05000425/LER-2007-001, Regarding RWST Sludge Mixing Valves Was Determined to Be in a Condition Which Was Prohibited by TS
| ML070580545 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 02/27/2007 |
| From: | Tynan T Southern Nuclear Operating Co |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| NL-07-0441 LER 07-001-00 | |
| Download: ML070580545 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4252007001R00 - NRC Website | |
text
Tom Tynan Southern Nuclear Vlce Pres~dent - Vogtle Operating Company, lnc.
7821 Rlver Road Waynesboro, Georg~a 30830 Tel 706.826 3151 Fax 706.826.3321 February 27,2007 Docket No.:
50-425 SOUTHERN A COMPANY E n e r a to Serve Your World '
U. S. Nuclear Regulatory Commission ATI'N: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 2 Licensee Event Report 2-2007-00 1 RWST Sludge Mixing System Valves in a Condition Prohibited bv TS Ladies and Gentlemen:
In accordance with the requirements of I0 CFR 50.73, Southern Nuclear Operating Company hereby submits a Vogtle Electric Generating Plant licensee event report for a condition that was determined to be reportable on January I, 2007.
This letter contains no NRC commitments. If you have any questions, please advise.
Sincerely, Tom E. Tynan Vice President - Vogtle Vogtle Electric Generating Plant 782 1 River Road Waynesboro, GA 30830 Enclosure: LER 2-2007-00 1 cc:
Southern Nuclear Operating Companv Mr. J. T. Gasser, Executive Vice President Mr. D. H. Jones. Vice President - Engineering RType: CVC7000 U. S. Nuclear Regulatorv Commission Dr. W. D. Travers, Regional Administrator Mr. B. K. Singal. NRR Project Manager - Vogtle Mr. G. J. McCoy, Senior Resident Inspector - Vogtle
Enclosure Vogtle Electric Generating Plant - Unit 2 Licensee Event Report 2-2007-00 1 RWST Sludge Mixing System Valves in a Condition Prohibited by TS
LICENSEE EVENT REPORT (LER) 20503. If a means used to impose an information (See reverse for required number of digitslcharacters for each block)
SUBMISSION On January 1, 2007 at 13 10 EDT, while at 100% power, Unit 2 Refueling Water Storage Tank (RWST) sludge mixing valves 2HV-10957 and 2HV-10958 were discovered to have been inoperable for 24 days, placing them in a condition prohibited by Technical Specification (TS). The subject valves were placed in the jack open position and tagged using a clearance to facilitate maintenance on another component. The clearance was returned to the control room, and signed off as removed. Operability was determined by stating that the tagout had been released and the LC0 was exited. This determination of operability was incorrect and left the valves inoperable for 24 The primary cause of this event was no procedural guidance was given to verify the valves were operable following being placed on the manual jack. A contributing factor was inadequate use of human performance tools. The operator removing the clearance and the independent verifier did not have a clear understanding of how the jack worked for these valves and made an incorrect assumption of how these valves operated. Other contributing causes included the pre-job brief was not held prior to the release of the tagout, and the discussion about the valves in the clearance concerning their current position or the required position had little detail and was unclear to the
A. REQUIREMENT FOR REPORT This report is required per 10 CFR 50.73 (a)(2)(i)(B), any operation or condition which was prohibited by Technical Specifications (TS). TS LC0 3.5.4 requires these valves to automatically close on an Refueling Water Storage Tank (RWST) low-level signal, and the valves were incapable of closing.
B. UNIT STATUS AT TIME OF EVENT The RWST sludge mixing valves were determined to have been in a condition prohibited by TS on January 1,2007 at 13 10 EDT. At the time of the event, Unit 2 was at 100% power.
C. DESCRIPTION OF EVENT
Unit 2 RWST sludge mixing valves 2HV-10957 and 2HV-10958 were placed in the jack open position and tagged using a clearance to help facilitate maintenance on another component. After maintenance was completed, the tagout was released and operations performed an independent verification on the valves.
The first operator did not Mly understand the term "Available Ensure Off the Jack" as stated on the clearance release sheet. The operator assumed that this meant the hand wheel on the valve needed to be full up. Also, he was not aware that the jacks on these valves hold them open.
When the second operator independently verified the position of the valves, he made the same assumption as the first operator. He turned the hand wheel to the closed position to verify the valve was open and then returned the hand wheel to full open. The clearance was returned to the control room, and signed off as removed. Operability was determined by stating that the tagout had been released and LC0 2-2006-157 was exited. This determination of operability was incorrect and left the valves inoperable for 24 days. On January 1, 2007 surveillance 14825-2 was attempted and valves 2HV-10957 and 2HV-10958 did not stroke. This is when the valves were discovered jacked open, and were removed from the jack returning them to operable status.
D. CAUSE OF EVENT
The primary cause of this event was no procedural guidance was given to verify the valves were operable following the valves being placed on the jack.
(If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)
- 4. "Operation of valves with Jacks will be included as part of the Initial and Continuing core tasks for licensed and non-licensed operators. Estimated to be included by May 23,2007.
G. ADDITIONAL INFORMATION
I 11 None
- 2) Failed Components:
None
- 3) Previous Similar Events:
None
- 4) Energy Industry Identification System Codes:
Chemical and Volume Control Makeup and Purification System - CB High Pressure Safety Injection System - BQ Residual Heat Removal 1 Low Pressure Safety Infection System - BP Containment Spray System - BE cNRC FORM 266 (6-2004)