Deposition Rate of Suspended Hematite in a Boiling Water System under BWR Conditions

Abstract

The state and rate of deposition of suspended hematite ware studied on a bolling heat transfer surface under the heat flux, temperature, and pressure similar to those In BWR power plants. As the depositlon proceeded, the deposition state changed from hemispheric deposits at the bolling sites, through their coalescence and lamination, to a flat deposit covering the bolling surf ace. This deposit contained a lot of water and had a number of pores from which steam bubbies emerged. Before reaching the break point, the amount of deposit (w) is expressed as a function of hematite concentration (c), heat flux (q), heat of evaporation (r), and time (t): w = 0.17 (glr)18ct. Once the amount of deposit reached 2-4 mg/cm 2, the apparent depositlon rate decreased sharply. The amount of deposit at this point decreased with the lowering of the hematite concentration and Increased with a rise In the heat flux. If the amount of deposit can be held below the break point during fuel element operation, the radioactive corrosion products level is expected to reduce considerably in reactor water. AbstractFatigue crack growth rate has been studied in an X65 pipeline steel, submerged in crude oil containing hydrogen sulfide in concentrations from 30 ppm to saturation. The studies provide data needed to estimate the corrosion fatigue life of flawed structures operating in "sour" crude oil. The results show that crack growth rate in crude oil is a functionof hydrogen sulfide content. The effect of cyclic frequency in the range 0.1 to 10 Hz is minor and can be neglected.

Corrosion and deposition on the secondary circuit of steam generators

“…Some studies suggested that the average deposition rate of iron oxide during the initial deposition period, over a pressure range of 0.1-18 MPa, was proportional to the square of the heat flux and directly proportional to the iron concentration [55]. While others suggested that the initial deposition rate was directly proportional to the heat flux and iron concentration [56,57]. The deposition rate in the steady-state deposition period of both in-reactor and out-of-reactor boiling water loops was shown to be dominated by the heat flux and the iron concentration [58] and increases when pressure increasing [59].…”

Characterization of phases in ‘crud’ from boiling-water reactors by transmission electron microscopy

“…In one approach (e.g., [3,4] boiling water with a composition similar to that in reactor cooling-water systems and analyzed the resulting phases using X-ray diffraction. A second approach involves modeling of the effects of the radiolysis of water in the reactor on the formation of specific minerals [5].…”