05000483/LER-2005-001, Regarding Reactor Trip While Replacing RP043 Control Cabinet Power Supply
| ML050830259 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/18/2005 |
| From: | Sandbothe L AmerenUE |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| ULNRC05134 LER 05-001-00 | |
| Download: ML050830259 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4832005001R00 - NRC Website | |
text
AmerenUE CallawayPlant PO Box 620 Fulton, MIO 65251 March 18, 2005 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 ULNRC05134 wAmeren UFE Ladies and Gentlemen:
DOCKET NUMBER 50483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.
FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 2005-001-00 Reactor trip while replacing RP043 Control Cabinet Power Supply The enclosed licensee event report is submitted in accordance with I OCFR50.73(a)(2)(iv)(A) to report a reactor trip that occurred while replacing a power supply within Control Cabinet RP043.
This letter does not contain new commitments.
Sincerely, Louis S. Sandbothe Superintendent, Design Engineering LSS:EWH:slk Enclosure a
subsidiary ofAmeren Corporation
ULNRC05134 March 18, 2005 Page 2 Mr. Bruce S. Mallett 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 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360 Records Center Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, GA 30339
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06130/2007
~6-2004) the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Callaway Plant Unit 1 05000 483 1 OF 5
- 4. TITLE Reactor trip while replacing RP043 Control Cabinet Power Supply
- 5. EVENT DATE
- 6. LER NUMBE R
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR Y
SEQUENTIAL REV MONTH DAY YEAR FACILrTY NAME DOCKET NUMBER MONTH AY YEA YEAR NUMBER NO.
MNH DY YA FACILITY NAME DOCKET NUMBER 1
19 2005 2005 - 001 -
00 3
18 2005
- 9. OPERATING MODE 11.THIS REPORTISSUBMITTED PURSUANTTOT HE REQUIREMENTS OF 10 CFR§: (Check althatapply) o 20.2201(b) 0 20.2203(a)(3)(i) a 50.73(a)(2)(i)(C)
[I 50.73(a)(2)(vii) 1 0
20.2201(d) 0 20.2203(a)(3)(ii)
E 50.73(a)(2)(ii)(A)
[I 50.73(a)(2)(viii)(A) o 20.2203(a)(1)
El 20.2203(a)(4) 0 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B) 0l 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
E 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL
] 20.2203(a)(2)(ii) 01 50.36(c)(1)ii)(A) 0 50.73(a)(2)(iv)(A)
Dl 50.73(a)(2)(x)
El 20.2203(a)(2)(iii) 0 50.36(c)(2) a 50.73(a)(2)(v)(A)
El 73.71 (a)(4) 0 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
E 73.71 (a)(5) 100 0 20.2203(a)(2)(v)
[I 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
E OTHER 0
20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES At 1227, 1/18/05, an annunciator was received in the Callaway Control Room indicating a P/S had failed in one of the control cabinets. Investigation determined that the alarm was due to failure of the primary P/S in 7300 Control Cabinet RP043. After discussing the situation, the Shift Supervisor and Emergency Duty Officer decided to perform emergent on-line maintenance and replace the failed P/S supply on the following AM shift.
Using instructions from previous similar P/S replacements, a work package was created for replacement of the failed RP043 primary P/S. On the morning of 1/19/05, two formal pre-job briefs were conducted, one with the Instrument and Control (I&C) personnel performing the replacement, and a second involving the I&C personnel and Control Room staff. During the first l&C brief, OE16445 was discussed involving the use of a separation plate (commonly referred to as a skid plate) between the primary and secondary P/S. In the second brief with l&C and Control Room staff, major steps of the evolution were discussed as well as contingencies for the complete loss of the secondary power supply plus the need to manually trip the reactor should a loss occur.
When work commenced on the primary P/S replacement, it was determined that the work instructions did not identify that an air gap of approximately two inches existed between the upper primary P/S and the lower secondary P/S. At this point, work was stopped based upon concerns that the primary P/S should not be dropped onto the secondary P/S. It was identified that the space was approximately the same dimensions as a 'screw catcher" device normally used for Foreign Material Exclusion (FME) purposes.
Without revising the work instructions, it was decided to insert the screw catcher and skid plate in the air gap to support lowering the primary P/S while it was being removed. The screw catcher was placed onto the secondary P/S and the skid plate was placed on top of the screw catcher device. As the primary P/S was being removed and lowered onto the skid plate and screw catcher device, the screw catcher device exerted pressure on the secondary P/S top vented cover causing the cover to distort inward and momentarily short an energized heat sink within the secondary power supply. This caused a momentary power interruption from the secondary P/S [Manufacturer: North Electric Company, Model: PEC3569] and thus cabinet RP043. The momentary power interruption caused "A" Main Feedwater Regulating Valve to close, both Main Feedwater Pump speed controllers to decrease to minimum output, and the following control functions to revert to manual:
(if more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)
IV.
PREVIOUS SIMILAR EVENTS
The 1/1 8/05 failure of the 7300 Control Cabinet primary P/S was documented in Callaway Action Request (CAR) 200500322 and the ensuing reactor trip while replacing the failed P/S was documented in CAR 200500354.
A review of the Callaway Action Request System (CARS) was conducted to determine if any similar failures had occurred within the past three years. The search encompassed the time frame from 1/1/02 until the reactor trip on 1/19/05. Only one prior occurrence of a similar failure was identified. This failure is documented in CAR 200208057 and documents failure of the primary P/S in Protection Cabinet SB042.
On this occurrence, the failed primary P/S was successfully replaced while at power and without any consequences.
A review of LERs from 2002 until present did not reveal any similar events.
V.
ADDITIONAL INFORMATION
The system and component codes listed below are from the IEEE Standard 805-1984 and IEEE Standard 803A-1984 respectively.
System:
JG Component:
JX