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| Entered date | Event description | |
|---|---|---|
| ENS 54206 | 8 August 2019 17:03:00 | Pursuant to 10 CFR 21.21(d)(3)(i), this is a non-emergency notification by Energy Northwest concerning a defect on a control power transformer (CPT) resulting in a failed starter coil while in service at Columbia Generating Station. The defect was associated with a CPT provided by Spectrum Technologies (model Micron B150-2957-1). On June 14, 2019, a failure analysis was completed that determined that the failure of the coil occurred because the starter coil was exposed to chronic elevated temperatures. These elevated temperatures were caused by the associated control power transformer (CPT) secondary voltage being maintained outside the coil's rated voltage range. Previously on June 10, 2019, it was determined that the CPT installed in the Spectrum Technologies motor starter assembly did not meet procurement specifications resulting in a turns ratio that produced higher voltages on the motor starter coil than its rated voltage. This led to overheating and breakdown of the coil insulation that created a short between two windings. On August 5, 2019, Energy Northwest completed a Part 21 evaluation in accordance with 10 CFR 21.21(a)(1) and determined that this deviation could create a substantial safety hazard as defined in 10 CFR 21.3. The NRC Resident Inspector has been notified. The licensee has 14 Spectrum transformers that are continuously energized that could be affected. The one transformer that experienced the failure was out of service for maintenance at the time of discovery. Four other coils were inspected for extent of condition and no more failures were found. |
| ENS 52913 | 17 August 2017 17:55:00 | Pursuant to 10 CFR 21, this is a non-emergency notification by Energy Northwest concerning a defect in General Electric (GE) Nuclear HMA124A2 relays received at Columbia Generation Station. On August 12, 2017, Energy Northwest completed a 10 CFR 21 evaluation of a condition associated with GE Nuclear HMA124A2 relays supplied by GE Hitachi Nuclear Energy Americas, LLC, and intended for use at Columbia Generating Station. The evaluation was performed to determine the applications where the relays were approved for installation, and where they were installed in the plant, and to determine if the failure of the relays could result in a Substantial Safety Hazard as defined In 10 CFR 21.3. Two of the HMA124A2 relays received had back plates that were mounted upside down, causing the terminals to not match the standard configuration. Although the internal wiring to the physical stud locations was correct, the numbering scheme embossed on the back plate did not match the correct configuration. With the incorrectly mounted back plate, the internal coil of the energizing circuit could be wired to the incorrect portion of the control circuitry, which would not energize when required and could result in the failure of a safety function. This deviation presents a Substantial Safety Hazard as defined In 10 CFR 21.3, as these relays were approved for use in safety related applications; however, there was no actual risk to plant safety since this deviation was recognized and resolved by station craft prior to installation of the relays. This condition is reportable under 10 CFR 21.21(d)(1) as a defect as defined in 10 CFR 21.3. The defective HMA124A2 relays were installed in the plant in the correct configuration with post-maintenance testing performed to ensure operability of the relays. The remaining HMA124A2 relays were examined and no additional defects were identified. GE Hitachi has been notified of the condition. The licensee will notify the NRC Resident Inspector. |
| ENS 52615 | 16 March 2017 15:07:00 | Pursuant to 10 CFR Part 21, this is a non-emergency notification by Energy Northwest concerning a defect in Size 1 Freedom Series Starters with nominal 120 VAC coils manufactured by AZZ/NLI (Nuclear Logistics Inc.) used at Columbia Generating Station. On February 8, 2017 Energy Northwest was notified by NLI of a deviation associated with starter contactors used at Columbia that failed to close due to overheating of the starter coil. The coils that were provided were determined to not meet specified voltage ratings. The evaluation completed by Energy Northwest on March 14, 2017 concluded that the deviation did create a Substantial Safety Hazard, and is reportable under 10 CFR 21.21(d)(1) as a defect. A 30 day report will be issued by April 13, 2017 per 10 CFR 21.21(d)(4). The licensee performed a prompt operability assessment for the two starters currently installed. The licensee will notify the NRC Resident Inspector. |
| ENS 51068 | 12 May 2015 22:13:00 | On 4/21/2015, during performance of source check surveillance on the liquid effluent radiation monitor for the Plant Service Water (TSW), a non-radioactive system, it was discovered that the instrument was determined to be nonfunctional. It was determined on 4/25/15 that the failure was due to an incorrect 'as left' setting from testing conducted on 4/3/2015. The instrument was determined to be non-functional from the period 4/03/15 to 4/25/15 when the setting was corrected. On 5/12/15 it was recognized that because no compensatory measures were implemented during the time the instrument was non-functional that this condition constituted a major loss of radiation assessment capability which is reportable in accordance with 10 CFR 50.72(b)(3)(xiii). The NRC Resident Inspector will be notified. |
| ENS 42950 | 31 October 2006 10:04:00 | Reactor trip at 0445 following a turbine trip. Initial indication of cause is turbine trip due to low auto stop oil pressure. There were no complications in plant response. Plant is stabilized in mode three, heat removal is being maintained by turbine bypass valves. All control rods fully inserted on the trip, no safety or relief valves lifted during the transient, reactor water level 3 isolations did isolate, and the minimum level attained during the transient was -6 inches. Vessel water level is being maintained with normal feedwater flow and the electrical lineup is the normal shut-down electrical lineup. The cause of the low auto stop oil pressure is under investigation. The licensee notified the NRC Resident Inspector.
In response to questions raised during this event notification, a verbal response was provided to the NRC that an 8 hour notification in accordance with 50.72(b)(3)(iv)(A) (Specified System Actuation) was required. Upon further review it has been determined by Energy Northwest that this notification was not required because all required reporting was satisfied by 50.72(b)(2)(iv)(B). The licensee will notify the NRC Resident Inspector. Notified R4 DO (D. POWERS) |