FALLOUT CONTROL. Final Report

Technical Report · Fri Aug 01 04:00:00 EDT 1958

OSTI ID:4258155

Lapple, C E

Following the explosion of a nuclear weapon, a great deal of radioactive material, primarily fission products from the weapon, is introduced into the atmosphere. This material falls or is carried to earth at various times and distances from the time and point of the explosion, much of it being distributed over the entire earth. Some of the radioactive fall-out has a relatively short life; although its intense radiation constitutes the primary hazard at sites close to the point of detonation, it soon decays. It is the widely distributed, long-lived fallout that constitutes weapons testing's primary somatic hazard to man, because it can bo assimilated by vegetation, animals, and humans over vast areas and over long periods of time. The direct human intake of radioactive materials from drinking water, from air, and through the skin is small compared with the indirect intake through foods such as fruits, vegetables, milk, and meat. The ability of at least some forms of vegetation and organisms to concentrate specific elements accounts for the predominant role of vegetation as the major source of human intake of radioactive materials. The fission of uranium-235 and plutonium-239, the two materials in common use in weapons today, results in a wide variety of radioactive materials. The fission yields from both of these materials are very similar, and discussions refer to the fission of uranium-235, since most of the interpretative information in the literature has been given for uraniunn-235. Of the fission products, only strontium-90, and to a lesser extent cesium-137, are of direct biological concern. Neither material is found to any significant extent as a primary fission product but are the product of decay of one or more precursors. Strontium-90 and cesium-137 are considered to be the most hazardous fission products because of their long lives and relatively high emission rates. Of these, strontium-90 is considered the most dangerous. Because of its similarity to calcium, it tends to concentrate in the bone structure rather than being excreted quickly, and hence has a relatively long biological life. For most populations the bulk of the strontium-90 enters man through milk and dairy products, which in turn reflect the transfer of strontium- 90 from vegetation to the cow. The origin, types, and destiny of radioactive fall-out are outlined. Basic data on fall-out are reviewed. The entry and biological hazards of strontium-90 in the human food-chain are discussed. The feasibility is considered of various conceivable control measures for fall-out which may be applied to the firehall or cloud during weapons testing. Suggestions are included for a program for experimentally developing additional information necessary for the assessment of control measures. Data are appended on the terminal settling velocities and diffusion coefficients for aerosol particles, vapor pressure and melting points for various compounds, fission product decay relationships, diffusion growth and deposition of particles, and particle scavenging. 1101 references. (C.H.)

• Research Organization: Stanford Research Inst., Menlo Park, Calif.
• NSA Number: NSA-13-012569
• OSTI ID: 4258155
• Report Number(s): SRIA-3
• Country of Publication: United States
• Language: English

Related Subjects

ABSORPTION
AEROSOLS
AIR
ANIMALS
ATMOSPHERE
BIBLIOGRAPHY
BONES
CALCIUM
CESIUM 137
DECAY
DIFFUSION
DISTRIBUTION
ENRICHMENT
FALLOUT
FISSION PRODUCTS
FOOD
HALF-LIFE
HAZARDS
HEALTH AND SAFETY
MAN
MELTING POINTS
MILK
NUCLEAR EXPLOSIONS
PARTICLES
PLANTS
PLUTONIUM 239
PRESSURE
RADIATION INJURIES
RADIOACTIVITY
SAFETY
SKIN
STRONTIUM 90
TESTING
URANIUM 235
VAPORS
VELOCITY
WATER