05000425/LER-2005-001, Regarding High Flux at Shutdown Alarm Inoperable - Operation in a Condition Prohibited by the Technical Specifications
| ML052140129 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/01/2005 |
| From: | Grissette D Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-05-1296 LER 05-001-00 | |
| Download: ML052140129 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4252005001R00 - NRC Website | |
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Southern Nuclear Don E. Grissette Vice President Tel 205.992.6474 Fax 205.992.0341 August 1, 2005 Docket No.:
50-425 Operating Company, Inc.
40 lnverness Center Parkway Post Off ice Box 1295 Birmingham. Alabama 35201 SOUTHERN A COMPANY Energy to Serve Your World' U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 2 Licensee Event Report 2-2005-001 High Flux At Shutdown Alarm Inoperable - Operation In A Condition Prohibited By The Technical Svecifications Ladies and Gentlemen:
In accordance with the requirements of 10 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 June 2,2005.
Sincerely, Don E. Grissette Enclosure: LER 2-2005-00 1 cc:
Southern Nuclear Ooerating Company Mr. J. T. Gasser, Executive Vice President Mr. T. E. Tynan, General Manager - Plant Vogtle RType: CVC7000 U. S. Nuclear Regulator?, Commission Dr. W. D. Travers, Regional Administrator Mr. C. Gratton, NRR Project Manager - Vogtle Mr. G. J. McCoy, Senior Resident Inspector - Vogtle
LICENSEE EVENT REPORT (LER)
(See reverse for required number of On June 2,2005, Unit 2 was in Mode 5 (Cold Shutdown) and personnel were performing surveillance testing of neutron flux instrumentation. The high flux at shutdown alarm (HFASA) annunciator did not actuate when tested. At 0 1 15 EDT, it was found that both trains of the solid state protection system (SSPS) were in "input error inhibit," which rendered both channels of HFASA inoperable. Further review determined that this condition had existed since May 25,2005. Because the alarm was inoperable longer than the completion time for the required actions of Technical Specification (TS) LC0 3.3.8 Condition B, the unit had operated in a condition prohibited by the TS. Following the discovery of this event at 01 15 EDT, on June 2,2005, TS action requirements were met by 0417 EDT, and HFASA was returned to service at 1 100 EDT.
The cause of this event is the improper use of a procedure on May 25,2005, when SSPS was removed from service while the unit was shutdown. The procedure, 13503-2, "Reactor Control Solid State Protection System," did not have a section written specifically for placing both trains of SSPS in TEST.
A portion of the procedure section for de-energizing both trains of SSPS was used, thereby rendering both trains of HFASA inoperable. Procedures 13503-112 have been revised, other procedures utilizing SSPS
LICENSEE EVENT REPORT (LER)
Vogtle Electric Generating Plant - Unit 2 A. REQUIREMENT FOR REPORT This report is required per 10 CFR 50.73 (a)(2)(i)(B). The unit operated in a condition prohibited by the Technical Specifications (TS) when the high flux at shutdown alarm was inoperable for a period of time greater than that allowed by the action requirements.
B. UNIT STATUS AT TIME OF EVENT At the time of this event, Unit 2 was in Mode 5 (Cold Shutdown) at 0% of rated thermal power.
Other than that described herein, there was no inoperable equipment that contributed to the occurrence of this event.
C. DESCRIPTION OF EVENT
On May 25,2005, plant operators were attempting to remove the solid state protection system (SSPS) from service by placing it in TEST using procedure 13503-2, "Reactor Control Solid-State Protection System." Prior to disabling the SSPS, the operators realized that the procedure did not have a section written specifically for placing both trains of SSPS in TEST. A timeout was called to evaluate the available procedural guidance. After multiple reviews, the operating crew determined that it would be acceptable to use a section of the procedure that was written for de-energizing the solid-state protection system cabinets. This procedure section resulted in both trains of SSPS Input Error Inhibit Switches being in the INHIBIT position. Therefore, both channels of HFASA were disabled at 1016 EDT on May 25,2005 by placing the Input Error Inhibit Switches in INHIBIT.
On June 2,2005, personnel were performing surveillance testing of neutron flux instrumentation. The high flux at shutdown alarm (HFASA) annunciator did not actuate when tested. At 01 15 EDT, it was found that both trains of the solid state protection system (SSPS) were in "input error inhibit," which rendered both channels of HFASA inoperable. Further review determined that this condition hadexisted since May 25,2005, when SSPS was removed from service, as is normally the case when the unit is shutdown. With the Input Error Inhibit Switch of one train in the INHIBIT position, the Input Error Inhibit Switch of the other train must be in the NORMAL position in order for HFAS A to function.
Because the alarm was inoperable longer than the completion time for the required actions of Technical Specification LC0 3.3.8 Condition B, the unit had operated in a condition prohibited by the TS.
Following the discovery of this event at 01 15 EDT, on June 2,2005, TS action requirements were met by 0417 EDT, and HFASA was returned to service at 1100 EDT by placing the Input Error Inhibit Switch of one train of SSPS in the NORMAL position.
LICENSEE EVENT REPORT (LER)
Vogtle Electric Generating Plant - Unit 2
D. CAUSE OF EVENT
The cause of this event is the improper use of a procedure on May 25,2005, when SSPS was removed from service while the unit was shutdown. The procedure section that was used was written for de-energizing the solid-state protection cabinets, not for placing both trains of SSPS in TEST.
E. ANALYSIS OF EVENT
Had a high flux condition occurred with HFASA inoperable, redundant visual indication is available to control room operators that would have allowed them to take necessary actions. Additionally, no reactor coolant system dilutions occurred during the time HFASA was inoperable and shutdown margin verification was performed in accordance with the surveillance requirement of LC0 3.1.1. Based on these considerations, there was no adverse effect on plant safety or on the health and safety of the public as a result of this event.
This event does not represent a safety system functional failure.
F. CORRECTIVE ACTIONS
- 1) Upon discovery, actions were taken to comply with TS action requirements, and HFASA was restored to service shortly thereafter.
- 2) Procedures 13503-112 have been revised to address the proper disabling of both trains concurrently.
Procedure 12006-C will be revised by August 5,2005 to provide guidance to place SSPS in TEST while HFASA remains operable. Other procedures utilizing SSPS will be reviewed and revised by September 16,2005, to address the proper disabling of both trains concurrently.
- 3) By August 17,2005, this event will be addressed in licensed operator re-qualification training.
- 4) A broadness review was conducted of Condition Reports over the last three years and discussions were held with responsible personnel for repeat events. It was determined loss of both channels of HFASA has not occurred previously.
G. ADDITIONAL INFORMATION
- 1) Failed Components:
NRC FORM 386A (1-2001)
- 2) Previous Similar Events:
There have been no previous similar events in the past three years.
- 3) Energy Industry Identification System Code:
Solid State Protection System - JG