Neptunium (V) Solubility in the Presence and Absence of WIPP Relevant Ligands

Technical Report · Wed Dec 21 23:00:00 EST 2022

DOI:https://doi.org/10.2172/1907754· OSTI ID:1907754

Kaplan, Ugras ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

CRA (Compliance Recertification Application)-2024 will update the oxidation state specific model used to calculate actinide solubility in the WIPP (Waste Isolation Pilot Plant). The pentavalent Np(V) ion is the most stable ion in solution within the An(V) series. This valence stability of Np(V) in aqueous solution makes Np a useful representative element for studying the aqueous complex chemistry of all An(V), but in the predicted WIPP scenario, this is the only TRU component that increases in the inventory with time as it is the main daughter product of ²⁴¹Am decay (alpha, n) so its relative importance increases throughout the 10,000-year performance period of the WIPP, it is only used to represent itself. This work is focused on confirming organic, borate and carbonate effects on solubility of Np(V) in WIPP simulated brines and 5 M NaCl and reassessing the predicted model speciation to strengthen the overall WIPP An(V) model.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Environmental Management (EM); USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 1907754
• Report Number(s): LA-UR-22-33109; LCO-ACP-30
• Country of Publication: United States
• Language: English

Related Subjects

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