Download or read book A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.
Download or read book INVESTIGATION OF THE POTENTIAL FOR CAUSTIC STRESS CORROSION CRACKING OF A537 CARBON STEEL NUCLEAR WASTE TANKS written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The evaporator recycle streams contain waste in a chemistry and temperature regime that may be outside of the current waste tank corrosion control program, which imposes temperature limits to mitigate caustic stress corrosion cracking (CSCC). A review of the recent service history (1998-2008) of Tanks 30 and 32 showed that these tanks were operated in highly concentrated hydroxide solution at high temperature. Visual inspections, experimental testing, and a review of the tank service history have shown that CSCC has occurred in uncooled/un-stress relieved F-Area tanks. Therefore, for the Type III/IIIA waste tanks the efficacy of the stress relief of welding residual stress is the only corrosion-limiting mechanism. The objective of this experimental program is to test carbon steel small scale welded U-bend specimens and large welded plates (12 x 12 x 1 in.) in a caustic solution with upper bound chemistry (12 M hydroxide and 1 M each of nitrate, nitrite, and aluminate) and temperature (125 C). These conditions simulate worst-case situations in Tanks 30 and 32. Both as-welded and stress-relieved specimens have been tested. No evidence of stress corrosion cracking was found in the U-bend specimens after 21 days of testing. The large plate test is currently in progress, but no cracking has been observed after 9 weeks of immersion. Based on the preliminary results, it appears that the environmental conditions of the tests are unable to develop stress corrosion cracking within the duration of these tests.
Download or read book General Corrosion and Stress Corrosion Cracking Studies on Carbon Steels for Application in Nuclear Waste Disposal Containers written by E. Smailos and published by . This book was released on 1993 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book General corrosion and stress corrosion cracking studies on carbon steels for application in nuclear waste disposal containers written by and published by . This book was released on 1993 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book POTENTIAL FOR STRESS CORROSION CRACKING OF A537 CARBON STEEL NUCLEAR WASTE TANKS CONTAINING HIGHLY CAUSTIC SOLUTIONS written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The evaporator recycle streams of nuclear waste tanks may contain waste in a chemistry and temperature regime that exceeds the current corrosion control program, which imposes temperature limits to mitigate caustic stress corrosion cracking (CSCC). A review of the recent service history found that two of these A537 carbon steel tanks were operated in highly concentrated hydroxide solution at high temperature. Visual inspections, experimental testing, and a review of the tank service history have shown that CSCC has occurred in uncooled/un-stress relieved tanks of similar construction. Therefore, it appears that the efficacy of stress relief of welding residual stress is the primary corrosion-limiting mechanism. The objective of this experimental program is to test A537 carbon steel small scale welded U-bend specimens and large welded plates (30.48 x 30.38 x 2.54 cm) in a caustic solution with upper bound chemistry (12 M hydroxide and 1 M each of nitrate, nitrite, and aluminate) and temperature (125 C). These conditions simulate worst-case situations in these nuclear waste tanks. Both as-welded and stress-relieved specimens have been tested. No evidence of stress corrosion cracking was found in the U-bend specimens after 21 days of testing. The large plate test was completed after 12 weeks of immersion in a similar solution at 125 C except that the aluminate concentration was reduced to 0.3 M. Visual inspection of the plate revealed that stress corrosion cracking had not initiated from the machined crack tips in the weld or in the heat affected zone. NDE ultrasonic testing also confirmed subsurface cracking did not occur. Based on these results, it can be concluded that the environmental condition of these tests was unable to develop stress corrosion cracking within the test periods for the small welded U-bends and for the large plates, which were welded with an identical procedure as used in the construction of the actual nuclear waste tanks in the 1960s. The absence of evidence of stress corrosion cracking and general corrosion in the laboratory-scaled specimens indicate that this type of nuclear waste tank is not susceptible to highly caustic solutions up to 12 M hydroxide at 125 C when sufficient nitrite inhibitor is present.
