Administrative Limit - In addition to federal regulations, which limit a worker's occupational radiation exposure to 5000 mrem annually, NASA has established daily (100 mrem), weekly (250 mrem) and annual (1,000) mrem administrative limits to enable close monitoring of workers and their incremental radiation dose.

Alpha – radiation made up of particles that include two neutrons and two protons each. Alpha radiation travels only a few inches in air and can be blocked by a sheet of paper or skin.

B-25 box – a standard container for transporting Class A, solid, low-level radioactive waste.

Background radiation  –  The radiation levels that occur naturally (from other than man-made sources) in the environment. Naturally occurring radiation comes from sources such as the sun (cosmic rays), radon from the ground, elements in the soil, water and food.

Barnwell Disposal Facility   –  located in Barnwell , South Carolina , one of two sites in the US licensed to accept low-level radioactive waste for disposal.

Beta – radiation particles that are smaller but have more energy than alpha. Beta radiation can travel up to 12 to 15 feet in air and can penetrate skin. About an inch of shielding – glass, wood, plastic or metal can block beta particles.

Bioassay   –  a physical test that NASA performs, at the start and routinely during employment, on decommissioning workers to determine and track the types and amounts of isotopes that are present in the body (from natural sources and from previous radiation work).

Bio-shield - a concrete and steel structure that had provided an extra layer of protection around the reactor when it was operational.

Brokk - The Brokk is a remotely operated piece of machinery, resembling a small backhoe. Its long arm can be fitted with a number of tools, including a large shaver head that was mounted for use in decontaminating the Hot Cells, scraping away lightly contaminated concrete a quarter-inch at a time. The underlying concrete was surveyed to ensure it was clean and the process repeated until it met project cleanup levels.

Buried Piping – Pipe systems covered with soil but not encased in concrete, as is embedded dipping. Buried piping is mostly located outside of Reactor Facility buildings. There is an estimated 33,000 feet of buried piping on facility grounds but most contains little or no contamination.

“Burrito Bag” – soft-sided fabric containers used for transporting contaminated soil for disposal by train in bulk rail cars.

Cadmium – a metal in control rods which had been used to govern the reactor's power when it was operational.

Canal – alleyway that separates quadrants within the reactor vessel.

Cask – standard shipping container certified by the NRC to transport Class B, solid, low-level radioactive waste.

Cathodic Protection System - A system of holes and tubes around the Containment Vessel that run as much as 50 feet below grade. When the reactor was operational, this system was used to protect the Containment Vessel from corrosion.

CFR – Code of Federal Regulations

Cesium 137 – A man-made radioactive isotope that gives off energy in the form of gamma rays. It has a half-life of 30 years.

Characterization   –  Sampling and analysis that identifies types and amounts of isotopes present, including the mix of isotope types in each area. Information gathered is used to identify radiation hazards as well as safety procedures and personal protective equipment needed. It also helps plan for decontamination, packaging and transporting waste for disposal, and supports the final site status survey required by the NRC before NASA's license can be terminated.

Class A, B, C, GTCC  –  The NRC classifies solid LLRW for disposal in these categories:

A   –  extremely low levels of LLRW

B   –  higher levels of LLRW

C   –  highest levels of LLRW allowed in a LLRW disposal facility

GTCC   –  Greater Than Class C waste

Cleanup goal – after decommissioning a person could live on the site, eating all crops grown there and using groundwater for drinking, receiving no more than 25 millirem per year over the 360 millirem of background radiation that an average American receives annually. This level is achieved by having specific levels for each and every isotope present so that the total dose will not exceed the 25 millirem a year. This cleanup goal is termed the Resident Farmer Scenario in that, at this cleanup, level a farm family could theoretically live safely on the site, drink its groundwater and safely grow crops there.

Cobalt 60 - A man-made radioactive isotope that gives off energy in the form of gamma rays. It has a half-life of 5.2 years.

Cold Pipe Tunnel - When the Reactor Facility was operational, this tunnel contained all of the air, electrical and water lines that ran between the Service Equipment Building , the Reactor Building and the cooling tower.

Cold Retention Area - Two concrete basins that had a total capacity of one million gallons, which were used to hold lightly contaminated water when the Reactor Facility was operational.

Community Information Bank – Location for Decommissioning documents and reference materials made available for public review by NASA at BGSU Firelands Library.

