Event Notification Report for March 25, 2010

AUTOMATIC REACTOR SHUTDOWN DUE TO MAIN TURBINE TRIP

"At 1627 EDT on 3/25/10, the reactor mode switch was taken to shutdown following an automatic scram due to a main turbine trip. The scram was uncomplicated, and all control rods fully inserted into the core. The lowest reactor vessel water level reached was 136 inches, and as expected, HPCI & RCIC did not actuate. No safety relief valves (SRV) actuated. Reactor water level is being controlled in the normal band using the control rod drive and reactor feedwater systems. All isolations and actuations for reactor water level 3 occurred as expected.

"The cause of the Main Turbine Trip is under investigation.

"At the time of the scram all Emergency Core Cooling Systems and [Emergency Diesel Generators] EDGs were operable, and no safety related equipment was out of service."

The licensee notified the NRC Resident Inspector.

HIGH PRESSURE SAFETY INJECTION INOPERABLE DUE TO VOIDS IDENTIFIED IN SUCTION PIPING

"At 1028 CDT today 3/25/2010, a rejectable void was found in one of the suction lines (cooled suction line) to the B HPSI [High Pressure Safety Injection] pump. The main suction line is water filled. The piping was declared inoperable and the appropriate technical specification was entered. At 1357 CDT the void was cleared from the cooled suction line and the piping was declared operable. Subsequently, at 1409 CDT a similar rejectable void was discovered in the other cooled suction line for HPSI pumps A and C. The piping was declared inoperable. The appropriate technical specification was entered. At 1447 CDT the void was cleared and the piping was declared operable. Due to the close proximity of these occurrences the station is conservatively reporting this as a safety system functional failure as it appears that both trains of HPSI cooled suction were inoperable at the same time."

The licensee notified the NRC Resident Inspector.

* * * RETRACTION FROM ERICK MATZKE TO VINCE KLCO ON 5/24/10 AT 1517 EDT * * *

"Subsequent to making this event notification a detailed analysis of the event was performed by FAUSKE / Westinghouse Engineering. This evaluation determined the quantity of gas voiding in the piping, the duration of time the pump(s) would be subjected to gas voiding and potential effects on the piping support design loading. The hydraulic data was then reviewed by the HPSI pump manufacturer (Sulzer) to determine the effect on pump performance. Based on these evaluations, it has been determined that the HPSI pumps were not degraded, and that they were capable of performing their design basis function at all times and were operable. Therefore, this event does not meet the 10 CFR 50.72 reporting criteria and the notification is being retracted."

The licensee notified the NRC Resident Inspector. Notified the R4DO (Shannon).

HIGH HEAD SAFETY INJECTION INOPERABLE DUE TO VOIDS IDENTIFIED IN PIPING

"At 1540 on 3/25/2010, engineering identified a gas void in the Unit 4 B Cold Leg High Head Safety Injection (HHSI) pipe which exceeded the station's allowable gas accumulation acceptance criteria. This condition rendered the cold leg injection flow path inoperable and required entry into Technical Specification 3.0.3 at 1540. The void was immediately vented and Technical Specification 3.0.3 was exited at 1750."

The licensee notified the NRC Resident Inspector.

* * * UPDATE AT 0830 EDT ON 04/23/10 FROM MARK JONES TO S. SANDIN * * *

The licensee is retracting this report based on the following:

"At 2018 on 3/25/2010, an event notification (#45791) was reported to the NRCOC as follows:

"'At 1540 on 3/25/2010, engineering identified a gas void in the Unit 4 B Cold Leg High Head Safety Injection [HHSI] pipe which exceeded the station's allowable gas accumulation acceptance criteria. This condition rendered the cold leg injection flow path inoperable and required entry into Technical Specification 3.0.3 at 1540. The void was immediately vented and Technical Specification 3.0.3 was exited at 1750 [on 3/25/2010].'

"The decision to enter TS 3.0.3 was based on the plant procedural guidance and the results of ultrasonic testing.

"Following the discovery of the void, the failure investigation process required that an engineering evaluation be performed. The evaluation performed calculations to determine if, during a hypothetical HHSI pump start with the measured gas void present, the resulting water hammer conditions would cause the Unit 4 HHSI piping design pressure or Unit 4 HHSI piping supports design loading to be exceeded, thereby challenging the integrity of the Unit 4 HHSI discharge flow path to the reactor coolant system (RCS).

