United States Nuclear Regulatory Commission - Protecting People and the Environment

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 
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                                                       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 

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