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Information Notice No. 83-49: Sampling and Prevention of Intrusion of Organic Chemicals into Reactor Coolant Systems
SSINS No.: 6835 IN 83-49 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C., 20555 July 25, 1983 Information Notice No. 83-49: SAMPLING AND PREVENTION OF INTRUSION OF ORGANIC CHEMICALS INTO REACTOR COOLANT SYSTEMS Addressees: All nuclear power reactor facilities holding an operating license (OL) or construction permit (CP). Purpose: This information notice is, provided to inform licensees of two events involving the contamination of nuclear plant water systems. The first event illustrates the advantages of sampling programs for the detection of organic contaminants in reactor water cleanup and storage systems. The second event illustrates the problems that can result from the failure to detect such contaminants before they are conveyed into the reactor or other vital water systems. It is expected that recipients will review the information for applicability to their facilities. No specific action or response is required. Description of Circumstances: On February 13, 1983, at the Hatch 1 facility, 3000 gallons of glycol and water mixture were spilled as the result of a faulty valve lineup. The spill flow path was through an opening left by the removal of a relief valve in the "B" train of the off-gas system condenser cooler. The mixture ran into the floor drains and was transported to the radwaste system where it mixed into a total volume of 47,000 gallons of radwaste. Glycol, being nonionic, is not removed by the radwaste demineralizers. However, the contaminant was detected by a subsequent, sample analysis for total organic carbon. This prevented the transfer of the glycol to the condensate storage tank and then to the reactor coolant system. The practice of conducting sample analyses for total organic carbon was initiated as a result of the chemical intrusion incident at Hatch 1 in April 1982 (Information Notice No. 82-32). The second event which occurred at the LaSalle 1 facility on May 5, 1983 involved the intrustion of an organic dry cleaning solvent into the reactor coolant. At 1210 hours, with the reactor shut down, the reactor water pH 8306270412 . IN 83-49 July 25, 1983 Page 2 of 2 dropped to 5.2 which is below the limiting condition for operation of 5.3. At the same time there was an increase in both conductivity and the chloride concentration. Except for brief periods, the pH remained below 5.3 until 0001 hours on May 8, when it was brought back, and stayed, within specifications. As a result of extensive investigation, it was determined that the contaminants were freon and other organic solvents in the condensate storage tank and that they entered the reactor with the control rod drive cooling water. The freon is used as a dry cleaning solvent in the laundry system. It is believed that the solvents may have entered the radwaste discharge tank through the floor drains. Water from the radwaste was processed through a flash evaporator, where some of the volatile organic material was carried over with the steam. The evaporator condensate was eventually routed to the condensate storage tank. Some of the condensate storage tank water was routed to the suppression pool causing this water to become contaminated too. When the organic contaminants were injected into the reactor, they were broken down by the action of the heat and radiation causing the observed decrease in pH and increase in conductivity and chloride concentration. The reactor water was cleaned up using the normal water cleanup system. The condensate storage tank was drained and vacuum cleaned. The suppression pool was circulated and heated to 105 degrees F, and the pool spray and an air sparge were run to evaporate the organic material out of solution. Information on other previous intrusions of organic contaminants into reactor coolant systems is provided by INPO Significant Operating Experience Report 82-13, which discusses seven such events. No written response to this notice is requested. If you have any questions regarding these two events, please contact the Regional Administrator of the appropriate NRC Regional Office, or this office. Edward L. Jordan Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement Technical Contact: D. C. Kirkpatrick, IE 492-24510 Attachment: List of Recently Issued IE Information Notices .
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