Toshiba 4S
Encyclopedia
General description
The plant design is offered by a partnership that includes ToshibaToshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
and the Central Research Institute of Electric Power Industry
Central Research Institute of Electric Power Industry
The Central Research Institute of Electric Power Industry is a Japanese non-profit foundation that conducts research and development of technologies in a variety of scientific and technical fields related to the electric power industry. Also, CRIEPI researches many aspects of social matters...
(CRIEPI) of Japan.
The technical specifications of the 4S reactor are unique in the nuclear industry. The actual reactor would be located in a sealed, cylindrical vault 30 m (98 ft) underground, while the building above ground would be 22×16×11 m (72×52.5×36 ft) in size. This power plant is designed to provide 10 megawatts of electrical power with a 50 MW version available in the future.
The 4S is a fast neutron reactor
Fast neutron reactor
A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons...
. It uses neutron reflector
Neutron reflector
A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, and tungsten carbide, or other materials...
panels around the perimeter to maintain neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
density. These reflector panels replace complicated control rods, yet keep the ability to shut down the nuclear reaction
Scram
A scram or SCRAM is an emergency shutdown of a nuclear reactor – though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads...
in case of an emergency. Additionally, the Toshiba 4S utilizes liquid sodium as a coolant
Liquid metal cooled reactor
A liquid metal cooled nuclear reactor, liquid metal fast reactor or LMFR is an advanced type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal cooled reactors were first adapted for nuclear submarine use but have also been extensively studied for power generation...
, allowing the reactor to operate 200 degrees hotter than if it used water. Although water would easily boil at these temperatures, sodium remains a liquid; the sodium coolant therefore exerts very low pressure on the reactor vessel even at extremely high temperatures.
The Toshiba 4S Nuclear Battery is being proposed as the power source for the Galena Nuclear Power Plant
Galena Nuclear Power Plant
The Galena Nuclear Power Plant is a proposed nuclear power plant to be constructed in the Yukon River village of Galena in the U.S. state of Alaska...
in Alaska.
Current developments
Currently Toshiba, together with its WestinghouseWestinghouse Electric Company
Westinghouse Electric Company LLC is a nuclear power company, offering a wide range of nuclear products and services to utilities throughout the world, including nuclear fuel, service and maintenance, instrumentation and control and advanced nuclear plant designs...
subsidiary, is in the preliminary design review stage of the Design Certification process before the United States Nuclear Regulatory Commission (USNRC). Application for certification of the design is currently planned for 2012 when the standardized Design Certification application will be filed for the 4S. The most recent meeting with the NRC took place on August 8, 2008, at which time the NRC's staff met with representatives of Toshiba and Westinghouse for a pre-application presentation of a Phenomena Identification and Ranking Table (PIRT) for the Toshiba 4S (Super-Safe, Small and Simple) reactor. Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
recently released an interesting study on the Toshiba 4S design, which provides an overview of the 4S design and suggests that certain goals may be easier to meet if lead is used as the coolant rather than sodium, due to lead's high transparency to neutrons and low transparency to gamma radiation, though lead has a higher melting point than sodium does.
The NRC received the latest version of the letter of intent from the designers of the reactor as of March 13, 2009. The approval process is on track for official submission to the USNRC in October 2010 of a standard application for Design Certification. During the week of October 16, 2009, persons or organizations unknown submitted a Freedom of Information Act request to the USNRC requesting that "documents related to the Super-Safe, Small and Simple (4s) Nuclear Reactor from Toshiba Corporation particularly related to possible placement in Galena, Alaska, including tech info on reactor, safety assessments, nuclear material security, etc." be released to the requestors.
The latest developments at NRC suggest that currently the biggest obstacle facing 4S, or all other small nuclear reactor designs, is not technical nor safety related but rather insurance and legal requirements burdens. Current obligatory insurance and legal compliance is blind to the scale of a reactor and places virtually the same burden on multi-gigawatt power plants and comparatively small 30 kW installations. The NRC is aware of this barrier, and has held a number of public reviews to devise a new scheme that would make it financially feasible to build and operate small reactors, while at the same time maintaining appropriate level of protection at large LWR installations, the latest of which took place in December 2010, setting January 2011 as the time frame for preparation of official white paper proposal.
External links
- IAEA Advanced Reactors Information System: 4S
- NRC overview Official information from Nuclear Regulatory Commission
- Atomic Insights article information about the reactor, its specifications, and engineering aspects and challenges.
- ROE: Technical details about the 4S planned for Galena, Alaska.
See also
- NuScaleNuScaleNuScale Power LLC is a company formed to construct and sell dedicated design of relatively small nuclear reactors, which they claim will be modular, inexpensive, inherently safe, and proliferation-resistant.-History:The basic design is based on the MASLWR developed at Oregon...
- Hyperion nuclear reactorHyperion Power GenerationHyperion Power Generation, Inc. is a privately held corporation formed to construct and sell several designs of relatively small nuclear reactors, which they claim will be modular, inexpensive, inherently safe, and proliferation-resistant...
(hydride) - mPower by Babcock & Wilcox CompanyB&W mPowerThe B&W mPower is a proposed 125 MW modular, advanced light water nuclear reactor. The reactor is to be built by Babcock & Wilcox Co. in North America, and shipped by rail to generating sites. The reactor's power output is approximately 125 MWe, or approximately 10% of a typical reactor...
- Traveling wave reactorTraveling wave reactorA traveling-wave reactor, or TWR, is a type of conceptual nuclear reactor that theorists speculate can convert fertile material into fissile fuel as it runs using the process of nuclear transmutation...