05000410/LER-2009-001, Regarding Momentary Loss of Control Power to High Pressure Core Spray Pump Due to Degraded Fuse Block Connection
| ML093020117 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 10/22/2009 |
| From: | Lynch T Constellation Energy Nuclear Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 09-001-00 | |
| Download: ML093020117 (7) | |
| 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 |
| 4102009001R00 - NRC Website | |
text
Thomas A. Lynch Plant General Manager P.O. Box 63 Lycoming, New York 13093 315.349.5205 315.349.1321 Fax Constellation Energy Nine Mile Point Nuclear Station October 22, 2009 U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
SUBJECT:
Document Control Desk Nine Mile Point Nuclear Station Unit No. 2; Docket No. 50-410 Licensee Event Report 2009-001, Momentary Loss of Control Power to High Pressure Core Spray Pump Due to Degraded Fuse Block Connection In accordance with 10 CFR 50.73(a)(2)(v)(D), please find attached Licensee Event Report 2009-001, Momentary Loss of Control Power to High Pressure Core Spray Pump Due to Degraded Fuse Block Connection.
There are no regulatory commitments in this submittal.
Should you have questions regarding the information in this submittal, please contact T. F. Syrell, Licensing Director, at (315) 349-5219.
Very truly yours, TAL/RJC
Attachment:
Licensee Event Report 2009-001, Momentary Loss of Control Power to High Pressure Core Spray Pump Due to Degraded Fuse Block Connection cc:
S. J. Collins, NRC R. V. Guzman, NRC Resident Inspector, NRC
ATTACHMENT LICENSEE EVENT REPORT 2009-001 MOMENTARY LOSS OF CONTROL POWER TO HIGH PRESSURE CORE SPRAY PUMP DUE TO DEGRADED FUSE BLOCK CONNECTION Nine Mile Point Nuclear Station, LLC October 22, 2009
T, ONRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)
, the NRC may not conduct digits/characters for each block) or sponsor, and a person is not required to respond to, the information digis/carater foreac blck)collection.
j3. PAGE Nine Mile Point Unit2 05000410.
1 OF 5
- 4. TITLE Momentary Loss of Control Power to High Pressure Core Spray. Pump Due to Degraded Fuse Block Connection
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEUENT REVMONTH DAY YEARIS ETA
'FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEARSEUNILRVM TH DY EA NUMBER NO.
NA NA FACILITY NAME DOCKET NUMBER 08 23 2009 2009 001 00 10 22 2009 NA NA
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) 0 20.2201(b) 0 20.2203(a)(3)(i)
[3 50.73(a)(2)(i)(C)
[l 50.73(a)(2)(vii)
[1 20.2201(d)
EC 20.2203(a)(3)(ii)
EC 50.73(a)(2)(ii)(A)
EC 50.73(a)(2)(viii)(A)
[C 20.2203(a)(1)
EC 20.2203(a)(4)
EC 50.73(a)(2)(ii)(B)
EC 50.73(a)(2)(viii)(B)
[_ 20.2203(a)(2)(i)
[I 50.36(c)(1)(i)(A)
EC 50.73(a)(2)(iii)
EC 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL [J 20.2203(a)(2)(ii)
EC 50.36(c)(1)(ii)(A)
EC 50.73(a)(2)(iv)(A)
EC 50.73(a)(2)(x)
[C 20.2203(a)(2)(iii)
EC 50.36(c)(2)
[3 50.73(a)(2)(v)(A) 0 73.71(a)(4)
[] 20.2203(a)(2)(iv)
EC 50.46(a)(3)(ii)
EC 50.73(a)(2)(v)(B)
EC 73.71(a)(5) 100 E] 20.2203(a)(2)(v)
EC 50.73(a)(2)(i)(A)
E3 50.73(a)(2)(v)(C)
EC OTHER C 20.2203(a)(2)(vi)
EC 50.73(a)(2)(i)(B) 0 50.73(a)(2)(v)(D)
Specify in Abstract below or in
D. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES
August, 23, 2009:
0915 HPCS loss of power annunciators were received in the control room:
091525 HPCS System INOP 091525 BKR102-2 DN/NO CONT PWR ALARM 091526 HPCS System ALMCLR 091526 BKR102-2 DN/NO CONT PWR ALMCLR 1715 Troubleshooting revealed that the contact gap for one of the receiver connections internal to the stationary section of the CLOSE fuse block was wider than the other 3 receiver connections. The HPCS system was declared inoperable per Technical Specification 3.5.1.
2043 The fuse block connection was repaired by readjusting the receiver connection. HPCS was returned to standby and the HPCS pump was declared inoperable, but available.
