Oxidation of Zirconium and Zirconium Alloys in Liquid Sodium

Mackay, T. L.

doi:10.1149/1.2425919

Cited by 9 publications

(2 citation statements)

References 11 publications

(17 reference statements)

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“…ρ ment ΔG/S) does not depend on the oxygen concentration in the sodium (from the minimal concentration up to several hundreds ppm) [12,13]. At this concentration, the weight increment is also independent of the sodium velocity.…”

Section: Numerical Modeling Of Impurity Mass Transfer In Cold Traps Imentioning

confidence: 99%

Studies validating a sodium purification system for fast reactors

Kozlov¹,

Alexeev²,

Kovalev³

et al. 2012

At Energy

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The sources of impurities entering the sodium in fast reactors were investigated. The analysis showed that oxygen and hydrogen can be removed from the sodium by using cold traps in all operating regimes of a nuclear power plant as well as hot traps. An operating regime preventing hydrogen accumulation in the first-loop cold trap is proposed for a system purifying the first two loops. A computer code for calculating the impurity mass transfer is perfected. Test calculations showed that the procedure developed and the code are both serviceable. The deviation of the computational results from the experimental data is about 30% on average. For a built-in purification system, it is essential to develop a cold trap with a large impurity capacity. It is shown on the basis of experiments that such cold traps can in principle be developed. Thermohydraulic and mass-transfer codes must be developed in order to realize this possibility.Sodium-coolant purification systems in nuclear power plants with fast reactors must provide the required purity in all operating regimes taking account of all sources of impurities and must have the capacity required to handle the impurities accumulating in the purification system (it is permissible to replace the elements of the system during purification but the number of such replacements must be minimal). When significant contamination is present (routine maintenance, refueling, and accidental contamination), their capacity must ensure that impurities will be removed from the coolant as quickly as possible before the power reaches the operating level and the accumulation of suspensions in the first loop must be prevented.At the present stage of development of nuclear power, considering that safety, cost-effectiveness, and environmental compatibility must be improved, the requirements for the equipment in a nuclear power facility have been raised. Specifically, it has been decided that all systems with radioactive sodium be placed inside the reactor tank. This limits the dimensions of the first-loop systems. Therefore, the positive experience gained in placing purification systems outside the reactor tank cannot be fully utilized.For optimization, the purification characteristics were analyzed for the first loop. The analysis is based on evaluating the possible sources of impurities: their composition, amount, and rate of flow into the coolant in all possible operating regimes of a nuclear power plant. The relationship between the first-and second-loop purification systems and their effect on the distribution of impurities and the possibility and desirability of using not only cold traps but also other methods of purification, for example, hot traps, the structural implementation of the purification system, and the operation regime were all examined.The sources of impurities in systems with sodium coolant are oxygen, hydrogen (determining amount by mass and volume), products of corrosion of the structural materials, tritium, cesium if fuel-elements become depressurized, gaseous fission prod...

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Section: Numerical Modeling Of Impurity Mass Transfer In Cold Traps Imentioning

confidence: 99%

Studies validating a sodium purification system for fast reactors

Kozlov¹,

Alexeev²,

Kovalev³

et al. 2012

At Energy

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“…Oxidation in liquid sodium.--It has been observed that zirconium oxidation in liquid sodium follows an approximate parabolic law and has an activation energy (10) of about 52 kcal/mole. What is the mechanism of oxidation in sodium and why is the rate constant about a factor of 100 larger (at 600~ for oxidation in oxygen than for oxidation in liquid sodium?…”

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confidence: 99%

Mechanism of the Oxidation of Zirconium in Oxygen and Liquid Sodium

Smith¹

1965

J. Electrochem. Soc.

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A rigorous analysis using Fick's second law diffusion equation (for film growth and diffusion into the metal) is given which explains the observed variation of apparent activation energy between about 28 and 50 kcal/mole for the oxidation process. This analysis also explains the observed differences between oxidation in oxygen and oxidation by oxygen in liquid sodium. An empirical equation is given that will accurately describe the experimental data of weight gain vs. time (for Zr, Ti, and Cu) as this relationship goes from approximately parabolic, to quasi‐cubic, to parabolic again. The derivation of this equation stems from the hypothesis that the diffusion coefficient (for oxygen into the metal) decreases as the oxygen consumption increases.

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Untersuchung von Korrosionseffekten durch Natrium an Metallen der vierten und fünften Nebengruppe

Borgstedt¹,

Frees²

1968

Materials & Corrosion

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Der Angriff von flüssigem Na auf Ti, Zr, V und Nb erfolgt über einen Austasch von Sauerstoff von der flüssigen zur metallischen festen Phase; wegen der hohen Bildungsenergie der Oxide dieser Metalle genügen schon Na2O‐Gehalte von weniger als 10 ppm für die Auslösung der Reaktion. Der Sauerstoff wird direkt in die Matrix der Metalle eigebaut, ohne daß eine Oxidschicht entsteht; die Aufnahme von Sauerstoff ist immer mit Versprödung verbunden. In vielen Fällen reichert sich der Sauerstoff in der Randzone des Metalls an, wobei mehrere Schichten unterschiedlicher Struktur und schlechter Haftung entstehen. Die Sauerstoffkonzentration läßt sich mittels Mikrohärtemssungen bestimmen.

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Oxidation of Zirconium and Zirconium Alloys in Liquid Sodium

Cited by 9 publications

References 11 publications

Studies validating a sodium purification system for fast reactors

Studies validating a sodium purification system for fast reactors

Mechanism of the Oxidation of Zirconium in Oxygen and Liquid Sodium

Untersuchung von Korrosionseffekten durch Natrium an Metallen der vierten und fünften Nebengruppe

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