05000341/LER-2010-004, High Pressure Coolant Injection System Inoperable Due to Inoperable Minimum Flow Valve
| ML110560220 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 02/23/2011 |
| From: | Plona J Detroit Edison |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NRC-11-0003 LER 10-004-00 | |
| Download: ML110560220 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(iv)(A), System Actuation 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)(i)(B), Prohibited by Technical Specifications |
| 3412010004R00 - NRC Website | |
text
Joseph H. Plona Site Vice President 6400 N. Dixie Highway, Newport, MI 48166 Tel: 734.686.5910 Fax: 734.586.4172 10 CFR 50.73 February 23, 2011 NRC-11-0003 U. S. Nuclear Regulatory Commission Attention: Document Control Desk WashingtonD C 20555-0001
Reference:
Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43
Subject:
Licensee Event Report (LER) No. 2010-004 Pursuant to 10 CFR 50.73(a)(2)(v)(D), Detroit Edison is submitting the enclosed LER No. 2010-004. This LER documents the December 28, 2010 loss of the High Pressure Coolant Injection System due to an inoperable minimum flow valve.
No commitments are being made in this LER.
Should you have any questions or require additional information, please contact Mr. Rodney W. Johnson of my staff at (734) 586-5076.
Sincerely, Enclosure cc: NRC Project Manager NRC Resident Office Reactor Projects Chief, Branch 4, Region III Regional Administrator, Region III Supervisor, Electric Operators, Michigan Public Service Commission
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: No, 3150-0104 Expires 10/31/2013 (10-2010)
, 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 Fermi 2 05000341 1 OF 3
- 4. TITLE High Pressure Coolant Injection System Inoperable Due To Inoperable Minimum Flow Valve
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED iSEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR 05000 12 28 2010 2010 004 00 02 23 2011 FACILITYNAME DOCKETNUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT SUBMITTED PURSU ANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
E 20.2201(b)
O 20.2203(a)(3)(i) 0 50.73(a)(2)(i)(C)
O 50.73(a)(2)(vii) 1 20.2201 (d) 20.2203(a)(3)(ii) 5 50.73(a)(2)(ii)(A) 5 50.73(a)(2)(viii)(A)
D 20.2203(a)(1)
J 20.2203(a)(4) 50.73(a)(2)(ii)(B)
O 50.73(a)(2)(viii)(B)
O 20.2203(a)(2)(i)
[
50.36(c)(1)(i)(A)
O 50.73(a)(2)(iii) 5 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 0 20.2203(a)(2)(ii)
E 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 0 50.73(a)(2)(x)
O 20.2203(a)(2)(iii) 50.36(c)(2)
O 50.73(a)(2)(v)(A) 73.71 (a)(4) 75 l 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 0 50.73(a)(2)(v)(B) 0 73.71 (a)(5) j 20.2203(a)(2)(v)
[
50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(C)
D OTHER
]
20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THS LER FACILITY NAME TELEPHONE NUMBER (Include Area Code)
Rodney W. Johnson - Manager, Nuclear Licensing (734) 586 - 5076CAUSE SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX B
BJ CNTR G082 Yes
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED M
TH DAY Y
SUBMISSION MONTH DAY YEAR SUBMISSION L YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
E NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On December 28, 2010, during the HPCI turbine trip portion of a HPCI surveillance test, the HPCI minimum flow valve open and close indicating lights in the control room began blinking simultaneously. After a short duration (approximately 1 minute) the blinking faded and both indicators went out at 1220 EST. The HPCI minimum flow valve did not fully close as expected. Upon discovery of the problem and performance of minor troubleshooting, Operations determined that the ability of the HPCI minimum flow valve to perform its intended function was unreliable, and the valve was declared inoperable at 1220 EST. System troubleshooting, diagnostic testing, and analysis were performed, and components were identified that could be responsible for the problem. These components were replaced. Post maintenance testing was successfully completed on December 30, 2010 at 1027 EST. The HPCI minimum flow valve was closed, the system returned to service, and the LCO cleared December 30, 2010 at 1042 EST. Subsequent evaluation determined that the valve failure was caused by the close contactor, auxiliary contact alignment or high resistance, or high resistance connections. Those problems were corrected prior to returning HPCI to service. The safety consequences of this event were evaluated and determined to be low.
