The boundary condition (26) on the earth's surface should reflect the nature of the interaction of diffusing particles with the underlying surface. The vertical flow of admixture in this case is equal to K,; B is a constant with the dimenƏz

sionality of rate, characterizing the interaction between the diffusing admixture and the underlying surface. K2 is the coefficient of vertical diffusion. An expression for q(x,y,z,t,h) may be written in the following manner:

k2

where: Q(t) the total amount of radioactive admixture falling out in the long

range fallout zone

The value of o(t), the dispersion of a diffusing particle's coordinate with time, is described either by the conditions σ2~ t2 at small values of t or o2 = 2kt (semiempirical) at large values of t. In this case the scale of turbulence in different studies turns out differently, and in view of the limited nature of measurements, the transition to o2~t is impossible to establish. For this reason values of the diffusion coefficient K are usually cited in the bibliography which are obtained in different experiments for a definite diffusion time. If we consider that

for a time of more than one or two days the rule σ ~ √t, applies, then, taking values determined from experiment Kx = Ky = 109 cm2/sec, K2 = 2 × 105 cm2/ sec, in accordance with formula (27), at large value of t and z = 0, we obtain:

q(x,0,0,t,h) 2.4 × 10−13 hQ(t) 。−(h/0.3t) — [(x — vt)2/1.5 × 10❜t] Curies†

~

π(x,0,0,t,h) ~

Bh

m3

2.4 × 10-1hQ(t)-(h2/0.3t)-[(x-vt)2/1.5 x10't]_Curies‡

(28)

(29)

km2-hour

*Editors Note: should be t.

† Editors Note: Equation should read:

q(x,0,0,t,h) ~ 2.4 × 10−13 hQ(t) 。−(h2/0.3t) — {(x − vt)2/1.5 × 103t] Curies

Equation should read:

π(x,0,0,t,h)~

42-051 - 70 - pt. 2 39

Bt

m3

2.4 × 10−4hQ(t) −(h2/0.3t) — [(x− )2/1.5 × 103t)

t

Curies km2-hour

where π = Bq is the flow of the admixture through the surface of the earth, i.e., the density of radioactive fallout at a distance of x km from the epicenter; Q(t) is the amount of radioactive products falling out in the long range zone, which comprises a value ~105 Curies/kt one day after the explosion; h is the cloud altitude (km); and t is the time from the moment of explosion (in hours); the numerical value of B ~ 3.6 × 10-2 km/hr. The curve of measurement of the value of radioactive fallout density with distance from the epicenter for an explosion of 1 kt power is shown in Figure 28.

The relationship in Figure 28 was constructed with account taken of the decay in time of the fractionated mixture of radioactive products falling out in the long range zone. The points in Figure 28 represent the maximum values of density of radioactive fallout recorded at various distances in the case of the "1003" explosion.

On the basis of the relationships shown in Figure 28, it is possible to forecast long range fallout. In this case it is possible to consider that the percentage wise portions of the activity in the long range fallout of Sr 90 and Cs 137, converted to the 7th day after the explosion, are 0.2-0.6% and 0.4% respectively.

Fig. 28 CHANGE IN THE VALUE OF FALL-OUT DENSITY IN THE LONG-RANGE PATTER OF AN UNDERGROUND NUCLEAR EXPLOSION.

BIBLIOGRAPHY

1. Zel'dovich, Ya. B. and Rayzer, Yu. P., Physics of Shock Waves and High Temperature Hydrodynamic Phenomena, Moscow, “Nauka” Publishing House, 1966.

2. Johnson, et al., Jour. Geophys. Res., v. 64, NIO 1457 (1959).

3. Johnson, G., Higgins, G., "Technical Applications of Nuclear Explosive Devices According to the 'Plowshare' Project," Paper No. P/291 at the International Geneva Conference, 1964.

