布林.

The 陰陽魔界 episode "The Shelter英語The Shelter (The Twilight Zone)", from a Rod Serling英語Rod Serling script, deals with the consequences of actually using a shelter.

In the Only Fools and Horses英語Only Fools and Horses episode "The Russians are Coming英語The Russians Are Coming (Only Fools and Horses)", Derek Trotter buys a lead fallout shelter, then decides to construct it in fear of an impending nuclear war caused by the Soviet Union (who were still active during the episode's creation).

The 1982 album The Nightfly英語The Nightfly by Donald Fagen英語Donald Fagen features a song, 'New Frontier', about an early-1960s teenager enticing his girlfriend into spending a romantic weekend with him in his family's backyard fallout shelter.

In 1999 the 電影超時空寵愛英語Blast from the Past (film)》was released. It is a 浪漫喜劇 about a 原子核物理學家, his wife, and son that enter a well-equipped, spacious fallout shelter during the 1962 古巴飛彈危機. They do not emerge until 35 years later, in 1997. The film shows their reaction to contemporary society.

In book 11 of the 怪奇馬戲團 book series, Darren and Harkat must go into an alternate world. They then find a fallout shelter with post cards on the refrigerator from the late 1940s and realized that they had gone forward in time.

The輻射系列 of computer games depicts the remains of human civilization after an immensely destructive nuclear war; the United States of America had built underground vaults that were advertised to protect the general population against a nuclear attack, but were, in fact, grand social experiments that did little to protect their inhabitants.

妄想症, a role-playing game, takes place in a form of fallout shelter, which has become ruled by an insane computer.

The 地鐵2033 book series by Russian author Dmitry Glukhovsky英語Dmitry Glukhovsky depicts survivors' life in the subway systems below Moscow and Saint-Petersburg after a global nuclear holocaust.

戈馬克·麥卡錫's book The Road and the accompanying movie has its main characters finding a shelter (bomb英語bomb shelter or fallout) with uneaten rations.

參見

參考資料

  1. ^ [1][失效連結]
  2. ^ Civil Defense Museum-Community Shelter Tours Main Page. www.civildefensemuseum.com. [2008-09-14]. 
  3. ^ FALLOUT FEVER: Civil Defense shelters dotted area cities during the Cold War – My Web Times. mywebtimes.com. [2008-09-14]. 
  4. ^ DOE.gov
  5. ^ Fortune magazine November 1961 Pages 112–115 et al
  6. ^ Los Angeles Times, November 15, 1961 「Board Asks Full Study of Shelters」 [2]
  7. ^ Los Angeles Times, Oct 15, 1961
  8. ^ Los Angeles Times, December 3, 1961 「Businessman Appointed to CD Group」 [3]
  9. ^ 9.0 9.1 9.2 Ball, Deborah. Swiss Renew Push for Bomb Shelters. Wall Street Journal. June 25, 2011 [18 December 2012]. 
  10. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 6–10. ISBN 0-942487-01-X. 
  11. ^ FOR 1995-03-15 nr 254: Forskrift om tilfluktsrom. Lovdata.no. [2012-08-15]. 
  12. ^ Halving-thickness for various materials. "The Compass DeRose Guide to Emergency Preparedness - Hardened Shelters". 
  13. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 37–45. ISBN 0-942487-01-X. 
  14. ^ Secret U.S. Bunkers. Lost Worlds英語Lost Worlds (TV series). 第18集. August 29, 2007. The History Channel. 
  15. ^ 15.0 15.1 15.2 Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 51–56. ISBN 0-942487-01-X. 
  16. ^ Foulkes, Imogen. Swiss still braced for nuclear war. BBC News, Switzerland. 10 February 2007 [15 August 2012]. 
  17. ^ Monteyne, David. Fallout Shelter: Designing for Civil Defense in the Cold War. Minneapolis: University of Minnesota, 2011. Print.
  18. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 24. ISBN 0-942487-01-X. 
  19. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 133–134. ISBN 0-942487-01-X. 
  20. ^ Hammes, JA. Fallout shelter survival research. 1966: 154–159. 
  21. ^ Kearny, Cresson H. The KFM, A Homemade Yet Accurate and Dependable Fallout Meter (PDF). Oak Ridge, TN: Oak Ridge National Laboratory. 1978. 
  22. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 95–100. ISBN 0-942487-01-X. 
  23. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 111–117. ISBN 0-942487-01-X. 
  24. ^ 24.0 24.1 24.2 Note that this image was drawn using data from the OECD report and the second edition of The Radiochemical Manual
  25. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 45. ISBN 0-942487-01-X. 
  26. ^ 26.0 26.1 Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 44. ISBN 0-942487-01-X. 
  27. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 11–20. ISBN 0-942487-01-X. 
  28. ^ 28.0 28.1 Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 131. ISBN 0-942487-01-X. 
  29. ^ Kearny, Cresson H. Nuclear War Survival Skills. Oak Ridge, TN: Oak Ridge National Laboratory. 1986: 39. ISBN 0-942487-01-X. 
  30. ^ site: Robert A. Heinlein – Archives – PM 6/52 Article

外部連結