TROUBLESHOOTING AND CORRECTIVE ACTIONS
9.4 Nitrite/Molybdate-Treated Systems
9.4.1 System Leakage
Symptoms • Decreasing pH
• Loss of nitrite and molybdate • Excessive makeup
• Loss of conductivity (following makeup water additions to the system) • Constant conductivity-to-nitrite or molybdate-to-nitrite concentration ratio • Loss of azole
Corrective Actions
• Consider increasing the sampling frequency for inhibitor • Add inhibitor if necessary
• Locate and repair system leakage • Adjust pH if necessary
• Consider use of dye or tracer to find leaks
9.4.2 Water In-Leakage
Symptoms
• Possible pH change depending on pH of water entering the CCW system • Loss of nitrite and molybdate
• Loss or gain of conductivity (depending on conductivity of water entering the CCW system) • Constant or increasing conductivity-to-nitrite concentration ratio depending on conductivity
• Constant molybdate-to-nitrite concentration ratio • Loss of azole
• Increase in storage tank level
• Increase in concentrations of impurities or radioactivity (depending on which impurities are present in water entering the CCW system)
Corrective Actions
• Repair system in-leakage
• Evaluate impact of contaminants from in-leakage on system • Consider need for feed and bleed, drain and refill, or filtration • Increase inhibitor concentration if necessary
• Consider need to analyze for dissolved oxygen • Adjust pH if necessary
9.4.3 Bacterial Growth
Symptoms
• ATP, total bacteria, or plate counts in excess of specified maximum • Possible decrease in pH
• Possible flow restrictions • Loss of heat transfer capability Corrective Actions
• Add biocide
• Consider need for alternate biocide or alternating biocides • Adjust pH if required
• Consider need for feed and bleed or drain and refill • Consider need for system cleaning
9.4.4 Nitrate-Forming Bacteria Growth
Troubleshooting and Corrective Actions
• Constant molybdate • Constant azole
• No significant change in conductivity (between chemical additions) • Increase in nitrate
• Increase in conductivity-to-nitrite or molybdate-to-nitrite ratio • Observation of deposit accumulation
Corrective Actions • Add biocide
• Consider need for alternate biocide or alternating biocides
• Consider increasing the monitoring frequency for nitrifying bacteria and/or nitrate concentration
• Obtain and analyze surface samples for sessile bacteria if possible • Consider need for feed and bleed or drain and refill
• Add nitrite inhibitor if necessary • Make pH adjustment if necessary • Consider need for system cleaning
9.4.5 Ammonia-Forming Bacteria Growth
Symptoms
• Increasing pH due to ammonia production
• Loss of nitrite concentration (nitrite might not decrease significantly; ammonia might come from the breakdown of organic nitrogen compounds)
• Constant molybdate concentration • Increasing ammonia concentration
• No significant change in conductivity (between chemical additions)
• Increase in conductivity-to-nitrite or molybdate-to-nitrite concentration ratio • Constant azole
Corrective Actions • Add biocide
• Consider increasing the monitoring frequency for ammonia-forming bacteria and/or ammonia concentration
• Obtain and analyze surface samples for sessile bacteria if possible • Consider need for feed and bleed or drain and refill
• Add nitrite inhibitor if necessary • Adjust pH if necessary
• Consider the need for system cleaning
9.4.6 Acid-Forming Bacteria Growth
Symptoms • Decreasing pH
• Constant nitrite concentration • Constant molybdate concentration • Small increase in conductivity
• Constant conductivity-to-nitrite and molybdate-to-nitrite concentration ratio • Constant azole
Corrective Actions • Add biocide
• Consider need for alternate biocide or alternating biocides
• Increase the monitoring frequency for aerobic and anaerobic acid-forming, endospore- forming bacteria
• Obtain surface samples for sessile bacteria if possible • Consider the need for feed and bleed or drain and refill • Adjust pH if necessary
• Consider the need for system cleaning
9.4.7 Increase in System Corrosion Rates
Symptoms
Troubleshooting and Corrective Actions
• Visible corrosion, tuberculation, or pitting during inspection • Corrosion indications as a result of NDE evaluations
• Occurrence of leaks Corrective Actions
• Consider increasing the sample frequency for iron and/or copper analysis • Determine cause for increase in corrosion rates and correct
• Evaluate effect of elevated iron and copper in the system • Consider need for feed and bleed or drain and refill • Increase inhibitor concentrations if necessary • Review microbiological control status
9.4.8 Oil In-Leakage
Symptoms
• Possible increase in sulfate and/or phosphate • Possible visible sheen on system samples
• Possible unexplained decrease in TTA/BZT concentration (oil can interfere with TTA analysis)
Corrective Actions
• Initiate testing for TOC, oil and grease, sulfate, and/or phosphate • Locate oil source and develop corrective action plan
• Evaluate impact of oil in system
• Remove via cleaning, feed and bleed, or drain and refill • Evaluate if azole addition is necessary
9.4.9 Contaminant Ingress
Symptom
• Increase in the contaminant found in the in-leakage source but not normally found in the treated system
Corrective Actions
• Identify source of contaminant and develop corrective action plan • Evaluate effect of contaminants on the system
• If elevated contaminant will result in increased corrosion rate or degraded system performance, place system in feed and bleed, drain and refill, or increase inhibitor concentration(s) to compensate
9.5 Chromate-Treated Systems
9.5.1 System Leakage
Symptoms • Decreasing pH • Loss of chromate • Excessive makeup
• Decreasing conductivity (following makeup water additions to system) • Loss of azole if present in the system
Corrective Actions
• Increase sampling frequency for inhibitor as appropriate • Locate and repair system leakage
