ReNuclear

redefining nuclear energy in hopes of transitioning to a society run on carbon-free electricity

Nuclear Waste

Introduction

One of the biggest concerns about nuclear energy production comes from the production of nuclear waste.To date there is approximately 22,000 m3 of high-level nuclear waste currently in storage, but not all of this was produced by nuclear power plants (World Nuclear Association, 2017). The long term storage of this high level waste is the  primary issue when discussing nuclear waste. Currently, there is no centralized government storage facility in the United States, so every nuclear plant stores its produced nuclear waste on site. This has been a pressing concern for the United States government since 1982.

Types of Nuclear Waste

There are two levels of nuclear waste,high-level and low-level nuclear waste. Low-level nuclear waste can be produced by a variety of processes. Some examples of low level nuclear waste include medical instruments such as medical tubes, syringes and other medical tools as well as other objects that have come into contact with high levels of radioactivity. These other objects can be clothes, reactor water treatment residue, mops, and other objects used to maintain nuclear plants (United States Nuclear Regulatory Commission [U.S.NRC], 2015). Low-level radioactive waste may be stored on site until the material’s radiation decays enough for regular disposal or it can be sent to an approved low-level radioactive waste site. There are currently eight approved facilities across the United States (U.S.NRC, 2015). High-level nuclear waste is produced primarily by nuclear plants and reactors. High-level nuclear waste is uranium fuel that no longer has the capability of producing anymore energy. Another source of high-level nuclear waste comes from the reactor themselves. The steel components used to construct the reactors become radioactive over the life of the plant. Fortunately, the half-life of this radioactive material is short, resulting in steel being non-hazardous after 50 years (World Nuclear Association, 2017). Other forms of high-level nuclear waste can have significantly longer half-lifes. For example, Pu239, an isotope produced in nuclear reactors, can have a half-life of 24,000 years (U.S.NRC, 2015). It is this type of long lasting, high-level nuclear waste that causes concern in the industry.

Reprocessing High-level Nuclear Waste

High level nuclear waste can be recycled using the PUREX process. PUREX stands for plutonium, uranium extraction. The process is used to separate usable uranium and plutonium from spent nuclear fuel the extracted metals can then be turned into more nuclear fuel. This reduces the volume of high level radioactive waste and increases the efficiency of the fuel cycle by recycling the extracted metals. The PUREX process works by dissolving the spent fuel in nitric acid, then extracting the uranium and plutonium with a thirty percent solution of tributyl phosphate in a hydrocarbon solvent.

Temporary Storage

High-level nuclear waste is stored at the sites where it is produced in spent fuel pools and dry casks. Spent fuel pools are made with reinforced concrete several feet thick with steel lining, and typically have 40-feet of water (U.S.NRC, 2015). These pools are used to cool and shield the fuel for the reactor. Spent fuel pools are used as a temporary storage space for waste that is too radioactive to be immediately moved to dry casks. Spent fuel is usually stored in the pools for five years before it becomes cool enough to transfer to the casks. Dry casks are made from stainless steel and are surrounded by concrete, they . The NRC (Nuclear Regulatory Commission) certifies dry casks for up to forty years with the option for renewal (U.S.NRC, 2015). Both the spent fuel pool and dry casks are considered temporary storage with the intent to move the nuclear waste to a centralized nuclear waste facility in the future.

Centralized Government Storage Facility

Yucca Mountain, Nevada

The plan to make a centralized government controlled nuclear waste storage facility has been in progress since the Nuclear Waste Policy Act of 1982. This act highlighted the desire for adequate long term high-level nuclear waste storage, the growing amount of nuclear waste being produced, and the underachieving effort to solve these issues over the past 30 years (Nuclear Waste Policy Act, 2004). The task of solving these problems was given  to the Department of Energy (DOE). The DOE came forward with a proposal to create a centralized nuclear storage facility located at Yucca Mountain, Nevada in 1987. Yucca Mountain was going to be an underground geologic repository to store the nations high-level nuclear waste. Since this initial proposal by the DOE, Nevada has consistently tried to prevent the construction and implementation of this site. The NRC was reviewing the site in 2008, but the project was cancelled in 2010. The NRC resumed its review in 2013, (U.S.NRC, 2015), however, the Yucca Mountain nuclear waste center has remained abandoned since 2010 (Eureka County, Nevada, 2017).

Deep Borehole Disposal

Deep Borehole Disposal is an alternative to the Yucca mountain nuclear waste storage facility. This approach involves drilling a borehole 5,000 meters deep, placing nuclear waste containers in the bottom 2,000 meters, and making two levels of seals. There would be a seal at 1,500 meter deep and a specialty seal at 3,000 meters deep (Arnold W. Bill, et. all, 2013). In 2013 there was a proposal made to the DOE to create a test deep borehole drilling with the depth being 2,000 meters. This will allow the DOE and other researchers to see the feasibility of creating this system.

Conclusion:

Since the 1940’s the United States government has been creating large amounts of nuclear energy from a variety of sources. The production of nuclear weapons and nuclear waste produce highly radioactive waste that needs to be properly stored. Currently, this nuclear waste has been stored in temporary containers on site with no current plan for a permanent storage facility. Over the past 30 years the United States government has been working on creating a centralized government storage facility with the most focus on Yucca mountain in Nevada. Although, the DOE has had numerous complications with resistance by the state of Nevada preventing the construction of the site. Other than the site of Yucca mountain there has been some research on a deep borehole storage facility. Whether the deep borehole or Yucca mountain proposals are constructed it is necessary that the United States stores its 22,000m3  and growing high-level nuclear waste. If there can be a safe and permanent solution to storing high-level nuclear waste, nuclear energy production would be a more viable option for energy production.

Citations:

  1. Eureka County, Nevada. (2017, July 12). Yucca Mountain Timeline. Retrieved March 22, 2018, from http://www.yuccamountain.org/time.htm
  2. Sandia National Laboratories. (2013). Deep Borehole Disposal Research: Demonstration Site Selection Guidelines, Borehole Seals Design, and RD&D Needs. Washington, DC: Arnold W. Bill, et. all.
  3. United States, Department of Energy, Office of Civilian Radioactive Waste Management. (2004). Nuclear Waste Policy Act As Amended (pp. 1-146). Washington D.C.
  4. United States Environmental Protection Agency. (2017, August 7). Nuclear Weapons Production Waste. Retrieved March 22, 2018, from https://www3.epa.gov/radtown/weapons-production-waste.html
  5. United States Nuclear Regulatory Commission. (2015, April 3). Backgrounder on Radioactive Waste. Retrieved March 22, 2018, from https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste.html
  6. World Nuclear Association. (2017, June). Radioactive Waste Management. Retrieved March 22, 2018, from http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-wastes/radioactive-waste-management.aspx

 

%d bloggers like this: