Surface contamination with beryllium becomes a hazard to health only when the potential exists for resuspension in air in enough quantity and for enough time to exceed the prescribed standards for airborne exposures. There are several factors governing the rate and nature of resuspension phenomena. These factors include: the quantity and properties of the particular beryllium compound causing the contamination, the nature of the surface, activities in the vicinity, ventilation in the area which might affect the dilution of resuspended particles, and the presence of other control measures such as respiratory protection and use of wet methods. Generally, it has been found that the problem is minimal and can be easily controlled by exercising good judgement based upon consideration of pertinent factors governing resuspension, and a knowledge of the nature of beryllium toxicity.

Boron-10 has a high thermal neutron capture cross section (3880 barns). Following neutron capture, the subsequent nuclear disintegration produces an alpha particle and a lithium-7 nucleus with the release of an average of 2.34 MeV for the particle irradiation, and in 93% of the reactions there is also the emission of an 0.48 MeV gamma ray: [equation not transcribed]. The kinetic energy is divided between the lithium-7 nucleus and the alpha particle giving the equal and opposite momentums with a range in tissue of about 8-14μ or approximately 1 cell diameter (1). This fact and the reported favorable partition of boron between tumor and the normal brain suggested a possible therapeutic usefulness which has been investigated clinically. The object of our study is to document the biological effects of the B10 (n,α) Li7 reaction on the brain of dogs injected with boron-10 30 minutes prior to irradiation with thermal neutrons. For this, we felt it desirable to estimate a dose for the boron-10 reaction which if exceeded, produces destruction of normal tissue. This dose could then be a reference dose to be utilized as a maximal limit for the irradiation of normal tissue. We have assured that the largest fluence …

Report that summarizes multiple laboratories' reports on global fallout deposition. Reports include data on Strontium-90 deposition recorded by the Health and Safety Laboratory, data from other laboratories, related interpretive reports, and recent publications related to fallout.

Technical report on the activities of the Oak Ridge National Laboratory Biology Division for the report period including a list of 346 publication and lectures and 205 short articles by members of the division on their research and activities.