• Adjust pH if necessary • Adjust chromate if necessary
9.5.2 Water In-Leakage
Symptoms
• Possible pH change depending on pH of water entering the CCW system • Loss of chromate
• Loss or gain of conductivity (depending on conductivity of water entering the CCW system) • Loss of azole if present in the system
• Increase in concentrations of impurities or radioactivity (depending on which impurities are present in water entering the CCW system)
Troubleshooting and Corrective Actions
Corrective Actions
• Locate and repair system in-leakage
• Evaluate effect of contaminants in the system • Consider need for feed and bleed or drain and refill
• Increase chromate concentration to compensate if necessary • Adjust pH if necessary
9.5.3 Increase in System Corrosion Rates
Symptoms
• Increasing trend in total iron or total copper concentration
• Increase in corrosion rates on weight loss coupons or electrochemical monitor (if used) • Visible corrosion or tuberculation during inspections
• Occurrence of leaks Corrective Actions
• Increase sample frequency for iron and/or copper analysis • Determine cause for increase in corrosion rates and correct • Evaluate effect of elevated iron and copper in the system • Evaluate need for feed and bleed or drain and refill
9.5.4 Oil In-Leakage
Symptoms
• Possible increase in sulfate and/or phosphate • Possible visible sheen on system samples
• Possible unexplained decrease in azole if used (oil can interfere with analytical test) Corrective Actions
• Initiate testing for TOC, oil and grease, sulfate, and/or phosphate concentration • Locate oil source and correct
• Evaluate impact of oil in the system and remove via cleaning, feed and bleed, or drain and refill
9.5.5 Contaminant Ingress
Symptom
• Increase in contaminant found in the in-leakage source but not normally found in the treated system
Corrective Actions
• Identify source of contaminant and correct.
• Evaluate effect of elevated contaminant level in the system.
• If elevated contaminant will result in increased corrosion rate or degraded system
performance, place the system into feed and bleed or drain and refill, or increase inhibitor concentration(s) to compensate. 9.6 Hydrazine-Treated Systems 9.6.1 Hydrazine Decomposition Symptoms • Increasing pH, conductivity • Loss of hydrazine • Increase in ammonia Corrective Actions
• Evaluate need for feed and bleed to remove ammonia and replace with fresh demineralized water
• Add inhibitor to maintain specified levels
9.6.2 System Leakage
Symptoms
• Loss of hydrazine
• Decrease in pH, conductivity • Increase in dissolved oxygen
Troubleshooting and Corrective Actions
Corrective Actions
• Increase sampling frequency for inhibitor as appropriate • Repair system leakage
• Adjust inhibitor concentration as needed
9.6.3 Water In-Leakage
Symptoms
• Increased conductivity
• Increase in concentration of impurities found in water entering the CCW system Corrective Actions
• Repair system in-leakage
• Evaluate effect of contaminants on the system
• Evaluate need for feed and bleed or increase inhibitor concentration to compensate if necessary • Adjust pH if necessary 9.7 Silicate-Treated Systems 9.7.1 System Leakage Symptoms • Decreasing pH • Loss of silicate • Excessive makeup
• Loss of conductivity (following makeup water additions to the system) • Loss of azole
Corrective Actions
• Increase sampling frequency for inhibitor as appropriate • Repair system leakage
9.7.2 Water In-Leakage
Symptoms
• Possible pH change depending on pH of water entering the CCW system
• Loss or gain of conductivity (depending on conductivity of water entering the CCW system) • Loss of silicate
• Possible turbidity • Loss of azole
• Increase in concentrations of impurities or radioactivity (depending on which impurities are present in water entering the CCW system)
Corrective Actions
• Repair system in-leakage
• Evaluate effect of contaminants on the system
• Evaluate need for feed and bleed, drain and refill, or increase silicate concentration to compensate if necessary
• Adjust pH if necessary
9.7.3 Increase in System Corrosion Rates
Symptoms
• Increasing trends in total iron or total copper
• Increase in corrosion rates on weight loss coupons or electrochemical monitor (if used) • Visible corrosion or tuberculation during inspections
• Occurrence of leaks Corrective Actions
• Increase sample frequency for iron and/or copper analysis • Determine cause for increase in corrosion rates and correct • Evaluate effect of elevated iron and copper in the system • Evaluate need for feed and bleed or drain and refill
Troubleshooting and Corrective Actions 9.7.4 Oil In-Leakage
Symptoms
• Possible increase in sulfate and or phosphate • Possible visible sheen on system samples
• Possible unexplained decrease in azole (oil can interfere with analytical test) Corrective Actions
• Initiate testing for TOC, oil and grease, sulfate, and/or phosphate concentration • Locate oil source and correct
• Evaluate impact of oil in the system and remove via cleaning, feed and bleed, or drain and refill
9.7.5 Contaminant Ingress
Symptoms
• Increase in contaminant found in the in-leakage source but not normally found in the treated system
• Possible turbidity Corrective Actions
• Identify the source of contaminant and correct.
• Evaluate effect of elevated contaminant level in the system.
• If elevated contaminant will result in increased corrosion rate or degraded system
performance, place the system into feed and bleed or drain and refill, or increase inhibitor concentration(s) to compensate.
9.7.6 Bacterial Growth
Symptom
• ATP, total bacteria, or plate counts in excess of specified maximum • Possible decrease in pH
Corrective Action • Add biocide
• Consider need for alternate biocide or alternating biocides • Adjust pH if required
• Evaluate need for feed and bleed or drain and refill • Consider need for system cleaning
9.8 Pure Water Systems