Study on the nuclide behavior in nuclear fuel recycling system

Fujii, Toshiyuki*; *

JNC TJ9400 2000-003, 36 Pages, 2000/02

JNC-TJ9400-2000-003.pdf:1.36MB

For establishing a recycling system based on low-decontamination, the distribution behaviors of radionuclides in the process are essential information for the design of the system. Molybdenum and palladium are less radioactive fission products, but attention should be paid to them because they are likely to extremely affect the performance of the recycled fuels. In this context, in this study, the extraction behaviors of molybdenum and palladium under conditions of PUREX and TRUEX extraction process were experimentally studied, and their chemical mechanisms were discussed. In cojunction with the extraction experiments, absorption spectrometry was applied to identify the related species and the extraction mechanism. As a result, knowledge for the distribution characteristics of molybdenum and palladium in PUREX and TRUEX process was reinforced.

Study of lanthanide (III) nitrate complexes in CMPO/TBP systems by nuclear magnetic resonance (II)

Sano, Yuichi; *; ; *; Koyama, Tomozo; Tanaka, Yasumasa

PNC TN8410 96-362, 19 Pages, 1996/10

PNC-TN8410-96-362.pdf:2.27MB

The coordination properties of the lanthanide (La, Ce, Pr, Nd, Sm and Eu) complexes in lanthanide/TBP (tributylphosphate), lanthanide/CMPO (octyl(phenyl)-N,N-diisobutycarbamoylmethylphosphine oxide) and lanthanide/CMPO/TBP systems were investigated by NMR (nuclear magnetic resonance) measurements. In the lanthanide/CMPO/TBP system, it is shown that the structure of lanthanide complex is changed by the concentration ratio for added CMPO to the lanthanide ion ; lanthanide/CMPO/TBP system ([CMPO]/[Ln] 3 (mole ratio)) NO - the similar coordination in the Ln/TBP system TBP, CMPO - These coordinate to the lanthanide ion together. (the existence of several complexes) lanthanide/CMPO/TBP system ([CMPO]/[Ln} 3(mole ratio)) NO - the same coordination in the Ln/CMPO system TBP, CMPO - Only CMPO coordinates to the lanthanide ion. TBP doesn't exist within the first coordination sphere, but affects the CMPO exchange reaction.

None

PNC TJ1545 96-001, 137 Pages, 1996/03

PNC-TJ1545-96-001.pdf:5.98MB

no abstracts in English

Behavior of third phase formation in solvent extraction using CMPO(II)

; ; ; ; *

PNC TN8410 93-046, 46 Pages, 1993/03

PNC-TN8410-93-046.pdf:0.99MB

The TRUEX process has been developed to recover transuranium elements from high level liquid waste. This process uses octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) which is able to extract tri-valent actinides. It is already well known that a third phase appears at the interface when rare earths and other metal ions are extracted from a concentrated solution into TRUEX solvent which consists of CMPO with TBP - dodecane mixture. The basic researches concerning behavior of third phase formation and elimination were done in previous experiments. Succseively, dependency of temperature on organic phase composition, behavior of U extraction, applicability to high level liquid waste and diluent effect were investigated in these experiments. Consequently, these results were made obviously. By composition analysis of solvent which extracted nitric acid, it was found that not only concentration of extracted species, but temperature also influences on the composition of split phase. Extraction of high uranium concentration caused yellow precipitation. Critical concentration for precipitation were constant in each system and not dependent on temperature significantly. This precipitation was considered to affect extraction procedure, so that the condition should be selected carefully. In experiment using simulated waste, it's found that with appropriate condition of TBP concentration and temperature, dilution of concentrated liquid waste would not be necessary. From this work, 1.4 M for TBP concentration and 40 C are promisible and that are typical values for concentrated waste. However, to determine the practical conditon for real waste treatment, further experiments should be done. From comparison of hydrocarbon composed of 12 carbons with n-dodecane as diluent, carbon chain length and banching influence on critical concentration of third phase formation.

Annual report 1991 on partitioning of actinide and fission product elements in high active liquid waste by truex process

; Nomura, Kazunori; ; ; Kuno, Yusuke

PNC TN8410 92-172, 112 Pages, 1992/06

PNC-TN8410-92-172.pdf:3.23MB

Basic distribution studies and counter-current flowsheet experiments employing a mixture of CMPO with TBP as a reference solvent were conducted to evaluate the applicability of the TRUEX process to high level liquid wastes(HLLW) generated from the PUREX reprocessing process. Real highly active raffinate (HAR) solutions were used for these experiments. Concerning the major nuclide components of HLLW, various effecting factors on D values such as acidity, temperature, the ratios of CMPO/TBP and components concentration were investigated, respectively. Earlier (the first and second) counter-current flowsheet runs with laboratory scale mixer-settlers have shown excellent capability of the TRUEX process for actinides separation from real HAR solution. However, these tests showed unexpected significant retention of ruthenium and plutonium in the solvent. In the successive third run, some improvements to increase separation factor of these two nuclides and neptunium were demonstrated. This annual report summarizes results derived from the counter-current runs and basic study that treat the distribution of Np (IV, V, VI), other actinides and fission products, and the solubilities of extracted complexes to clarify the third phase split conditions. The results from supporting study which will cover solvent degradation and cleanup, and innovating new extractant, etc. are also included.