CHARACTERIZATION AND EVALUATION OF CAUSTIC WASH TANK AND SOLVENT HOLD TANK SAMPLES FROM MCU FROM AUGUST TO SEPTEMBER 2011

Fondeur, F. ; Fink, S.

关键词: AR FACILITIES;    AQUEOUS SOLUTIONS;    AROMATICS;    CESIUM;    CHROMATOGRAPHY;    DECONTAMINATION;    EFFICIENCY;    EVALUATION;    IMPURITIES;    NITRIC ACID;    PERFORMANCE;    PROCESS SOLUTIONS;    PROCESSING;    SOLVENT EXTRACTION;    SOLVENTS;    SPECTROSCOPY;    TANKS;    TESTING;    WASHING;   

DOI  :  10.2172/1047458
RP-ID  :  SRNL-STI-2012-00324
PID  :  OSTI ID: 1047458
Others  :  TRN: US1203993

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

During processing of Salt Batches 3 and 4 in the Modular Caustic-Side Solvent Extraction Unit (MCU), the decontamination efficiency for cesium declined from historical values and from expectations based on laboratory testing. This report documents efforts to analyze samples of solvent and process solutions from MCU in an attempt to understand the cause of the reduced performance and to recommend mitigations. CWT Solutions from MCU from the time period of variable decontamination factor (DF) performance which covers from April 2011 to September 2011 (during processing of Salt Batch 4) were examined for impurities using chromatography and spectroscopy. The results indicate that impurities were found to be of two types: aromatic containing impurities most likely from Modifier degradation and aliphatic type impurities most likely from Isopar{reg_sign} L and tri-n-octylamine (TOA) degradation. Caustic washing the Solvent Hold Tank (SHT) solution with 1M NaOH improved its extraction ability as determined from {sup 22}Na uptake tests. Evidence from this work showed that pH variance in the aqueous solutions within the range of 1M nitric acid to 1.91M NaOH that contacted the solvent samples does not influence the analytical determination of the TOA concentration by GC-MS.