SNAP-10A is a 500-watt electrical power system required by the Air Force for future operational satellite missions, and, like SNAP-2, will demonstrate feasibility in the Atomic Energy Commission-Air Force flight test program. This system will use the SNAP-2 reactor with minor modifications, and a thermoelectric power con version system. The flight test program will lead to a flight qualified unit with a lifetime of 1 year. At the point when the components, subsystems, and systems have demonstrated a 90-day capability, orbital tests will be performed to confirm this capability in an orbital environment which cannot be simulated on the ground.

The above funding reflects the level of development leading to a lifetime, weight, and reliability suitable for operational units and includes the effort required to deliver units to the Air Force in late fiscal year 1964 for the 90-day demonstration flights. This activity includes a continued life testing of development systems which begin operation in fiscal year 1964; the analysis of data obtained from the orbital flight test, and the fabrication and testing of critical components to assure adequate reliability and to extend their lifetime.

The previous delivery date of the first 90-day flight unit has been extended approximately 9 months due to technical difficulties experienced with certain components in the ground test phase of the development systems, and the need for more extensive life testing of components and systems to assure the reliability of the flight systems. The importance of the initial orbital flight tests of the SNAP-10A system dictates that the flight units be as reliable as is reasonably possible to accomplish. The decision has been made therefore, to extend the qualification test period and to add an additional development system to the development schedule to verify overall system performance and the integrated behavior of all components during the acceptance, ascent, prestartup, startup, and 90-day operating phases. The implementation of this decision in fiscal year 1963 defers the delivery systems into late fiscal year 1964 versus early fiscal year 1964 as previously planned. The overall decrease in this development program in fiscal year 1964 reflects the essential completion of the development effort required to provide the initial flight units for the 90-day demonstration flights.

This effort is conducted to produce the basic technical information required to support the SNAP reactor systems currently under development, and as such, has been indispensable in the anticipation of development problems and their solution. There is a continuing need for this support to assure that the current development is performed on an efficient and timely basis.

The areas of investigation and experimentation include nuclear and compact shielding analysis, control and stability analysis, basic heat and mass transfer, compact nuclear experiments, and high temperature fuels, cladding and coatings.

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(Additional information of a classifed nature se presented in the ebusited pp. 220 through 225. 10. General reactor technology av

The general objectives of general reactor technology programs are to provida basic data on reactor systems and related problems to carry out engineering development of a general and fundamental nature, and to investigate the tonal bility and potential of new methods for improving reactors and associated nucleat devices. It includes three areas of research and development which apply to long-range civilian, military, and space reactor problems and problems Dint gra common to a variety of reactor concepts and thus not suitable for support unise specific projects. These areas are; reactor physics; fuels and materiala devolop ment to improve the performance of reactor fuels and to obtain a fundamental understanding of reactor materials; and engineering and development diredal toward the solution of fundamental engineering problems, such as hunt transfer, applicable to all reactor concepts and to the development of componente fuk power reactors. In addition to these programs directly related to penkton desjen, there is one other program-chemical separations which is directed toward rain tion of this item in the fuel cycle cost for power reactors and to the development of methods for processing new fuel types.

This program includes studies on basic combinations of reactor materials in the form of exponentials, subcriticals, and critical assemblies. Results of these studies provide the basis for determining reactor system behavior with regard to conversion coefficients, reactivity life, effects of enrichment, effects of changes in neutron spectra, etc., as well as general correlations of experiments with theory. Accurate measurements are undertaken of constants fundamental to reactor design such as neutron ages, resonance integrals, and the number of neutrons produced per fission.

The increased effort in fiscal year 1964 is primarily for initial preparation of a reactor physics program using the proposed high temperature lattice test facility. This program will permit optimization of future reactor systems more economically and with greater predictability.

(2) Neutron physics:

Fiscal year 1963.

Fiscal year 1964.

$1, 824, 000 1, 730, 000

Investigations conducted under this activity are designed to yield data on the fission process and the interaction of neutrons with matter. The program provided herein is well coordinated with the national effort through the Neutron Cross Section Advisory Group. It differs from other programs primarily in its emphasis on reactor materials and obtaining a high degree of accuracy and detail sufficient for reactor design applications.

(3) Radiation effects:

Fiscal year 1963.

Fiscal year 1964..

$323, 000 360, 000

This program undertakes studies of radiation damage to reactor materials such as metals, alloys, and ceramics. The research determines physical property changes in materials subjected to nuclear radiation.

(4) Shielding:

Fiscal year 1963..

Fiscal year 1964..

$370,000 370, 000

This program is concerned with basic shielding studies directed to the advancement of shielding technology of value to a wide variety of shielding requirements. It includes studies of radiation penetration through ducts, investigation of optimization methods to minimize weight, generation of both microscopic and integral type handbook data, and the evaluation of calculation methods and codes for the determination of shield effectiveness.

(5) Data centers:

Fiscal year 1963..

Fiscal year 1964..

$330,000 335, 000

This program provides for two data centers. The reactor Physics Constant Center at Argonne National Laboratory is primarily responsible for the compliation, evaluation, and publication of nuclear data, formulas and reactor constants. The Reactor Cross Section Evaluation Center at Brookhaven National Laboratory is responsible for evaluation of reactor cross sections.

