Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 49262 | 10 August 2013 10:38:00 | Calvert Cliffs was notified at 0711 (EDT) by Calvert Control Center that a siren in the Calvert County Area was activated. (It was) determined to be Siren C15 on Lloyd Bowen Road. Per CNG-NL-1.01-1004 this is a verbal report to Calvert Control Center. This event is reportable as a 4-hour non-emergency notification (under) 10CFR50.72(b)(2)(xi) as 'Any event resulting in notification to other government agencies that has or will be made.' The licensee informed the NRC Resident Inspector. |
| ENS 49012 | 9 May 2013 00:09:00 | The reactor automatically tripped at 2147 EDT. All control rods fully inserted on the trip and all systems responded as expected. Decay heat removal is to the main condenser. The plant is in its normal shutdown electrical lineup. The licensee is investigating the cause of the reactor trip. The licensee notified the NRC Resident Inspector. |
| ENS 48233 | 26 August 2012 17:05:00 | The Calvert Cliffs control room was notified at 1530 EDT on 8/26/2012 by a site employee that Siren C15 was intermittently alarming. This is a repeat of a similar actuation that had been reported in EN #48231. The licensee has notified the Calvert County Control Center that the siren had actuated. The licensee has deactivated the siren until further investigation and repairs can be accomplished. As was noted in the original event, adverse inclement weather conditions existed at the time the siren was alarming. The licensee notified the NRC Resident Inspector. |
| ENS 48124 | 21 July 2012 13:10:00 | (Calvert Cliffs Nuclear Power Plant) CCNPP U1 identified RCS Pressure Boundary Leakage from the instrument line to 1-PDT-123A, 11A reactor coolant pump differential pressure transmitter. Technical Specification 3.4.13, Action B was entered and requires that the Unit be placed in Mode 3 within 6 hours and Mode 5 within 36 hours. (The licensee has) initiated plant shutdown in accordance with this Technical Specification. Therefore, this is reportable under 10CFR50.72(b)(2)(i) Plant Shutdown Required by Technical Specifications. This is also reportable under 50.72(B)(3)(ii)(A) as a material defect in the primary coolant system that cannot be found acceptable under ASME Section XI, IWB-3600 or ASME Section XI, Table IWB-3410-1. The leak is from an instrument line which monitors reactor coolant pump differential pressure. It is for monitoring purposes only. The leak rate is currently about .08 gpm. The licensee has begun power reduction of the unit and is currently at approximately 73% rated thermal power. The recovery plan is to complete the unit shutdown and then enter containment and repair the leak. The leak is believed to be coming from the same instrument line that was reported to be leaking on July 17, 2012 (see EN #48116). At that time, power was reduced to approximately 10% and a containment entry was made. At that time it was believed that the leak had been isolated and full power operations were resumed. Based on containment sump pump run times and another containment entry, it was determined that the leak apparently had not been isolated. The licensee notified the NRC Resident Inspector. |
| ENS 47684 | 22 February 2012 13:58:00 | Calvert Cliffs will be performing planned U-1 Refueling Outage maintenance to a portion of the sites 1E Electrical Distribution System. This maintenance window is expected to be 36 hours long and will start at 1400 today. This will impact the dissemination of plant data to the TSC, EOF, and OSC. ERDS will also be out of service for both Unit-1 and Unit-2. Should an emergency be declared during this period, the Control Room will continue to have the capability to retrieve plant data inputs to assess plant conditions and perform core damage assessment. Control Room Emergency Response Organization personnel will use backup methods already captured in emergency response procedures to disseminate plant parameter data to the effected Emergency Response Facilities and NRC during the plant data network outage. MIDAS (Meteorological Data) will continue to be operational at the site. The licensee notified the NRC Resident Inspector. |
| ENS 47632 | 3 February 2012 08:22:00 | LOSS OF PLANT COMMUNICATIONS DUE TO SCHEDULED MAINTENANCE
"Calvert Cliffs will be implementing scheduled maintenance to the plant data network to install a data diode to meet the new cyber security requirements listed in 10 CFR 5.71. This work will require the TSC, OSC and subsequently the EOF to lose normal data flow from the plant data network for a period of approximately 6 to 8 hours. ERDS will also be unavailable during this maintenance. Should an emergency be declared during this period, the Control Room will continue to have the capability to retrieve plant data inputs to assess plant conditions and perform core damage assessment. Control Room Emergency Response Organization personnel will use backup methods already captured in emergency response procedures to disseminate plant parameter data to the effected Emergency response Facilities and NRC during the plant data network outage. MIDAS (Meteorological Data) will continue to be operational at the site." The licensee notified the NRC Resident Inspector. |
