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| Entered date | Event description | |
|---|---|---|
| ENS 50568 | 25 October 2014 13:42:00 | The normal and high range ventilation process radiation monitors (3HVR*RE 10 A/B) were removed from service for preplanned maintenance for greater than 72 hours. The radiation monitors will be returned to service following maintenance and completion of operational testing. The licensee has notified the NRC Resident Inspector, the State of Connecticut and Waterford township.. |
| ENS 50400 | 26 August 2014 11:54:00 | Millstone removed their unit 2 high range site radiation monitor, RM-8168, from service for pre-planned maintenance. RM-8168 was restored to service at 1012 EDT on 8/26/14. The licensee notified the NRC Resident Inspector, the State of Connecticut, and the town of Waterford. |
| ENS 50281 | 15 July 2014 13:20:00 | The Unit 2 stack high range radiation monitor (RM 8169) was removed from service at 0940 EDT for planned maintenance. The monitor was returned to service at 1119 EDT after the completion of maintenance. The licensee notified the NRC Resident Inspector, the Connecticut Department of Energy and Environmental Protection, and the city of Waterford for this event. |
| ENS 49893 | 11 March 2014 11:49:00 | At 0931 EDT on 3/11/14, the Millstone Station Stack Radmonitor RM-8168 was removed from service for pre-planned maintenance. This resulted in a loss of assessment capability and is being reported under 10 CFR 50.72 (b)(3)(xiii). The licensee informed State/local agencies and the NRC Resident Inspector. |
| ENS 49349 | 16 September 2013 16:57:00 | System(s) Affected: RM-8169 Vent Stack Radiation Monitor Actuations & Their Initiation Signals: None Causes (If known): Pre-Planned Maintenance Effect of Event on Plant: Loss of assessment capability Actions Taken or Planned: Compensatory samples - restore RM-8169 to service ASAP. Additional Information: None The licensee notified the NRC Resident Inspector, the State of Connecticut and local Waterford Dispatch. |
| ENS 49047 | 17 May 2013 12:05:00 | On May 17, 2013 at 0439 EDT, with the unit in Mode 3, operators identified RCS temperature decreased below 551 deg. F with the reactor trip breakers closed. The condition existed for approximately one hour after which operators identified this was below the procedurally required value identified to support power range nuclear instrumentation trip operability. The condition was then immediately corrected. The plant remains stable in Mode 3. This condition is reportable pursuant to 10 CFR 50.72(b)(3)(ii)(B) for an unanalyzed condition. The NRC Senior Resident Inspector has been notified. The reactor trip breakers were closed to support rod testing at the time this event occurred. RCS temperature was decreasing due to Terry turbine testing which was being performed at the same time. The reactor trip breakers were opened when the operators identified RCS temperature below 551 degrees. The RCS temperature was returned to above 551 degrees. This temperature limit is specified in Millstone 3 FSAR section 15.4.1, "Uncontrolled rod cluster control assembly bank withdrawal from a subcritical or low power startup condition". The licensee notified state and local authorities.
The purpose of this call is to retract the report made on May 17, 2013, Event Number 49047. Upon further review, the condition in which Reactor Coolant System (RCS) temperature decreased below a procedural limit while in Mode 3 did not result in an unanalyzed condition. Engineers verified that RCS boron concentration was sufficiently high that criticality could not have occurred during any inadvertent control rod withdrawal. The details of the engineering review have been provided to the NRC Senior Resident Inspector. Notified R1DO (Gray). |
| ENS 49034 | 15 May 2013 11:55:00 | On May 15, 2013, at 0400 EDT, it was discovered that an equalizing valve for the outer containment air lock was leaking by its seat rendering the outer containment air lock inoperable. This condition was discovered by maintenance personnel as they were exiting containment through the inner containment air lock. The containment inner door was open for transit, which resulted in the Loss of Containment Integrity. With both containment air lock doors open at the time of discovery of the leaking equalizing valve, this condition is reportable pursuant to 10 CFR 50.72(b)(3)(v). The inner air lock door was immediately closed and has remained closed since. Technical Specification 3.6.1.1 Primary Containment Integrity is applicable in Modes 1,2,3, and 4. Since Primary Containment Integrity was rendered inoperable, Dominion is reporting that this condition could have prevented the fulfillment of the safety function to control the release of radioactive material. The NRC Senior Resident Inspector has been notified. |
| ENS 48956 | 23 April 2013 09:46:00 | System Affected: Site Stack Radiation Monitor; RM-8169 Causes: Planned Maintenance Effect on Plant: Loss of Assessment Capabilities Actions Taken or Planned: Pre-planned maintenance of the RAD monitor. Additional Information: RM-8169 will be removed from service at approximately 1100 (EDT) on 4/23/13 for a period of approximately 3 hours. The licensee notified the state and local government. The licensee notified the NRC Resident Inspector. |
| ENS 48941 | 18 April 2013 13:52:00 | System(s) Affected: Site Stack Radiation Monitor, RM-8169 Causes: Failure of radiation monitor bypass pump. Effect of Event on Plant: Loss of assessment capabilities from radiation monitor. Actions taken or planned: Repair of radiation monitor. Additional information: Radiation monitor inoperable at 2030 (EDT) on 4/16/13. Further review identified the reportable condition. The licensee informed the State of Connecticut, Waterford dispatch, and the NRC Resident Inspector. |