United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: ABB COMBUSTION ENGINEERING
SITE: ABB COMBUSTION ENGINEERING EN NUMBER: 35862
DOCKET: EVENT DATE: 06-25-99
RX TYPE: EVENT TIME:
VENDORS: NOTIFY DATE:06-25-99
EMERGENCY CLASS: N/A REGION: 1 STATE: CT TIME: 16:34
OPS OFFICER: BOB STRANSKY
10 CFR SECTION: CCCC UNSPECIFIED PARAGRAPH

10CFR PART 21 REPORT REGARDING ABB COMBUSTION ENGINEERING 4KV VACUUM BREAKERS

The following text is excerpted from a facsimile received in the NRC Operations Center:

"The defect concerns ABB 1200A 4KV Vacuum Breakers delivered to Baltimore Gas and Electric Company's (BG&E's) Calvert Cliffs Nuclear Power Plant (CCNPP). Specifically, the defect concerns the breaker performing a trip free operation when a close signal is received by the breaker. This defect results in the breaker failing to remain in the closed position. The defect could lead to non-conservative failure of not starting certain plant equipment upon demand such as an Emergency Core Cooling Pump."

* * * UPDATE AT 1613 ON 06/30/99 BY VIRGIL PAGGEN TO JOLLIFFE * **

The above 10CFR Part 21 Report was submitted to the NRC via ABB Combustion Engineering Letter #LD-99-035, dated 06/25/99. The following is an update to the above 10CFR Part 21 Report via ABB Combustion Engineering Letter #LD-99-039, dated 06/30/99, Same Subject.

The activity for which this report is being filed is the use of ABB 1200A 4KV Vacuum Breakers in an application where the breaker is normally open and must close on demand. This defect applies only to BG&E's CCNPP.

The defect identified is associated with the use of the ABB 1200A 4KV Vacuum Breaker only in applications where the breaker must close on demand. The defect was detected during site testing of the breaker during installation into CCNPP. During this test, a close signal was applied to the breaker and the breaker tripped free (i.e., failed to remain in the closed position).

These breakers are intended for both normally open and normally closed operation. In some applications, the breaker must close upon demand. This may be for electrical distribution applications or component control applications (e.g., start an Emergency Core Cooling pump). Demands can be automated (e.g., by ESFAS) or based on manual operator demands. If the breaker does not remain closed when demanded (i.e., trips free), the safety function cannot be performed. This breaker is intended for use in multiple redundant safety divisions. Multiple redundant divisions could be affected by this defect.

The defect applies only to ABB 1200A 4KV Vacuum Breakers delivered to CCNPP. Thirty-seven (37) of these breakers were delivered to CCNPP. ABB Combustion Engineering understands that several of these breakers have been installed at CCNPP, however, none are installed in any application that requires a close on demand function.

The NRC Operations Officer notified the R1DO Larry Doerflein and NRR Vern Hodge (via fax).



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