tailieunhanh - Radiation and Health - Chapter 9

Chương này là có liên quan với liều bức xạ cho công chúng từ các thử nghiệm vũ khí hạt nhân, cũng như những kết quả từ vụ tai nạn lò phản ứng hạt nhân đã xảy ra trong những năm qua. Kể từ khi liều lượng tham gia chủ yếu là nhỏ (nhỏ hơn so với liều bức xạ tự nhiên), nó là vô cùng khó khăn để xác định ảnh hưởng sức khỏe từ những liều thêm. Đây là một vấn đề được tranh luận rộng rãi và sẽ được thảo luận chi tiết hơn trong Chương 11. | Chapter 9 Nuclear Weapons and Reactor Accidents Nuclear Bomb Tests This chapter is concerned with radiation doses to the public from nuclear weapons tests as well as those resulting from nuclear reactor accidents that have occurred over the years. Since the doses involved are mostly small smaller than the doses from natural radiation it is extremely difficult to pinpoint the health effects from these extra doses. This is a widely debated issue and will be discussed in more detail in Chapters 11 and 12. Here we will concentrate on the doses. During the period from 1945 to 1981 461 nuclear bomb tests were performed in the atmosphere. The total energy in these tests has been calculated to be the equivalent of about 550 megatons of TNT TNT is the abbreviation for trinitrotoluene . The bombs in Hiroshima and Nagasaki had a blasting power of respectively 15 and 22 thousand tons of TNT. Nuclear tests were particularly frequent in the two periods from 1954 to 1958 and 1961 to1962. Several nuclear tests were performed in the lower atmosphere. When a blast takes place in the atmosphere near the ground large amounts of activation products are formed from surface materials drawn up into the blast. The fallout is particularly significant in the neighborhood of the test site. One of the best known tests with significant fallout took place at the Bikini atoll in the Pacific in 1954 see next page . 2003 Taylor Francis 94 Radiation and Health A bomb test in the Pacific On March 1 1954 the United States detonated a hydrogen bomb with a power of about 15 million tons of TNT at the Bikini-atoll in the Pacific. The bomb was placed in a boat in relatively shallow water. Considerable amounts of material such as coral were sucked up into the fireball and large amounts of activation products were formed. A couple of hours after the blast the instruments on the American weather station on Rongerik island about 250 km away indicated a high radiation level. The radiation increased rapidly and