LIFE ESTIMATION OF TRANSFER LINES FOR TANK FARM CLOSURE PERFORMANCE ASSESSMENT

Subramanian, K

Savannah River Site (S.C.)

关键词: Corrosion;    Stainless Steels;    36 Materials Science;    Thickness;    Soils;   

DOI  :  10.2172/920660
RP-ID  :  WSRC-STI-2007-00460
RP-ID  :  DE-AC09-96SR18500
RP-ID  :  920660

美国|英语

来源: UNT Digital Library

【 摘 要 】

A performance assessment is being performed in support of closure of the F-Tank Farm. The performance assessment includes the life estimation of the transfer lines that are used to transport waste between tanks both within a facility (''intra-area'' transfer) and to other facilities (''inter-area'' transfers). The transfer line materials of construction will initially provide a barrier to contaminant escape. However, the materials will degrade over time, most likely due to corrosion, and will no longer provide a barrier to contaminant escape. The life estimation considered the corrosion of the core pipe under exposure to soil, estimated the thickness loss due to general corrosion, and the percentage of wall area breached due to localized corrosion mechanisms. There are three types of transfer lines that are to be addressed within the performance assessment: Type I, Type II/IIA and Type III. The life of the transfer lines were estimated as exposed to soil. Localized and general corrosion of the transfer lines exposed to soil was estimated to provide input to the fate and transport modeling of the performance assessment. Pitting corrosion was found to be the controlling mechanism for the degradation of the transfer lines and their consequent ability to maintain confinement of contaminants. It is assumed that 75% of the transfer line is needed intact to provide this confinement function, i.e. once 25% of the line wall is breached, the lines are considered incapable of confining contaminants. It is recommended that the percentage breached curves be utilized for each transfer line as shown in Figure 1 for the various stainless steel transfer lines.