Download or read book Influence of Microstructure on Stress Corrosion Cracking of Mild Steel in Synthetic Caustic nitrate Nuclear Waste Solution written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of alloy microstructure on stress corrosion cracking of mild steel in caustic-nitrate synthetic nuclear waste solutions was studied. An evaluation was made of the effect of heat treatment on a representative material (ASTM A 516 Grade 70) used in the construction of high activity radioactive waste storage tanks at Savannah River Plant. Several different microstructures were tested for susceptibility to stress corrosion cracking. Precracked fracture specimens loaded in either constant load or constant crack opening displacement were exposed to a variety of caustic-nitrate and nitrate solutions. Results were correlated with the mechanical and corrosion properties of the microstructures. Crack velocity and crack arrest stress intensity were found to be related to the yield strength of the steel microstructures. Fractographic evidence indicated pH depletion and corrosive crack tip chemistry conditions even in highly caustic solutions. Experimental results were compatible with crack growth by a strain- assisted anodic dissolution mechanism; however, hydrogen embrittlement also was considered possible. (auth).
Download or read book General Corrosion and Stress Corrosion Cracking Studies Oncarbon Steels for Application in Nuclear Waste Disposal Containers written by I. Azkarate and published by . This book was released on 1993 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book INHIBITION OF STRESS CORROSION CRACKING OF CARBON STEEL STORAGE TANKS AT HANFORD written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The stress corrosion cracking (SCC) behavior of A537 tank steel was investigated in a series of environments designed to simulate the chemistry of legacy nuclear weapons production waste. Tests consisted of both slow strain rate tests using tensile specimens and constant load tests using compact tension specimens. Based on the tests conducted, nitrite was found to be a strong SCC inhibitor. Based on the test performed and the tank waste chemistry changes that are predicted to occur over time, the risk for SCC appears to be decreasing since the concentration of nitrate will decrease and nitrite will increase.
Download or read book Prediction of Stress Corrosion of Carbon Steel by Nuclear Process Liquid Wastes written by and published by . This book was released on 1978 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive liquid wastes are produced as a consequence of processing fuel from Savannah River Plant (SRP) production reactors. These wastes are stored in mild steel waste tanks, some of which have developed cracks from stress corrosion. A laboratory test was developed to determine the relative agressiveness of the wastes for stress corrosion cracking of mild steel. Tensile samples were strained to fracture in synthetic waste solutions in an electrochemical cell with the sample as the anode. Crack initiation is expected if total elongation of the steel in the test is less than its uniform elongation in air. Cracking would be anticipated in a plant waste tank if solution conditions were equivalent to test conditions that cause a total elongation that is less than uniform elongation. The electrochemical tensile tests showed that the supernates in salt receiver tanks at SRP have the least aggressive compositions, and wastes newly generated during fuel repocessing have the most aggressive ones. Test data also verified that ASTM A 516-70 steel used in the fabrication of the later design waste tanks is less susceptible to cracking than the ASTM A 285-B steel used in earlier designs.
Download or read book Control of Stress Corrosion Cracking in Storage Tanks Containing Radioactive Waste written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bombita y la Goya written by and published by . This book was released on with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book THE SENSITIVITY OF CARBON STEELS SUSCEPTIBILITY TO LOCALIZED CORROSION TO THE PH OF NITRATE BASED NUCLEAR WASTES written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hanford tank reservation contains approximately 50 million gallons of liquid legacy radioactive waste from cold war weapons production, which is stored in 177 underground storage tanks. The tanks will be in use until waste processing operations are completed. The wastes tend to be high pH (over 10) and nitrate based. Under these alkaline conditions carbon steels tend to be passive and undergo relatively slow uniform corrosion. However, the presence of nitrate and other aggressive species, can lead to pitting and stress corrosion cracking. This work is a continuation of previous work that investigated the propensity of steels to suffer pitting and stress corrosion cracking in various waste simulants. The focus of this work is an investigation of the sensitivity of the steels' pitting and stress corrosion cracking susceptibility tosimulant pH. Previous work demonstrated that wastes that are high in aggressive nitrate and low in inhibitory nitrite are susceptible to localized corrosion. However, the previous work involved wastes with pH 12 or higher. The current work involves wastes with lower pH of 10 or 11. It is expected that at these lower pHs that a higher nitrite-to-nitrate ratio will be necessary to ensure tank integrity. This experimental work involved both electrochemical testing, and slow strain rate testing at either the free corrosion potential or under anodic polarization. The results of the current work will be discussed, and compared to work previously presented.