"The engineering evaluation determined that under the specific conditions in the Unit 4 HHSI piping on 3/25/2010:

"(1) Unit 4 HHSI piping design pressure would not have been exceeded should the HHSI pumps have started.

"(2) Unit 4 HHSI piping support design loading would not have been exceeded should the HHSI pumps have started.

"Therefore, the analysis of the void concluded that both the pipe and the support structural integrity would have withstood the pressure and axial loads due to the gas void and the HHSI system would have continued to perform its safety related function.

"The Unit 4 HHSI system discharge flowpath to the RCS remained operable at all times. Technical Specification 3/4.5.2, ECCS SUBSYSTEMS: Tavg GREATER THAN OR EQUAL TO 350 degrees F, Limiting Condition for Operation was satisfied at all times. Entry into Technical Specification 3.0.3 was not required at any time before or after the void discovery. The Unit 4 HHSI system remained capable of fulfilling the design safety function to mitigate the consequences of an accident on Unit 4, and an immediate notification to the NRCOC, discussed in 10 CFR 50.72(b)(3)(v)(D), was not required."

The licensee informed the NRC Resident Inspector. Notified R2DO (Ayres).

OFFSITE NOTIFICATION DUE TO PIPING LEAK THAT CANNOT BE CLEANED UP WITHIN 24 HOURS

The licensee made a 15 minute notification to the New Jersey Department of Environmental Protection due to a piping leak that cannot be cleaned up within 24 hours. The leak is on piping from the steam generator blowdown system to the non-radioactive waste bin and is leaking onto the asphalt beneath the piping. The leakage rate was approximately 1/2 gal/minute upon discovery but has since been stopped. There is no known primary to secondary leakage through the steam generator. No contact with the groundwater is suspected. The licensee has taken actions to divert leakage to the waste holdup system.

The licensee will be notifying authorities in the Lower Alloways Creek Township and the NRC Resident Inspector.

STANDBY GAS TREATMENT DECLARED INOPERABLE AFTER DISCOVERY OF OPEN DEMISTER DOOR

"System Affected: Standby Gas Treatment (SBGT)

"Condition: Demister Door Discovered open rendering both trains of SBGT INOP

"At 2255 [EDT] on 3/25/2010, a Demister Door on 'B' Train of Standby Gas Treatment (SBGT) was found open. The door was closed upon discovery. The door was opened during performance of a scheduled surveillance during the dayshift and it appears that the door was not closed at the completion of work. With this door being open the 'B' Train of SBGT was INOP. Due to the physical configuration of the SBGT System it cannot be immediately verified that the 'A' Train of SBGT would have been able to perform its Safety Related Function since there is a probability that it could have drawn suction through the demister door of the 'B' Train and a normally open crosstie between the Trains. A 10 CFR 50.72 notification is conservatively being made based on the information currently available.

"This condition has no impact on the health and safety of the public.

"Both trains of SBGT are currently operable."

The licensee informed the NRC Resident Inspector.

PROCESS GAUGE SHUTTER MALFUNCTION

The following information was received from the State of Nebraska via facsimile:

"The licensee uses fixed industrial gauges for measuring densities in fly ash hoppers at the station's precipitator building. The industrial gauges contain a Cesium 137 sealed source. The Cesium 137 sources were originally installed in 1975 and at the time contained 50 millicuries per source.

"The sources were manufactured and installed by Kay Ray Inc.

"The gauges are Model No. 7700-50.

"The licensee was attempting to close the shutter on the fixed gauge prior to performing maintenance. One of the external closure cables was found to be slightly bound up and only partially closed the 'internal' source shutter. The cable closure was reopened, which reopened the source shutter up at the sealed source. Closure was tried again. This time the cable, which connects the handle at the floor to the sealed source shutter mechanism 20 feet above, bent instead of sliding the cable to the closed position.

"This 'event' happened at 11:35 am and was reported to the station's Shift Supervisor who in turn contacted the plant electricians to make repairs so the precipitator 'tag-out' could continue. By 11:45 am the cable had been closed and the lab contacted to perform a survey to verify the source shutter was now in the closed position. No personnel were exposed to radiation during this event."

PART 21 INVOLVING A POTENTIAL WELD DEFECT

The following information was received via fax as a supplement to a report originally submitted to the NRC Document Control Desk:

"This is a supplement to the above subject Part 21 letter issued by Crane Nuclear, Inc. on March 25, 2010 and NRC ref. ML100920093.

"In the referenced letter, Crane Nuclear Inc., located at [860 Remington Boulevard, Bolingbrook, Illinois 60440], filed a 10CFR21 Notification of a Potential Weld Defect to the US Nuclear Regulatory Commission and also the affected customers. Copies of these letters were provided to the NRC.

"This letter is intended to supplement that initial notification letter by providing further details on when Crane Nuclear became aware of the issue and the potential safety hazard associated with the issue.

"During the NUPIC [Nuclear Procurement Issues Committee] Audit of Crane Nuclear the week of February 2, 2010 an audit finding was issued to Crane Nuclear for not effectively reviewing a customer complaint. The complaint was relative to a potentially undersized fillet weld and the audit finding documented that Crane Nuclear did not review the issue through to completion, or with regard to potentially affecting other customers. In response to the NUPIC Audit Finding, Crane Nuclear generated a Corrective Action Report (CAR) CAR 10-22 on 03/01/10. This CAR identified two required actions and they were: 1) Create a formal procedure that ensures all customer complaints are thoroughly investigated until they are complete and that Part 21 applicability is considered for the initial complaint and the potential it affects other customers; and, 2) Evaluate the complaint on the potentially undersized fillet weld to determine if Part 21 reporting is required.

"During that NUPIC Audit, Crane was asked to provide a statement relative to the potential defect or failure and the safety hazard which is created or could be created by a potentially undersized weld and the following statement was provided to the NUPIC Audit team and as of today this statement has been provided to the customers that received the initial notification - the following is the Statement that was provided to NUPIC and the notified customers:

"Assessment of Undersized Weld on Valve Safety Function

"Auxiliary connections on valve bodies, bonnets and covers are used for drains, vents or leak-off. The welds used to attach these connections are tested as part of the pressure boundary and subjected to ASME/ANSI hydrostatic test pressure (1.5 X cold working pressure). Because the pipe nipples used are short and fairly rigid, if the lines remained capped and not connected to a piping system it is unlikely that the combined stresses due to pressure and bending at the weld due to seismic accelerations would exceed the stress due to the pressure load applied during the hydrostatic test. However, a complete and instantaneous failure of the weld could result in a capped line becoming a missile and pressure boundary violation. If a line was connected to a piping system, if properly supported it is also unlikely the welded joint would see loads that would over stress the weld. However, if loads were generated at the welded connection that exceeded the strength of the weld a crack could be initiated and the pressure boundary violated.

"In response to the first required corrective action, Crane Nuclear created and released a robust customer complaint procedure CCP-1 titled, 'Customer Complaint Procedure.' This procedure requires a documented management review by the Customer Service Manager, Engineering Manager, Site Leader and Quality Director, for each and every customer complaint. The complaint form requires completion of a 'yes or no' check box that needs to be completed with respect to 10CFR21 applicability and it also has a 'yes or no' check box to document whether other customers are affected.

"In response to the second required action on the CAR, all Crane Nuclear designs with any kind of bleed off or other venting/leak type designs using fillet welds were isolated and each inspection 'as-built' record for each design and order were reviewed. The review of the 'as-built' inspection records confirmed that the fillet welds were in compliance with the drawing except for potentially those that were identified in the Part 21 notification referenced above. The review of all inspection documentation was completed on Friday March 19th and in accordance with our procedure the President was notified at 8:48PM that evening and the notification was completed on March 2, 2010. CAR 12-26 was later generated on 07/27/12 and closed on 08/21/12 for filing the report on the 6th day. If you have any further questions please contact [Rosalie Nava] at one of the following, phone 630-226-4940, email rnava@cranevs.com., or by fax 630-226-4646."

Affected licensees include Dominion, Duke Energy, Omaha Public Power District and TVA Nuclear.