An Empirical Model for Estimating World-wide Deposition from Atmospheric Nuclear Detonations

Abstract

An empirical model is presented for estimating the surface deposition of "worldwide'' radioactivity from atmospheric nuclear detonations given the yield, latitude, season and type of each burst. The procedure is readily adaptable to computer calculation.The model is based primarily on injection-deposition experience gained from the U.S. and U.S.S.R. nuclear tests in 1958. Use of the technique to estimate %r deposition from the 1961-62 tests shows the predictions are usually within a factor of two of the observed deposition.

Chlorine-36 in the Terrestrial Environment

“…The scale on the right-hand side of the graph is fallout in atoms ^^Cl m"^ s"^ between 30°N and 50°N latitude. The conversion from global fallout was made according to Peterson (1970) In order to test these predictions ^^Cl concentrations in a Greenland ice core, a well-understood shaUow aquifer, and the vadose zone in an arid re gion were measured.…”

“…10-1). The natural meteoric ratio is therefore 10 X 10"^^ The bomb-pulse input at 10°Ν to 10°S is estimated from that which occurred at 3O-50°N (7.5 X 10^^ ^^Cl atoms) by multiplying by 25% (Peterson, 1970). The average yearly input ratio over the 12-year period from 1952 to 1964, 8800 X 10-^^ is obtained by dividing the bomb-pulse input by both 12 and the yearly rainfall chlo ride multiplied by 1.3.…”

Measurements of low-level anthropogenic radionuclides from soils around Maralinga

“…From the point of view of using plutonium as a tracer of soil movement nuclear weapons tests can be divided into two categories: (i) high yield explosions that inject Pu into the stratosphere, where it remains with a residence half-life of 8 -24 months [1] and becomes relatively well mixed before returning to the surface as "global fallout", and (ii) low yield detonations (< ~300 kT) for which the bulk of the nuclear debris are confined to the troposphere, for a residence half-life estimated at ~70 days [2] and which leads to "regional fallout" over an area determined largely by the fission yield of the device and by the meteorological conditions at the time of the test and in the period thereafter. Fallout in the immediate vicinity of tests carried out close to ground level can also have relatively large particles derived from bomb fragments or contaminated ground material that are deposited from the atmosphere as "local fallout" within hours or days of the test [3].…”

Radiocesium in caribou and reindeer in northern Canada, Alaska and Greenland from 1958 to 2000

“…Because of its 30-y physical half-life, its role as a surrogate for potassium in biological systems, and the ease with which it accumulates in wildlife species and agricultural livestock, 137 Cs contamination of the biosphere has been a major public health concern since the early 1950s. UNSCEAR (1982) has estimated that a total of 960 Â 10 15 Bq of 137 Cs was released in the atmosphere during weapons testing, with the largest portion having been deposited between 30 and 70 N latitude (Feely et al, 1966;UNSCEAR, 1982) in 1963and 1964(Peterson, 1970. The higher deposition rates in mid-to high-latitudes, combined with the efficient uptake and accumulation of 137 Cs from lichen, led to the contamination of the lichenecaribouehuman food chain in northern Canada during the 1960s.…”