Abstracts and Available Papers Presented at the
2002 International RERTR Meeting
CORROSION OF RESEARCH REACTOR AL-CLAD SPENT FUEL IN WATER
O.S.Bendereskaya1, P.K.De2, R.Haddad3, J.P.Howell4, A.B. Johnson Jr.5, S.Laoharojanaphand6,
S.Luo7, L.V.Ramanathan8, I.Ritchie9, N.Hussain10, I.Vidowsky11 and V.Yakovlev12
1- NIIAR, Ulyanovsk
Region, Russian Federation;
2- BARC, Mumbai, India;
3- CNEA, Buenos Aires;
4- SRS, Aiken, SC, USA;
5- PNNL, Hanford, USA;
6- OAEV, Chatuchak, Thailand;
7- CIAE, Beijing, China;
8- IPEN, São Paulo, Brazil;
9- IAEA, Vienna, Austria,
10- PINST, Islamabad, Pakistan;
11- KFKI-AERI, Budapest, Hungary;
12- KI, Moscow, Russia.
In the early 1990’s, corrosion of aluminium-clad spent nuclear fuel stored for extended periods in light water filled basins became a concern and many programmes were implemented at various sites to improve fuel storage conditions. An IAEA sponsored Co-ordinated Research Project (CRP) on “Corrosion of research reactor aluminium-clad spent fuel in water”, was initiated in 1996. This is an ongoing project and has as its objectives: (a) establishing uniform practices for corrosion monitoring and surveillance; (b) providing technical basis for continued wet storage of research reactor spent fuel; (c) collecting data to help in the prediction of lifetimes of fuel handling tools and storage racks and (d) establishing a uniform basis for the characterization of water in fuel storage basins. Nine countries that included Argentina, Brazil, China, Hungary, India, Pakistan, Russia, Thailand and the United States were invited by the IAEA to participate in the CRP.
In phase-I of this project that ended in 2000, Al alloy coupon racks were immersed in fuel storage pools at various sites in the participating countries. The aluminium alloys selected for the coupons were representative of typical cladding alloys, handling tools and storage racks. Coupons were stacked and/or allowed to contact other coupons to simulate pitting, crevice and bimetallic corrosion of the Al alloys. The participants were encouraged to add site-specific alloy coupons to the racks and monitor water parameters such as pH, conductivity, chloride ion content and other impurities at regular intervals. After exposures that ranged from 3-24 months the racks were disassembled and all relevant features recorded. This was followed by visual as well as photographic evaluation of coupon surfaces. Corrosion pit depths on Al coupons were also measured. Correlation of coupon surface state and basin water parameters lead to many conclusions and the main ones are: (a) pitting was the main form of corrosion; (b) crevice and galvanic effects predominated; (c) reduction in conductivity and chloride ion content were essential to maintain low corrosion rates and (d) dust sediments on Al alloys specimens contributed to pit initiation.
An IAEA document giving details about this CRP and other guidelines for spent fuel storage is in press. Further details of this project and the basis for its extension to phase- II will be presented and discussed.
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Dr. Lalgudi Ramanathan
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