This activity is comprised of two subactivities: (1) high-temperature materials research and development, and (2) general reactor fuels and materials development.

Areas of research under this program include basic and engineering investigations on ceramic and metallic nuclear fuel, development of protective coatings for use in high temperature corrosive environments, containment of molten metals at elevated temperatures, and studies of the effects of radiation on properties of metals and alloys at high temperatures. Such research is of prime importance to the success of advanced civilian, military and space reactors, and is directly related to current developmental effort in these areas.

Research provided by the increase include liquid metal corrosion studies, development of refractory alloys, studies on materials for fuel elements, and cladding for use at temperatures in excess of 2,000° F. Effort will also be initiated on developing uranium carbide and uranium nitride as fuel materials for advanced reactor concepts.

Objectives of research performed under this activity are: (1) more efficient utilization of fissionable and fertile materials in reactor cores; including military space and civilian; (2) fundamental and design information of nuclear fuels and materials; and (3) selection and evaluation of potential new reactor materials as to feasibility, application and production.

Research necessary to meet the first objective requires studies to increase reactor core life, burnup, and stability to radiation, to reduce fuel fabrication costs, and to ensure high temperature operation of fuel assemblies. To achieve the second objective operational data must be obtained over a broad range of temperature, environment, stress, and radiation fields. The third objective necessitates studies on materials now considered exotic, such as rare earth metals, complicated refractory alloys, ceramics, and cermets. Methods of production fabrication, testing, and utilization must be established on those materials which possess potential reactor worth.

This research effort is categorized in the following areas at the indicated dollar levels:

Fuels research is divided into two categories, metallic fuels and ceramic fuels. Metallic fuels include pure uranium and plutonium and alloys of these metals having improved properties. Studies are undertaken to determine the influence of structure and fabrication history on radiation stability and reactor lifetime and to obtain physical and mechanical data necessary to reactor designers. Dispersions of various types are under investigation in order to reduce radiation induced swelling in the metallic fuel systems.

Certain ceramic fuels, such as UO2, possess excellent resistance to corrosion by reactor coolants, have higher temperature capability, and are more resistant to swelling on irradiation than metal fuels. However, with the exception of the

carbides, they have low thermal conductivity and are brittle. Improvements are sought through variations in materials preparation techniques or development of ceramics of different elemental composition to increase the effectiveness of ceramic fuels in a nuclear reactor.

The principle increases are in the following areas:

Mixed carbide systems. Increases in irradiation evaluation as well as compatibility studies are foreseen to develop alloy carbide systems for use at temperatures anticipated for advanced reactor systems.

Uranium nitride.-Work is being initiated on UN in order to define more adequately the potential of this material as a high temperature fuel. Plutonium.-Additional investigations will be undertaken on plutonium compounds and compound alloys, to be evaluated separately or in conjunction with materials containing uranium.

(b) Cladding and container materials:

Fiscal year 1963.

Fiscal year 1964..

$2, 474, 000 3, 077, 000

Cladding materials must be compatible with the fuel material and reactor coolant, and have adequate strength at operating temperatures. They should be resistant to radiation damage and have a low cross section for neutrons in the spectrum encountered. Materials for structural applications should have adequate strength at operating conditions, be compatible with the reactor environment and resistant to radiation damage.

This program seeks to improve utilization of the properties of metals or alloys, evaluate environmental effects, and to characterize evaluated temperature properties.

Investigations cover materials for the containment of potassium, mercury, lithium, Nak, and sodium; studies on the development and testing of better alloys for cladding nuclear fuel for operation above 1,000° F; and selection and testing of containment materials for liquid metal systems in nuclear powered space systems.

The principle increase requested covers a substantial effort in the field of refractory alloys including molybdenum, tungsten, and tantalum. Other increases requested cover studies on liquid metal corrosion, fuel cladding, and coatings.

(c) Fabrication techniques:

Fiscal year 1963.

Fiscal year 1964_

$165, 000 425, 000

Fuel element fabrication involves all steps between chemical processing and the production of assemblies to be placed in reactors. Elements fabricated must meet stringent requirements on quality and dimensions to avoid inreactor failure. The use of recycle fuel or plutonium requires the adaptability of fabrication techniques to remote or glove box operation.

A reduction in fabrication costs of fuel elements could have an appreciable effect on the overall fuel cycle cost. The programs in this subactivity are intended to devise processes and techniques leading to such economics.

The increase will permit initiation of effort in the areas of extrusion of refractory metal tubing such as niobium, tantalum, and tungsten.

(d) Irradiation techniques:

Fiscal year 1963..

Fiscal year 1964..

$3,807, 000 3, 625, 000

Design of reactor cores and components requires a definitive exposure to the neutron and gamma fluxes on material properties. Pre- and post-irradiation examination do not always give an adequate determination of what took place during an exposure. Complex and expensive capsules must be devised to obtain accurate data while the material is being irradiated.

The radiation damage investigation of reactor structural materials is a program necessary to determine the safety of reactor pressure vessels and core structures and a radiation damage investigation of reactor structural materials covering a systematic and comprehensive investigation of the effects of irradiation on completely characterized materials under known conditions of temperature, flux, and environment.

(e) Fundamental properties:

Fiscal year 1963...
Fiscal year 1964.

$1, 687, 000 729, 000