Experimental Investigation on Denting in PWR Steam Generators: Causes and Corrective Actions

1983 ◽  
Vol 105 (4) ◽  
pp. 755-762 ◽  
Author(s):  
F. Nordmann ◽  
G. Pinard-Legry ◽  
J. Daret ◽  
J. P. Brunet
Keyword(s):  
Carbon Steel ◽  
Boric Acid ◽  
Calcium Hydroxide ◽  
River Water ◽  
Ph Value ◽  
Steam Generators ◽  
Oxide Morphology ◽  
Specific Effects ◽  
On Line ◽  
Oxygen Addition

Denting studies have been undertaken in order to assess the influence of the most important parameters which could initiate corrosion of the carbon steel occurring in the tube-tube support plate crevices of some PWR steam generators. Tests have been carried out in model boilers where feedwater was polluted with sea or river water. Specific effects of chloride or sulfate and influence of oxygen content, magnetite addition and pH value were investigated. In magnetite prepacked crevices, denting is obtained within 1000 hrs for seawater pollution of 0.3 ppm chloride at the blowdown. In neutral chloride or in river water, denting is observed only with oxygen addition. Denting prevention is effective in the case of an on-line addition of phosphate, boric acid, or calcium hydroxide. For denting stopping, boric acid or calcium hydroxide is efficient even with a high seawater pollution. Soaks cannot stop denting if they are not followed by an on-line treatment (boric acid, calcium hydroxide). With quadrifoil holes, denting doesn’t occur. In very severe test conditions, 13 percent Cr steel can be corroded, but the corrosion rate is low and oxide morphology is different from that growing on carbon steel.

Chemical Neutralization to Control Denting in Nuclear Steam Generators

1983 ◽  
Vol 105 (4) ◽  
pp. 763-770 ◽  
Author(s):  
T. A. Beineke ◽  
J. F. Hall ◽  
K. E. Marugg ◽  
D. B. Scott ◽  
R. M. Orsulak ◽  
...  
Keyword(s):  
Boric Acid ◽  
Calcium Hydroxide ◽  
Calcium Concentration ◽  
Chloride Concentration ◽  
Line Treatment ◽  
Steam Generators ◽  
Adverse Side Effects ◽  
On Line ◽  
Full Power ◽  
Power Operation

Laboratory testing at Combustion Engineering has indicated promise in controlling simulated steam generator tube denting through chemical neutralization. Testing was limited to on-line treatment, and two neutralizers have been evaluated: (i) calcium hydroxide, and (ii) boric acid. On-line treatment with calcium hydroxide successfully halted active denting whenever the bulk calcium concentration (in ppm) equaled or exceeded the bulk chloride concentration (in ppm). Calcium hydroxide also was effective as an alternative to ammonia as a pH controlling agent in two tests conducted without ingress of chloride. On-line treatment with boric acid consisted of a four-day soak at simulated low (approximately 30 percent) power with 50 ppm B followed by one month full-power operation with 10 ppm B. This treatment also halted denting. Nondestructive and destructive examination of test boilers gave no indication of adverse side effects associated with either neutralizer.

scholarly journals Optical Methods for On-line Quality Assurance of Welding Processes in Nuclear Steam Generators

10.5772/15579 ◽  
2011 ◽  
Author(s):  
Adolfo Cobo ◽  
Jesus Ma ◽  
David Solana ◽  
Alfonso Alvarez-de-Miranda ◽  
Pilar-Beatriz Garcia-Allende ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Optical Methods ◽  
Steam Generators ◽  
On Line ◽  
Welding Processes

Identification of Cationic Herbicides in Deionized Water, Municipal Tap Water, and River Water by Capillary Isotachophoresis/On-Line Raman Spectroscopy

1997 ◽  
Vol 51 (9) ◽  
pp. 1394-1399 ◽  
Author(s):  
Patrick A. Walker ◽  
Jeremy M. Shaver ◽  
Michael D. Morris
Keyword(s):  
Drinking Water ◽  
River Water ◽  
Electrolyte Solution ◽  
Tap Water ◽  
Deionized Water ◽  
Capillary Isotachophoresis ◽  
Raman Spectroscopic ◽  
River Water Samples ◽  
On Line ◽  
Detection Window

