Ground surface bursts

The Specific Activity of Nuclear Debris from Ground Surface Bursts as a Function of Particle Size... 

The specific activities of radionuclides in debris from ground surface bursts are generally complicated functions of the particle size, in accordance with the composite nature of the debris. 

T,he size and mass frequency distributions of the particles in clouds from ground surface bursts have an essential bearing on predictions of the fallout field resulting from such nuclear explosions. Fallout models that are still in use employ size distributions which have been derived... 

Table II. Sampling Data for Some Cloud Samples from Ground Surface Bursts...

Pittman (1972) performed five experiments with titanium-alloy pressure vessels which were pressurized with nitrogen until they burst. Two cylindrical tanks burst at approximately 4 MPa, and three spherical tanks burst at approximately 55 MPa. The volume of the tanks ranged from 0.0067 m to 0.170 m. A few years later, Pittman (1976) reported on seven experiments with 0.028-m steel spheres that were pressurized to extremely high pressures with argon until they burst. Nominal burst pressures ranged from 100 MPa to 345 MPa. Experiments were performed just above ground surface. 

For Class D hazards, the company has defined the evaluation case event to be 8 x 106 Btu (8.4 x 106 kj) energy release as a hemispherical ground level explosion, unless a comprehensive analysis defines a lesser event as the evaluation case. For a VCE evaluation, this is further defined as the release and vaporization of 10,000 lb. (4,500 kg) of ordinary hydrocarbons, or the release and vaporization of 6,600 lb. (3,000 kg) of fast-burning materials [fundamental burning velocity >24 in/sec (>60 cm/sec)] within 5 minutes, when the largest connection to a tank or vessel is broken. [On a TNT basis, this is equivalent to a surface burst of approximately 2 tons (1,800 kg) TNT, calculated on the basis of 4% efficiency for ordinary hydrocarbons or 6.6% efficiency for fast-burning materials.]... 

Kingery, C. N., and Bulmash, G., "Airblast Parameters from TNT Spherical Air Burst and Hemispherical Surface Burst," Ballistic Research Laboratory Technical Report ARBRL-TR-02555, Aberdeen Proving Ground, MD., 1984. 

Overpressure Versus Time Histories (Nuclear and TNT Surface Bursts) , BRL-1638, Ballistic Res labs, Aberdeen Prov Gmds (1973) (Limited distrib) 133) D.W. Murrell, AEWES-TR-N-74-3, Army Engr Waterways Exptl Sta, Vicksburg (1974) 134) I.S. Sandler et al, Ground... 

Hemispherical TNT Surface Bursts, BRL Report No. 13, Aberdeen Proving Ground, Md., September 1966. (U)... 

In this chapter, we will examine craters created from ground-level bursts, above-surface bursts, and buried bursts. We will find methods to scale from existing databases that wilt allow us to correct for the type of explosive as well as the type of ground medium. 

Use the scaling data for surface bursts to scale crater dimensions for aboveground bursts. Correct these data for ground medium and explosive type, but also correct the explosive equivalent weight by the ratio of percent energy coupled at height of burst to 33% (% coupled at HOB = 0). Combined with the equation shown in Figure 29.6, this becomes... 

B. Surface Burst. A surface burst weapon is detonated on or slightly above the surface of the earth so that the fireball actually touches the land or water surface. The area affected by blast, thermal radiation, and initial nuclear radiation will be less extensive than for an air burst of similar yield, except in the region of ground zero where destruction is concentrated. In contrast with airbursts, local fallout can be a hazard over a much larger downwind area than that which is affected by blast and thermal radiation. 

C. Subsurface Burst. A subsurface burst weapon is detonated beneath the surface of land or water. Cratering will generally result from an underground burst, just as for a surface burst. If the burst does not penetrate the surface, the only other hazard will be from ground or water shock. If the burst is shallow enough to penetrate the surface, blast, thermal, and initial nuclear radiation effects will be present, but will be less than for a surface burst of comparable yield. Local fallout will be very heavy if penetration occurs. 

Kingery, C.N. and G. Bulmash, irWsurface bursts. 1984, Balistic Research Laboratory, Aberdeen Proving Ground, Maryland, US. 

Surface burst a nuclear weapon explosion that is close enough to the ground for the radius of the fireball to vaporize surface material fallout from a surface burst contains very high levels of radioactivity... 

For BLEVEs or pressure vessel bursts that take place far from reflecting surfaces, the above method may be used if a few modifications are made. The blast wave does not reflect on the ground. Thus, the available energy E is spread over twice the volume of air. Therefore, instead of using Eq. (6.3.15), calculate the energy with... 

Such large weapons cause the hot fireballs to rise into the stratosphere (NAS, 1975). A several fold increase in the penetration of ultraviolet radiation to the earth s surface would result. This was considered to be the main, long-term, global, atmospheric effect of a total nuclear war. By cursory comparison with the reported effects of major volcanic explosions, the production of dust from nuclear ground bursts was estimated to lead to rather insignificant changes in the earth s climate. 

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