Summary: The design, construction and assembly of all components were completed during the first contract year previous to December 1963. These efforts, defined by Tasks A-F, are document in (1), (2), and (3). Brief summaries of these completed efforts are given in the introduction to each of the tasks in the text of this report. The digest given below covers only the shakedown and analysis work carried out in the fourth quarter of the first contract year. Task G Shakedown Tests. The photographic procedure has been experimentally defined for the glass test section. Four automatic 35 mm cameras and four strobe light sources have been ordered on ATL funds and their respective mounting arrangements are in place. Roughly ten test runs were carried out in the glass test section during the course of the above work. Satisfactory recorder traces have been obtained on all measurement systems. These systems presently meet the accuracy and linearity specifications initially set. An x-ray void fraction signal adjustment and filtering circuit has been design and installed to provide equal resolution across the test section. Calibration disc inserts have been installed to permit satisfactory beam intensity calibration. Good agreement has been obtained between calculated and measured …

Summary: The High Power Density Project includes a comprehensive fuel development program which has the objective of developing and demonstrating the performance of a nuclear reactor core having a high power density, long fuel life, and low fabrication cost. The fuel program is made up of two principal tasks. Task 1A consists of irradiation tests in the VBWR of Type 304 stainless steel clad, UO2 pellet type fuel rods fabricated by current commercial processes. Task 1B consists of the investigation of lower cost fabrication processes and the irradiation testing of fuel elements fabricated by these processes. Both tasks include the investigation of the feasibility and use of thin-wall stainless steel cladding as a means of improving the neutron economy and fuel cycle costs of stainless steel clad fuel. Irradiation of the Task 1A fuel assemblies in the VBWR was initiated in September, 1960. Subsequently, Task 1B fuel assemblies were inserted in the VBWR as various fabrication processes and design concepts were investigated. Fuel cladding failures have occurred in fuel rods in both Task 1A and 1B. As of this date, cladding failures have occurred in twenty-two rods of approximately 700 fuel rods which have been irradiated. Twenty of the failures …