Community Information Session – Annual forum where community members can talk directly with the Decommissioning Team about any aspect of the project.

Community Workgroup  – A group of local citizens who meet regularly to receive information from NASA and to provide feedback about decommissioning the Reactor Facility at Plum Brook Station.

Constellation Program - NASA’s exploration program whose goal is to send astronauts back to the Moon and eventually to Mars.

Containers  –   The Department of Transportation (DOT) has three classification for shipping LLRW:

Limited Quantity and LSA   –  Waste with very low levels of radioactivity can be shipped in "strong, tight containers" such as steel drums, B-25 boxes, and "Sealand" containers pre-mounted on trucks.

Type A – containers that must pass tests simulating normal transportation conditions such as pressure and vibration in which very low levels of radioactive waste can be packaged.

Type B – engineered casks that may have double walls of thick steel and heavy lead, which must undergo demanding test simulating both normal transportation and accident conditions.

Containment Vessel  –  the structure or vessel that encloses the components of the reactor coolant pressure boundary, and serves as an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment.

Contamination – Radioactive material located where it should not be present

Critical path  –  refers to the work or activities that must get done before certain other ones can begin.

Cumulative dose – the measure of both internal and external radiation dose from occupational exposure.

Curies   – A unit of measure for radioactivity, based on the number of disintegrations that happen each second. Contamination can be measured in the number of curies in a volume of soil.

DCGL's – Derived Concentration Guideline Levels – cleanup levels for each isotope present that when added together, the total will not exceed the cleanup goal for unrestricted use.

Decay – radioactive atoms undergo a natural process that occurs when an atom spontaneously gives off its extra energy.

Decommission   –  to remove a facility or site safely from service and reduce residual radioactivity to a level that permits: (1) Release of the property for unrestricted use and termination of the license; or (2) Release of the property under restricted conditions and termination of the license.

Decommissioning Plan - A plan, outlining the procedure for decommissioning a reactor facility in accordance with federal regulations, that must demonstrate to the Nuclear Regulatory Commission reviewers that plans, personnel, policies and procedures have been thoroughly considered for the duration of decommissioning.

Decontamination  –   To rid structures, equipment and the site of residual radioactivity or other contamination through onsite treatment, or removing material for disposal offsite.

Decontamination and Waste Disposal Contract - To be issued this spring, the contract will address all the remaining tasks for completion of decommissioning.

Direct Radiation – refers to type and amount of isotopes present, and measures how much energy is being emitted.

Dismantle  –  the act of taking apart equipment and structures in order to dispose of them properly.

DOE – U. S. Department of Energy

Dose –  refers to the amount of radiation energy that is actually absorbed by the human body.

Dose estimate - the calculated radiation exposure level based on available survey data and the time it would take a specified number of workers to complete a particular task in a radioactive environment.

Dosimeter  –   Commonly referred to as a film badge, this device is worn on a person's body and measures accumulated radiation over a period of time. They are mandatory at facilities that use radioactive materials.

DOT – U.S. Department of Transportation

Earthen trenches – At some licensed disposal facilities some higher level LLRW is disposed in large concrete vaults in excavated areas to 20 feet below grade.

EMA - The Emergency Management Agency is the county agency that coordinates
responses to any public safety emergency. 

Embedded Piping – Pipe systems encased in concrete, and located as much as 46 feet below grade in Reactor Facility buildings.

Emergency Response Plan - prepared by a Local Emergency Planning Committee (LEPC), this plan outlines specific procedures to be followed, as well as roles and responsibilities of personnel, in case of a hazardous materials release.

Emergency Retention Basin - was used on rare occasions to hold large volumes of water that resulted from operations. Water containing levels of radioactivity remained in the retention basin to be treated, allowed to decay, or verified to be within acceptable limits to discharge.

Energy Solutions – A nuclear waste management company that owns two subcontractors working on the Decommissioning Project, the former Duratek (of Tennessee) and the former Envirocare of Utah, Inc. , which is one of two sites in the US licensed to accept low-level radioactive waste for disposal.

Engineered cells – At some licensed disposal facilities some low-level radioactive waste (LLRW) is disposed aboveground vaults that when filled are covered with dense layers of natural materials.

Environmental Baseline Survey – a study that looks at all possible non-radiological contamination within the Reactor Facility.

EPA – Environmental Protection Agency

Exposure  – refers to the amount of radiation energy that reaches an object's surface (worker's body) in a given time period.

