2009 Copyright ©NACE International. All rights reserved. Paper Number 09434 reproduced with permission from CORROSION 2009 Annual Conference and Exhibition, Atlanta. A STUDY OF STRESS CORROSION CRACKING AND LOCALIZED CORROSION OF CARBON STEEL IN NITRATE BASED NUCLEAR WASTE C. S. Scott, F. Gui, C. S. Brossia, J. A. Beavers CC Technologies – A DNV Company 5777 Frantz Road Dublin, OH 43017 G. L. Edgemon ARES Corporation 1100 Jadwin Ave, STE 400 Richland, WA 99352 K. D. Boomer CH2M Hill – Hanford Group PO Box 1500 Richland, WA 99352 G. S. Frankel Ohio State University 477 Watts Hall 2041 College Rd Columbus, OH 43210 B. J. Wiersma Savannah River Nuclear Solutions Savannah River National Laboratory Aiken, SC 29808 L. Stock Consultant 6695 SW 86 th Avenue Portland, OR 97223 Abstract The Hanford tank reservation contains approximately 50 million gallons of liquid legacy radioactive waste from cold war weapons production, which is stored in 177 underground storage tanks. The tanks will be in use until waste processing operations have been completed. The wastes tend to be high pH (over 10) and nitrate based. Under alkaline conditions carbon steels tend to be passive and undergo relatively slow rates of uniform corrosion. However, the presence of nitrate and other aggressive species, can lead to pitting and stress corrosion cracking. This work is a continuation of previous work that investigated the propensity of steels to suffer pitting and stress corrosion cracking in various waste simulants. The focus of this work is the waste from Tank 241-AP-105. The waste is high in nitrate, but low in inhibitory nitrite, making it a candidate for localized corrosion problems. This experimental work involved slow strain rate and electrochemical testing. Initial work indicated a propensity for interfacial corrosion at the liquid/vapor interface. The results of the current work will be discussed, and compared to work previously presented. Keywords: stress corrosion cracking, interfacial corrosion, carbon steel, nitrate, nitrite, pH, Hanford, nuclear waste 1 Paper No. 09434