Functional design criteria radioactive liquid waste line replacement, Project W-087. Revision 3

ABSTRACTProgress on separating the long-lived fission products from the high level radioactive liquid waste (HLW) has led to the development of specific host matrices, notably for the immobilization of cesium. Hollandite (nominally BaAl2Ti6O16), one of the main phases constituting Synroc, receives renewed interest as specific Cs-host wasteform. The radioactive cesium isotopes consist of short-lived Cs and Cs of high activities and Cs with long lifetime, all decaying according to Cs+→Ba2++e- (β) + γ. Therefore, Cs-host forms must be both heat and (β,γ)-radiation resistant. The purpose of this study is to estimate the stability of single phase hollandite under external β and γ radiation, simulating the decay of Cs. A hollandite ceramic of simple composition (Ba1.16Al2.32Ti5.68O16) was essentially irradiated by 1 and 2.5 MeV electrons with different fluences to simulate the β particles emitted by cesium. The generation of point defects was then followed by Electron Paramagnetic Resonance (EPR). All these electron irradiations generated defects of the same nature (oxygen centers and Ti3+ ions) but in different proportions varying with electron energy and fluence. The annealing of irradiated samples lead to the disappearance of the latter defects but gave rise to two other types of defects (aggregates of light elements and titanyl ions). It is necessary to heat at relatively high temperature (T=800°C) to recover an EPR spectrum similar to that of the pristine material. The stability of hollandite phase under radioactive cesium irradiation during the waste storage is discussed.

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Removal of 99Tc from low level radioactive liquid waste using di-tert-butyldibenzo-18-crown-6 impregnated sorbent

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-020-07553-3 ◽

2021 ◽

Author(s):

D. A. Thakur ◽

N. L. Sonar ◽

J. N. Sharma ◽

T. P. Valsala

Keyword(s):

Liquid Waste ◽

Radioactive Liquid Waste ◽

Low Level

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Studies on hydrolysis and radiolysis of N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide

Radiochimica Acta ◽

10.1524/ract.2002.90.3_2002.161 ◽

2002 ◽

Vol 90 (3) ◽

Cited By ~ 106

Author(s):

Y. Sugo ◽

Y. Sasaki ◽

S. Tachimori

Keyword(s):

Gamma Irradiation ◽

Room Temperature ◽

Degradation Products ◽

Liquid Waste ◽

Amide Bond ◽

Radioactive Liquid Waste ◽

Ether Bond ◽

Nuclear Fuel Reprocessing ◽

High Level ◽

Fuel Reprocessing

SummaryHydrolytic and radiolytic stabilities of a promising extractant, N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA), for actinides in high-level radioactive liquid waste from nuclear fuel reprocessing were investigated in air at room temperature. Hydrolysis by nitric acid was not observed, whereas radiolysis by gamma irradiation was notably observed. The radiolysis study showed that an amide-bond, an ether-bond, and a bond adjacent to the ether-bond tended to be broken by gamma irradiation, and dioctylamine and various N,N-dioctylmonoamides were identified as the main degradation products by GC/MS and NMR analyses. The

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