05000354/LER-2009-003
| Docket Numbersequential Revmonth Day Year Year Month Day Yearnumber No. N/A | |
| Event date: | |
|---|---|
| Report date: | |
| Initial Reporting | |
| ENS 45048 | 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material |
| 3542009003R00 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
General Electric — Boiling Water Reactor (BWR/4) Incore Monitoring System — EIIS Identifier {IG}* Isolation Valve — EIIS Identifier {ISV} *Energy Industry Identification System {EIIS} codes and component function identifier codes appear as {SS/CCC}
IDENTIFICATION OF OCCURRENCE
Event Date: May 6, 2009 Discovery Date: May 8, 2009
CONDITIONS PRIOR TO OCCURRENCE
Hope Creek was in Operational Condition 1 during the startup from refueling outage 15. The TIP machines were being used to calibrate the local power range monitors (LPRMs) in the reactor core in accordance with procedure HC.RE-SO.SE-0001, "Traversing Incore Probe System Operation". No structures, systems or components were inoperable at the time of discovery that contributed to the event.
DESCRIPTION OF OCCURRENCE
At 0817 on May 8th 2009, an instrument and controls (I&C) technician noted that the TIP containment isolation valve indications for four of the five TIP detector machines (A, C, D, E) in the control room indicated open with the machines de-energized. Upon investigation, the operations crew energized the machines and discovered that four of the five machines had their TIP detectors at the indexer position which is inside primary containment. The containment isolation valves were open and the required position for the valves with the machines de-energized is closed.
During performance of the LPRM calibration on May 6, 2009, at approximately 70% CTP, a RE operated the TIP machines in accordance with procedure HC.RE-SO.SE-0001 to obtain the core performance data for HC.RE-ST.SE-0003, "LPRM Calibration Surveillance". The RE was accompanied by a trainee who was observing the performance and assisting. The RE Manager was initially in the area and left after the procedure prerequisites were completed. The RE Manager returned to review the TIP data obtained.
The RE performing the TIP machine operations began placekeeping the procedure steps performed, but did not effectively maintain placekeeping as the machines were operated through repetitive steps.
At one point, the RE left the TIP machines to go to the computer room and verify that the TIP information was acceptable and in the correct format for l&C to use to complete the LPRM gain adjustments. The RE Manager also ensured the data was correct and instructed the RE to secure the TIP machines. Upon his return, the RE did not recognize where he was in the procedure due to his not performing adequate placekeeping during the earlier activities.
� The RE did not consult with the RE Manager on the procedure when he realized that he had lost his place.
The RE did not use available human performance tools to address the error likely situation he had placed himself in, such as OOPS {Outside of Procedures, Parameters or Processes}.
The RE proceeded to a step he believed would secure the TIP machines. In doing so, the RE did not perform the steps that would fully withdraw the detectors and verify that they were at the 'in shield' position with the isolation valves closed. Thus, when the machines were secured, the TIP isolation valves were still in the open position with the detectors at the indexers.
After discovery and verification of the TIP system configuration, the operations crew contacted RE to address the condition. The REs energized the TIP machines, withdrew the four detectors, closed the associated isolation valves and secured the TIP machines. It was determined that the TIP machines were inappropriately secured on May 6, 2009 at 1146, and thus the isolation valves were open for approximately 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
SAFETY CONSEQUENCES AND IMPLICATIONS
The safety consequence of this event was minor in that no containment isolation signals occurred during the time the isolation valves were inoperable. Even though the automatic containment isolation function would not have fully isolated the penetrations, a backup manual system was available to fully isolate the penetrations if needed.
The TIP system contains 'shear' valves that are used to manually isolate the penetrations. These consist of one explosive-operated valve per penetration that forces a metal wedge into the penetration opening which will cut the TIP cable and close the penetration. The licensed operators are trained to use the shear valves to complete the isolation if the normal isolation valves do not fully shut. Thus the ability to isolate these penetrations was not lost. Manual action would have been required by the licensed operators from the control room to complete the isolation should one have been required. This action is directed by the system abnormal procedures and is included in the licensed operator training program.
The TIP system consists of a 'dry tube' that passes into the containment, through the indexer and to the reactor core. The dry tube is designed to maintain integrity during plant operations and operational transients. If a containment isolation was required and the isolation valve did not fully close on any
- penetration, the procedures would then direct the operation's crew to use the shear valves for any open TIP penetration to complete the containment isolation.
