The University of Cincinnati Education and Research Center sponsored an interdisciplinary field trip to the Oak Ridge National Lab (https://www.ornl.gov/) on August 24, 2018. There were 7 students and 1 postdoc from the Environmental and Industrial Hygiene program, 3 from Occupational Health Nursing, 1 Occupational Medicine resident, and 3 Occupational Safety and Health Engineering students as well as 2 faculty hosts from Occupational Health Nursing.

The group toured several facilities at the lab including, the Graphite Reactor, Spallation Neutron Source, High Flux Isotope Reactor, and the Leadership Computing facility. See the following sections for re-caps of the different facilities written by the students and postdocs that attended the trip.

The Oak Ridge Graphite Reactor

By Vishal Nathu, Mike Benjamin, Yao Addor, and David Lang

Students had the opportunity to attend an ERC sponsored trip to Oak Ridge National Laboratory, which is sponsored by the U.S. Department of Energy. The state-of-the-art facility is a multi-program science and technology laboratory known for groundbreaking research in Advanced Materials, Clean Energy, Supercomputing, Neutron Science and Nuclear Science.
One site we visited was the graphite reactor dating back to World War II as part of the Manhattan project. It is one of the few reactors on site responsible for nuclear activity. Its objectives were to produce reactors converting uranium to plutonium, separating the two from each other, and developing an atomic bomb. The Oak Ridge site was chosen for its sparse population and hilly terrain (to reduce impact if radioactive fission products were released), accessibility by road and rail transportation, nearby labor sources, large amounts of electricity and cooling water, and mild climate for year-round construction. Throughout its rich history, the graphite reactor had reached critical level in 1943, produced gram quantities of plutonium used at sister facilities, converted to research activities in 1945, and was shut down in 1963 to be later designated a National Historic Landmark.

Vishal’s reflection: During my visit I learned some fascinating facts about the Graphite reactor. For instance, this reactor enabled studies for health hazards of reactor radiation, a vital aspect of workplace health and safety at similar operations across the U.S. From an Industrial Hygiene standpoint, it was interesting to see how far we have come in safety and health. When this reactor was first being used, the workers would wear ordinary clothes and not your typical present day personal protective equipment. Time, distance, and shielding to protect against radioactive exposure was not known at the time. In conclusion, this trip was very rewarding and gave students an in-depth look into previous, current, and even future research activity in the fields of medicine, industrial hygiene, engineering, and more.  

Mike’s reflection: I agree it was interesting to see that much was still being learned at that time about the health effects of radiation, and practices to reduce exposure were not as advanced as what they are today. I also found it interesting that uranium for the bomb dropped on Hiroshima was processed at Oak Ridge.

Yao’s reflection: Beside the intriguing occupational health and safety aspects, I was fascinated by the high-level research conducted at the site. I was moved by its tie with the history of WWII and Albert Einstein. I had the feeling of having touched a mystery. 

David’s Reflection: I found the reactor to be a fascinating look back into the development of a technology which has shaped the modern world. In particular it was amazing to see the journal of the scientist opened up to the day when he first achieved a fission reaction. One can only imagine the number of occupational hazards which must have been incompletely characterized at the time and the likely medical sequelae of working at the plant.

Supercomputing

By Carson Whitehead, Yanbo Fang, Maria Kander, and Rachel Zeiler

While visiting the Oak Ridge National Laboratory campus, we toured several incredible facilities. Each facility we visited was unique and had its own research purpose. Through our interactions with the professionals there, we were able to gain invaluable knowledge regarding several disciplines. The Oak Ridge Leadership Computing Facility (OLCF) is one of two leadership facilities in the United States, the other being the Argonne National Laboratory facility in Chicago, IL. OLCF is the facility responsible for providing the largest computers for the Department of Energy (DOE). OLCF not only houses computers for the DOE, but also for the National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Air Force. The DOE encourages individuals conducting research that need additional computational power to use their machines, and it is free to do so if the research findings will be submitted for publication. To get time on one of the supercomputers, individuals must first prove their need for the additional computational power and show they will use the majority of the resources available on the machine they’re requesting. 

