Event Notification Report for August 16, 2010

AUTOMATIC REACTOR TRIPS AT BOTH UNITS

"Braidwood Unit 2 automatically tripped at 0206 [CST] due to a turbine generator trip due to generator lockout relay actuation. All systems responded as expected, with the auxiliary feed water pumps starting on Low-2 Steam Generator level. The Unit is stable in Mode 3, all primary systems are stable with the secondary heat sink being maintained via aux feed water and the steam dumps. Offsite power is supplying Unit 2, and both emergency diesel generators are available. Cause of generator lockout is under investigation.

"Braidwood Unit 1 automatically tripped at 0219 [CST] on a turbine trip caused by a loss of condenser vacuum. All systems responded as expected, with the auxiliary feed water pumps supplying steam generator levels. Secondary heat sink is steam generator PORVs. One steam generator safety valve is not fully seated. No steam generator tube leakage. Cause of the loss of vacuum is under investigation.

"For both Units all control rods fully inserted. There were no complications during the trip and all systems functioned as required. Offsite power remained available throughout the transient.

"The licensee notified the NRC resident inspector."

Braidwood Unit 1's loss of condenser vacuum was caused by the loss of an electrical bus supplying the circ water pumps. At the time of this report, both plants were in a normal shutdown electrical lineup with the exception of the deenergized bus supplying power to the circ water pumps on Unit 1. The steam generator safety valve that has not fully seated was characterized as weeping a small amount of steam. The licensee is uncertain if the Unit 1 trip is related to the Unit 2 trip.

NPDES LIMIT WAS EXCEEDED FOR RIVER TEMPERATURE DISCHARGE REQUIREMENTS

"Browns Ferry Nuclear Plant inadvertently exceeded a limitation of its National Pollutant Discharge Elimination System (NPDES) Permit for Tennessee River temperature conditions which was reported to the Alabama Department of Environmental Management (ADEM) at 1340 Central Daylight Time, on August 16, 2010. As such, this is being reported in accordance with 10 CFR 50.72(b)(2)(xi) as 'Any event or situation, related to the health and safety of the public or on-site personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made.'

"The NPDES Permit requires that when the 24 hour ambient average river temperature exceeded 90 degrees Fahrenheit, the 24 hour average downstream river temperature may equal but not exceed the upstream value. The 24 hour average upstream temperature was found to be 90.4 (rounded to 90) degrees Fahrenheit and the downstream temperature was found to be 90.6 (rounded to 91) degrees Fahrenheit.

"Browns Ferry had been maintaining compliance with the NPDES permit. The departure is thought to be due to a summer storm cooling off the upstream temperature. With the time delay between upstream temperature changes and the ensuing rate at which the downstream temperature changes are observed, the resultant 24 hour average downstream river temperature exceeded the upstream value. Duration of this condition was found to be only several hours.

"The three Browns Ferry units, which had already been derated to approximately 50 percent rated thermal power in order to maintain compliance with the NPDES Permit river temperature limits, were further derated to achieve compliance with the NPDES Permit.

"There is no corresponding requirement for written follow-up in accordance with 10 CFR 50.73."

The licensee has notified the NRC Resident Inspector.

AGREEMENT STATE REPORT - DAMAGED CO-60 CASTER GAUGE

Received the following report from the State of Ohio via email:

"At approximately 2000 [CDT] on 8/16/2010 a molten metal overflow event occurred at Charter Steel. Molten metal flowed down a tube outside the crucible where the caster gauge is located. The caster gauge, a Berthold LB300MLT containing 5 mCi of Co-60, was covered in molten metal as a result. On the morning of 8/17/2010 the licensee's environmental contractor was called to help assess the situation. Radiological surveys were conducted and no contamination was found. The gauge manufacturer recommended that the licensee contact Radiametrics (Ohio license # 03225480000) to recover the gauge. Radiametrics responded on the afternoon of 8/17/2010. Ohio Department of Health dispatched an inspector to investigate the incident and observed as Radiametrics removed the gauge from the now solidified block of steel. The gauge was found intact and the shutter was found in the closed position. Radiation surveys indicated that the source was intact and was not leaking. At approximately 1400 on 8/17/2010 the gauge was placed in secure storage at Charter Steel. The licensee has contracted with Radiametrics to transfer the source to a new Berthold gauge when it arrives in the next few days."

Ohio Incident # OH100010

CALIFORNIA AGREEMENT STATE REPORT - LOST TRITIUM EXIT SIGNS

The following information was received from the State of California via email:

"On 08/20/10, the ARSO at Stanford University called and informed RHB [California Department of Public Health - Radiologic Health Branch] of the following:

"On 8/16/10, it was discovered that one of our Contractors, Vance Brown, lost control of 28 signs they removed from two buildings (Building 05-600 Moore South (row 475) and Building 05-610 Moore North (row 493). The signs were placed into a plastic bin and Vance Brown cannot determine what happened to them.

"Representatives from Vance Brown and Redwood City Electric, the electrical subcontractor who removed the signs, conducted an investigation to determine the fate of the signs. They determined that while the signs had been removed and stored properly awaiting disposal by EH&S [Stanford University Environmental Health and Safety], they vanished from the secured construction site at an undetermined time between 6/28/2010 and 8/16/10.

"EH&S met with representatives from Vance Brown and Redwood City Electric on 8/19/10. Several avenues were explored during the meeting. Vance Brown explained that the site was broken into on 7/29/2010 and several tools and other valuables were stolen. Vance Brown filed a police report, but did not notice the signs missing at that time. Vance Brown and Redwood City Electric also questioned their employees, reviewed truck logs, and looked through both construction site storage containers and their off-site warehouses.

"Stanford EH&S has also conducted an internal investigation to determine if any Stanford employees had picked up the signs. None had. Stanford EH&S also queried the waste hauler used by Redwood City Electric (Quick Light Recycle) who stated they had not picked up the signs.

"At this time Vance Brown and Stanford EH&S has exhausted potential locations for the plastic bin of 28 tritium exit signs and considers them to be lost and/or missing. "

California Report No.: 5010-082010

THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

This source is not amongst those sources or devices identified by the IAEA Code of Conduct for the Safety & Security of Radioactive Sources to be of concern from a radiological standpoint. Therefore is it being categorized as a less than Category 3 source