Event Notification Report for October 22, 2010

MANUAL REACTOR TRIP DURING PHYSICS TESTING DUE TO PROBLEMS WITH THE ROD CONTROL IN HOLD OUT SWITCH

"On 10/22/2010 at 0636 hours, North Anna Unit-1 reactor was manually tripped during physics testing and 1-E-0 was entered due to problems with the Rod Control In Hold Out Switch. The out direction of the switch was not functioning properly and the reactor was tripped to put the plant in a condition to perform maintenance. All control rods fully inserted into the reactor core. This was an uncomplicated reactor trip with no automatic ESF actuation required.

"Unit 1 is currently stable at normal operating temperature and pressure in MODE 3 (Hot Standby)."

The plant electrical line-up is normal. Decay heat removal is via the steam dumps. Notification will be made to the local county administrator's office.

The NRC Resident Inspector has been notified.

SPENT FUEL STORAGE RELATED DEFECT - CASK LEAKAGE RATE GREATER THAN TECHNICAL SPECIFICATION

"On 10/22/10, at 1058 EDT, a troubleshooting of Independent Spent Fuel Storage Installation (ISFSI) Cask TN-50-A indicated that a leak existed in the cask lid sealing area at a rate greater than allowed by ISFSI Cask Technical Specification (TS) Section 3.1.3, Cask Helium Leak Rate. TS 3.1.3 limits the Cask Helium Leak Rate to 1.0 E-05 ref-cc/sec. The cask is currently in unloading operations and is located within the Peach Bottom Atomic Power Station Unit 3 containment building. Preliminary review indicates that a leak exists at the weld plug that provides sealing of the drilled interseal passageway associated with the drain port penetration of the cask lid. This leak effectively provides a bypass of the main lid outer confinement seal.

"This report if being submitted pursuant to 10CFR72.75(c)(1) as a result of a material defect in a weld in the cask main lid. This report is also being submitted pursuant to 10CFR72.75 (c) (2) as a result of a resolution in the effectiveness of the cask confinement system.

"The Certificate of Compliance for this cask is 1027 (Amendment 1).

"The NRC Resident Inspector has been informed of this notification."

POTENTIAL INOPERABILITY OF OSCILLATION POWER RANGE MONITORS

"At 1751 [CDT] on Oct 22, 2010, Dresden Nuclear Power Station (DNPS) determined that current Oscillation Power Range Monitors (OPRM's) setpoints, as outlined in the Core Operating Limits Report (COLR), for Dresden U2 are non-conservative. This renders the Technical Specification (TS) function of the OPRM's in the Reactor Protection System (RPS) inoperable.

"This event was initiated as a result of notification by Westinghouse Nuclear Fuels (NF-BEX-10-157) that an error exists in the McSLAP computer code which affects the Safely Limit Minimum Critical Power Ratios (SLMCPR) for Dresden. Currently the COLR and installed, amplitude setpoint (Sp) is 1.13 and the confirmation count setpoint (Np) is 15. This is required to be adjusted to 1.12 (Sp) and 14 (Np).

"Alternative methods to detect and suppress thermal hydraulic instabilities were initiated as required by Technical Specifications.

"This non-conservative computer code error could potentially have prevented fulfillment of the OPRM system's safety function and is therefore reportable per 10 CFR 50.72(b)(3)(v)(A), 'An event or condition that could have prevented the fulfillment of a safety function - shutdown the reactor and maintain it in a safe shutdown condition.'"

Corrective actions include the following:

"1. Revise U2 Core Operating Limit Report (COLR) to reflect correct values as determined by Westinghouse Nuclear Fuels Letter (NF-BEXÀl0-157).

"2. Adjust OPRM setpoints to comply with COLR values."

The licensee will notify the NRC Resident Inspector.

* * * RETRACTION FROM RILEY RUFFIN TO ERIC SIMPSON AT 1207 EST ON 12/3/10 * * *

"On October 22, 2010, Dresden Nuclear Power Station was notified by Westinghouse that an error in McSlap computer code resulted in a non-conservative MCPR safety limit. The preliminary results of the Westinghouse evaluation concluded that the setpoints for the Oscillation Power Range Monitors were also non-conservative. As a result of the notification, Dresden declared all channels of OPRM inoperable and took the required action of the plant's technical specifications. This was considered a loss of function.

"This condition was reported as a condition that could have potentially prevented the fulfillment of the OPRM system's safety function in accordance with 10 CFR 50.72(b)(3)(v)(A), an event or condition that could have prevented the fulfillment of a safety function - shutdown the reactor and maintain it in a safe shutdown condition.

"However, subsequent evaluation of the preliminary result determined that the original conclusions were overly conservative and the OPRM setpoints did not require revision. Based on the later evaluation, the function of the OPRMs was not adversely impacted by the installed setpoints. Thus, the system was always capable of performing its intended safety function.

"Therefore the notification associated with Event Number 46354 is being retracted."

The licensee notified the NRC Resident Inspector.

