Certifying the Waste Isolation Pilot Plant: Lessons Learned from the WIPP Experience

In May 1998, the US Environmental Protection Agency (EPA) certified the US Department of Energy's (DOE) Waste Isolation Pilot Plant (WIPP) as being in compliance with applicable long-term regulations governing the permanent disposal of spent nuclear fuel, high-level, and transuranic radioactive wastes. The WIPP is the first deep geologic repository in the US to have successfully demonstrated regulatory compliance with long-term radioactive waste disposal requirements. The first disposal of TRU waste at WIPP occurred on March 26, 1999. Many of the lessons learned during the WIPP Project's transition from site characterization and experimental research to the preparation of a successful application may be of general interest to other repository programs. During a four-year period (1992 to 1996), the WIPP team [including the DOE Carlsbad Area Office (CAO), the science advisor to CAO, Sandia National Laboratories (SNL), and the management and operating contractor of the WIPP site, Westinghouse Electric Corporation (WID)] met its aggressive schedule for submitting the application without compromising the integrity of the scientific basis for the long-term safety of the repository. Strong leadership of the CAO-SNL-WID team was essential. Within SNL, a mature and robust performance assessment (PA) allowed prioritization of remaining scientific activities with respect to their impact on regulatory compliance. Early and frequent dialog with EPA staff expedited the review process after the application was submitted. Questions that faced SNL are familiar to geoscientists working in site evaluation projects. What data should be gathered during site characterization? How can we know when data are sufficient? How can we know when our understanding of the disposal system is sufficient to support our conceptual models? What constitutes adequate ''validation'' of conceptual models for processes that act over geologic time? How should we use peer review and expert judgment? Other lessons learned by SNL and the WIPP team are more specific to the regulatory context of the project and the demands imposed by pervasive review by the regulator and other external organizations. How should we document the relationship between site data and the parameter values used in computer models? How can we manage software configuration and use it to support the regulatory requirement that analyses be traceable and reproducible? Can we institute a quality assurance (QA) program that will meet the regulatory requirements and enhance the process without unreasonable budget and schedule impacts? How can we resolve technical disputes, both within the project and with external critics? How should we involve regulators and stakeholders in the compliance process? The WIPP teams answers to these questions, and others like them, were, in many cases, pragmatic solutions based on the needs of the pro-warn at the time. Some problems encountered and their solutions may be of limited interest. However, that it is possible to license a geologic repository in a regulatory proceeding while incorporating meaningful public review and criticism is a lesson of general interest to all radioactive waste management programs