NRC Joins Five Other Agencies in Addressing Uranium Contamination on the Navajo Nation

Dominick Orlando
Senior Project Manager

 

Navajo coverLast year, after five years of work to reduce risks from uranium contamination on territory that is part of the Navajo Nation, the NRC, along with four other federal agencies, reported on our progress to Congress. This week, the five federal agencies issued a plan that spells out how we’ll continue coordinating that work for the next five years.

 The agencies’ second Five-Year Plan builds on lessons learned from the first five years. It reflects new information and defines the next steps to address the most significant risks to human health and the environment. The new plan commits us to working together to reduce these risks and find long-term solutions.

 In October 2007, Congress asked the agencies to develop a plan to address the contamination on Navajo land, which dates back to the 1940s when uranium was in high demand. The Navajo Nation had large uranium deposits but regulations were not what they are today and mining companies left extensive contamination requiring cleanup. Legislation and new regulatory provisions were put in place to address these issues.

 The 2013 report capped off a five-year program the agencies conducted, in consultation with Navajo and Hopi tribal officials, to address uranium contamination on their land. Part of this work was government-to-government consultations with the Navajo.

 The program was a joint effort among EPA, the NRC, the Department of Energy, the Bureau of Indian Affairs, the Centers for Disease Control and the Indian Health Service. It focused on collecting data, identifying the most imminent risks, and addressing contaminated structures, water supplies, mills, dumps, and mines with the highest levels of radiation. We also learned more about the scope of the problem and the work that still remains.

 The NRC’s role is to oversee the work done by DOE, which is the long-term custodian for three sites storing uranium mill tailings—a sandy waste left over from processing uranium—and one former processing site. We do that by reviewing and, if acceptable, concurring on DOE’s plans to clean up contaminated groundwater, visiting the sites to evaluate how DOE is performing long-term care activities, and reviewing DOE’s performance and environmental reports.

 We will work closely with EPA, DOE, the New Mexico Environment Department, and the Navajo during the cleanup of the Northeast Church Rock site—which EPA and Navajo officials identified as the highest priority site for cleanup. The NRC will also be part of outreach activities detailed in the plan, including participating in stakeholder workshops and contributing, as appropriate, to educational and public information activities.

 Five years from now, we look forward to being able to say that with close coordination among all the parties, we have continued to make major progress in addressing concerns about uranium contamination.

NRC Science 101: What is Plutonium? UPDATED

Maureen Conley
Public Affairs Officer
 

science_101_squeakychalkIn earlier Science 101 posts, we talked about what makes up atoms, chemicals and matter. In this post, we will look at a specific chemical element — plutonium.

Plutonium is a radioactive, metallic element with the atomic number 94. It was discovered in 1940 by scientists studying the process of splitting atoms. Plutonium is created in a nuclear reactor when uranium atoms, specifically uranium-238, absorb neutrons. Nearly all plutonium is man-made.

Plutonium predominantly emits alpha particles—a type of radiation that does not penetrate and has a short range. It also emits neutrons, beta particles and gamma rays. It is considered toxic, in part, because if it were to be inhaled it could deposit in lungs and eventually cause damage to the tissue.

Plutonium has five “common” isotopes, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. All of the more common isotopes of plutonium are “fissionable”—which means the atom’s nucleus can easily split apart if it is struck by a neutron.

The various isotopes of plutonium have been used in a number of applications. Plutonium-239 contains the highest quantities of fissile material, and is notably one of the primary fuels used in nuclear weapons. Plutonium-238 has more benign applications and has been used to power batteries for some heart pacemakers, as well as provide a long-lived heat source to power NASA space missions. Like uranium, plutonium can also be used to fuel nuclear power plants, as is done in a few countries. Currently, the U.S. does not use plutonium fuel in its power reactors.

plutoniumNuclear reactors that produce commercial power in the United States today create plutonium through the irradiation of uranium fuel. Some of the plutonium itself fissions—part of the chain reaction of splitting atoms that is the basis of nuclear power. Any plutonium that does not fission stays in the spent fuel. Spent nuclear fuel from U.S. reactors contains about one percent plutonium by weight.

The different isotopes have different “half-lives” – the time it takes for one-half of a radioactive substance to decay. Pu-239 has a half-life of 24,100 years and Pu-241’s half-life is 14.4 years. Substances with shorter half-lives decay more quickly than those with longer half-lives, so they emit more energetic radioactivity.

Like any radioactive isotopes, plutonium isotopes transform when they decay. They might become different plutonium isotopes or different elements, such as uranium or neptunium. Many of the “daughter products” of plutonium isotopes are themselves radioactive.

Many metric tons of plutonium are currently contained in spent nuclear fuel around the world. To be usable, plutonium needs to be separated from the other products in spent fuel through a method called reprocessing. Reprocessing separates plutonium from uranium and fission products through chemical means. Once separated, plutonium oxide can be used as fuel for nuclear power reactors by mixing it with uranium oxide to produce mixed oxide or MOX fuel. The U.S. government has historically discouraged the use of this technology for national security and environmental reasons.

The NRC is currently overseeing construction of a facility in South Carolina to make MOX fuel using plutonium removed from U.S. nuclear weapons declared excess to military needs, as part of a Department of Energy program to convert it into a proliferation-resistant form that would be difficult to convert again for use in nuclear weapons.

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