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U.S. Department of Energy
Office of Scientific and Technical Information

Steam generator secondary pH during a steam generator tube rupture

Technical Report ·
DOI:https://doi.org/10.2172/5375670· OSTI ID:5375670

The Nuclear Regulatory Commission requires utilizes to determine the response of a pressurized water reactor to a steam generator tube rupture (SGTR) as part of the safety analysis for the plant. The SGTR analysis includes assumptions regarding the partitioning of iodine between liquid and vapor in steam generator secondary. Experimental studies have determined that the partitioning of iodine in water is very sensitive to the pH. Based on this experimental evidence, the NRC requested the INEL to perform an analytical assessment of secondary coolant system (SCS) pH during an SGTR. Design basis thermal and hydraulic calculations were used together with industry standard chemistry guidelines to determine the SCS chemical concentrations during an SGTR. These were used as input to the Facility for Analysis of Chemical Thermodynamics computer system to calculate the equilibrium pH in the SCS at various discrete time during an SGTR. The results of this analysis indicate that the SCS pH decreases from the initial value of 8.8 to approximately 6.5 by the end of the transient, independent of PWR design.

Research Organization:
EG and G Idaho, Inc., Idaho Falls, ID (United States)
Sponsoring Organization:
NRC; Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
AC07-76ID01570
OSTI ID:
5375670
Report Number(s):
EGG-NE-10046; ON: DE92012219
Country of Publication:
United States
Language:
English