It will take at least “the next several months” to clean up a cesium-137 spill from May at a University of Washington medical research building in Seattle, a spokesperson for the U.S. National Nuclear Security Administration (NNSA) said Thursday.
The public has been barred from the seven-floor Research and Training Building near the Harborview Medical Center since May, following the breach of the cesium-137 source that was part of an irradiator the university was getting rid of under an NNSA-funded program that aims to secure potentially dangerous radionuclides.
The contractor on that job was International Isotopes, of Idaho Falls, Idaho. The nuclear medicine and source removal specialist is now in charge of cleaning up the spill it caused and has “just about finished up characterization” of the accident site, the NNSA spokesperson said in the email.
“The remediation process is expected to last the next several months,” the spokesperson wrote. “When that is completed, the state of Washington’s Department of Health has the authority to release the building for occupancy of laboratory personnel, building maintenance staff and other building occupants, as well as the general public.
Details of the amount of cesium that spilled and the remediation process have not been made public. The work in the building poses no public-health threat, the spokesperson added.
The NNSA trucked the damaged irradiator, manufactured by J.L. Shepherd & Associates, out of the Research and Training Building in July. It had been guarded in a sealed lead container at the building’s loading dock after the accident. The accident spread contamination throughout all seven floors of the Research and Training Building, the Washington state Department of Health has said.
Energy Department personnel at the Pacific Northwest National Laboratory are now studying the damaged irradiator some 200 miles away from Seattle in a hot cell near the agency’s Hanford Site: the hub of plutonium production during the Cold War nuclear-arms race, and now the agency’s largest environmental cleanup project.
The NNSA has said it plans to dispose of the damaged irradiator outside of Washington state.
In the May 2 accident, 13 people in the Research and Training Building were exposed to finely powdered cesium chloride powder from the broken irradiator. Cesium-137 emits highly penetrative gamma-rays, which can destroy human cells.
The University of Washington was getting rid of the irradiator with a grant from NNSA’s Cesium Irradiator Replacement Project: an effort that helps organizations replace medical devices that use potentially dangerous radionuclides with analogous devices that use X-rays instead. Cesium could be used to craft a population-sickening “dirty bomb” radiation dispersal device.
The Canadian Nuclear Laboratories on Aug. 30 announced the full transfer of contaminated soil from three locations in Port Hope, Ontario, into a long-term storage facility.
The project – covering 80,000 metric tons of waste temporarily stored Pine Street North Extension, the Municipal Sewage Treatment Plant, and Center Pier – is one part of a much broader environmental remediation of low-level radioactive waste in the Ontario municipalities of Port Hope and Clarington. Both municipalities were widely contaminated by uranium and radium refining in Port Hope from 1933 to 1988.
In total, the Port Hope Area Initiative is expected to cost $1.3 billion CAD ($976 million U.S.) and to be completed around 2025.
Amec Foster Wheeler was the contractor for the soil relocation, beginning work July 2018 in under a contract worth $2.6 million CAD ($1.9 million U.S.). The material is now being held in the Long-Term Waste Management Facility (LTWMF) at Port Hope.
“After years of meticulous planning, it’s very rewarding for the local community and our staff as we continue to restore the lands in Port Hope,” Scott Parnell, general manager of Canadian Nuclear Laboratories’ Historic Waste Program Management Office, said in a press release. “With these three locations complete, CNL has transported over 80,000 tonnes of waste to the LTWMF, where it will be safely isolated from the environment in an engineered containment mound.”
Canadian Nuclear Laboratories is a science and technology operated by the Canadian National Energy Alliance, a consortium of Jacobs, Fluor, and SNC-Lavalin.
Remediation of residential properties also continues in Port Hope. With testing of public and private properties expected to wrap up in two years, waste requiring cleanup has been identified on approximately 800 properties, with the total number trending toward 1,200 sites. That largely involves removal of contaminated soil, with some removal of structures.
“Exterior remediation has been completed at one commercial property and two residential properties using conventional excavation methods,” CNL spokeswoman Shernette Muccuth Henry said by email Wednesday. “Properties that have small, shallow pockets of isolated low-level radioactive waste are being remediated by hydro-excavation, using pressurized water to excavate soil; to date, hydro-excavation has been completed at 14 properties.”
Cleanup has started or will soon begin on about 60 residential properties, she added.
The U.S. Nuclear Regulatory Commission expects to give stakeholders more time to provide input on its draft regulatory basis for a potential rulemaking on disposal of Greater-Than-Class C (GTCC) low-level radioactive waste.
“No extension yet, but one is likely,” agency spokesman David McIntyre said by email Tuesday.
On Aug. 29, the Texas Commission on Environmental Quality (TCEQ) asked for at least 60 additional days for public comment beyond the current Sept. 20 deadline. That was among several requests for additional time, Stephen Koenick, chief of the NRC’s Low-Level Waste and Projects Branch, said Wednesday at the ExchangeMonitor’s RadWaste Summit in Henderson, Nev.
“This extension is necessary in order to provide all stakeholders sufficient opportunity to not only review the Draft Regulatory Basis and associated documents, but also review and consider the input from Texas stakeholders and other interested parties when the transcripts from the August 22, 2019 NRC webinar and the August 27, 2019 public meeting are publicly available,” TCEQ Executive Director Toby Baker wrote in a letter to NRC Secretary of the Commission Annette Vietti-Cook.
The U.S. Energy Department is legally responsible for disposal of GTCC waste and GTCC-like waste, a growing stockpile eventually expected to accumulate to 12,000 cubic meters. In a 2016 environmental impact statement, the agency said its preferred methods for disposal are the Waste Isolation Pilot Plant in New Mexico and/or generic commercial facilities. In another environmental assessment last year, DOE narrowed that preference down to Waste Control Specialists’ Federal Waste Facility in Andrews County, Texas.
Federal regulations now require that GTCC waste be buried in a geologic repository unless the NRC approves a specific application for another means of disposal. In the draft regulatory basis issued in July, NRC staff said most of the waste could be safely disposed of in a near-surface facility. It offered three options for the commission to address the issue: not changing the existing regulatory framework; providing new guidance, which would keep the current rules in place but might provide useful data and direction for a disposal application; and conducting a rulemaking that would establish regulations specifically for placing GTCC waste in a low-level radioactive waste facility.
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