AGU Fall 2006 Meeting Neptune and Company, Inc. Radioactive Waste Disposal in Hydrologically-Challenged Environments: Opportunities for Waste Disposal Resource Optimization John Tauxe, PhD, PE and Paul Black, PhD

AGU Fall 2006 Meeting Presentation Outline introduction of the disposal resource identification of exposure mechanisms mathematical coupling probabilistic analysis modeling for regulatory compliance modeling for resource optimization conclusions

AGU Fall 2006 Meeting Nevada Test Site as a Waste Disposal Resource remotely sited unmatched performance permitted operations radioactive waste is an insignificant addition to existing contamination from weapons testing

AGU Fall 2006 Meeting NTS is in the Basin and Range of NV Frenchman Flat Yucca Flat Area 5 RWMS >

AGU Fall 2006 Meeting Nearly 1000 Tests at Yucca Flat

AGU Fall 2006 Meeting The Area 3 RWMS In Yucca Flat

AGU Fall 2006 Meeting The Area 5 RWMS In Frenchman Flat

AGU Fall 2006 Meeting Mechanisms Controlling Exposure and Potential Dose radon diffusivity and emanation factor ant activity cover thickness environmental fate and transport human behaviors site access and occupancy inhalation rate

AGU Fall 2006 Meeting Engineering Controls active controls: signs, fences security force passive controls: site knowledge cover thickness barriers photo copyright George Steinmetz

AGU Fall 2006 Meeting Mathematical Coupling of Modeled Processes Physical processes are modeled as coupled partial differential equations: radioactive decay and ingrowth gaseous diffusion aqueous diffusion aqueous advection bioturbation plant uptake and redistribution soil/water chemical partitioning air/water partitioning chemical solubility atmospheric resuspension

AGU Fall 2006 Meeting Probabilistic Analysis modeling parameters are defined stochastically, capturing uncertainty Monte Carlo is handled by GoldSim * sensitivity analysis performed on results sensitive parameters are identified value-of-information analysis performed revisions through Bayesian updating *GoldSim is modeling software for probabilistic systems analysis.

AGU Fall 2006 Meeting Regulatory Compliance: A common reason for assessment regulations (by EPA, NRC, and DOE) are ultimately concerned with protecting human health by specifying a maximum potential dose or release objective performance objectives are assessed through modeling fate and transport and future potential doses to a member of the public or intruder

AGU Fall 2006 Meeting Resource Optimization: A new reason for assessment cost/benefit analysis can help inform candidate waste acceptance and disposal technology and configuration decisions takes advantage of attributes of the resource optimization can be done only through probabilistic modeling and sensitivity analysis ALARA - a decision analysis process to keep doses As Low As Reasonably Achievable

AGU Fall 2006 Meeting Optimization of Operations design disposal operations to minimize future human health effects assess candidate waste streams before they are packaged and shipped evaluate closure options and expenses minimize long-term maintenance and monitoring costs

AGU Fall 2006 Meeting Conclusions optimization (cost/benefit) is made possible through probabilistic modeling and decision analysis extension of decision analysis to other environmental problems......CERCLA, RCRA, water resources... NTS RWMS: a resource worth saving

AGU Fall 2006 Meeting