JAERImark Design of a Supersafe, Supercompact Reactor RAPID-L in Pursuit of Extreme Size and Weight Reduction

- Results of JAERI's Fundamental Nuclear Research Promotion Program based on public applications -
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JuI 4, 2001

The Japan Atomic Energy Research Institute (JAERI, President Kenichi MURA- KAMI) has obtained encouraging insights for the implementation of a supersafe, supercompact lithium-cooled fast reactor (RAPID-L*) which features fully auto- mated reactor operation. This is the result obtained by the research program en- trusted to the Central Research Institute of the Electric Power Industry, (CRIEPI, President Motohide SATO).

This research was aimed at establish a reactor with a fully automated operational capability from startup to shutdown in order to ensure extremely high safety by eliminating human errors. The new design does not use control rods. Instead, it employs newly developed systems such as the Lithium Expansion Module (LEM) for the control of reactors by utilizing the thermal expansion of liquid lithium 6, which is a neutron absorber, a Lithium Injection Module (LIM) for shutting down the reactor and a Lithium Release Module (LRM) for starting it up. In order to valify these new systems, the reactivity worth has been measured using JAERI's Fast Critical Assembly (FCA) and the functions have been investigated by neutron ra- diography technique at JAERI's research reactor (JRR-3). For the high-performance thermoelectric energy conversion system with a twice or better performance than previous systems, which will be adopted as the power conversion system, an op- erational test has been conducted under the temperature condition of 1,000°C.
With a thermal power of 5,000 kW and electric power of 200 kW, the output of this reactor is much smaller than large power-generating reactors. However, it has a very compact size and the very low total weight of 7.6 tons and it is capable of continual operation without refueling for ten years. Potential uses for RAPID-L are in power plants in urban areas of industrialized nations to relieve the peak load, and for developing countries where remote regions cannot be conveniently connected to the main grid and where it is economical to provide local generation capacity.
Also this reactor can be applied as a power source for lunar base where neither air nor water is available and maintenance by astronauts would be difficult.

This research was conducted in the framework of JAERI's Fundamental Nuclear Research Promotion Program prepared for all the applicants outside of JAERI. The person responsible for the research was Senior Researcher Mitsuru KAMBE of CRIEPI and other researchers also participated from the Mitsubishi Research In- stitute Inc., Tohoku University and Kyoto University.

* RAPID-L: Refueling by All Pins Integrated Design - Lunar Base

Supplementary Explanation

For inquiries on this subject, please contact: Takamichi IWAMURA
Chief, Future Reactor Research Group,
Energy Systems Research Division,
Tokai Research Establishment, JAERI
Tel.: (+81)-29-282-5272
Fax.: (+81)-29-282-5276