Internal exposure   –  occurs when radioactive material (usually alpha or beta particles) is taken into the body by eating, drinking, breathing, or through the breaks in the skin.

External exposure   –  occurs when radiation (usually x-rays or gamma rays) penetrates the body.

FER – Fixed equipment removal

Film badge – see dosimeter

Final Status Survey - NRC's final survey that certifies radiation levels are safe and meet the strict cleanup criteria. Only then will the NRC terminate NASA's license.

Final Status Survey Plan – A document submitted to the NRC that specifies how NASA will achieve the strict cleanup standards established for the reactor site at the end of decommissioning.

Fixed contamination – radioactivity embedded in the material.

Fixed equipment – components that remain fastened in place or attached to the structure.

Free-released – materials that can be reused, having been surveyed and found to be below the required cleanup level.

Frisker – a hand-held radiation detection device.

Gamma  – radiation that is made up of energy waves similar to light or radio waves but with more energy. Gamma rays can travel great distance and penetrate matter. Concrete or lead is typically used to shield people form gamma radiation.

Gamma Logger – a steel-tubed probe device used for taking shale samples as part of NASA's off-site sampling program.

Geiger Counter  – a hand-held instrument that detects the presence and intensity of radiation from a radioactive substance.

Geoprobe – a two-pronged steel device used to take radiation samples in soils and bedrock as deep as 20 feet or more below the surface. These soil samples will be evaluated in the Final Status Survey. The Geoprobe has also been used to take bedrock and soil samples in Sandusky Bay .

GRC – NASA's Glenn Research Center

Haag Environmental - The Sandusky-based hydrogeological consulting company that conducted an in-depth, off-site sampling program (more than 1,000 samples) to identify trace amounts of cesium along the length of Plum Brook. The program showed that no sample posed any public health concern.

Half-life – The time required for half of any quantity of identical radioactive atoms to undergo radioactive decay, so that half of the atoms in the substance are no longer emitting radiation and are no longer considered to be radioactive.

Hazardous waste – a material containing a hazardous substance regulated for handling and disposal by the US EPA and classified by their properties of toxicity, ignitability and reactivity, and by the process they came from or how they were used.

Hot Cells – Seven rooms used when the Reactor Facility was operational, where irradiated experiments were examined. They are currently being dismantled and decontaminated.

Hot Dry Storage – a 31-foot-deep vault area in the Hot Laboratory where irradiated equipment was stored.

Hot Retention Area – A large, concrete vault located 90% underground that contained eight 60,000-gallon steel tanks. When the reactor was operational, the tanks were used to hold water contaminated from reactor operations until the radiation levels were reduced and the water in the tanks could then be discharged or reused. The tanks were emptied when the Reactor Facility was shut down in 1973.

HP   – Health Physics consists of trained radiological professionals. During the Decommissioning Project, HP's are conducting a site-wide characterization of the Reactor Facility to determine radiation levels.

Hydrolaze - A high-pressure (20,000 pounds per square inch) water washer that was used in decontamination activities, cleaning the inside of embedded pipes in some Reactor Facility buildings.

IH  –  Industrial Hygiene refers to personal protection programs and gear-including personal radiation monitoring for workers on the Decommissioning Project.

Independent Verification Survey (IVS) – A third-party site survey after NASA submits its Final Status Survey report to NRC checking NASA's data and certifying the cleanup goal has been achieved.

Intermodal – a waste container that can be transported by truck and easily transferred to a train.

Inventory – an itemized list or catalog of property remaining within the Reactor Facility.

Isotope - atoms that are similar but have differing numbers of neutrons.

Label – information placed on outside of a package for quick identification of the type and radioactive level of material being stored or transported.

LEPC – Local Emergency Planning Commission

Limited Quantity – The Department of Transportation's designation for LLRW having very low levels of radioactivity that can be shipped in strong, tight containers.

LLRW  –   Low-Level Radioactive Waste - a by-product of processes that use radioactive materials. It can include general trash, protective clothing and gloves, test tubes and vials, machinery parts, filters and other items that may have become contaminated by radioactive particles. It is not spent nuclear fuel or high-level radioactive waste.

Loose contamination – radioactive “dust” on the surface of equipment detected by using a swipe sample that will be analyzed by a certified laboratory.

Loose equipment – components that are not fastened in place or attached to the structure.

