05000247/LER-2010-008, For Indian Point Unit 2, Regarding Safety System Functional Failure Due to Inoperable Refueling Water Storage Tank Low-Low Level Alarms
| ML103270062 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 11/09/2010 |
| From: | Joseph E Pollock Entergy Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-10-121 LER 10-008-00 | |
| Download: ML103270062 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation 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 |
| 2472010008R00 - NRC Website | |
text
~Enter~gy Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tei (914) 734-6700 J. E. Pollock Site Vice President NL-10-121 November 9, 2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop O-P1-17 Washington, D.C. 20555-0001
SUBJECT:
Licensee Event Report # 2010-008-00, "Safety System Functional Failure Due to Inoperable Refueling Water Storage Tank Low-Low Level Alarms" Indian Point Unit No. 2 Docket No. 50-247 DPR-26
Dear Sir or Madam:
Pursuant to 10 CFR 50.73(a)(1), Entergy Nuclear Operations Inc. (ENO) hereby provides Licensee Event Report (LER) 2010-008-00. The attached LER identifies an event which is reportable as a safety system functional failure under 10 CFR 50.73(a)(2)(v)(D). This condition was recorded in the Entergy Corrective Action Program as Condition Report CR-IP2-2010-05713.
There are no new commitments identified in this letter. Should you have any questions regarding this submittal, please contact Mr. Robert Walpole, Manager, Licensing at (914) 734-6710.
Sincerely, JEP/sp cc:
Mr. William Dean, Regional Administrator, NRC Region I NRC Resident Inspector's Office, Indian Point 3 Mr. Paul Eddy, New York State Public Service Commission LEREvents@inpo.org
,.1
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME:
INDIAN POINT 2
- 2. DOCKET NUMBER
- 3. PAGE 05000-247 1
OF 3
- 4. TITLE: Safety System Functional Failure Due to Inoperable Refueling Water Storage Tank Low-Low Level Alarms
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
FACILITY NAME DOCKET NUMBER MONTSEQUENTIAL REV.
MONTH DAY YEAR 05000 A
YEAR YEAR NUMBER NO.
M FACILITY NAME DOCKET NUMBER
~.
05000 9 1 200 2010- 008 00 11 12 2010 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Checkall thatapply)
El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C) rl 50.73(a)(2)(vii)
El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
EL 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[1 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
RE 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
[E 50.73(a)(2)(x)
- 10. POWER LEVEL
]E 20.2203(a)(2)(iii)
[I 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71 (a)(4) 7.1 El 20.2203(a)(2)(iv)
[] 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5)
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B) 0 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER FACILITY NAME TELEPHONE NUMBER (Include Area Code)
Vincent Andreozzi, System Engineer Supervisor (914) 734-6816MANU-REPORTABLE MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT
CAUSE
SYSTEM COMPONENT FACTURER EPOA FACTURER TO EPIX FACTURER TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR El YES (If yes, complete 15. EXPECTED SUBMISSION DATE) 0 NO SUBMISSION DATE
- 6. ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced type written lines)
On September 13, 2010, during performance of alarm checks, Panels SA-SC did not illuminate.
The Refueling Water Storage Tank low-low level alarms, required by Technical Specification 3.5.4, were rendered inoperable as a result of the loss of power. Operations entered procedure AOP-ANNUN-l for failure of flight or supervisory panel annunciators and replaced a fuse found to be blown. Since the RWST low-low level alarms are required by Technical Specifications, this was considered a safety system functional failure.
Overcurrent condition is the direct cause of the fuse blowing. The apparent cause is intermittent grounds in combination with alarm testing resulted in the over current condition. Corrective action requires determining the source of the intermittent grounds.
The event had no effect on public health and safety.
NRC FORM 366 (10-2010)
Note:
The Energy Industry Identification System Codes are identified within the brackets {0.
DESCRIPTION OF EVENT
On September 13, 2010, while at a steady 7.1% reactor power, alarm checks were being performed on the main control room annunciator panels by pushing the test button and verifying the alarm can illuminates and the horn sounds.
When operations pushed the test button, panels SA-SC (IB} did not illuminate. At 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> Operations declared the Refueling Water Storage Tank (RWST){BP}
{TK} inoperable per Technical Specification (TS) 3.5.4 Condition C and entered Procedure AOP-ANNUN-I "Failure of Flight or Supervisory Panel Annunciators" to diagnose the problem.
