Washington State University Reactor
Encyclopedia
The Washington State University Reactor (WSUR) is housed in the Washington State University Nuclear Radiation Center (WSUNRC), and was completed in 1961. The (then) Washington State College Reactor was the brainchild of Harold W. Dodgen, a former researcher on the Manhattan Project where he earned his PhD from 1943 to 1946. He secured funding for the ambitious 'Reactor Project' from the National Science Foundation, the Atomic Energy Commission, and the College administration totaling $479,000 (roughly $3.5 million in today's dollars). Dodgen's basis for constructing a reactor was that the College was primly located as a training facility for the Hanford site, as well as Idaho National Laboratory
because there was no other research reactor in the West at that time. After completing the extensive application and design process with the help of contractors from General Electric
they broke ground in August 1957 and the first criticality was achieved on March 7, 1961 at a power level of 1W. They gradually increased power over the next year to achieve their maximum licensed operating power of 100 kW.
It was initially a General Electric
MTR plate-type reactor, but was upgraded in 1967 to a 1MW General Atomics
TRIGA
(Teaching Research Isotopes General Atomics) reactor. Standard TRIGA
fuel rods are cylindrical rods, clad in stainless steel
utilizing Uranium-235 dispersed in a ceramic zirconium-hydride matrix as fuel. The WSUR operated with this TRIGA
fuel until the Fuel Life Improvement Program (FLIP) once again upgraded the reactor in 1976 with a partial new core of high-enriched 'TRIGA
FLIP' fuel designed for an extended lifetime. Two years later, in 1978, due to fears of nuclear proliferation
it was federally mandated that all high-enriched reactor fuel (except for military use) be replaced with Low Enriched Uranium
Fuel (LEU). Due to the extensive work, cost, and the number of research reactors undergoing the procedure, the WSUR was not converted until October 2008. All FLIP fuel was replaced by another TRIGA
fuel known as 30/20 LEU and when the new core went critical on October 7, 2008 it became the world's only mixed 8.5/20(Standard TRIGA) and 30/20 LEU core.
, shield, and moderator. Inside the core box there is a bottom grid-plate into which 3 and 4-rod clusters of TRIGA
fuel sit separated by boron-aluminum (Boral) control elements. These control elements are raised out of the core via servo-motors to control reactor power. Power is monitored via three different and independent detectors that sit inside the core structure; there is a compensated ion chamber, an uncompensated ion chamber, and a fission chamber in three of the four corners of the grid box.
Due to the highly energetic nature of the fission process, a substantial amount of heat is generated during operation (~350 °C).The fuel is cooled by the natural convection of light water which is circulated through a plate-type heat exchanger with a primary and secondary loop. A cooling tower is utilized to discharge heat from the secondary loop to the environment, ensuring that the system remains well within temperature limits while preventing environmental exposure of water which has contacted the reactor. The WSUR is purely a research reactor
, lacking both a pressure vessel
and steam turbine
which are used to generate electricity
in power reactors
.
The primary use for the WSUR is to generate neutrons which can be used for a multitude of experimental purposes. There are several specialized experimental facilities for NAA and isotope production (see below), and several generalized sample rotator tubes whereby samples are lowered into the core for a set time, then pulled back out and sent to the laboratory where the data analysis will take place.
is a method used to determine elemental concentrations in unknown samples. It is especially useful for determining amounts of heavy metals (to parts per billion) in samples that are often as small as 10 mg. The WSUR can even do NAA research by pulsing samples. Examples of past research projects that have used this unique and valuable analysis method include determining quantities of toxic metals, such as arsenic, zinc, and selenium in air filters, tree rings, and other environmental samples. NAA can also be used to find trace elements in biological materials. This can be especially useful in plant or animal nutrient and health studies. Argon dating of geological samples can even be performed using the reactor and associated NAA equipment.
The WSUR also uses the neutrons it generates to produce isotopes for various other fields.
gamma irradiator is also housed in the reactor pool and is a separate system from the reactor itself. The WSU College of Veterinary Medicine, as well as several Biology graduate students use the source as a means for sterilization of biological samples as it is much cheaper and faster than an autoclave
.
Idaho National Laboratory
Idaho National Laboratory is an complex located in the high desert of eastern Idaho, between the town of Arco to the west and the cities of Idaho Falls and Blackfoot to the east. It lies within Butte, Bingham, Bonneville and Jefferson counties...
because there was no other research reactor in the West at that time. After completing the extensive application and design process with the help of contractors from General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
they broke ground in August 1957 and the first criticality was achieved on March 7, 1961 at a power level of 1W. They gradually increased power over the next year to achieve their maximum licensed operating power of 100 kW.
It was initially a General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
MTR plate-type reactor, but was upgraded in 1967 to a 1MW General Atomics
General Atomics
General Atomics is a nuclear physics and defense contractor headquartered in San Diego, California. General Atomics’ research into fission and fusion matured into competencies in related technologies, allowing the company to expand into other fields of research...
TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
(Teaching Research Isotopes General Atomics) reactor. Standard TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
fuel rods are cylindrical rods, clad in stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
utilizing Uranium-235 dispersed in a ceramic zirconium-hydride matrix as fuel. The WSUR operated with this TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
fuel until the Fuel Life Improvement Program (FLIP) once again upgraded the reactor in 1976 with a partial new core of high-enriched 'TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
FLIP' fuel designed for an extended lifetime. Two years later, in 1978, due to fears of nuclear proliferation
Nuclear proliferation
Nuclear proliferation is a term now used to describe the spread of nuclear weapons, fissile material, and weapons-applicable nuclear technology and information, to nations which are not recognized as "Nuclear Weapon States" by the Treaty on the Nonproliferation of Nuclear Weapons, also known as the...
it was federally mandated that all high-enriched reactor fuel (except for military use) be replaced with Low Enriched Uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
Fuel (LEU). Due to the extensive work, cost, and the number of research reactors undergoing the procedure, the WSUR was not converted until October 2008. All FLIP fuel was replaced by another TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
fuel known as 30/20 LEU and when the new core went critical on October 7, 2008 it became the world's only mixed 8.5/20(Standard TRIGA) and 30/20 LEU core.
Design
The WSUR reactor core consists of a rectangular aluminum box suspended from a movable bridge structure. Surrounding the core is a 242,000 liter pool of high purity deionized light water, which is used as both a coolantCoolant
A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor...
, shield, and moderator. Inside the core box there is a bottom grid-plate into which 3 and 4-rod clusters of TRIGA
TRIGA
TRIGA is a class of small nuclear reactor designed and manufactured by General Atomics. The design team for TRIGA was led by the physicist Freeman Dyson.TRIGA is the acronym of Training, Research, Isotopes, General Atomics.-Design:...
fuel sit separated by boron-aluminum (Boral) control elements. These control elements are raised out of the core via servo-motors to control reactor power. Power is monitored via three different and independent detectors that sit inside the core structure; there is a compensated ion chamber, an uncompensated ion chamber, and a fission chamber in three of the four corners of the grid box.
Due to the highly energetic nature of the fission process, a substantial amount of heat is generated during operation (~350 °C).The fuel is cooled by the natural convection of light water which is circulated through a plate-type heat exchanger with a primary and secondary loop. A cooling tower is utilized to discharge heat from the secondary loop to the environment, ensuring that the system remains well within temperature limits while preventing environmental exposure of water which has contacted the reactor. The WSUR is purely a research reactor
Research reactor
Research reactors are nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or maritime propulsion.-Purpose:...
, lacking both a pressure vessel
Reactor vessel
In a nuclear power plant, the reactor vessel is a pressure vessel containing the Nuclear reactor coolant and reactor core.Not all power reactors have a reactor vessel. Power reactors are generally classified by the type of coolant rather than by the configuration of the reactor vessel used to...
and steam turbine
Steam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....
which are used to generate electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
in power reactors
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...
.
The primary use for the WSUR is to generate neutrons which can be used for a multitude of experimental purposes. There are several specialized experimental facilities for NAA and isotope production (see below), and several generalized sample rotator tubes whereby samples are lowered into the core for a set time, then pulled back out and sent to the laboratory where the data analysis will take place.
Pulsing
Like many TRIGA reactors, the WSUR has the ability to pulse. Ordinarily the WSUR runs at a steady state power level of 1MW, however because of the unique characteristics of TRIGA fuel it can be pulsed to approximately 1000 times this power for a very short amount of time. This ability is due to the fact that TRIGA fuel is designed with a prompt negative temperature coefficient of reactivity, which means that: as the fuel heats up, it becomes less and less reactive (it shuts itself down). So when one of the control elements (known as the transient rod) is ejected from the core via air pressure at high speeds, the reactor jumps in power from ~80 watts to over a 1 billion watts and back down again in 50 milliseconds, causing a bright blue flash of Cerenkov radiation. There is a video of this effect on the WSUR webpage (see references).Research
Neutron activation analysisNeutron activation analysis
In chemistry, neutron activation analysis is a nuclear process used for determining the concentrations of elements in a vast amount of materials. NAA allows discrete sampling of elements as it disregards the chemical form of a sample, and focuses solely on its nucleus. The method is based on...
is a method used to determine elemental concentrations in unknown samples. It is especially useful for determining amounts of heavy metals (to parts per billion) in samples that are often as small as 10 mg. The WSUR can even do NAA research by pulsing samples. Examples of past research projects that have used this unique and valuable analysis method include determining quantities of toxic metals, such as arsenic, zinc, and selenium in air filters, tree rings, and other environmental samples. NAA can also be used to find trace elements in biological materials. This can be especially useful in plant or animal nutrient and health studies. Argon dating of geological samples can even be performed using the reactor and associated NAA equipment.
The WSUR also uses the neutrons it generates to produce isotopes for various other fields.
Epithermal neutron beam facility
The WSU TRIGA reactor has an external epithermal neutron beam facility. This beam is a well-collimated, high-flux, medium energy dry neutron beam. It can also be modified to generate low energy neutrons. This beam facility is enclosed in a special high-radiation area room, and was built in conjunction with the Idaho National Engineering Laboratory for cancer research. Ongoing projects include Boron-Neutron Capture Therapy (BNCT) research, especially that research for a cure for brain tumors, although the beam can be used for any neutron-capture therapy. This beam can also be used for neutron radiography, a non-destructive technique for examining 'heavy' materials such as steel for internal 'light' materials, such as cracks in castings, voids in welds, or fluid flows inside pipes.Cobalt-60 source
The Cobalt-60Cobalt-60
Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60...
gamma irradiator is also housed in the reactor pool and is a separate system from the reactor itself. The WSU College of Veterinary Medicine, as well as several Biology graduate students use the source as a means for sterilization of biological samples as it is much cheaper and faster than an autoclave
Autoclave
An autoclave is an instrument used to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and the contents. It was invented by Charles Chamberland in 1879, although a precursor known as the...
.