Japan sodium-cooled fast reactor system

Figure 5.4 Sodium-cooled fast reactor system (loop type). All rights reserved by Japan Atomic Energy Agency.

With a purpose of probing a commercially feasible fast reactor system, a feasibility study on commercialized fast reactor cycle systems (FS) was initiated in 1999 (Aizawa, 2001). In the FS, survey studies were made to identify the most promising concept among various systems such as sodium-cooled fast reactors, gas-cooled fast reactors, heavy metal-cooled fast reactors (lead-cooled fast reactors and lead-bismuth cooled fast reactors), and water-cooled fast reactors with various fuels types such as oxide, nitride, and metal fuels. The FS concluded to select an advanced loop-type SFR with mixed oxide fuel named Japan sodium-cooled fast reactor (JSFR Kotake et al., 2005). 

Kamide, H., et al., 2010. Sodium experiments on decay heat removal systems of Japan sodium cooled fast reactor — start-up transient of decay heat removal system. In Presented at Seventh Korea—Japan Symp. Nuclear Thermal Hydraulics and Safety, Chuncheon, Korea, November 14—17, 2010. 

A new thermochemical and electrolytic hybrid hydrogen production system in lower temperature range has been developed by the Japan Nuclear Cycle Development Institute (JNC) to achieve the hydrogen production from water by using the heat from a sodium cooled fast reactor (SFR) [7]. 

The technical basis for the RAPID includes general experience with sodium cooled fast reactors. Specifically, the RAPID concept includes no control rods but incorporates the passive lithium expansion modules, lithium injection modules and lithium release modules to enable an operator-free operation mode. These systems utilize Li as a liquid poison instead of B4C rods. To verify the reactivity worth of Li, the criticality test [XVII-5] using the fast critical assembly (FCA) of the Japan Atomic Research Institute (JAERI) has been conducted. Also, the manufacturing technology of the lithium modules was mastered, and the performance and neutron radiography tests of the lithium expansion and lithium injection module pilots were conducted. 

The construction of Monju, the prototype fast breeder reactor (FBR) which PNC has built as part of the Japanese FBR development programme, was completed in April 1991, and system start-up tests are presently underway. Monju is a loop-type sodium-cooled fast breeder reactor with U-Pu mixed oxide fuel. It supplies 280 MWe to the grid and is situated on the Tsuruga Peninsula facing the Sea of Japan, about 400 km west of Tokyo. 

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