Download or read book Stress Corrosion Cracking of Candidate Materials for Nuclear Waste Containers written by and published by . This book was released on 1989 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Types 304L and 316L stainless steel (SS), Incoloy 825, Cu, Cu-30%Ni, and Cu-7%Al have been selected as candidate materials for the containment of high-level nuclear waste at the proposed Yucca Mountain Site in Nevada. The susceptibility of these materials to stress corrosion cracking has been investigated by slow-strain-rate tests (SSRTs) in water which simulates that from well J-13 (J-13 water) and is representative of the groundwater present at the Yucca Mountain site. The SSRTs were performed on specimens exposed to simulated J-13 water at 93°C and at a strain rate 10−7 s−1 under crevice conditions and at a strain rate of 10−8 s−1 under both crevice and noncrevice conditions. All the tests were interrupted after nominal elongation strains of 1--4%. Examination by scanning electron microscopy showed some crack initiation in virtually all specimens. Optical microscopy of metallographically prepared transverse sections of Type 304L SS suggests that the crack depths are small (
Download or read book Corrosion and Failure Processes in High level Waste Tanks written by and published by . This book was released on 1992 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.
Download or read book Localized Corrosion and Stress Corrosion Cracking of Candidate Materials for High level Radioactive Waste Disposal Containers in the US written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Container materials may undergo any of several modes of degradation in this environment, including: undesirable phase transformations due to lack of phase stability; atmospheric oxidation; general aqueous corrosion; pitting; crevice corrosion; intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This paper is an analysis of data from the literature relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of these alloys. Though all three austenitic candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these forms of localized attack. Both types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented for Alloy 825 under comparable conditions. Gamma irradiation has been found to enhance SCC of Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while microbiologically induced corrosion effects have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. Of the copper-based alloys, CDA 715 has the best overall resistance to localized attack. Its resistance to pitting is comparable to that of CDA 613 and superior to that of CDA 102. Observed rates of dealloying in CDA 715 are less than those observed in CDA 613 by orders of magnitude. The resistance of CDA 715 to SCC in tarnishing ammonical environments is comparable to that of CDA 102 and superior to that of CDA 613. Its resistance to SCC in nontarnishing ammonical environments is comparable to that of CDA 613 and superior to that of CDA 102. 22 refs., 8 figs., 4 tabs.
Download or read book Localized Corrosion and Stress Corrosion Cracking of Candidate Materials for High level Radioactive Waste Disposal Containers in the US written by J. C. Farmer and published by . This book was released on 1988 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Container materials may undergo any of several modes of degradation in this environment, including: undesirable phase transformations due to lack of phase stability; atmospheric oxidation; general aqueous corrosion; pitting; crevice corrosion; intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This paper is an analysis of data from the literature relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of these alloys. Though all three austenitic candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these forms of localized attack. Both types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented for Alloy 825 under comparable conditions. Gamma irradiation has been found to enhance SCC of Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while microbiologically induced corrosion effects have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. Of the copper-based alloys, CDA 715 has the best overall resistance to localized attack. Its resistance to pitting is comparable to that of CDA 613 and superior to that of CDA 102. Observed rates of dealloying in CDA 715 are less than those observed in CDA 613 by orders of magnitude. The resistance of CDA 715 to SCC in tarnishing ammonical environments is comparable to that of CDA 102 and superior to that of CDA 613. Its resistance to SCC in nontarnishing ammonical environments is comparable to that of CDA 613 and superior to that of CDA 102.
Download or read book Characterisation of Residual Stress and Investigation of Environmental Effects on Atmospheric induced Stress Corrosion Cracking of Austenitic Stainless Steel Nuclear Waste Containers written by Yin Jin Janin and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research has investigated the conditions necessary for atmospheric-induced stress corrosion cracking to occur in material taken from an intermediate level nuclear waste storage container by means of experiments in a humidity chamber. It has also characterised the residual stresses associated with the container welds by modelling and measurement. Based on the work conducted in this research, the major findings can be summarised as follows:• Deliquescence of salt particles is dependent on relative humidity but independent of the quantity of salt present.• The time to initiate cracking may be sensitive to temperature, getting longer as the temperature decreases, but the timeframe of work as not long enough to establish this conclusively.• AISCC can occur at a stress (residual or applied) of 400MPa (0.2% strain) or more if the other necessary conditions are present. While AISCC was not observed when no stress was present, the threshold of stress below which AISCC will definitely not occur has not been determined in this work.
