STAINLESS‐STEEL CORROSION BY DILUTE NITRIC ACID: at Elevated Temperatures and Pressures

Pearce, M. L.; Griffiths, V. S.

doi:10.1108/eb019719

Cited by 2 publications

(7 citation statements)

References 4 publications

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“…After a period of nine calendar years [The number of full power years (FPY) is unknown as the authors do not provide the % operation per year.] and 364 000 kW h of operation investigators reported an Fe concentration of 0?6 mg cm 23 , which corresponded to a uniform reduction in wall thickness of approximately 0?0001 in. (0?28 mm/year).…”

Section: Corrosion In Uranyl Nitrate Solutions and Simulantsmentioning

confidence: 98%

“…23 In some cases 10 g L 21 U (0?042M, presumably 238 U) was added to the solution. Exposures were conducted in both the This corresponds to a concentration that is somewhat more concentrated than the hexahydrate salt.…”

Section: Corrosion In Uranyl Nitrate Solutions and Simulantsmentioning

confidence: 99%

“…Pearce and Griffiths investigated 18-8 SS (which nominally covers the compositions of SS301, 302, 304) wires in various concentration of HNO 3 . 23 In some cases 10 g L 21 U (0?042M, presumably 238 U) was added to the solution. Exposures were conducted in both the vapour and solution phases.…”

Section: Corrosion In Uranyl Nitrate Solutions and Simulantsmentioning

confidence: 99%

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A review of corrosion issues related to uranyl nitrate base aqueous homogeneous reactors

Lillard

2010

Corrosion Engineering, Science and Technology

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Aqueous homogeneous reactors (AHRs) are liquid fuel nuclear reactors, typically consisting of an acidified nitrate or sulphate base solution of enriched uranium-235 ( 235 U). The goal of this paper is to review both the report and research literature on the topic of materials corrosion issues related to uranyl nitrate base AHRs. The materials of interest are stainless steel (SS)347, SS304L, SS304L-NAG, SS316L and zirconium (Zr) base alloys. In nitric acid solutions, SS and Zr alloys are passive, although there is some increased susceptibility of SS347 to intergranular corrosion (IGC) and knife-line attack as compared to other alloys. This is likely a result of the higher carbon (C) content in SS347. In uranyl nitrate fuel simulants corrosion rates increased as compared with nitric acid alone with the corrosion rate of SS347 being the highest while SS316 was the lowest of the austenitic stainless steels tested. In comparison, corrosion rates of Zr based alloys remained relatively unchanged in uranyl nitrate base solutions. The most prominent issue for these materials appears to be iodide (I 2 ) induced pitting corrosion on the walls of the off-gas extraction system with the potential for stress corrosion cracking. For Zr alloys, vapour phase I 2 pitting and SCC are well documented failure mechanisms with the threshold I 2 concentration being on the order of 1-2 ppm. In the off-gas extraction system of a 200 kW AHR calculations indicate that the I 2 concentration may be as high as 0?4-0?6 ppm warranting further study in this area. The influence of a prototypic AHR neutron flux on corrosion rates and susceptibility to underfilm corrosion, due to precipitation of UO 2 (OH) 2 , was not available from the literature.

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Section: Corrosion In Uranyl Nitrate Solutions and Simulantsmentioning

confidence: 98%

Section: Corrosion In Uranyl Nitrate Solutions and Simulantsmentioning

confidence: 99%

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A review of corrosion issues related to uranyl nitrate base aqueous homogeneous reactors

Lillard

2010

Corrosion Engineering, Science and Technology

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“…However, it dissociates (soluble) in weaker nitric acid to form chloride ions. This event most likely occurs in the midrange trays (8)(9)(10)(11)(12).…”

Section: Chloride Circulation Profilementioning

confidence: 99%

“…The nature of strong acids is a serious health risk and poses severe environmental threats to soil, groundwater, river and lake water, vegetation, terrestrial and aquatic organisms [11]. Temperature is also an important factor, along with the pH and oxygen level, for determining the level of crevice and pitting corrosion of a stainless steel structure [12]. Many processes within nuclear fuel manufacturing facilities operate at high temperatures.…”

Section: Introduction 11 Corrosion In the Nuclear Manufacturing Industry Overviewmentioning

confidence: 99%

Reducing chloride corrosion of stainless steel in the nuclear fuel manufacturing industry : an electrochemical-environmental perspective

Spence¹

2021

Preprint

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Chloride extraction from nitric acid is an important technique for reducing corrosion of stainless steel. However, there has been a limited amount of research conducted in this area. Pumping ozone-enriched air through nitric acid is a corrosion reduction method that is widely used in the nuclear fuel manufacturing industry, including the Blind River Refinery (BRR), to purge chlorine gas out of the acid. However, this method has been shown to produce significant environmental impacts. Overall, it is an inconsistent and cost-deficient method for reducing chloride corrosion of stainless steel in nitric acid mediums below 7.2M (37.0% volume). This thesis builds on existing literature and demonstrates that oxidizing chloride ions in nitric acid using oxygen, nitric oxide and nitrous oxide is an efficient and cost-effective chloride extraction method for the case study (BRR). It was shown that the level of chloride extraction from nitric acid increased significantly when the acid strength was elevated above 8.4M (42.0%volume) and sparged with various oxidants. The most effective oxidants at this nitric acid strength were: oxygen, ozone, nitric oxide and nitrous oxide. Nitric oxide and nitrous oxide can be produced by sparging 43.0% nitric acid with air or sparging 43.0% nitric acid with NOx fumes. In terms of the BRR case study, it was shown that using operational-specific combinations of these methods can drastically reduce the environmental impacts associated with their chloride removal process; significantly increase the level of chloride extraction; reduce energy consumption and operating costs by as much as 54.0%; and reduce material requirements by as much as 80.0%.

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STAINLESS‐STEEL CORROSION BY DILUTE NITRIC ACID: at Elevated Temperatures and Pressures

Cited by 2 publications

References 4 publications

A review of corrosion issues related to uranyl nitrate base aqueous homogeneous reactors

A review of corrosion issues related to uranyl nitrate base aqueous homogeneous reactors

Reducing chloride corrosion of stainless steel in the nuclear fuel manufacturing industry : an electrochemical-environmental perspective

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