NRC FORM 366 (10-2010)
Initial Plant Conditions
Mode 1
Reactor Power 75 percent Description of the Event On December 28, 2010 at approximately 0950 EST the quarterly High Pressure Coolant Injection (HPCI) [BJ]
system surveillance procedure was released for performance. The system and the minimum flow valve (E4150F012) performed as expected during the startup of the HPCI System.
During the HPCI turbine trip portion of the surveillance, however, the HPCI minimum flow valve open and close indicating lights in the control room began blinking simultaneously. After a short duration (approximately 1 minute) the blinking faded and both indicators went out at 1220 EST. The HPCI minimum flow valve did not fully close as expected. Operations manually operated and closed the valve. Upon discovery of the problem and performance of minor troubleshooting, Operations determined that the ability of the HPCI minimum flow valve to perform its intended function was unreliable, and the valve was declared inoperable at 1220 EST. With an inoperable minimum flow valve, the system may not have been able to perform its intended function since the valve is relied upon for pump protection under low flow and high discharge pressure conditions that accompany system startup.
System troubleshooting, diagnostic testing, and analysis were performed, and a number of components were identified that could be responsible for the problem. These components were replaced. Post maintenance testing was successfully completed on December 30, 2010 at 1027 EST. The HPCI minimum flow valve was closed, and the system returned to service on December 30, 2010 at 1042 EST.
Significant Safety Consequences and Implications
The HPCI system, a single train safety system, was rendered inoperable when the operation of the HPCI minimum flow valve was determined to be unreliable and the valve was declared inoperable. The purpose of the HPCI system is to provide emergency core cooling in the event of an accident involving loss of coolant from a small break. Reactor steam is used to drive the HPCI turbine, which in turn drives the main and booster pumps to provide a source of high pressure water to the reactor. The Reactor Core Isolation Cooling [BN] and Standby Feedwater [SJ] systems remained available for high pressure injection in the event of an emergency. Additionally, the Automatic Depressurization System [JE] was available to reduce reactor pressure to within the capabilities of the low pressure Emergency Core Cooling Systems.
This event resulted in approximately 46-hours where HPCI was inoperable. Technical Specification 3.5.1 allows HPCI to be taken out of service for planned outages for up to 14 days. This risk increase associated with HPCI being out of service for approximately 46-hours has been evaluated by the Probabilistic Safety Analysis (PSA) group and determined to be low.U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE YEAR SEQUENTIAL REVISION Fermi 2 05000341 1
NUMBER NUMBER 3 OF 3 2010 004 00 This report is made in accordance with 10 CFR 50.73(a)(2)(v)(D), for any event or condition that could have prevented the fulfillment of a safety function of structures or systems that are needed to mitigate the consequences of an accident. An eight-hour non-emergency notification was made pursuant to 10 CFR 50.72(b)(3)(v)(D) as a condition that at the time of discovery could have prevented the fulfillment of a safety function to mitigate the consequences of an accident based on loss of a single train safety system (EN 46515).
Cause of the Event
A number of potential causes were identified related to the HPCI minimum flow valve. The potential causes that were not ruled out by troubleshooting and failure analysis were the close contactor, auxiliary contact alignment or high resistance, and high resistance connections (power fuse clip, loose leads).
Corrective Actions
The close contactor was replaced. The auxiliary contacts were removed, inspected and cleaned, and proper operation verified following installation. Circuit leads were inspected and tightened, and power fuse tightness verified during fuse replacement. This event has been documented in the Fermi 2 Corrective Action Program and additional actions may be taken as determined by the program.
Additional Information
A.
Failed Component:
Component: Contactor Function: Controls power to the valve actuator motor Manufacturer: General Electric Model Number: CR305T026 Failure Cause: Internal contactor failure B.
Previous LERs on Similar Problems:
There are no other LERs on similar problems noted within the past five years