Sodium cooled small fast long-life reactor “4S”

• Published in: Progress in nuclear energy (New series) Vol. 47; no. 1; pp. 222 - 230
• Main Authors: Ueda, Nobuyuki, Kinoshita, Izumi, Minato, Akio, Kasai, Shigeo, Yokoyama, Tsugio, Maruyama, Shigeki
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Tarrytown, NY Elsevier Ltd 01.01.2005; Oxford Elsevier
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fast Reactor; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Long-life core; Metallic Fuel; Nuclear fuels; Passive Safety; Small Reactor; Fast Reactor; Long-life core; Metallic Fuel; Passive Safety; Small Reactor; Engineering design; Liquid metal cooled reactors; Sodium; Fission reactor safety; Fast reactor; Void fraction; Passive system; Nuclear reactor
• ISSN: 0149-1970
• DOI: 10.1016/j.pnucene.2005.05.022

CRIEPI and Toshiba Corp. have been exploring to realize a small-sized nuclear reactor for the needs of dispersed energy source and multi-purpose reactor. A conceptual design of 4S ( Super- Safe, Small and Simple) reactor is proposed to meet the following design requirements: (1) All temperature feedback reactivity coefficients including whole core sodium void reactivity are negative; (2) The core integrity is secured against all anticipated transient without reactor scram; (3) No emergency power nor active mitigating system is required; (4) The reactivity core lifetime is more than 10 years. The 4S reactor is a metallic fueled sodium cooled fast reactor. A target of an electrical output is 10–50 MW. A remarkable feature of 4S is that its reactivity is not controlled by neutron absorber rods but by neutron reflectors to cope with a long core lifetime and a negative coolant void reactivity. This study includes a design consideration of 4S. Design discussions are mainly focused on various core designs to meet above requirements. A tall core active height is adopted to gain long core lifetime. An averaged fuel burn-up is tried to be increased up to 100 GWd/ton from a point of economic view. The reference 4S designs are 10 MWe (30 years core lifetime) and 50 MWe (10 years core lifetime).