Hideout and return of chloride salts in heated crevices prototypic of support plates in steam generators: Topical report

Technical Report · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6907865

Mann, G M.W.; Castle, R

Solutions of NaCl (7 ..mu..g/kg - 70 mg/kg Cl) were pumped into an autoclave at 280/sup 0/C and boiled in an annular crevice 50% filled with carbon fiber. The weight of NaCl concentrated in the crevice was monitored from the increase in salt concentration at the autoclave outlet after switching off the crevice heater. Salt accumulated initially in the crevice at a constant rate given by the product of the bulk concentration and the evaporation rate. Hideout continued until an equilibrium weight of salt was reached. The equilibrium weight depended primarily on the superheat in the crevice and weakly on the bulk concentration. On reducing power or bulk concentration, salt was released as long as the weight of salt in the crevice exceeded the equilibrium weight corresponding to the altered condition. Very little salt was released from the crevice during pressure changes. Subsequently the crevice was corroded using NH/sub 4/Cl solutions and some hideout tests with NaCl were repeated. The corroded crevice was less efficient at concentrating salt due to the presence of a steam blanket. A model of the concentration process was developed and applied to the tube/support plate crevice in PWR steam generators.

• Research Organization: Central Electricity Research Labs., Leatherhead (UK); Electric Power Research Inst., Palo Alto, CA (USA)
• OSTI ID: 6907865
• Report Number(s): EPRI-NP-5015; ON: TI87920244
• Country of Publication: United States
• Language: English

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