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was signed by DOE, DOD, and NASA in early October 1985. Specifically, DOE is responsible for the ground engineering system development. The SDIO is responsible for overall program direction and--with the Air Force as its executing agent-military mission analysis and requirements definition. NASA is responsible for civil mission analysis and requirements definition, as well as for advanced aerospace technology that could ultimately enhance an SP-100 system.

A planned 300 kWe SP-100 nuclear electric propulsion flight demonstration for SDIO in the early 1990s timeframe was established in September 1985. This reference mission will serve to demonstrate and flight qualify SP-100 for follow-on dedicated

mission use. Preliminary reference mission planning will be

completed in mid-1986. Funding for this planned flight demonstration has been programmed by the SDIO in their outyear budget projections starting with FY 1987.

The Department is committed to the SP-100 Ground Engineering
System (GES) development and testing project as are our other

SP-100 partners. Its success will provide a new energy option to mission users in the 1990's and beyond.


The need for powerful new, space-based defense weapons and

surveillance systems for protection against the threat of nuclear

missiles has been established as a top national priority.


proposed weapons and surveillance systems require large amounts of electrical power, significantly more than can be provided by current power systems.

The SDIO has established a program to develop nuclear and nonnuclear systems that can separately or in combination meet the SDI multimegawatt power requirements. Responsibility for

developing nuclear power system concepts and technology has been assigned to DOE. The Air Force has been assigned responsibility

for nonnuclear power systems development.

A key objective of the MMW Space Nuclear Power Program is to

identify and develop at least one space nuclear power system

concept by 1991 that alone, or in combination with a nonnuclear

power system, meets SDI MMW power requirements and for which technical feasibility issues have been resolved.

To meet the SDI requirements for safe, reliable, compact MMW power sources, significant advances in space nuclear power technology must be achieved. SDI missions such as space-based

defense weapons, imaging radars and electric propulsion have high

electrical power requirements: hundreds of megawatts for up to

2,000 seconds (burst mode) for some weapons; tens of megawatts for up to 1 year total operating time (alert mode) for imaging radars, weapons readiness, and electric propulsion; and hundreds of kilowatts to a few megawatts for as many as 7 years (continuous mode) for station-keeping activities and


During FY 1985 and FY 1986, the program focus has been on developing a MMW Space Nuclear Program Plan and on assessing and investigating various system concepts and related critical technology areas that must be advanced if these reactor system concepts are to be able to meet the power, mass, volume, and longevity requirements of the SDIO. The program plan addresses system requirements, and provides concept and technology overview, program strategy, costs, schedules and milestones, as well as concept and technology developing activities. Work under the plan was initiated in FY 1986.

The FY 1987 effort will continue the evaluation and development of potential multimegawatt space power concepts. In addition,

work will continue on experimental testing and development of key enabling technologies that are required if the preferred concepts are to become fully viable. These experimental testing and development efforts will focus on advanced nuclear fuels,

materials, safety, and reliability.

Advanced reactor control

techniques and neutronics, shielding and thermal hydraulic codes will also be developed.


The needs of military spacecraft in the planning process include higher power requirements and increased survivability to threats directed at disablement or destruction of the space system. The current standard spacecraft power source, arrays of photovoltaic cells, lacks required features of hardness and has too much volume that could constrain the maneuverability of these new space systems. One class of spacecraft of current interest for high priority missions, requires power in the range of 1 to 10 kilowatts of electrical power; stringent attitude control and station keeping; and survival from the threats projected for the 1990 time period. In order to make certain that a highly

reliable and efficient isotope powered system in the one to ten

kilowatt electrical range is a viable option for military planners, a joint DOD/DOE program is being initiated.

The dynamic isotope power system (a combined turbine alternator, isotope-fueled power subsystem) is an enabling technology for these military space missions which require survivability against various threats, higher power missions performance, and a small power supply to improve the spacecraft sensors field of view and overall spacecraft pointing accuracy. DOD missions such as the Boost Surveillance and Tracking Systems (BSTS) are currently

under active mission requirements definition and analysis as part of the SDI program. All of the DOD contractors have recommended the DIPS as the primary power source for the BSTS application.

The goal of the DIPS program is to develop and demonstrate the necessary technology required to provide this type of space electrical power in the range of one to ten kilowatts output for use by these types of emerging military space missions in the mid 1990's and beyond. The specific objective of this development program is to develop the DIPS, as a viable enabling technology as the electrical power supply for the SDI space surveillance



There is a military, and potentially a civilian, need for ground

based power systems that can operate continuously in harsh environments with minimum attendance and freedom from the need for frequent replenishment of fuel supplies such as diesel oil. These systems must have high reliability, low maintenance, long lifetimes, and simplified logistics. Nuclear reactor technology appears to offer feasible and improved alternatives to conventional power systems for such applications as the North Warning System, which is the upgrade of the Distant Early Warning (DEW) line across northern Canada.

Because of the logistics and resupply costs of maintaining diesel generators a reactor power system is being considered as an alternative. Such a reactor system would require only minimum maintenance, and it would potentially result in significant savings in operation and maintenance costs and in overall life cycle costs. An assessment of the concept was undertaken in FY 1984. Based on the positive findings of that assessment, conceptual design efforts on reactors for the North Warning System (now called the Small Nuclear Power Source Demonstration

Project) were initiated in FY 1985: The Department of Energy, the United States Air Force (USAF), and Atomic Energy of Canada, Limited (AECL), are jointly funding a program to investigate and demonstrate the feasibility of using a 15 kwe reactor power source for an application such as the North Warning System. In FY 1986, the design is being completed, component development testing is underway, and the demonstration reactor is being fabricated.

In FY 1987, zero power tests will be conducted on the nuclear and heat pipe subassemblies to verify the neutronics performance of the subsystem. The complete system will be installed in a test cell at AECL's Whiteshell facility and system startup tests will be initiated in early FY 1988.

Basically, all of the system components use state-of-the-art technology that has been used in other systems. For example, the nuclear fuel will consist of pellets of the type used in hightemperature gas-cooled reactors, and the organic rankine cycle will be similar to those used on fossil-fueled generators for communications on the Alaskan oil pipeline and for waste heat recovery on several industrial processes. The initial objective of the program is to place a demonstration reactor in ground testing by late FY 1987.


In response to interest by the Air Force (as well as SDIO) an effort is underway which will lead to the design of a hardened nuclear powerplant with a nominal 10 MWe rating. This plant will feature a passively safe design, a capacity factor in excess of 90 percent, refueling intervals which could range from 4 to 10 years, and will be hardened against specified military

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