Isotachophoresis (ITP), coupled with Raman spectroscopic detection, is used to separate and identify two cationic herbicides, paraquat and diquat, in spiked deionized water, municipal drinking water, and river water samples. On-line preconcentration is achieved with the use of field-amplified injection into a 0.03–0.1 M H2SO4 or Na2SO4 leading electrolyte solution, and isotachophoresis is achieved with the use of a 0.03–0.1 M tris(hydroxymethyl)—aminomethane (Tris) trailing electrolyte solution. The herbicides are concentrated to above 10−3 M at the detection window, allowing measurement of Raman spectra with 1-s integration windows. Spectra of the herbicides are obtained from solutions at initial concentrations in deionized water at 3.5 × 10−7 M (90 ppb) paraquat/5.8 × 10−8 M (20 ppb) diquat, from drinking water initially at 1.3 × 10−6 M (335 ppb) paraquat/1.0 × 10−6 M (360 ppb) diquat, and river water initially at 5.0 × 10−6 M (1.3 ppm) paraquat and 3.0 × 10−6 M (1.0 ppm) diquat. The utility of correlation to identify the presence of analytes and of factor analysis to recover spectra from solutions at low initial concentrations of the herbicides is demonstrated.

Automated Fluorometric Analysis of Calcium Pantothenate in Multivitamin Preparations

1978 ◽  
Vol 61 (3) ◽  
pp. 720-726
Author(s):  
Ram B Roy ◽  
Anthony Buccafuri
Keyword(s):  
Acid Solution ◽  
Boric Acid ◽  
Fluorescence Intensity ◽  
Analytical Data ◽  
Boric Acid Solution ◽  
Calcium Pantothenate ◽  
Magnesium Trisilicate ◽  
On Line ◽  
The Mean ◽  
Fluorometric Analysis

Abstract An automated fluorometric procedure is described for assaying calcium pantothenate in multivitamin preparations. Sample extracts containing calcium pantothenate are treated on-line with a slurry of magnesium trisilicate which removes any interfering riboflavin that may be present. The nitrate is resampled, mixed online with a slurry of Dowex 50W-X4 (H+) which removes any interfering β-alanine that may be present, and dialyzed. Dialysates are hydrolyzed in an alkaline medium and reacted with a mixture of o-phthalaldehyde and 2-mercaptoethanoI in boric acid solution. The fluorescence intensity due to the formation of a fluorogenic compound is measured at 455 nm after excitation at 350 nm. The procedure developed is capable of analyzing 20 samples/hr. Analytical data indicate that calcium pantothenate is assayed reliably both from real and synthetic multivitamin preparations. The mean recovery of calcium pantothenate added to sample solutions of tablet composites was 95.4%.

Ultrasonic Transmission Characteristics of Continuous Casting Slab for Medium Carbon Steel

2005 ◽  
Vol 297-300 ◽  
pp. 2201-2206
Author(s):  
Jun Youn Lee ◽  
Soon Bok Lee ◽  
Jae Kyung Yi
Keyword(s):  
Carbon Steel ◽  
Continuous Casting ◽  
Surface Defects ◽  
Medium Carbon Steel ◽  
Carbon Steels ◽  
Ultrasonic Waves ◽  
Transmission Characteristics ◽  
Medium Carbon ◽  
Continuous Casting Slab ◽  
On Line

Until now, surface defects of continuous casting slab have been removed by the enforced surface scarfing to produce high quality steel materials. An evaluation technique for surface and internal defects of slab is required to enhance the production of medium carbon steels and acquire defect-map. Accordingly as a preliminary step, longitudinal wave testing and Rayleigh wave testing were carried out on slab specimens of medium carbon steel to get basic transmission characteristics of ultrasonic waves. This research provides as basic data for on-line defect estimation using a laser ultrasonic or EMAT in non-contact ultrasonic detecting techniques in future.

Micro- and Nano-Scopic Aspects of Passive Surface on Pearlite Structure of Carbon Steel in pH 8.4 Boric Acid-Borate Buffer

2019 ◽  
Vol 166 (11) ◽  
pp. C3409-C3416
Author(s):  
Koji Fushimi ◽  
Ryogo Nakagawa ◽  
Yuichi Kitagawa ◽  
Yasuchika Hasegawa
Keyword(s):  
Carbon Steel ◽  
Boric Acid ◽  
Borate Buffer
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