A Case for Employing Near-field Measurements to Detect Important Effluents from Nuclear Material Processing Operations

Abstract

SummaryThe proliferation of nuclear weapons is a major international security threat. It is important to be able to detect nuclear processing operations that could enable either proliferant nations or subnational groups to obtain materials needed to develop and deploy nuclear weapons. In the ideal world, detection technologies would be available that could reliably detect, locate, and quantify all targeted reprocessing operations from large standoff distances. But this "magic tri-corder" technology does not exist. Monitoring may be performed by a combination of remote (i.e., large standoff distances), intermediate range, and near-field measurements. In situations where cooperative monitoring is practical, the intermediate and near-field measurements may be fairly easy to implement. In non-cooperative situations, the intermediate and near-field measurements are necessarily more challenging.Chemical effluents released to the environment from nuclear processing plants can provide evidence of on-going processing operations. For some persistent effluents, environmental residuals can provide evidence of former operations. While the effluents may be monitored for occupational safety or environmental compliance, they may also be exploited to gain insights into the operations that produced effluents.Critical processes targeted in this report include chemical reprocessing operations that extract plutonium (Pu) and other Special Nuclear Materials (SNM) from irradiated nuclear fuel. Further, the report focuses on the opportunity to exploit important, persistent process chemical effluent signatures that can be found near nuclear material processing plants and their supporting facilities to support more effective nuclear non-proliferation monitoring.The U.S. PUREX (Plutonium and Uranium Recovery by EXtraction) process and operations serve as the basis for this discussion as the PUREX process was disclosed during the Atoms for Peace era, and it has been adopted by many nations in the subsequent years. This report describes:• Key chemical groups employed in the PUREX and nuclear materials reprocessing operations that offer significant process insights and exhibit persistence in the environment after release from the facility;• Effluent release sources from the Hanford PUREX operation and its associated support facilities;• Plume propagation after the effluent plumes are released from process stacks and the probability that under some common atmospheric conditions, the plume likely reaches the ground within several kilometers of the stack;• The importance of considering the fate of chemicals in the environment to ensure that detection methods target viable signatures and in likely locations in the environment; and• Results of a preliminary analysis of soil samples collected near the Hanford PUREX plant and its associated supporting facilities that confirmed the presence of persistent chemical residues indicative of the PUREX plant processes.iii In summary, the near-field domain around potential nuclear material reprocessing oper...

Response of soil bacteria to PUREX chemicals suggests biomarker utility and bioremediation potential

“…Several chemicals involved in the PUREX process have been identified as the most likely to be released from nuclear materials processing plants during normal operation, due to their vapor pressure and volatility (4). These chemicals can be released through off gassing from cooling stacks, through venting of storage tanks, or from breakdown of storage tanks (8). In fact, hydrocarbons likely derived from storage tank leakage have been identified in soils surrounding the Hanford site (9).…”