Session: 07-01 - Public Involvement, Crosscutting Issues, Global Participation

Paper Number: 120444

120444 - Hanford Site Radioactive Waste Disposal 

More than 40 years of plutonium processing has left more than 56 million gallons of mixed radioactive waste sequestered in 177 underground tanks at the Hanford Site in Washington State.  Over the years, some of these tanks have been corroding and leaking, contaminating the ground water.  This and the proximity of the Columbia River to the tank farms necessitated the treatment and immobilization of the Hanford Radioactive Waste.

Three different processing technologies were employed for plutonium purification in addition to uranium scavenging and fission product removal from the tank waste.  All these chemical processes have contributed to a complex waste stream that varies from tank to tank and presents downstream processing challenges to render the waste into a safe form for long-term storage.  This led to the construction of the Waste Treatment and Immobilization Plant (WTP) at Hanford.  The current disposition pathway for Hanford tank waste is vitrification.  WTP is a first of a kind plant whose 40 year design life and inaccessibility of the hot cell areas presented many process and design challenges.  Some of these challenges are discussed in this paper.  To maximize waste loading and minimize the number of high-level waste canisters stored in a geologic repository, pretreatment of the waste is required. Both pretreatment and vitrification operations are impacted by the waste composition.

Presenting Author: Asif Arastu Unisont Engineering, Inc.

Presenting Author Biography: Dr. Asif Arastu has worked for more than 47 years on a variety of nuclear, fossil, and other power plant systems in the United States and abroad.
He specializes in fast fluid transients, thermal hydraulics, and nuclear plant systems. While at Bechtel, he has worked on resolving some of the technical issues/challenges on the Waste Treatment & Immobilization Plant Project (WTP). He was a member of the reference design team at Bechtel Power Corporation for the Simplified Boiling Water Reactor and helped developed the current passive cooling system concept. He was also the Bechtel project manager and principal investigator for a major water hammer research project (2856-03) sponsored by EPRI. Prior to Joining Bechtel, he worked in UK in the design and analysis of Advanced Gas Cooled reactors.
He has published 31 technical papers in conferences in USA and abroad. He is an ASME Fellow and is a member and past chair of ASME Nuclear Engineering Division and Clean Energy Technology Group. He is a founding member and special editor of the ASME Journal of Nuclear Engineering and Radiation Science (NES). Currently he is a special editor of the Elsevier Nuclear Engineering and Design journal and Associate editor for ASME Open Journal of Engineering (AOJE).
Dr. Arastu completed his B.Sc. and Ph.D. degrees in Nuclear Engineering at University of London, United Kingdom. He has been with Unisont Engineering, Inc. after retiring from Bechtel Power Corporation.