Status report on LWR spent fuel IAEA leach tests

Abstract

Spent light-water-reactor (LWR) fuel with an average burnup of 28,000 MWd/ MTU was leach-tested at 25°C using a modified version of the International Atomic Energy Agency (IAEA) procedure. Leach rates were determined from tests conducted in five different solutions: deionized water, sodium chloride (NaCl), sodium bicarbonate (NaHC0 3), calcium chloride (CaC1 2) and Waste Isolation Pilot Plant (WIPP) "B" brine solutions. Elemental leach rates are reported based on the release of 90Sr + 90y, 106Ru , 137Cs , 144Ce , 154 Eu , 239+240pu , 244' Cm and total uran i urn. After 467 days of cumulative leaching, the elemental leach rates are highest in deionized water. The elemental leach rates in the different solutions generally decreased from deionized water to the O.03~ NaCl solution to the WIPP "B" brine solution to the 0.03~ NaHC0 3 solution and was a factor of 20 lower in 0.015~ CaC1 2 solution than in deionized water. The leach rates of spent fuel and borosilicate waste-glass were also compared. In sodium bicarbonate solution, the leach rates of the two waste forms were nearly equal, but the glass was increasingly more resistant than spent fuel in calcium chloride solution, followed by sodium chloride solution, WIPP "B" brine solution and deionized water. In deionized water the glass, based on the elemental release of plutonium and curium, was 50 to 400 times more leach resistant than spent fuel.

Spent nuclear fuel as a waste form for geologic disposal: Assessment and recommendations on data and modeling needs

“…I u 5c5 (3) 5D5 (3) 3B5A (3) 3B5B (11) 243 ( a ) Number i n parentheses i n d i c a t e s t h e number o f whole p e l l e t s b e f o r e s i z e a n a l y s i s . P a r t i c l e s i z e s were a l s o obtained by Katayama, Bradley and Harvey (1980) f o r H. 6 . Robinson I 1 spent f u e l t h a t reached a burnup o f 28 MWd/kgM.…”

“…Microprobe Measured X-Ray I n t e n s i t i e s f o r Cesium, Z i r c o n i um, and I o d i n e (Katayama, Bradley and Harvey 1980) g r a d i e n t f r o m edge t o c e n t e r , w i t h a 47% r e d u c t i o n i n t h e x-ray i n t e n s i t y , 300 pm inward from t h e f u e l surface, and an a d d i t i o n a l 28% drop over t h e n e x t 3600 pm t o t h e f u e l c e n t e r . Technetium, barium, cerium, and cesium were s l i g h t l y e n r i c h e d a t t h e f u e l surface.…”

“…Microprobe Measured X-Ray I n t e n s i t i e s f o r Ruthenium, Tellurium, and Cerium (Katayama, Bradley and Harvey 1980) These d a t a were o b t a i ned by i n d u c t i v e l y coup1 ed plasma spectromet r y and a r e p r o v i d e d i n Table 3.9.…”

Spent fuel performance data: An analysis of data relevant to the NNWSI Project

“…This might explain why he saw very low solution concentrations of uranium in deionized water, an observation that is in agreement with the "true solution" concentration of uranium obtained in the NNWSI Project deionized water studies (Wilson, 1985a) after subtraction of the particulate component. Katayama et al (1980) reported results of the leaching of H. B. Robinson spent fuel in deionized water, 0.03M NaHCOj, -nd three other leachants. They used the same general test procedure as did Johnson (1982), but used bare fuel fragments 2 to 5 mm in size, 15 gof fuel, and 300 mL of soh'ticn.…”

“…In the future, it would be desirable to report the complete set of experimental data in a manner that allows others to evaluate the significance of the various components. Katayama et al (1980) also reported data for sodium bicarbonate water leaching. The bicarbonate concentration was approximately 1800 ppm, a level much higher than any of the groundwaters used in NNWSI, SKB/KBS, or Canadian fuel leaching.…”