Abstract: The data obtained from the radioassay of fish collected in vicinity of the Hanford Works between April, 1948 and June, 1950 are presented. Most of the radioactivity in the fish resulted from the concentration of p32 in the scales, bone, and certain visceral organs. The level of activity density in the fish was influenced by size, feeding habits and metabolic rate in addition to the activity density of the water. Changes in operation of nuclear reactors have resulted in progressive increases in activity densities of fish from one year to the next. The levels of radioactivity are not sufficiently high to be hazardous to either the fish or persons eating them.

A design study has been made of a graphite superheating reactor, a graphite moderated reactor with a heat rating of 305 Mw which produces superheated steam. It is designed for the production of plutonium and electrical power or for the production of electrical power only. The fuel elements for dual- purpose operation are U metal, while for single purpose action, they are uranium oxide. The fuel elements are cooled by a 7-pass system in which preheated water enters the bottom of the first pass and is discharged as superheated steam at the top of the seventh pass. The reactor control consists of shim control by the gas system, vertical gas-cooled control rods, vertical safety rods, and a ball safety system. Rough cost estimates indicate that the capital cost of the reactor should be comparable to other reactors of similar heat output.

Fillerwelding is a fusion welding process that provides for the automatic addition of controlled amounts of fillerwire during inert-gas-shielded tungsten-arc welding. Fillerwelding aluminum jacketed fuel elements has been successfully demonstrated and is being used on a routine basis. This manual was written to provide the necessary information to operate and maintain the fillerweld equipment.

Contemplated higher tube power for future reactor operation will probably require a fuel element jacketing material more corrosion resistant than presently available aluminum alloys. Zirconium and its alloys are generally regarded as the most promising jacketing candidates for high temperature operation, particularly for exposures of long duration. In order to obtain assembly, welding, and corrosion data, twenty Al-Si bonded and twenty unbonded Zircaloy fuel elements were prepared for KER loop testing. This report describes the technique developed to weld Zircaloy jacketed fuel elements and presents the results of end closure corrosion testing and metallographic examination.

This development work was undertaken to investigate and standardize scintillation detector and transistorized circuitry techniques in instruments used for detecting and measuring alpha and beta particles, gamma photons, and both slow and fast neutrons. At the present time, the standard radiation detection instrumentation used at Hanford employ vacuum-tube circuitry with typical detectors being ion chambers, G-M tubes, HF3 tubes, etc. The vacuum tubes require excessive battery power, and some of the circuits are adversely affected by humidity and temperature conditions.

In recent months, relatively large quantities of neptunium-237 have been recovered from Hanford irradiated uranium. The over-all recovery process consisted of 1) isolation from Purex plant solutions by solvent extraction, to yield an impure neptunium nitrate solution contaminated principally with uranium, plutonium, and fission products (2) purification by anion exchange 3) precipitation of neptunium (IV) oxalate; and 4) calcination of the oxalate to yield neptunium (IV) oxide, NpO2. This paper describes the oxalate precipitation process investigations and results.

This document authorizes the performance in accordance with the specifications noted, the PRTR Critical Tests described herein. The experiments described have the following objectives: