Work performed during the quarter is summarized by: direct measurement of fission gas pressure, loop operations, performance of UO2 fuel, UO2 grain growth and melting studies.

Summary: Transition boiling data was taken with an improved flow loop, to explore the influence of loop characteristics on rod temperature fluctuations the transition region was found to be much smaller than for comparable conditions with a different loop. Also the amplitude, and frequency of the temperature oscillations, were significantly less than before. These results indicate that loop characteristic and flow disturbance parameters play a prominent part in governing the transition temperature fluctuations. Additional two-rod transition boiling data are presented. The results include data taken at high wall temperature levels during a demonstration test at low steam qualities, and the effect of a change in rod spacing on heat transfer performance.

A better understanding of the maximum operating characteristics that can be achieved with the use of UO2 as a reactor fuel is the primary purpose of this program for Euratom and the Atomic Energy Commission. During this program work will be undertaken in two areas that have been of concern to the reactor core designer for a long time, viz. fission gas release and central melting in fuel rods.

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. Quarterly progress: Project fuel fins irradiated to 1860, 3000, and 5300 MWD/T have been successfully sampled in the Radioactive Materials Laboratory. The samples have been dissolved and aliquots delivered to Chemistry for Mass Spectrometry and burnup determination. The first Stanford Pool Irradiation indicated that there was some inconsistency in the thermal flux and the near thermal epithermal flux. The experiment was repeated, increasing the number of foil wheel positions from two to three. The data from the second measurement are being reduced. The EPITHERMOS code modification has been completed. Comparisons between the results computed by the code and experimental data show much improved agreement. The metallographic photomicrographs of a polished half-pellet from rod F, irradiated to 5000 MWD/T, show structure very similar to that shown by the pellet from rod S, irradiated to 1860 MWD/T.

Abstract: Residual and fission gas release from UO2 were studied in the laboratory and in in-reactor experiments. Arc-fused powder and sintered pellets were used to determine the rate of evolution and types of residual gases as a function of temperature. Fission gas release was related to the average UO2 temperature and fission gas release calculations were made using the latest thermal conductivity values, isotopic half lives, and branching ratios available in the literature. The results obtained were compared with those available in the literature, and a satisfactory agreement was found among the groups of comparable data.

Summary: Technical report describing the testing of eight Potter Meters, for metering inlet flow and measuring exit steam qualities in the Consumers Big Rock Point Instrumented Fuel Assemblies, were individually calibrated for flow and pressure drop up to 500 gpm in the low temperature (130 F) fluid flow facility. The flow calibration comparison made with an ASME orifice installation, agreed to within + - 1 percent among seven of the meters, and meter Serial No. 8 was 2.8 percent lower than the others. Pressure drop among the meters was within about 5 percent. Locked rotor pressure drop data was obtained on one meter. A fully instrumented fuel bundle was tested in the low temperature facility and pressure drop data obtained for the tieplates and meters, spacers, and channel rods. A mock-up of the exit end of the instrumented fuel bundles, composed of 1 foot of fuel rods, tieplate, and Potter Meter was tested in the High Pressure Heat Transfer Facility. Data was obtained for single- and two-phase calibration of total flow and exit steam quality in an instrumented bundle. Each meter was operated, for a minimum of 6-8 hours after bearing modifications necessitated by seizure of the rotors, in the …

A program is in progress for the design of a zirconium base alloy for steam service as nuclear fuel cladding. Thirty-one alloys selected for study of corrosion rate, hydriding rate and hydrogen embrittlement are in test. The corrosion testing of 1800 coupons to 3000 hours at at 300, 400, and 500 degrees C in refreshed steam has been completed. Statistical data analysis of the corrosion results are reported and alloys showing better corrosion performance at all test temperatures than that for Zircaloy-1 are discussed. Preliminary data for hydrogen uptake after long exposures at 400 and 500 degrees C are presented; the uptake for alloys showing the best corrosion performance is discussed. Post-corrosion mechanical property measurements are also reported along with the preliminary results of x-ray diffraction and metallographic studies relating to hydrogen embrittlement. A wide variation in resistance to embrittlement at a given hydrogen level was observed and can be tentatively correlated with original ductility, crystallographic texture, and hydride platelet orientation. The testing of a second round of ten alloys is also in progress. Studies concerning the mechanism of corrosion and hydriding in zirconium alloy are also reported. The results of recent neutron activation analyses of stripped corrosion films are …

Abstract: This technical report covers the development work conducted during a planned program with the U.s. Atomic Energy Commission, Contract AT(04-3-189, Project Agreement 22, directed toward the development of high temperature, nuclear radiation resistant, telemetering devices. The development program is devoted to: (1) investigation and selection of two possible telemetering devices, and electromechanical commutating switch and an AM oscillator employing TIMM circuit elements, (2) procuring the electromechanical commutating switch to specification, (3) building and operating a TIMM oscillator, and (4) temperature testing of both devices. A resistance-coupled Wien-bridge sine wave TIMM oscillator was build and tested both as an oscillator, and in combination with other oscillators to simulate a telemetering system. An electromechanical commutating switch rated for 350 F operation, instead of 700 F as originally specified, was procured and tested. The drive motor and gear reduction unit which is designed to drive the commutating switch, is rated for 750 F operation and designed to operate in an nuclear reactor radiation environment of 1 x 10(17) nvt and 1 x 10(10) R.

Quarterly report discussing progress on the Fast Ceramic Reactor Development Program, "an integrated analytical and experimental program directed toward the development of fast reactors employing ceramic fuels, with particular attention to mixed plutonium-uranium oxide" (p. 1).

Quarterly progress report discussing activities related to the Vallecitos Boiling Water Reactor (VBWR) and related facilities

A research program is being conducted to obtain experimental data in the irradiation of plutonium-enriched fuel to confirm a theoretical model for predicting isotopic composition and reactivity changes in plutonium-enriched, light-water-moderated reactors. All program efforts have been temporarily deferred except for those associated with the irradiation of the program fuel element in the VBWR. The program fuel element was exposed to a burnup of 831 MWD/T during the quarter which brings the total to 3165 MWD/T. Applying the same scale factor between logged exposure and Ce-Cs analysis of the first fuel sample gives a corrected exposure of 3774 MWD/T.

Activities in a program to develop techniques in the use of pulsed neutron sources to measure shutdown parameters related to large thermal power reactors are reported. The development of pulsed neutron source techniques for large power reactors has led to a new theoretical model recently developed by E. Garelis and J.L. Russell, Jr. The theory is presently based on a bare, one-group model with m-delayed precursors and takes all spatial modes into account. Results indicate, however, that the application of this model is much broader. Experiments were designed and carried out to both verify this new theory and to demonstrate the performance of the experimental hardware in a large power reactor.

The United States and the European Atomic Energy Community (Euratom), on May 29, and June 18, 1958, signed an agreement which provides a basis for co-operation in programs for the advancement of the peaceful applications of atomic energy. The work described in this report represents the Joint U.S.-Euratom effort. The over-all development program is designed to obtain the test data and operating experience necessary to eventually realize a 50 percent increase in the output of the Garigliano Nuclear Power Station located at Sessa Aurunca (Campania, Italy). Two tasks are in progress: Task III-F involves the preparation of test specimens of reactor vessel material for irradiation; Task IV consists of the formulation of specification for a complete data logging and computer system.

Introduction: The Transition Boiling Heat Transfer Program is sponsored jointly by the USAEC and Euroatom and is being conducted by the General Electric Company. The work commenced on this program February 11, 1963. The objective of this program is to perform basic investigation and measurement of the transition boiling regime in high pressure bulk boiling water flows, with particular emphasis i the high range of steam qualities.

From introduction: "Development of nuclear reactor cores having high power density, long fuel life, and low fabrication costs is the objective of this program sponsored by the AEC."

The following conclusions are based on the out-of-pile general corrosion and localized attack studies completed to-date on several 300 series stainless steels: (1) Utilizing a sodium chloride-cycle test that produces a type failure that can occur in a superheat reactor system, Types 347 and vacuum-melted 304 SS have failed while vacuum-melted 310 SS was acceptable. (2) An improved chloride cycle test utilizing ferric chloride as the additive has been developed that produces an intergranular type failure similar to that experienced in the fuel cladding failures in the SADE and ESADE facilities. types 304 and 315 SS have failed in the test. (3) Present methods of ultrasonic testing will find through cracks but are not completely dependable for assessing lesser degrees of intergranular attack. (4) It is hypothesized that a definite interplay exists between chemical attack and stress. The application of stress will orient intergranular attack preferentially in a direction perpendicular to the stress.

Experimental test loops have been used to study the problem of hydraulic stability. The oscillatory behavior of a single-phase and two-phase natural circulation loop has been examined at atmospheric pressures and oscillating modes of operation were studied in terms of heat input.

This report summarizes the radiation and shielding analysis for a 30,000 SHP natural circulation boiling water reactor for ship propulsion. The reactor is proposed for installation in a 60,000 DWT, 18 knot tanker of the T-7 class.

Abstract: Continued irradiation experience under the AEC - Euratom, UO2 High Performance Program provided five separate and distinct sets of data on UO2 thermal conductivity. Four of these results are expressed in terms of the value of the thermal conductivity. The first two of these measurements were applicable -- strictly -- to poly crystalline UO2. Recently, three additional sets of measurements have been obtained -- all pertinent to UO2 after the formation of large columnar grains. The extent of melting in the experiments on which the results are based ranges from slight, to greater than 70 percent of the fuel cross section. The conclusions from all of these thermal conductivity measurements considered together are: (1) The true value of the UO2 conductivity integral form 0 degrees C to melting (2805 - 15 degrees C) lies in the range from 90 to 96 W/cm. The most probable value is closer to 90 W/cm. To ensure no central melting and the associated clad swelling the maximum thermal performance level for solid pellet, UO2 fuel rods should not exceed 90 W/cm. (2) Any improvement in thermal conductivity due to the formation of large, columnar UO2 grains is small and not detectable within the …

The United States and the European Atomic Energy Community (Euratom), on May 29, and June 18, 1958, signed an agreement which provides a basis for co-operation in programs for the advancement of the peaceful applications of atomic energy. The work described in this report represents the Joint U.S.-Euratom effort. The over-all development program is designed to obtain the test data and operating experience necessary to eventually realize a 50 percent increase in the output of the Garigliano Nuclear Power Station located at Sessa Aurunca (Campania, Italy). One task is in progress: Task I - Data Logging and Computer System. The work on the other tasks is being planned and initiated.

Three edge loaded thoria-urania nuclear fuel samples were assembled into a capsule, irradiated and examined. This irradiation was the first of a series to develop thoria-urania fuel for high heat flux, specific power and burn-up operation in a sodium graphite reactor.

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.

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.

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.