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發表人 nicenter 於 2019/2/18 10:18:09 (7 人讀取)

NRC seeks input on legacy uranium cleanup

The US Nuclear Regulatory Commission (NRC) is seeking public comment on its environmental review of proposed cleanup work at the former Northeast Church Rock uranium mine in New Mexico. The proposal would allow mine owner United Nuclear Corporation (UNC) to transfer contaminated soil from the mine for disposal at the former Church Rock uranium mill.

Remediation work at the Northeast Church Rock mine site, pictured in 2009 (Image: EPA)

The Northeast Church Rock mine is about 17 miles (27 kilometres) northeast of Gallup, New Mexico in the Pinedale Chapter of the Navajo Nation, and operated from 1967 to 1982 during which about 3.5 million tons of ore were extracted. Ore from Northeast Church Rock was processed at the Church Rock mill, under a licence from the State of New Mexico.

The mill has since 1988 been under the dual regulatory oversight of the NRC and the Environmental Protection Agency (EPA), under a memorandum of understanding between the two agencies. The NRC is the lead agency regulating surface reclamation and closure activities at the mill site, while the EPA is the lead agency regulating cleanup of the mine. In September 2018 UNC - a subsidiary of General Electric - submitted its request for a licence amendment to the NRC.

Over 200,000 tons of contaminated soil has already been removed from the residential area around the mine and brought back to the mine waste pile, which has been temporarily covered and stabilised until it can be removed. UNC now wants to excavate about 1 million cubic yards (765,000 cubic metres) of mine spoils and transfer them to the adjacent mill site, which has an existing tailings impoundment facility.

Waste that meets EPA action levels for cleanup - that is, 2.24 picocuries per gram (pCi/g) of radium-226 and 230 mg/kg natural uranium or less - would be moved from the mine site and placed within the footprint of the existing tailings impoundment on the mill site. Any waste containing 200 pCi/g or more of radium-226 or 500 mg/kg of total uranium would be segregated and transported to an offsite licensed facility for disposal and therefore would not be placed at the mill site. Construction of a cover between the underlying tailings and the mine spoils is proposed, as well as a cover over the final mine waste surface. The proposal is part of a broader cleanup action which has been approved by the EPA.

The Navajo Nation covers over 27,000 square miles of the states of Arizona, New Mexico and Utah, and has a population of over 250,000. From 1944 to 1986, nearly 30 million tons of uranium ore were extracted from Navajo lands under leases with Nation. However, a legacy of uranium contamination remains, including over 500 abandoned uranium mines. Federal agencies are working together to reduce the highest risks to Navajo people from uranium contamination resulting from the abandoned mines, and since 1994 the Superfund Programme has provided technical assistance and funding to assess potentially contaminated sites and develop a response.

The EPA and the Navajo Nation EPA have identified 46 of the 500 abandoned mines as priorities for cleanup, based on gamma radiation levels, proximity to homes and potential for water contamination. Northeast Church Rock has been identified as the highest priority mine because of the proximity of residents to the mine site.

The EPA has overall responsibility for establishing environmental standards for decommissioning of uranium production facilities under the Uranium Mill Tailings and Radiation Control Act of 1978, with the NRC responsible for licensing and regulating uranium production and related activities, including decommissioning.

Members of the public have until 19 April to comment on the scope of NRC's environmental review. The commission will then prepare an environmental impact statement to examine the potential environmental impacts of the proposed action. The draft EIS will be made available for public comment.

Researched and written by World Nuclear News

source: http://www.world-nuclear-news.org/Articles/NRC-seeks-input-on-legacy-uranium-cleanup

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發表人 nicenter 於 2019/2/15 13:21:15 (16 人讀取)







source: https://www.aec.gov.tw/newsdetail/headline/4766.html

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發表人 nicenter 於 2017/6/14 9:29:38 (246 人讀取)


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