Corrosion monitoring on a large steel pressure vessel by thin-layer activation

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Corrosion (Houston); (USA)

DOI:https://doi.org/10.5006/1.3585009· OSTI ID:6951493

Wallace, G ^[1]; Boulton, L H ^[2]; Hodder, D ^[3]

---

1. Inst. of Nuclear Sciences, Dept. of Scientific and Industrial Research, P.O. Box 31312, Lower Hutt (NZ)
2. Auckland Industrial Development Div., Dept. of Scientific and Industrial Research, P.O. Box 2225, Auckland (NZ)
3. NZFP Pulp and Paper Ltd., Private Bag, Tokoroa (NZ)

Thin-layer activation (TLA) is a technique in which a surface is irradiated by a nuclear accelerator and thereby labeled with an accurate depth profile of low-level radioactivity. By monitoring this activity it is possible to calculate how much of that surface has been removed by corrosion. As the radioactivity is marked by the emission of penetrating gamma rays, it is possible to monitor this corrosion remotely through several centimeters of steel. This technique has been used to monitor erosion-corrosion occurring on the inner carbon steel wall of a continuous Kraft pulp digester at a paper mill. Representative coupons of the same steel as the digester wall were irradiated and fixed to the walls in the liquor extraction zone during a maintenance shutdown. The loss of metal over the six months was measured by external monitoring of gamma radiation through the vessel wall, and converted to a corrosion rate. Subsequent weight-loss measurements and comparison with ultrasonic thickness measurements established that the corrosion rate measured gave accurate results over a much shorter time scale. TLA thus enables current, rather than historical corrosion rates to be measured in a large steel pressure vessel.

• OSTI ID: 6951493
• Journal Information: Corrosion (Houston); (USA), Vol. 45:12; ISSN 0010-9312
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
22 GENERAL STUDIES OF NUCLEAR REACTORS
CARBON STEELS
PHYSICAL RADIATION EFFECTS
PRESSURE VESSELS
ACTIVATION ANALYSIS
ACTIVATION ENERGY
CALCULATION METHODS
GAMMA RADIATION
RADIOACTIVITY
REACTOR COMPONENTS
REACTOR PHYSICS
RELIABILITY
STRESS CORROSION
ALLOYS
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CONTAINERS
CORROSION
ELECTROMAGNETIC RADIATION
ENERGY
IONIZING RADIATIONS
IRON ALLOYS
IRON BASE ALLOYS
PHYSICS
RADIATION EFFECTS
RADIATIONS
STEELS
360106* - Metals & Alloys- Radiation Effects
360105 - Metals & Alloys- Corrosion & Erosion
220100 - Nuclear Reactor Technology- Theory & Calculation
220200 - Nuclear Reactor Technology- Components & Accessories