Corrosion studies in fuel element reprocessing environments containing nitric acid

Technical Report · Wed Mar 31 23:00:00 EST 1982

DOI:https://doi.org/10.2172/5367205· OSTI ID:5367205

Beavers, J A; White, R R; Berry, W E; Griess, J C

Nitric acid is universally used in aqueous fuel element reprocessing plants; however, in the processing scheme being developed by the Consolidated Fuel Reprocessing Program, some of the equipment will be exposed to nitric acid under conditions not previously encountered in fuel element reprocessing plants. A previous report presented corrosion data obtained in hyperazeotropic nitric acid and in concentrated magnesium nitrate solutions used in its preparation. The results presented in this report are concerned with the following: (1) corrosion of titanium in nitric acid; (2) corrosion of nickel-base alloys in a nitric acid-hydrofluoric acid solution; (3) the formation of Cr(VI), which enhances corrosion, in nitric acid solutions; and (4) corrosion of mechanical pipe connectors in nitric acid. The results show that the corrosion rate of titanium increased with the refreshment rate of boiling nitric acid, but the effect diminished rapidly as the temperature decreased. The addition of iodic acid inhibited attack. Also, up to 200 ppM of fluoride in 70% HNO/sub 3/ had no major effect on the corrosion of either titanium or tantalum. In boiling 8 M HNO/sub 3/-0.05 M HF, Inconel 671 was more resistant than Inconel 690, but both alloys experienced end-grain attack. In the case of Inconel 671, heat treatment was very important; annealed and quenched material was much more resistant than furnace-cooled material.The rate of oxidation of Cr(III) to Cr(VI) increased significantly as the nitric acid concentration increased, and certain forms of ruthenium in the solution seemed to accelerate the rate of formation. Mechanical connectors of T-304L stainless steel experienced end-grain attack on the exposed pipe ends, and seal rings of both stainless steel and a titanium alloy (6% Al-4% V) underwent heavy attack in boiling 8 M HNO/sub 3/.

• Research Organization: Oak Ridge National Lab., TN (USA); Battelle Columbus Labs., OH (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5367205
• Report Number(s): ORNL/Sub-7327/13; ON: DE82009939
• Country of Publication: United States
• Language: English

Related Subjects

050800* -- Nuclear Fuels-- Spent Fuels Reprocessing
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
CATIONS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM COMPOUNDS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
DATA
ELEMENTS
EXPERIMENTAL DATA
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HYDROFLUORIC ACID
HYDROGEN COMPOUNDS
INCONEL 671
INCONEL 690
INCONEL ALLOYS
INFORMATION
INORGANIC ACIDS
IONS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
METALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NITRIC ACID
NUMERICAL DATA
PIPES
REPROCESSING
SEPARATION PROCESSES
SIMULATION
STAINLESS STEEL-304
STAINLESS STEELS
STEELS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TITANIUM
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS