Event Notification Report for August 22, 2005

TECHNICAL SPECIFICATION SHUTDOWN DUE TO CORE PROTECTION CALCULATOR SYSTEM (CPCS) SOFTWARE NOT CONSISTENT WITH SYSTEM DESIGN REQUIREMENTS.

"The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.

"On August 22, 2005, at approximately 1605 hours Mountain Standard Time (MST), Palo Verde Nuclear Generating Station (PVNGS) Unit 2 commenced a reactor shutdown required by Technical Specification 3.0.3.

"Westinghouse notified Palo Verde that the current version of the Common Q based Core Protection Calculator System (CPCS) software is not consistent with the system design requirements and Technical Specification Bases regarding the system response to analog input module errors. In that a failed sensor input or failure of the two analog input modules in a given CPCS channel (four total channels) would not result in a CPCS channel trip. At Palo Verde, the CPCS provides the reactor trip functions for Low Departure from Nucleate Boiling Ratio (DNBR) and High Local Power Density (LPD). A failed input sensor would be the most likely cause for both of the redundant input modules to indicate errors simultaneously because the two redundant input modules within a safety channel are connected to a single sensor. A similar scenario would occur if both analog input modules simultaneously failed. In both cases the result would be a failure of the channel without initiating a trip signal.

"Operations evaluated the non-conforming condition and declared all four channels of the CPCS inoperable. Limiting Condition for Operability (LCO) 3.3.1 only addresses up to two automatic RPS trip channels inoperable, therefore Operations entered LCO 3.0.3 at approximately 13:26 MST.

"The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public. The required offsite power sources are operable and the electrical grid is stable.

"The Common Q based CPCS is installed at the following nuclear power plant site in the United States: Palo Verde Unit 2. At this time, this condition is not transportable to Palo Verde Units 1 and 3."

All Emergency Core Cooling systems and their Emergency Diesel Generators are fully operable if needed.

The NRC Resident Inspector was notified of this event by the licensee.

PART 21 - GAMMA KNIFE MICROPHONE CLIP

Lancaster General Hospital has been using a Leksell Model No. 23005 Type "B" Gamma Knife since 2000. The Gamma Knife unit has a metal clip which is velcroed to the patient's couch and it holds a microphone in which the patient can talk. A patient knocked the clip off, causing the clip to become detached from the couch (it was velcroed to the couch) and the microphone. The clip ended up in the Gamma Knife shielding. Due to the metal clip being stuck in the Gamma Knife shielding, the micro switches inside the Gamma Knife would not allow the jaws of the shielding to open. This prevented the patient from receiving the third treatment. Therefore the patient received only 2 out of 5 scheduled treatments (patient was under dosed) due to the clip failure.

See event number 41928 called in by Lancaster General Hospital on 08/18/2005 for background information.

*** UPDATE FROM MONTAGNESE TO KNOKE AT 12:07 EDT ON 09/07/05 ***

The licensee discussed this event with Region 1 (Gabriel and Henderson). It was determined that this event did not meet 10 CFR 21.21 requirements and notification to the NRC under Part 21 was unnecessary. The notification for this medical event (EN 41928) is still in effect.

Notifications were provided to R1DO (Holody), R2DO (Moorman), R3DO (Cameron), R4DO (Powers), NMSS (Morell) and Part 21 NMSS (Essig).

AGREEMENT STATE - VEHICLE ACCIDENT WITH SPILLED SOURCE

The State provided the following information via facsimile:

"A well logging licensee notified the [Colorado Department of Health] on 8/26/05, that one of their well logging vehicles was involved in a roll-over accident in Colorado on Monday, 8/22/05, resulting in the spill of a small quantity of Scandium-46. No other vehicles or personnel were involved.

"The licensee, ProTechnics, of Trinidad, Colorado, License Number CO-545-01, stated that the accident occurred in a remote area on state highway 550, south of Ouray, Colorado. Emergency vehicles responded to the scene, and the driver was taken to a local hospital with minor injuries. The licensee sent additional personnel to the site with survey meters, and they assisted with the clean up. They reported that the shipping container was ejected from the vehicle, and broke open. They reported that they were able to clean up all of the spilled material, except for one spot that was reading 15 [millirem per hour] on contact. The spot was located in a remote area, several feet to the side of the road.

"No other details are available at this time.

"The Department has initiated an investigation of this incident, and arrangements are being made to perform a confirmatory survey of the area."