Manifest – documentation that accompanies and traces waste shipments from generator to disposal. It describes the type of waste, volume, level of radioactivity, other waste characteristics and its ultimate destination.

Marcrist floor shaver - A piece of equipment, equipped with a vacuum hose, to remove lightly-contaminated concrete from floor and wall surfaces in Reactor Facility buildings.

Mixed Waste – a combination of a hazardous substance containing some level of radioactive contamination.

Monitoring:

Personal monitoring – tracking employees' radiation exposure on a regular basis using dosimetry (employees wearing film badges) and through routine urinalysis and nasal swabs.

Environmental monitoring – sampling of environment (air, water, soil, vegetation, animals) that is compared with baseline samples to see if any changes have occurred.

NASA's Nuclear Frontier - a book on the history of the Plum Brook Reactor facility was authored by Robert Arrighi and Dr. Mark Bowles, and published in 2004.

Negative pressure – air ventilation that keeps air flowing into, instead of being drawn out of a containment area.

NRC – Nuclear Regulatory Commission

ODH – Ohio Department of Health

OEPA – Ohio Environmental Protection Agency

Of Ashes and Atoms – the title of an historical documentary video of the Plum Brook Station Reactor Facility, which premiered in July 2004.

ORISE - The Oak Ridge Institute for Science and Education is the NRC’s contractor for the Independent Verification Survey.

Orion crew exploration vehicle - The eventual successor to space shuttle, this vehicle is being tested at NASA Glenn and Plum Brook Station.

OSHA – Federal Occupational Safety and Health Administration

PBRF – Plum Brook Reactor Facility

PBS – NASA Plum Brook Station

Pentolite Ditch – A ditch on NASA PBS property that was a permitted pathway for discharge of water into Plum Brook when the Reactor Facility was operational.

Physical samples – as part of characterization, direct radiation tests are conducted and analyzed including:

Reactor Office and Lab Building (ROLB) - The first Reactor Facility building to undergo Final Status Survey field work, which began during fall 2007.

Smears – swiping a surface using a dampened cloth

Sub-pile Room - A storage room 46 feet below grade, under the former location of the reactor tank. It underwent decontamination and FSS field work in early 2008.

Bulk samples – Actual soil samples or core borings of concrete or other material.

Picocurie – A measure of radioactivity equal to one-trillionth of a curie. Contamination in soil can be measured in picouries per gram.

Placard – signs posted on outside of trucks for quick identification of the type of material being transported

Plum Brook – The body of fresh water running from NASA Plum Brook Station to Sandusky Bay .

Primary Pump House – When the Reactor Facility was operational, this building housed the reactor's cooling system. This building was the site of initial decontamination activity in June 2004.

Process Ventilation System - filters air through a series of 16 HEPA filters and maintains a negative pressure inside the containment enclosure. Air is drawn from outside, is constantly circulated as a clean air source for workers, and is filtered of airborne contamination before being released outside.

Project Specific Action Limit (PSAL) – NASA set Project Specific Action Limits to serve as early indicators of any slight increase in radioactivity in air, surface water, sediment and groundwater as part of the comprehensive environmental monitoring program.

PSC - The Project Safety Committee consists of NASA and contractor personnel who meet weekly at Plum Brook Station to evaluate plans for each task undertaken on the Decommissioning Project. Tasks cannot move forward until PSC signoff is obtained.

Quadrant – pie shaped areas, (roughly 25-feet deep x 20-feet wide x 40-feet long), which were filled with water and served to protect workers and the environment from the radiation contained in the reactor vessel core.

Radiation – the excess energy an atom gives off or emits to achieve stability. When a radionuclide gives up its extra energy, that energy is called ionizing radiation. There are three kinds of radiation (or isotopes) emitted by radioactive elements – alpha, beta, and gamma.

Radiation field – the combined results of fixed and loose contamination.

Radiation Work Permit – identifies what the radiation risks are, what the exposure levels will be, and how to minimize radiation risks using engineering controls and personal protective equipment.

Radioactive – The condition of a material that is in an unstable atomic form and is spontaneously giving off energy (decaying) in order to reach a more stable form.

Radioactive Materials License – the Nuclear Regulatory Commission's authority for overseeing the safe use of radioactive materials at a given site.

