The primary objective of this program is to obtain improved data on the changes in nuclear characteristics with burnup of uranium oxide fuel in a boiling water reactor.

This is the third quarterly report on the work done under Contract AT(04-30-189, Project Agreement No.27, and covers the period August 12 to November 12, 1962.

The raw materials and fabrication procedures employed in preparing thirty two zirconium alloy compositions for evaluation as described in GEAP-3979 are reported. Considerations involved in the extension of reported laboratory procedures to larger scale production are discussed.

Work has continued on the development of accurate nuclear fuel burnup analysis. Work performed during the fourth quarter is summarized here.

The Fuel Cycle Program is an integrated program of investigation in the Vallecitos Boiling Water Reactor (VBWR) and other facilities to improve the technological limits of boiling water reactors.

A digital computer program, FORE, which calculates transients for a fast reactor, has been coded for the TRANSAC 2000 computer. Its purpose is to provide understanding of the dynamics of fast reactors with particular emphasis on large ceramic-fueled fast reactors. The program calculates reactor power and temperatures of fuel, coolant, clad, and structure.

The work described in this report represents progress toward an agreement signed by the United States and the European Atomic Energy Community which provides a basis for cooperation in programs for the advancement of peaceful applications of atomic energy.

Work has continued on the development of accurate nuclear fuel burnup analysis. Work performed by the third quarter of 1962 is summarized.

The Big Rock Point Reactor of the Consumers Power Company went critical for the first time on September 27, 1962. Summarized here are objectives and accomplishments of the pre-operational period as well as an indication of work scope remaining.

Three thin-wall stainless steel fuel specimens made using fabrication processes and materials similar to the Consumers Big Rock Plant research and development fuel rods were power cycled 3000 times between 500,000 and 75,000 BTU/hr-ft2 in the General Electric Test Reactor (GETR) Trail Cable facility. The fuel specimens were exposed to 1000 psi boiling water. All of the fuel specimens withstood the test without failing or without any significant changes in the clad characteristics.

This report is a supplement to GEAP-3759, Plastic Strain In Thin Fuel Element Cladding Due to UO2 Thermal Expansion. Cladding growth results are reported for repetitively irradiated, UO2 pellet-filled, annular capsules: for two UO2 powder-filled, annular capsules: and for six solid cylindrical pellet-filled capsules. Dimensional changes of the capsules irradiated during the entire program were analyzed, and the relationship of these results to the over-all fuel development program were evaluated.

This is the second quarterly report on the work done under Contract AT(04-3)-189, Project Agreement No. 27. The results reported here have to do primarily with the loss in a rectangular (1/2" x 1-3/4") channel in the horizontal orientation, without contraction-expansion inserts.

This report covers the S-I-5-B-M fuel irradiation in the GETR Maritime Loop during the final quarter of fiscal year 1962 plus the month of July 1962 to conclude the irradiation program. The data are summarized in Section II.

The Program fuel element has continued under irradiation in the Vallecitos Boiling Water Reactor, thermal energy group transfer cross sections for UO2 have been computed, and data have been reduced from the resonance wire activations performed last quarter. Future plans are included.

The Fuel Cycle Program is an integrated program of investigation in the Vallecitos Boiling Water Reactor (VBWR) and other facilities to improve the technological limits of boiling water reactors in several areas. This report presents updates on tasks related to those areas.

This report contains technical specifications and supporting data for the Critical Experiment Facility, information to justify operation of the facility, procedural control to be used to ensure safe operation, changes in neutron instrumentation and safety system, an evaluation of the safety of the Facility. It also contains descriptions of the site, the facility and the Critical Assemblies, operating standards and procedures. Amendment no.18 to license application for Critical Experiment Facility is also attached.

A code (RAPTURE) was programmed for the Philco TRANSAC 2000 computer to perform calculations needed for the evaluation of Doppler Coefficients in fast reactors with degraded neuron spectra. This code computes resonance integrals, averages them over resonance parameter distributions, and computes fission and capture cross sections as a function of fuel temperature and of potential scattering cross section per absorber isotope.

The nuclide Cs-137 is a fission product commonly used for measurement of uranium burnup in irradiated uranium fuel by the fission product to uranium ratio method. In the application of this method, the largest single error introduced in the measurement of burnup is the uncertainty in the half-life of Cs-137. Because of the uncertainty in this value and its importance in nuclear fuel burnup analysis, a reinvestigation was undertaken to obtain a more accurate value using the mass spectrometric method.

Work performed during the quarter is summarized by direct measurement of fission gas pressure, loop modifications, UO2 fuel performance

This report contains a listing of the bound-proton kernels for neutron scattering which were calculated in conjunction with the USAEC Control Rod Materials Program.

Previously reported results on the testing of small samples of boron carbide dispersed in nickel by electrolytic codeposition were adequately encouraging to lead to the development of a prototype control rod for operation in the Vallecitos Boiling Water Reactor. The operation of the control rod has been entirely satisfactory.

Control rod materials, designs, and fabrication processes are compared for their relative economies. Control rod lifetime data are calculated with a simple approximation of nuclear worth depreciation. These data are used in conjunction with the estimated fabrication costs to determine the cost of using several absorber materials in a typical power reactor on a cost-per-year basis. The effect the control system has on core power density and fuel lifetime is included.

The Fuel Cycle Program is an integrated program of investigation in the Vallecitos Boiling Water Reactor and other facilities to improve the technological limits of boiling water reactors in several areas. Progress is reported here.

This report covers the S-I-5-B-M fuel irradiation in the GETR Maritime Loop during the third quarter of fiscal year 1962. The data are summarized in Section II. Discussions on fuel performance, fuel environment (water chemistry), and loop operations are included.