Impurity hideout/hideout return at the Susquehanna 2 BWR

Technical Report · Tue Jun 01 04:00:00 EDT 1993

OSTI ID:6294740

Helmholz, H R; Sawochka, S G ^[1]

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1. NWT Corp., San Jose, CA (United States)

An impurity hideout return study was performed at the Susquehanna 2 BWR to provide an understanding of impurity hideout processes during normal operation and their impact on high temperature solution chemistry in corrosion product deposits on the fuel. Limited hideout return data obtained during shutdowns at 10 BWRs previously had indicated reasonable consistency with expectations based on MULTEQ high temperature solution chemistry modeling of hideout processes. Observations at Susquehanna 2 were consistent with expectations. Cumulative returns of species forming precipitates at low concentration factors above the bulk water concentration, e.g., calcium, magnesium, sulfate and silica were much greater than those of species having a minimal tendency to precipitate, e.g., sodium and chloride. Solutions present in the fuel cladding surface during normal operation were predicted to contain high concentrations (0.1 to 2 molal) of sodium, potassium, chloride, sulfate, silica and nitrate. The predicted solution pH at 300[degrees]C was 9.4 (neutral pH = 5.5). The increase in conductivity observed during and after shutdown was shown to be due to solubilization of precipitates with retrograde solubilities rather than chemical/resin intrusion. Variations in reactor water concentrations during reactor water cleanup system isolation and power reductions were consistent with predictions developed from a mass balance around the reactor coolant system.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); NWT Corp., San Jose, CA (United States)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 6294740
• Report Number(s): EPRI-TR-102520
• Country of Publication: United States
• Language: English

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21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
ALKALI METALS
ALKALINE EARTH METALS
BWR TYPE REACTORS
CALCIUM
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
COMPUTER CODES
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FUELS
IMPURITIES
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NUCLEAR FUELS
OXIDES
OXYGEN COMPOUNDS
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REACTOR MATERIALS
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SCALING
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