The following information is a synopsis of information received via E-mail:
On August 8, 2016 a user of commercial grade (non-Class 1E) 3DCU-5 batteries notified C&D of an issue with two units that exhibited high on-charge voltage and sulfated positive plates. The batteries were returned and analyzed. On September 13, 2016 C&D's laboratory issued a report showing that the batteries had failed welds between the terminal posts and the external battery terminals. This weld has the function of carrying current between the battery energy storage elements and the customer load. Failure of the welds could interrupt the current flow to customer loads during discharge.
Although the batteries were not sold or used in a nuclear safety related application, C&D conducted an extent of condition analysis to determine whether this condition could exist in DCU products sold into safety related products. Although no similar reports have been made from users of Class 1E DCU batteries, based on the results of this analysis, there is a risk that this condition may exist in safety related products.
The batteries in question are DCU Batteries, manufactured from April 2010 to August 2016. The battery manufacturing date is on the label.
The following nuclear plants were supplied DCU batteries for use in 1E applications, with shipment dates of April 2010 to August 2016: Energy Northwest - Columbia, Exelon - Nine Mile, Talen Energy - Susquehanna, Entergy - Grand Gulf, and Exelon - Limerick.
As corrective actions, C&D has implemented a discharge test to detect and eliminate any improperly made welds prior to shipment to end users. C&D has also performed additional training and qualification work with employees responsible for terminal welding on DCU products. These actions were implemented prior to shipment of Class 1E nuclear products in September 2016, and now are complete.