During our tour of the facility we focused on the two rooms responsible for housing OLCF’s supercomputers as well as each computer’s unique computational power, design, and purpose in research. While OLCF also hosts a variety of other networking and storage solutions, these were not our focus. Because it would be impossible to cram all the supercomputing details into a brief blog post, we will hit only on the high notes. A “supercomputer” is a computer deemed to be one of the largest and most powerful computers of our day. Supercomputer performance is measured in floating-point operations per second (FLOPS). In years past the computational power of a modern iPhone would be considered a supercomputer and would have taken up just as much space as modern supercomputers like “Titan” and “Kraken”. Despite not being able to enter the rooms housing the supercomputers, it was truly amazing to see how large they were when peering in through a series of windows. Specifically, the room housing three of OLCF’s supercomputers spanned 20,000 square feet. This is roughly the size of five collegiate basketball courts. The amount of power required to operate OLCF’s current supercomputers was also an astonishing amount. Operating the supercomputers costs ORNL several $100 million each year. The primary areas of interest for using these supercomputers include energy, astrophysics, climate science, nanoscience, biology, material science, and geoscience. These are studied through decreased time to solution, an increased complexity of models, and an improved realism of simulations. Lastly, it was interesting to learn supercomputers go out-of-date rather quickly and are replaced as a consequence of Moore’s law. Moore’s law is the observation in which the number of transistors in a dense integrated circuit doubles about every two years (which leads to improved performance).

In conclusion, our experience at the Oak Ridge National Laboratory was extremely fulfilling.  We were able to interact with passionate professionals to learn about future projects, as well as observe some of our nation’s finest research!

Spallation Neutron Source

By Mamadou Niang and Colin McConnell

During our tour at ORNL, we visited the Spallation Neutron Source (SNS) among many other facilities. SNS is a world-class facility for materials research based on neutron scattering. SNS produces one of the most intense neutron beams in the world. The neuron source is used in many scientific projects that affect our everyday life such as energy, manufacturing, transportation, environment, health, electronics, food and so on. SNS uses a technique similar to x-ray diffraction (XRD); however, it uses neutrons instead of photons and is able to be used on biological or organic materials without damaging them. SNS consists of negative hydrogen ion source, linear accelerator, proton accumulator ring, liquid mercury target, and neutron detector instrument. The detector instrument works by having Helium-3 absorb the neutrons and produce tritium and protons. Since the protons have a charge, an electric field, produced by a wire conducting a current, will be disrupted by them, thus allowing for neutron detection. The detectors vary greatly in size.

SNS is open to researchers from public institutions provided users publish their findings. According to our tour guide (Dr. Matthieu Doucet), there are about 800 companies per year that use SNS for public research and sometimes companies must sign a non-disclosure agreement to help companies make their experiment. One noteworthy example of companies using the SNS that Dr. Doucet told us about was the Mars candy company using neutron scattering to get a better understanding of the structure of a new candy they designed. Another company used the SNS to better understand how their diapers absorbed water.

Figure 4 (left): Robot arm used to automatically insert samples in front of the neutron stream

Figure 5 (right): Interior of the neutron source building; behind the wall on the left side of the image is the liquid Hg neutron source

Spallation Neutron Source

By Vianessa Ng and Sarah Issler

Do you ever wonder how scientists know the molecular structure of a material? Well, each year, hundreds of scientists are fortunate enough to use the Spallation Neutron Source (SNS), located at Oak Ridge National Laboratory (ORNL) in Tennessee, to analyze the structural and compositional make-up of any soft material. The discovery of neutrons was discovered using the graphite reactor and is considered one of the most powerful neutron sources in the world!

Only a handful of lucky scientists and engineers are able to use the SNS to study their material. Similarly, with using an x-ray diffractor or spectrometer, the main difference between x-rays and neutrons is how sensitive the material behaves and interacts electromagnetically with the cloud of electrons. Therefore, it will be very difficult to analyze the cross sections of heavier materials, thus neutrons are more sensitive to lighter elements (i.e. water or hydrogen). A most famous usage of the SNS was an experiment conducted with the Mars candy M&M’s (2012) on one of their products containing chocolate covered pretzels. By using the SNS, they were able to identify that the introduction and flow of water through the chocolate caused the chocolate to melt and the pretzel core to become soggy which then led to poor shelf-life.