| ENS 47292 | 26 September 2011 14:27:00 | The site's 800 MHz radio system was removed from service for approximately one (1) hour to support pre-planned maintenance to repair a degraded antenna. While the 800 MHz radio system is out of service, it will not be possible to activate any of the site's emergency sirens from any of the risk county Emergency Operations Centers nor from the plant. For the period of time that the sirens are non-functional, the three risk counties will be prepared to utilize the back-up method of route alerting to alert residents. The licensee has notified the NRC Resident Inspector. |
| ENS 46623 | 18 February 2011 02:31:00 | During a scheduled VT-2 boric acid examination on the Unit 2 Pressurizer lower level heater penetrations a boric acid leak was identified on heater penetration N-3." The licensee characterized the leak as inactive. The approximate sizes of the round boric acid deposits are 1/32 inch and 1/64 inch. The licensee continues to investigate and plan recovery actions. The licensee notified the NRC Resident Inspector. |
| ENS 45737 | 2 March 2010 11:30:00 | A Unit-1 Pressurizer Safety Relief Valve Nozzle to Safe-end Weld, (#4SR-1006-1) was discovered to have an indication not acceptable under ASME Section XI, IWB-3600. The weld is on a 4 inch diameter line to the pressurizer safety relief valve (RV-201). The weld is in our dissimilar metal weld inspection program and was scheduled to be examined this RFO (refueling outage) in accordance with MRP-139 requirements. Initial inspections on 3/1/10 found an indication and the indication was confirmed by a second NDE level 3 examiner. Indication is circumferential, initiated at ID and propagates approximately 1.8 inches circumferentially to about approximately 70% through wall. ASME IWB-3500 allows up to 12.5% through wall for class 1 welds. The defect was found using phased array Ultrasonic Testing (UT). The NDE report is being reviewed and characterized at this time. At this time, we believe the most probable cause of the indication is primary water stress corrosion cracking. No active leaks have been identified, the defect is not through wall. Unit 1 is in Mode 6. A team has been established and repair options are being investigated. The licensee notified the NRC Resident Inspector.
On March 7, 2010, manually indexed phased-array ultrasonic examination of the U1 Pressurizer Safety Relief Valve Nozzle to Safe-end Weld was performed. Based on these inspections, it was determined on March 13, 2010 that the indication does not exhibit stress corrosion cracking characteristics and is not consistent with ultrasonic responses associated with inside diameter (ID) connected geometry. Therefore, the U1 Pressurizer Safety Relief Valve Nozzle to Safe-end Weld is acceptable from an ASME Code Section XI perspective. On this basis, the indication did not result in the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded and the issue is not reportable under 10 CFR 50.72(b)(3)(ii)(A). The NRC resident was notified of this retraction. Notified the R1DO (Chris Cahill) |
| ENS 43335 | 1 May 2007 17:51:00 | The licensee made an offsite notification to the Maryland Department of the Environment based on the release of approximately 705 gallons of very acidic demineralized water (Ph of 1) to a storm drain. The drain is connected to a system that leads to the Chesapeake Bay. The acidic water is coming from a non-isolable leak from the 11 Waste Neutralizing Tank. The leakage is onto a gravel base below the tank which is about 5 feet from the storm drain. The leak rate is at a rate of about 1 GPM. The licensee has set up a system to divert some of the leakage from the storm drain and capture it in waste barrels but some of the water is still being spilled onto the ground. The long term remediation of this problem is to neutralize the tank with a caustic solution and then discharge the tank. The licensee has also notified Calvert County and the NRC Resident Inspector.
The licensee also made a report of this spill to the National Response Center (EPA). R1DO (Holoday) notified. |
| ENS 42517 | 20 April 2006 09:54:00 | A non-licensed contract supervisor tested positive for a controlled substance during a random test. The individual's access to the plant has been terminated. Contact the Headquarters Operations Officer for additional details. The licensee notified the NRC Resident Inspector. |