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Title: SNS Resonance Control Cooling Systems and Quadrupole Magnet Cooling Systems DIW Chemistry

Technical Report ·
DOI:https://doi.org/10.2172/1427619· OSTI ID:1427619
 [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

This report focuses on control of the water chemistry for the Spallation Neutron Source (SNS) Resonance Control Cooling System (RCCS)/Quadrupole Magnet Cooling System (QMCS) deionized water (DIW) cooling loops. Proper cooling-water chemistry is essential to preserving the DTL and CCL structures during their design lifetime. Appropriate water chemistry will protect cooling-water passages and brazed joints of the structure from erosion, corrosion, and fouling. The RCCS/QMCS DIW chemistry is managed by sidestreams built into the cooling loops; chemicals are not used. Data collected from spring 2013 through spring 2016 are discussed, and an operations regime is recommended. During the evaluation period, the pH, dissolved oxygen, and water resistivity of the cooling water were observed. The data were collected by instruments mounted on mobile chemistry carts, which were moved from one RCCS/QMCS DIW skid to another. During data reading, operational corrections were done on the polishing loops to improve the water chemistry regime. Therefore some trends changed over time. It was found that the RCCS operates with an average pH of 7.24 for all lines (from 7.0 to 7.5, slightly alkaline), the average low dissolved oxygen is in the area of < 36 ppb, and the main loop average resistivity of is > 14 MΩ-cm. The QMCS was found to be operating in a similar regime, with a pH of about 7.5 (slightly alkaline), low dissolved oxygen in the area of < 45 ppb, and main loop resistivity of 10 to 15 MΩ-cm. It is recommended that the cooling loops operate in a regime in which the water has a resistivity that is as high as achievable, a dissolved oxygen concentration that is as low as achievable, and a neutral or slightly alkaline pH. An RCCS/QMCS chemistry guidance document published in May 2017 describes and standardizes the methods and practices for water chemical treatment for the SNS RCCS and QMCS. It is very difficult to accurately measure the pH, dissolved oxygen, and water resistivity in highly pure water. Therefore, a regularly scheduled calibration program will be established for the instruments. Recommendations are given at the end of the report on how to run the RCCS/QMCS cooling water chemistry. Chemical analysis of the material trapped by the polishing loop prefilters is conducted twice a year. The analysis and its benefits are described in Chapter 9.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-00OR22725
OSTI ID:
1427619
Report Number(s):
ORNL/TM-2018/14; SNS-RAD-MS-TR-0017; R00
Country of Publication:
United States
Language:
English