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Buenos Aires 19-24 October 2008

Dose Prediction for Surface Nuclear Explosions
Case Studies for Semipalatinsk and Lop Nur Tests

Jun Takada, PhD, Professor, Sapporo Medical University

IRPA12 International Congress of the International Radiation Protection Association

Abstract. Dose prediction method RAPS after surface nuclear explosion has been developed by using the empirical dose function of USA nuclear test. This method which provides us external total dose, dose rate at any distant, at any time for any yield of nuclear explosion, is useful for radiation protection incase of nuclear events such as terrorism and nuclear war. The validity of RAPS has been confirmed by application to historical surface nuclear test explosions. The first test case study which was done for the first test explosion of the former USSR at the Semipalatinsk Nuclear Test Site on August 29th 1949, shows a good agreement with luminescence dosimetries on a brick. This dose prediction method was applied nuclear tests in Lop Nur. The results indicate dangerous nuclear radiation influences including fatal risk in the wide Uygur area.

論文和名：　地表核爆発に対する線量予測；　セミパラチンスクおよびロプノル実験の事例研究

Dangerous doses in Uygur

a Good agreement between dose values of Kazakhstan and RAPS suports validity in dose evaluation in Uygur area near the ground zeros. Capital Urmuchi and Turpan are along a line between Ground zero and Makanchi. These cities are located 380 km and 250 km far from the Ground zero.

Doses in air around Urmuchi are estimated to be 0.8 Sv (for Jun 17th, 1967 Exp.) and 1.5 Sv (for Jun 27th, 1973 Exp.). Doses in air around Turpan are estimated to be 0.8 Sv (for Jun 17th, 1967 Exp.) and 1.5 Sv (for Jun 27th, 1973 Exp.) [9]. These doses causes acute disease or fetus influence. Populations in those cities are 1.6 million and 0.24 million respectively at present. People in those area shoud be suffered not only externally but also internally by radioactive fallout.

Sites with fatal risky doses more than 4 Sv in downwind side are estimated to be within 250 km (for Jun 17th, 1967 Exp.) and 290 km (for Jun 27th, 1973 Exp.) in Chinese tests. Such accidental cases are recorded in history of nuclear tests in the USA and in the former USSR.

Lop Nur Nuclear Testing

Chinese the Lop Nur Nuclear Test site is located around at the eastern edge of Taklimakan Desert. The safety control of Chinese test has been unclear. The first nuclear test is conducted on the surface on October 16th in 1964. A total of 46 nuclear tests with about twenty megaton yield were conducted till 1996 at the Lop Nur nuclear test site, including about ten surface explosion. The maximam yield of a surface explosion was 4.0 Mt of thermonucler bomb on November 17th 1976.

The monitoring for Chinese nuclear tests was carried out at Kazafkstan near the Chinese bordering in the former USSR periode. A Kazakhstan report on dosimetry study shows us remarkable doses in Kazakhstan due to two thermonucler explosions. The first one was a test explosion with 2.0 Mt on Jun 6th 1967, the second was a test explosion with 2.5 Mt on Jun 17th 1973. The report presents that the doses in air are 0.14 Sv and 0.22Sv for the two tests at Makanchi about 1000 km far from the ground zero.
Dose predictions by RAPS have been applied for two megaton order surfase and near surfase thermonuclear explosions in the Lop Nur Nuclear Test Site [9]. A Kazafkstan report was used mainly for the initial values for calculations such as explosion yields, exposion hight, and wind velosities.

Internet survise of Google Earth has been used for determin of global positions of ground zeros, investigation objects, and distances. The difference of distance between values of Kazakhstan and of the present work is 40 km of 4% for a distance between Makanchi and Ground zero. It is acceptable for dose evaluation.

Doses values by RAPS with 50% of total yield as fission yield have a good agreement with values of Kazafkstan report. Then portion of fission yield in RAPS was modified slightly to make better agreement. The portion for fallout activity depends on the explosion height and technology of weapon devices

TS II.3.1 - 648