4. Izrael', Yu. A., Dokl. AN SSSR, vol. 169, No. 3, 573 (1966).

5. Martell, E. A., Science, vol. 148, N3678, 1756 (1965).

6. Izrael, Yu. A., Stukin, Ye. D., Gamma Radiation of Radioactive Fallout, 'Atomizdat" Publishing House, Moscow, 1967.

7. Johnson, G. W., Phys. To-Day, vol. 16, NII, 38 (1963).

8. PNE-201F, Final Report of Weather and Surface Radiation Prediction Activities for Project Sedan, Weather Bureau, 1962.

9. Miskel, I., UCRL-14778, 1966, NSA, 1966, vol. 20, N24 abstr. 45833. 10. Bonner, N. A. and Miskel, I. A., Science, vol. 150, N3695, p.489 (1965). 11. Nordyke, M. D., Wray, W., Journ. Geophys. Res., vol. 69, No4, 675 (1964). 12. Lane, W. B., PNE-229 F, 1964, NSA, 17, 23551.

13. Kroker, G., et al., in the collection Radioactive Fall-out from Nuclear Explosions, "Mir" Publishing House, Moscow, 1968, p.54.

14. Freiling, E. C., Science, vol. 133, N3469, 1991 (1961).

15. Grechushkina, M. P., Izrael', Yu. A., in the collection Radioactive Isotopes in the Atmosphere and Their Use in Meteorology, Moscow, “Atomizdat' Publishing House, 1965.

16. Bryant, E. A., et al., Science, vol. 132, 327 (1960).

17. Izrael', Yu. A., Dokl. AN SSSR, vol. 161, No. 2, 343 (1965).

18. Sinitsyn, N. M., et al., Zh-1 neogranich. khimii, vol. 13, 2778 (1968).

19. Petrov, V. N., Pressman, A. Ya., Dokl. AN SSSR, vol. 146, No. 1, 1962.

20. Knox, J., in the collection Radioactive Fall-out from Nuclear Explosions, "Mir" Publishing House, Moscow, 1968, p. 159-.

APPENDIX 10

AN APPROACH TO THE DEVELOPMENT OF GUIDELINES FOR PLOWSHARE*

By

E. G. Struxness and P. S. Rohwer**

Health Physics Division

Oak Ridge National Laboratory***
Oak Ridge, Tennessee

1.0 Introduction

The question of health and safety guidelines for wide-scale applications of peaceful nuclear explosives (PNE), particularly as it applies to nuclear cratering, was raised in the US-USSR talks in Vienna, April 14-16, 1969. The need for such guidelines was recognized. One suggestion indicated that guidelines patterned after those for reactor effluents might be a possibility. We present here an approach to the development of Plowshare guidelines somewhat like those which could be applied to reactor effluents.

*To be presented at the 2nd Session of US-USSR Technical talks being convened in Moscow, February 10-18, 1970.

**The views expressed in this paper are those of the authors only, and are not to be construed as having been endorsed by the International Commission on Radiological Protection, or the Federal Radiation Council.

***Work sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation.

As seen at the present time, we believe this effort will proceed as follows: (1) the selection and interpretation of appropriate radiation protection standards against which to gauge the safety of radioactive releases from nuclear excavations; (2) the development of reasonably simple controls which can be used to establish a plausible connection between concentrations of radionuclides in air, as determined by conventional radiological air monitors, and the potential radiation doses (internal and external) that might be received by man via two exposure pathways: inhalation of the airborne radioactivity and submersion in the radioactive cloud; and (3) the development of similar controls, as in (2) above, for application in situations involving external and internal exposures via contaminated landscape and food-chain pathways, respectively: external exposure from contaminated landscape and ingestion of contaminated food and water. This paper reports on progress to date in (1) and (2), and our intended approach to (3).

2.0 The ICRP's Guidelines

Our starting point is an assertion that the recommendations of the International Commission on Radiological Protection (ICRP) for the protection of members of the public apply in this case, as they do to other sources of radiation and radioactive contamination, save (1) (2) (3) for natural background and medical sources. It follows, then, that we should develop guidelines for Plowshare that are as

consistent as possible with ICRP's guidelines, even though they were