2046 The HPCS pump was run and then restored to operable status.
E. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED
None.
F. METHOD OF DISCOVERY
The fuse connection degradation was first suspected in the control room due to the two HPCS annunciators activating for 1 second.
G. MAJOR OPERATOR ACTION:
An operator was dispatched to the Division 3 switchgear room to investigate the cause of the alarms. After repairs were completed, the HPCS pump was run to verify operability.
H. SAFETY SYSTEM RESPONSES:
There were no safety system responses during this event and none were required.
II. CAUSE OF EVENT
The cause of this event is omission of relevant information from maintenance procedures.
In February, 1978, General Electric issued a Service Advisory Letter (SAL), SAL 322.1, "Type NEC Fuse Holders 30 Amp and 60 Amp," in order to address the potential for loose fuse holders. NMP1 does not use this type of fuse holder, but NMP2 uses them in the 4.16 kV and 13.8 kV switchgear. The SAL was reviewed by Condition Report (CR) 1998-0790, but one recommendation was not incorporated into the maintenance procedures for high voltage switchgear breakers.
Repeated removal and installation of the close fuses for the HPCS breaker resulted in the contact gap of one of the receiver connections within the stationary fuse block to be wider than it should have been. This caused the removable portion of the fuse block connection to not engage the stationary side properly. Had the adjustments recommended in the SAL been incorporated into the maintenance procedure for the HPCS breaker, the contact gap would have been adjusted at the last performed preventive maintenance evolution.
NMP CR 2009-005044 applies to this LER.
II1. ANALYSIS OF THE EVENT:
This event is reportable in accordance with 10 CFR 50.73(a)(2)(v)(D) which states that any event or condition that could have prevented the fulfillment of the safety system function of structures or systems that are needed to mitigate the consequences of an accident is reportable.
The HPCS system circuit issue revealed itself at 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br /> when the annunciators in the control room activated for one second. The HPCS system was declared inoperable 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> later at 1715 hours0.0198 days <br />0.476 hours <br />0.00284 weeks <br />6.525575e-4 months <br /> when it was determined that the HPCS fuse connection was degraded. The system was declared inoperable, but available, at 2043 when the circuit was re-energized. The HPCS pump was run with no further alarms and at 2046 the HPCS system was declared operable. The HPCS system was inoperable for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> and 31 minutes.
There were no other systems inoperable and no other system failures related to this event. There were no actual safety consequences for this event. HPCS is designed to provide a high pressure injection source to the reactor when required, including a LOCA (Loss of Coolant Accident). Throughout this event, the reactor was stable at 100% power. Had a LOCA occurred, RCIC (Reactor Core Isolation Cooling) was available as well as all other Emergency Core Cooling Systems (ECCS). Under this scenario, adequate core cooling is ensured by the operability of the redundant and diverse low pressure ECCS injection/spray subsystems in conjunction with the ADS (Automatic Depressurization System). Also the RCIC system would automatically provide makeup water at most reactor operating pressures.
This event resulted in a reduction in the Regulatory Oversight Process (ROP) Mitigating System Performance Index (MSPI) for the High Pressure Core Spray System from -1.8E-07 to -1.7E-07 compared to the Green-to-White threshold value of >1.OE-06. This reduction would not result in entry into the "Increased Regulatory (White) Response Band."
IV. CORRECTIVE ACTIONS
A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:
The CLOSE fuse block stationary and removable connections were adjusted and verified to fit tightly into each other.
B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:
To prevent reoccurrence, the procedures for the 4.16kV and 13.8 kV breaker PMs will be revised to include the fuse block contact gap adjustment.
V. ADDITIONAL INFORMATION
A. FAILED COMPONENTS:
The CLOSE fuse block stationary contact for HPCS pump breaker was the only failed component and it was repaired.
B. PREVIOUS LERs ON SIMILAR EVENTS:
There have been no previous LERs similar to this event.
C. THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT FUNCTION IDENTIFIER AND SYSTEM NAME OF EACH COMPONENT OR SYSTEM REFERRED TO IN THIS LER:
COMPONENT IEEE 803 IEEE 805 PART COMPONENT IDENTIFIER SYSTEM IDENTIFICATION NUMBER Fuse Block FUB BG 0132A1578001 High Pressure Core Spray Pump P
BG Division 3 Switchgear SWGR BG HPCS Breaker BKR BG Diesel Generator DG EK RCIC System N/A BN ADS System N/A N/A ECCS N/A BO D. SPECIAL COMMENTS:
None.