Radioactivity – The energy given off by radioactive material as it decays to a more stable condition

Radionuclide – a radioactive atom

Random samples – A collection of samples – in this case, of sediment along Plum Brook – based on a predetermined geographic distribution, designed to ensure fair coverage of all areas, even those with no detected, elevated readings. The Plum Brook sediment samples were collected along the center line of the stream every 50 feet, with alternating samples to the left and right, between the center points.

Reactor Vessel - Large concrete encased tank that shielded workers and the environment from radiation from the reactor core.

Redundant controls - numerous safety precautions and multiple barriers in place to ensure that workers are protected and airborne contamination is contained during decommissioning operations.

Rem or mrem - a unit of measurement that translates the energy measured into the dose or equivalent dose that a person receives. A mrem (millirem) is one-thousandth of a rem.

Research (or non-power) reactor– nuclear reactors that were used for experimentation, and not used to generate electricity for public consumption.

Roof Slabs –, these Concrete slabs that composed the roof of the Hot Cells. Four slabs, weighing at least 20 tons apiece were removed from Hot Cell #1, largest room, then decontaminated and free released as scrap concrete. In Hot Cell #2 three slabs, each weighing between four and nine tons, have also been removed for decontamination and free release.

Safety Review - takes into consideration the steps involved in each upcoming job and accounts for every potential hazard.

Sampling – measurements of radiation in air, surface water, sediment and groundwater taken and analyzed on a regular basis from areas in and around the Reactor Facility.

Scabbling – A decontamination method that uses a diamond-tipped drill head to take off top layers of contaminated concrete.

Science in Flux – a book on the history of NASA's nuclear program at Plum Brook Station, authored by Dr. Mark Bowles and published in September 2006.

“SeaLand” container – The Department of Transportation designates these steel rectangular boxes usually attached on specialized “low boy” trucks as “strong, tight containers” suitable for transporting Low Specific Activity waste.

Segmentation – the process of reducing the whole into pieces by taking apart reactor internals and vessel walls, reducing volume of some pieces, placing them in packages for shipping to offsite disposal facilities.

Shielding - physical structures that protect workers from radiation exposure.

Sodium Iodide Detector – A radiation monitor used for Plum Brook sampling

Split Samples – Plum Brook sediment samples divided and provided to independent laboratories and those utilized by the NRC and ODH for quality control and independent analysis of the samples.

Sponge Blaster - A device similar to a sandblaster, this machine is being used to decontaminate the Hot Cells, using small pieces of sponge with abrasive material attached to scrape concrete from the cell walls.

Sump – water pumps in the Reactor Facility building. NASA is routinely monitoring four sump locations for any trace of elevated radioactivity during decommissioning.

Super Sacks - Special bags rated by the U.S. Department of Transportation that are rated as "strong, tight containers."

Survey – using detection devices to take direct radiation readings of items inside reactor.

Swipe sample – using a cloth to collect surface “dust” to send to a laboratory for analysis of loose contamination.

TLD 's - thermo luminescent dosimeters

Targeted samples – Plum Brook sediment samples taken in areas where there had previously been elevated readings, above 300 counts per minute (the equivalent of 6 picocuries per gram) were detected. These samples were taken to identify the highest levels of contamination present.

Universal waste – a subcategory of hazardous wastes that includes batteries, pesticides, thermostats and lamps.

Unrestricted Use – the status given by the NRC to a decommissioned site with residual radiation levels at or below background levels and is considered safe for any purpose.

USEPA – U.S. Environmental Protection Agency

USNRC – U. S. Nuclear Regulatory Commission

Warm Handling Room - A workshop/bay area adjacent to the former Hot Cells in the Hot Lab Building. It underwent decontamination work in 2007 and early 2008.

Waste acceptance criteria – disposal sites are required to accept waste based on a set of specific characteristics, i.e., type, amount, form, etc.

WEMS: When the reactor was operational, the Waste Effluent Monitoring System (WEMS) was used to ensure that water being released from reactor operations met safe and strict discharge standards. The WEMS included a large, open-air pit that was cleaned of grass, leaves, mud and other organic material in late 2006.

WEP - Work Execution Packages are detailed planning documents that explain the work to be done and safety aspects of each task to be undertaken on the project. They must receive the signoff of the PSC before going forward.

Whole Body Counter – A machine used to perform checks of the total amount of radiation present in a person's body. Prior to having this machine on-site, workers needed to travel 4 hours round trip for the screening.  

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