The R3DO (Ring) was notified.

UNANALYZED CONDITION - BATTERY CHARGERS MAY LOCKUP DURING A DESIGN BASIS EVENT

"On October 22, 2010, the station confirmed the following:

"On a safety injection (SI) event with no loss of offsite power (LOOP), calculations show that at various points in the load sequence, the voltage at the charger Motor Control Center will dip low enough on the SI unit to lockup both of the chargers. Additionally, when considering out of sequence loads, such as the containment spray pump, starting on the emergency diesel generator during normal load sequencing, the potential exists that the voltage for any of the chargers on an SI event with a LOOP may drop to the point that would cause the chargers to lockup.

"On October 22, 2010, the station completed an operability evaluation of the 11, 12, 21, and 22 battery chargers, implemented compensatory measures to restore battery chargers in the event of an SI to maintain operability (a simple manual action to restart the charger), and determined that the battery chargers were operable but non-conforming.

"The NRC Resident [Inspector] has been informed."

The licensee is planning on correcting this issue during the next refueling outage.

AGREEMENT STATE REPORT - MEDICAL EVENT - DOSE ADMINISTERED IN WRONG LOCATION

The following report was received from the State of North Carolina via email:

"The patient has persistent small cell lung cancer after chemotherapy, in an area that has received prior external beam radiation therapy, and was symptomatic. Therefore, a course of endobronchial brachytherapy with a high-dose rate unit (HDR) was recommended to the left upper and left lower lobe bronchus where the tumor was present. The treatment prescription was 10 Gy x 2 fractions to the target volume as defined in the planning CT. The first treatment was delivered between 2 to 3 pm, on Oct 22, 2010. Unfortunately, due to errors in defining the starting dwelling positions of the source during the treatment planning, the actual dose was delivered to the wrong location along the catheters. Details of the process are described below.

"After two endobronchial catheters were placed under bronchoscopy in the OR [operating room], the patient was transferred to Radiation Oncology Department where a CT was obtained for treatment planning purposes. The two catheters were positioned correctly based on CT.

"In the first step of the treatment planning, the locations of the two endobronchial catheters were correctly identified in the CT images. The direction of the catheters was mistakenly reversed afterwards during the treatment planning, thereby changing the starting position of the HDR source. Therefore, instead of the patient being treated correctly to the identified tumor region in the left-sided airways, she was treated to a position more proximally along the path of the catheters (the larynx area). Although the plan was checked by a number of qualified physicists per operational protocol, the subtle orientation error was missed, both in the plan check and in the delivery check. The wrong treatment was delivered around 2:45 pm.

"The error was identified by the planning physicists when they were working on another patient case, about one hour after the patient's treatment. A computerized 3-D plan was generated to calculate the actual location and dose delivered due to this error. The estimated dose to the neck region was about 15-20 Gy. The plan delivered to the patient was also delivered on radiochromic film to confirm the location of the delivered dose.

"The attending physician, clinical director, and the director of physics were all notified immediately after the error was identified and confirmed. The Radiation Oncology Department chair was notified by the clinical director. The Radiation Safety Officer was notified also by the chief physicist.

"The attending physician reviewed the case and the dosimetry, and immediately tried to contact the patient. After several attempts the patient was reached around 6:00 PM and asked to come back to the hospital immediately for observation and prophylactic treatments. The patient was admitted to hospital around 9:00 PM on the same day (the time required for her to travel back to Duke from her home).

"Licensee's evaluation of why the event occurred:
a. Staff physicists were more focused on dose optimization and missed the catheter's orientation.
B The wrong orientation was again missed during the plan and delivery checks.
C. In addition to calculation checks, there was no experimental check, i.e. delivering dose to the film to verify the distance.

"The effect, if any, on the individual(s) who received the administration: The patient was admitted to Duke Hospital immediately after the error was discovered. She remained hospitalized for 4 days during which time she remained relatively asymptomatic. She did not develop increasing hoarseness, shortness of breath, or odynophagia. She underwent fiber optic laryngoscopy 36 hours after her treatment which showed minor edema of the supraglottic larynx but no airway compromise. She received the correct treatment while an inpatient, and after one additional day of observation was discharged home.

"What actions, if any, have been taken or are planned to prevent recurrence:
a. Conducted a root-cause analysis of the event among the physicists.
B. A new and more detailed standard operational procedure (SOP) for this type of treatment was generated by the members of the Brachytherapy team.
C. The existent HDR Patient QA form was edited to add extra check levels that will prevent this error from happening again.
D. A new verification procedure was added to the existent set of verification procedures. It involves the delivery of the treatment on Gafchromic film or alternative imaging device to verify the exact starting point of the treatment. This film will be compared with the plan and will have to be approved by two physicists and the attending for each case.

"Certification that the licensee notified the individual (or the individual's responsible relative or guardian) and if not, why not:
The patient was contacted, was returned to Duke and was admitted for evaluation and management."


Log # NC 10-47

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.