05000483/LER-2003-008, Regarding Technical Specification Violation Due to Valve Control Circuit Modification
| ML033180105 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 11/06/2003 |
| From: | Keith Young AmerenUE, Union Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| ULNRC-04913 LER 03-008-00 | |
| Download: ML033180105 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4832003008R00 - NRC Website | |
text
AmerenUE CalIaway Plant PO Box 620 Fulton, MIO 65251 November 6, 2003 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 ULNRC-049 13 WAmleren Uff Ladies and Gentlemen:
DOCKET NUMBER 50-483 Callaway PLANT UNIT 1 UNION ELECTRIC CO.
FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 2003-008-00 Technical Specification violation due to valve control circuit modification.
The enclosed licensee event report is submitted in accordance with I OCFR50.73(a)(2)(i)(B) to report a violation of Technical Specifications when implementing a modification to the valve control circuitry for a pressurizer power operated relief valve block valve.
Very truly yours, d M 6E?44-Keith D. Young
- Manager, Regulatory Affairs KDY/JER/slk Enclosure a subsidiary ofAmeren Corporation
K ULNRC-04913 November 6, 2003 Page 2 cc:
Mr. Bruce S. Mallet Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)
Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 7E1 Washington, DC 20555-2738 Manager, Electric Department Missouri Public Service Commission PO Box 360 Jefferson City, MO 65102 Records Center Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, GA 30339
Abstract
On 9/4/03 with Callaway in Mode 1 at 100 percent power, a modification to replace the handswitch for "B" Pressurizer (Pzr) Power Operated Relief Valve Block valve (BBHV8000B) was implemented. During post modification testing, the valve operator and control breaker were damaged. The modification required removal of a wire which had not been specified by the modification work instructions. Repairs were performed and the valve control circuitry was restored to pre-modification conditions. The reportable condition occurred 917/03 when the Technical Specification Required Actions were not met within the associated Completion Time. Interim corrective actions restrict planning of motor operated valve control circuit work documents. Long term corrective actions include strengthening the training and qualification process for the planning of motor operated valve modification work documents.
NRC; FORM 366 ([-ZU01)
(if more space is required, use additional copies of SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On 9/4/03, with Callaway in Mode 1 at 100 percent power, a modification was implemented to install a new hand switch for BBHV8000B, "B" Pressurizer (Pzr) Power Operated Relief Valve (PORV) Block valve. This modification would have resulted in a seal-in circuit for the momentary OPEN function of the handswitch and a maintained contact circuit for the CLOSED function. Following post modification testing, an on-coming Reactor Operator noted the OPEN indication for BBHV8000B was not lit. It was determined that breaker NG02BDF1 for BBHV8000B had tripped.
Subsequent investigation determined the thermal overload relays for NG02BDF1 (the valve's motor operator power supply) and limit switches for BBHV8000B were damaged. The modification package required a jumper wire be removed, but was not addressed in the work instructions. Because of this oversight, the valve control circuit modification was completed with the jumper wire still installed.
With the jumper wire installed, a continuous OPEN signal for BBHV8000B resulted anytime hand switch BBHIS8000B was in the AUTO or OPEN position. The jumper wire also bypassed the open limit switch and open torque switch for the Limitorque actuator. When the valve was stroked open, stem travel was stopped by engagement of the valve's backseat while the Limitorque motor remained energized as it tried to open the valve further. The constantly energized motor overheated resulting in short-circuiting the motor windings. The increased valve stem travel also caused the valve limit switches to be damaged. Inspection of the breaker cubicle revealed damaged overload relays. The power cables were megger tested and found to be undamaged.
BBHV8000B had been declared Inoperable at 0601 on 9/4/03 to implement the hand switch modification. The associated Technical Specification 3.4.11 Required Action was to restore the valve to OPERABLE status within the Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. It was determined that (if more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17) safety (i.e., reduced core damage frequency). Therefore, there were no adverse safety consequences as a result of the additional time in the Action Statement as discussed in the NOED submittal.
III.
CAUSE OF THE EVENT
A formal Root Cause Analysis team was assembled to review this event. The root cause of this event was determined to be lack of adequate work instructions in the modification work package.
IV.
CORRECTIVE ACTIONS
Interim corrective actions restrict planning of motor operated valve control circuit work documents. Long term corrective actions include strengthening the training and qualification process for the planning of motor operated valve modification work documents.
V.
PREVIOUS SIMILAR EVENTS
A search of the Callaway Action Request System (CARS) was performed to identify previous CARs related to this issue. No previous similar events were identified.
A review of LERs submitted from September, 2000 until present did not reveal any similar LERs.
VI.
ADDITIONAL INFORMATION
The system and component codes listed below are from the IEEE Standard 805-1984 and IEEE Standard 803A-1984 respectively.
System:
Component:
AB ISVNRC FORM 366A (1-2001)