A ten amp fuse (FU-CCR-SD-4A){FU} had blown on the negative feed in panel SD {EJ).
The fuse was replaced and the alarm test was performed satisfactorily. At 2013 hours0.0233 days <br />0.559 hours <br />0.00333 weeks <br />7.659465e-4 months <br /> the Panels SA-SC were restored to operation and the RWST was declared operable. CR-IP2-2010-5713 was generated for this event.
TS 3.5.4 requires the RWST to be operable in Modes 1, 2, 3,
and 4.
Condition B is entered with "One of two required channels of the RWST low-low level alarm inoperable" even though the LCO does not explicitly call out that the low-low level alarms {LA}.
The loss of the two low-low level alarms is considered a safety system functional failure (SSFF) because the TS 3.5.4 Condition B indicates that two channels are required which is consistent with the custom TS that required two alarm channels to be operable.
When the two channels of the RWST low-low level alarm were declared inoperable, the RWST was declared inoperable in accordance with TS 3.5.4 Condition C, RWST inoperable for reasons other than Condition A or B. This was not considered a SSFF at the time due to the continued availability of the RWST tank and the redundant RWST level indicators required by TS 3.3.3.
No eight hour emergency notification was made for a SSFF.
Operations concluded there was no SSFF due to the continued availability of the RWST and the availability of the redundant level indicators to initiate recirculation.
Condition Report CR-IP2-2010-5913 evaluates this event.
Past occurrences were evaluated.
In 1996 and 1997 alarm cans in panels SA-SC were found to have shorts and replaced.
The design of the annunciator alarm cans was upgraded from a flexible design to a hardwire design to address a relay contact issue (i.e., relays in the alarm cans aged due to temperature and this caused arcing and grounding that blew the fuses).
In 2005 a 10 amp fuse was found blown but the event was not called reportable and no apparent cause was performed.
The 1997 event and the current event occurred when coming out of a mini outage where most of the alarms are lit and temperatures are higher.
The corrective actions after the 1997 event are believed to have corrected temperature problems.
The 24 battery charger, which feeds the SA-SC annunciator panels, has a history of ground alarms which testing has been unsuccessful in fully identifying and eliminating. It was concluded alarm testing and an intermittent ground caused the overcurrent to blow the fuse.U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE SEQUENTIAL REVISION YEAR NUMBER NUMBER Indian Point Unit 2 05000-247 2010 008 00 J 3
OF 3
Cause of Event
Over current condition is the direct cause of the fuse blowing. The apparent cause is an over current condition due to intermittent grounds in combination with alarm testing.
Corrective Action
The following corrective actions have been or will be performed under the Corrective Action Program (CAP) to address the causes of this event.
" Replaced the fuse to restore panel SA-SC operability.
- Action to initiate work orders to check circuit 6 for grounds and check the 24 battery charger alarm circuit calibration.
- Action to initiate an engineering change request to replace the fast acting fuse with a time delay fuse.
Event Analysis
The event is reportable under 10CFR50.73(a) (2) (v) (D),
"Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to: "(D) mitigate the consequences of an accident."
On September 13, 2010, at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, the RWST was declared inoperable when power was lost to the panels SA-SC.
The power loss resulted in the loss of two RWST low-low level alarms.
TS 3.5.4 Condition B supports that two RWST low-low level alarms are required.
The alarms are used to alert the operator to initiate actions to transfer from injection phase to recirculation phase following a LOCA.
The RWST Level indicators and sump indicators covered under TS 3.3.3 can be used to confirm RWST level prior to the manual switchover to the cold leg recirculation phase.
The condition was originally not considered a SSFF due to an understanding that the RWST level indicators could be used to perform the function and, therefore, no 8-hour non-emergency notification was provided to the NRC under 10CFR50.72(b) (3) (v).
Condition report CR-IP2-2010-5913 evaluates the missed call.
Past Similar Events A review was performed of the past three years of Licensee Event Reports (LERs) for events that reported a SSFF due to the loss of a power supply.
No such events were identified and condition reports on such events were not found.
Safety Significance
This event had no effect on the health and safety of the public.
There were no actual safety consequences for the event because there was no accident requiring use of the RWST.
There were no significant potential safety consequences of this event because the redundant level indicators required by TS 3.3.3 were available and operations is trained to rely on these indicators for switchover to recirculation.