The following report records measurements and evaluations of fast neutron levels in remote areas monitored by personnel.

From abstract: "The Safety Program of the University of California Radiation Laboratory at Livermore, California, is discussed in terms of the functions of the six independent safety groups that comprise the laboratory's primary safety organization, namely, Industrial Safety, Medical Safety, Fire Prevention and First Aid, Health Chemistry, Health Physics, and High-Explosive Safety Groups."

"The code described here was designed to handle calculations of hydrodynamic motion in one-dimensional form, including provision for the disruption of a sample by 'spallation'. The term spallation refers to the rupture of the material by tension, induced by a rarefaction wave proceeding from a free surface."

"In these studies ions of several-kilovolts energy were extracted from an ion source located inside one of the peaks of the mirror field...The extraction slot of the source is located near the field injection plane, about midway between the mirror peak and the center, and ions are injected perpendicularly to magnetic field lines. In their traversal of the distance between the mirrors, the ions are in an inhomogeneous magnetic field and have a component of velocity along curved field lines. This gives rise to a to a 'guiding center' drift in the azimuthal direction and prevents the particle trajectory from intersecting the ion source after the first reflection. The magnetic field is increased during the injection period by an amount sufficient to move the reflection surface inside the ion source region by the time the ions have precessed completely about the symmetry axis."

The purpose of this report is to describe the shielding calculations and techniques used in sizing the MMSR primary shield, the results obtained, and the resulting shield thicknesses. The present report covers many of the items scheduled for presentation in the final MMSR shield design report to be issued in November of 1958. The primary shield in the MMSR consists of the reflector, thermal shields, pressure vessel wall, a 33" water annulus and a layer of lead shielding at the exterior of the primary shield tank vary from 3" to 1" in thickness.

Technical report was prepared by the Health and Safety Laboratory (HASL) with the objective of presenting a current picture of the Strontium Program. Abstract: Strontium 90 levels in fallout, milk, canned fish and tap water are summarized for data available up to April 5, 1958. Original data submitted during the month of March are included as an appendix. Data are presented to show the amount of Strontium 90 in fallout at sampling stations within and outside the United States.

Abstract: An analysis and a summary are.given of the radioactivity buildup program at the Army Package Power Reactor during the last nine months. · Due to the wide fluctuation of water and crud results, only general interpretations can be made with this data. Metal test coupon data indicate a substantially greater buildup on Croloy 16-1 metal than on Type 304 stainless steel. Coupled with the decreased ability to remove the radioactivity buildup on Croloy 16-1 by conventional descaling techniques, the implication is that this metal might pose a serious problem for use as steam generator material. It was emphasized, however, that results to date ae only preliminary and extensive additional experimentation would be required to reach more definite conclusions.

The Aircraft Reactor Experiment (ARE)was successfully concluded in November of 1954, and a detailed report of the operation was published the following year. At that time it was thought that an extensive examination of the reactor and system components after disassembly was warranted. It was realized, of course, that the level of radioactivity of the components would necessitate extensive delays in the examinations. Since examination of a few critical ARE samples showed nothing unexpected, much of the planned hot-cell inspection was postponed and complete examination of all but a few specimens was indefinitely suspended. The few examinations that were completed are described in this report, along with a description of the disassembly of the ARE system. Diagrams of the fuel system, sodium system, and off-gas system are presented in Figs. 1, 2, and 3 for reference use in visualizing the disassembly process.

For Co60 source at 15 meters, the air-scattered gamma dose rate predicted by theory is excerpted from ORNL-1575, pp. 167-203. This is compared with experimental measurements for the same source and comparable geometry reported by Convair in CVAC-170T. After applying an appropriate correction for ground scattering as estimated in Mart-55-16T (Convair), the two results are found to be in substantial agreement.