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10 CFR 21 + and 10 CFR 21.21 +
The following information is provided on a … The following information is provided on a potential defect in accordance with 10CFR Part 21, paragraph 21.21(b). NLI (Nuclear Logistics Inc) does not have the capability to perform the evaluation to determine if a defect exists. NLI has supplied safety related breakers with the Micrologic trip units only to First Energy-Beaver Valley and PSEG-Hope Creek. Both of these plants are aware of the issue and the corrective actions described below.</br>The basic component that contains a potential defect is the Micrologic trip device installed in Square D series NT and NW low voltage switchgear breakers. The nature of the potential defect is as follows:</br>- Under certain combinations of operating conditions, the trip unit spuriously trips the breaker. The conditions that cause the spurious trip are starting a motor directly by breaker closure (no starter in the circuit) and system transients that have not been defined.</br>The reported spurious trips are as follows:</br>- PSEG-Hope Creek has Square D NW series breakers installed. One spurious trip was identified in over 1000 motor starts using these breakers in 7 safety related applications that start motors directly.</br>- First Energy-Beaver Valley has Square D NT and NW series breakers installed. One NT breaker installed in a non-safety application had multiple spurious trips upon motor starting.</br>- There are no other reported spurious trips of breakers at PSEG-Hope Creek or First Energy-Beaver Valley. Spurious trips in other facilities have been reported to Square D.</br>- NLI is not aware of the installation of Micrologic trip devices in safety related applications in other nuclear plants in the United States.</br>The following actions and corrective action that has been taken:</br>- Root cause analysis and testing has been performed by Square D and NLI. It was determined that the spurious trip was due to a combination transient voltages during motor start and a breaker configuration that lasts approximately 100ms during breaker closure.</br>- The NT breaker was determined to be more sensitive to the spurious trip than the NW breaker.</br>- The reported spurious trip rate for the Micrologic trip units installed worldwide is estimated at approximately 0.05%.</br>- A modification was developed and tested to prevent the susceptibility of the trip unit. This modified design will be implemented on the existing breakers and all future units.</br>NLI is working with the impacted utilities to replace the existing trip units.lities to replace the existing trip units.
06:00:00, 23 November 2005 +
42,168 +
15:54:00, 23 November 2005 +
06:00:00, 23 November 2005 +
The following information is provided on a … The following information is provided on a potential defect in accordance with 10CFR Part 21, paragraph 21.21(b). NLI (Nuclear Logistics Inc) does not have the capability to perform the evaluation to determine if a defect exists. NLI has supplied safety related breakers with the Micrologic trip units only to First Energy-Beaver Valley and PSEG-Hope Creek. Both of these plants are aware of the issue and the corrective actions described below.</br>The basic component that contains a potential defect is the Micrologic trip device installed in Square D series NT and NW low voltage switchgear breakers. The nature of the potential defect is as follows:</br>- Under certain combinations of operating conditions, the trip unit spuriously trips the breaker. The conditions that cause the spurious trip are starting a motor directly by breaker closure (no starter in the circuit) and system transients that have not been defined.</br>The reported spurious trips are as follows:</br>- PSEG-Hope Creek has Square D NW series breakers installed. One spurious trip was identified in over 1000 motor starts using these breakers in 7 safety related applications that start motors directly.</br>- First Energy-Beaver Valley has Square D NT and NW series breakers installed. One NT breaker installed in a non-safety application had multiple spurious trips upon motor starting.</br>- There are no other reported spurious trips of breakers at PSEG-Hope Creek or First Energy-Beaver Valley. Spurious trips in other facilities have been reported to Square D.</br>- NLI is not aware of the installation of Micrologic trip devices in safety related applications in other nuclear plants in the United States.</br>The following actions and corrective action that has been taken:</br>- Root cause analysis and testing has been performed by Square D and NLI. It was determined that the spurious trip was due to a combination transient voltages during motor start and a breaker configuration that lasts approximately 100ms during breaker closure.</br>- The NT breaker was determined to be more sensitive to the spurious trip than the NW breaker.</br>- The reported spurious trip rate for the Micrologic trip units installed worldwide is estimated at approximately 0.05%.</br>- A modification was developed and tested to prevent the susceptibility of the trip unit. This modified design will be implemented on the existing breakers and all future units.</br>NLI is working with the impacted utilities to replace the existing trip units.lities to replace the existing trip units.
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00:00:00, 23 November 2005 +
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02:19:48, 2 March 2018 +
15:54:00, 23 November 2005 +
0.413 d (9.9 hours, 0.0589 weeks, 0.0136 months) +
06:00:00, 23 November 2005 +
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