So, how is the analysis performed? An ion beam source is shone linearly at the piece of chocolate, generating generally negative hydrogen ions – hydrogen atom with 2 electrons. Initially, these ions travel through a linac, which is a long tunnel approximately the length of 3-football fields, containing magnets (to keep a pea size of neutrons bunched up) and a proton accelerator ring (to move the neutrons at 90% the speed of light). The beam leaves the accumulator ring and is shot towards a mercury target, smashing it to bits and 20-30 neutrons are generated, scattered, and collected by a neutron detector.

Essentially the neutrons scatter at various angles and energies contribute in analyzing the structure of the material being studied at the atomic scale without destroying the sample. However, safety is first. They have a RCT team on site 24 hours per day, 7 days a week to promote, prevent, and handle any radiation and chemical hazards attributed from the SNS. The Figure represents the SNS and surrounding environment. 

High Flux Isotope Reactor

By: Nicole Harris & Darris Bohman

One of the main areas we toured at Oak Ridge National Laboratory was the High Flux Isotope Reactor (HFIR). Before entering the building where the HFIR is housed, there were several rules explained to us such as: stay with your escort, don’t enter the control room, don’t walk in any water or wet areas, don’t operate any switches, if there is an alarm- follow your guides instructions, be quiet, and several others. It was clear that safety is a major priority for their guests and employees.

Our tour guides explained that the HFIR first reached a critical level in 1965 and at that time its major use was to produce plutonium. It also was mentioned that this is the highest flux beam reactor in the United States. While the main mission of the HFIR at this time is neutron scattering, it also does irradiation testing, isotope production, and neutron analysis. They make the fuel for NASA in the HFIR and it is only one of two facilities with the capability to do so. 

While in the building, we were able to see the reactor bay and watch the maintenance team work during a maintenance outage. The pool the reactor sits in is approximately 45 feet deep and has a blue hue to it. Full power is 85 megawatts.

As nurses touring ORNL, it was a great experience to see how the experiments being conducted in this building transfer over to the healthcare field. For example, the work being done at the HFIR includes experiments regarding drugs and finding new ways for medications to more accurately target specific cells in the body. 

High Flux Isotope Reactor

Evan Frank

The high-flux isotope reactor (HFIR) facility is a historic nuclear-based facility that still operates today to support research by generating nuclear isotopes for use in experiments. The reactor unit is maintained in a 85,000-gallon pool overseen by a control room from the upper levels of the several-story facility. The chambers of the lower levels house the equipment that process the neutron isotopes produces by the reactor, such as a cold-neutron guide that uses super-cooled channels to study the behavior of neutrons at temperatures close to absolute zero. About 200 people work in the building.

Although the facility houses a nuclear reactor and features all attendant safety controls, occupational health hazards in the HFIR building are generally unrelated to reactor operation. Workers in the bay housing the reactor pool are monitored by a health physicist from the control room area but only wear a form of PPE that leaves the face uncovered. In general, redundant layers of fail-safes and engineering controls effectively contain any hazards directly related to reactor operation.

The building also handles large amounts of liquid helium in the cold neutron guide module and oxygen levels are continuously monitored in case of leaks in the closed-off chambers housing this equipment. These too appear to be very unlikely occurrences owing to the engineering of the facility. Rather, workplace hazards are related to the support activities and processes. Although the safety controls related to reactor operation require regular assessment for compliance to Dept. of Energy guidelines, most of the actual workplace hazards are similar to those expected in an industrial-scale lab. Trips, falls, and hazards related to the use of electrical equipment and high-pressure steam make up most of the past incidents reported in the facility. In 2017 the facility celebrated 1.5 million man-hours without suffering injury-related work loss. The supervisors credited this to encouraging a non-hurried pace of work conducive to safety.

Thank you ORNL!

Overall, this was a highly successful trip and received positive feedback from all the attendees. Thank you to the Oak Ridge National Lab facility and tour guides for allowing the UC ERC to visit and for providing a positive educational experience for our students and faculty.