Characteristics of solidified products containing radioactive molten salt waste.
The molten salt waste from a pyroprocess to recover uranium and transuranic elements is one of the problematic radioactive wastes to be solidified into a durable wasteform for its final disposal. By using a novel method, named as the GRSS (gel-route stabilization/solidification) method, a molten salt waste was treated to produce a unique wasteform. A borosilicate glass as a chemical binder dissolves the silicate compounds in the gel products to produce one amorphous phase while most of the phosphates are encapsulated by the vitrified phase. Also, Cs in the gel product is preferentially situated in the silicate phase, and it is vitrified into a glassy phase after a heat treatment. The Sr-containing phase is mainly phosphate compounds and encapsulated by the glassy phase. These phenomena could be identified by the static and dynamic leaching test that revealed a high leach resistance of radionuclides. The leach rates were about 10(-3) - 10(-2) g/m2 x day for Cs and 10(-4) - 10(-3) g/m2 x day for Sr, and the leached fractions of them were predicted to be 0.89% and 0.39% at 900 days, respectively. This paper describes the characteristics of a unique wasteform containing a molten salt waste and provides important information on a newly developed immobilization technology for salt wastes, the GRSS method.
Park
Hwan-Seo
HS
Advanced Fuel Cycle Development, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353, Korea. hspark72@kaeri.re.kr
Kim
In-Tae
IT
Cho
Yong-Zun
YZ
Eun
Hee-Chul
HC
Kim
Joon-Hyung
JH
D017607:Aluminum Compounds / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D009566:Nitrates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D011850:Radioactive Waste; D012492:Salts / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D018505:Waste Management / Q000379:methods*
D017607:Aluminum Compounds; D005782:Gels; D008670:Metals; D009566:Nitrates; D010756:Phosphoric Acids; D011850:Radioactive Waste; D012492:Salts; D017640:Silicates; C030242:phosphoric acid; C050609:aluminum nitrate