Information Notice No. 84-83: Various Battery Problems
SSINS No.: 6835 IN 84-83 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 November 19, 1984 Information Notice No. 84-83: VARIOUS BATTERY PROBLEMS Addressees: All nuclear power reactor facilities holding an operating license (OL) or construction permit (CP). Purpose: This information notice is provided to alert licensees and applicants of the potential for significant degradation of safety associated with various battery related problems. Recipients are expected to review the information for applicability to their facilities and consider actions, if appropriate, to preclude similar problems occurring at their facilities. However, suggestions contained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: Overloading D.C. Buses: At Quad Cities Unit 1 on May 10, 1984, the licensee discovered that the direct current (dc) power system could no longer provide power to the connected loads for the time (i.e. , 8 hours) stated in the Final Safety Analysis Report (FSAR) for postaccident conditions. Over the course of years, the licensee added new loads to the dc system so the battery would have been able to provide power only for about 4 hours. The licensee recognized this condition while preparing to perform a battery discharge test. The long term solution is to replace the battery with a larger one sized for the increased loads. Temporarily, the licensee implemented procedures to limit loads on the dc power system on loss of the battery chargers. Solvent Induced Case Cracking: At the Byron and Braidwood stations in April 1984, 55 instances of battery case cracking were evaluated by the supplier, GNB Batteries, Inc. The batteries were NCX-1200 type with styrene-acrylonitrile (SAN) cases that exhibited crescent shaped cracks at the jar-cover juncture and etching of the battery side walls. GNB Batteries attributed this cracking to the use of a solvent, trichloroethylene, used to clean the battery posts of anti-corrosion (No-ox-id "A") grease during rework of the intercell connections. 8411150064 . IN 84-83 November 19, 1984 Page 2 of 3 At Fitzpatrick in March 1983, while at power, the licensee discovered 4 cells leaking on the B train battery and 39 cells exhibiting non-through-wall cracking in both the A and B train batteries. This condition necessitated removing and jumpering two cells on the A train, battery to replace cells on the B train battery. The jumpering was done with the plant at power and the battery chargers carrying the dc loads. Subsequent investigation by the manufacturer, GNB Batteries, Inc. (then known as Gould, Inc.), suggested that the cracking was caused by the application of hydrocarbon-based grease to the vinyl straps on the battery racks, presumably to permit the cells to slide over the racks more easily and facilitate installation of the cells. The hydrocarbon oil in the grease acted like a solvent and attacked the cell cases which were made of SAN. Ultimately, all of the cells had to be replaced. Discussion: In general, matters related to the integrity of the Class 1E dc power system and its batteries are important to safety because complete loss of dc power would place a nuclear power plant in an unanalyzed condition. Although the addition of a small dc load may be accomplished by use of margin between the original design loads and the battery capacity, the cumulative effect of a number of small loads added over an extended period of time may overload the dc bus. The event at Quad Cities occurred because the licensee added loads to the Class 1E battery without analyzing the effect and comparing the results to the commitments in the FSAR regarding design margin for battery performance. A cracked battery case can cause loss of electrolyte and, consequently, reduce battery capacity or cause a short to ground. Although it may not occur instantaneously, complete loss of electrolyte in a single cell could open the battery circuit and cause loss of the entire battery. As illustrated by the event at Fitzpatrick, the loss of electrolyte because of solvent induced case cracking may go undetected, despite routine surveillance tests, and result in loss of a battery while the plant is at power. Besides GNB Batteries, Inc., other manufacturers also warn against use of solvents or solvent-containing substances near battery cases or covers. Licensees may wish to review their maintenance and surveillance procedures for station batteries to ensure that the use of solvents in the vicinity of batteries is carefully monitored and in accordance with procedures approved by the battery manufacturer's service department. Tests have shown that some commonly used solvents will induce almost instantaneous cracking of battery cases. Some battery manufacturers have advised us that the use of a solvent is not necessary to remove anti-corrosion grease from a battery terminal. . IN 84-83 November 19, 1984 Page 3 of 3 Although not specifically addressing the use of solvents on battery cases, Regulatory Guide 1.128, "Installation Design, and Installation of Large Lead Storage Batteries for Nuclear Power Plants," and Regulatory Guide 1.129 "Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Nuclear Power Plants," provide useful information on these subjects. No specific action or written response is required by this information notice. If you need additional information about this matter, 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: Eric Weiss, IE (301) 492-9005 Attachment: List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021