Due to the availability of the redundant (manual) system and the training and procedures directing its use, there was no danger to the health and safety of the public from this event.
_ The operating crew reported this event under ENS number 45048 on May 8, 2009 citing 10 CFR 50.72 (b)(3)(v). As explained above and in the ENS notification, this event did not defeat the containment isolation function of the TIP system, it only affected the automatic isolation feature. There were manual means to isolate the penetrations for which the procedures are in place and operations personnel are trained to perform if an automatic isolation does not occur. As the notification states, "The explosive shear valves are manually actuated per operations abnormal procedures should a ball valve not close during accident conditions and remained operable throughout the time the ball valves were impaired.
A review of this event determined that a Safety System Functional Failure (SSFF) has not occurred as defined in Nuclear Energy Institute (NEI) 99-02.
CAUSE OF OCCURRENCE
A root cause evaluation (RCE) was performed (corrective action program (CAP) number: 70097765) and determined that one root cause was that the RE did not secure the TIP machines in accordance with the applicable steps of the procedure. The RE failed to effectively use the applicable human performance tools of placekeeping and OOPS in that when the RE realized that he did not know where he left off in the procedure, he proceeded to a step that was not applicable for the TIP system configuration. A contributing cause was that no formal pre-job brief was held for this evolution because the REs considered operating the TIPs a routine evolution.
By securing the TIP machines without first withdrawing the TIPs back to their shielded location in the TIP Room, the RE inadvertently set up a condition that would have prevented the TIP isolation ball valves from fully closing upon receipt of a containment isolation signal.
The RCE identified a second root cause in that operations crews did not realize that the isolation valves were not in the required position for the plant conditions. It was determined that there was a reliance of Operations personnel on the RE Department's history of operating the TIP system, such that the configuration of the TIP system was not questioned by the Control Room crews. The RE's operation of the TIP system was independent of the operating crew and occurred at various times and frequencies. This led to an acceptance of TIP system configuration being controlled by the REs instead of by the operating crew. Another factor is that during a plant startup through 100% CTP equilibrium conditions, TIPs are run multiple times for periods of varying duration. It is not unusual for the TIP isolation valves to remain open for extended periods of time during a startup. With the TIP system energized, the TIP detectors will automatically withdraw upon a containment isolation signal and the isolation valves will automatically shut.
PREVIOUS OCCURRENCES
A review of the past three years of events did not reveal an instance where poor human performance traits led to the TIP containment isolation valves being left open.
� A review of the past three years of events revealed no adverse trends in control room monitoring of containment isolation valves or other static monitoring of configuration parameters. Several TIP notifications were identified; however they did not involve improper control board monitoring or improper procedure use:
On 11/12/2007 the D TIP probe was stuck just past the 'in shield' position and could not be inserted or retracted. (CAP number 70076720) On 11/14/2007 the D TIP detector was found to be at the 'core top' location after a tagging problem was noted with the TIP machine. After the tag was cleared the RE noted that the TIP detector had moved to the top of the core from the 'in shield' position. (CAP number 70076866)
CORRECTIVE ACTIONS
The following corrective actions to preclude recurrence have been identified from the RCE:
(1) Add independent verification to HC.RE-SO.SE-0001, "Traversing Incore Probe System Operation", for verification of the TIP machine status (probe at the "in shield" position with the isolation valve closed) prior to securing the TIP system.
(2) Add a control room operations staff verification of the status of the TIP isolation valves after securing the TIP machines.
(3) Add a requirement to log on and log off HC.RE-SO.SE-0001 in the Operations Shift Narrative Log.
(4) Add requirement for RE to have a pre-job brief with Operations prior to implementing HC.RE-SO.SE 0001.
The following additional corrective actions have been identified:
(1) Review, and revise as necessary, the RE certification guides and determine if any require oral boards or OJT/TPE to demonstrate the application of knowledge and which ones should have specific situational performance standards.
(2) Review the completed certification guides for REs and determine if oral boards are required for previously qualified REs.
(3) RE group will attend Human Performance Training including dynamic learning activities (DLA) for procedure use and adherence.
(4) RE Manager and Operations Director to meet on periodic basis to discuss RE group needs and oversight.
(5) Ensure the identified issue of operations control board awareness is included in existing training evaluation to reinforce rigor of standards — operations fundamentals.
(6) The Operations Director shall interview REs as part of their qualification process.
COMMITMENTS
This LER contains no commitments.
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