05000247/LER-2010-006, For Indian Point 2, Regarding Safety System Functional Failure Due to Inoperable Reactor Coolant Loop 21 and 22 Wide Range Hot Leg Temperature Indicators Credited for Remote Shutdown Per Technical Specification 3.3.4
| ML103130039 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  (DPR-026) |
| Issue date: | 10/27/2010 |
| From: | Joseph E Pollock Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-10-108 LER-10-006-00 | |
| Download: ML103130039 (5) | |
| 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 |
| 2472010006R00 - NRC Website | |
text
AEntergy Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tel (914) 734-6700 J. E. Pollock Site Vice President NL-10-108 October 27, 2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop O-P1-17 Washington, D.C. 20555-0001
SUBJECT:
Licensee Event Report # 2010-006-00, "Safety System Functional Failure Due to Inoperable Reactor Coolant Loop 21 and 22 Hot Leg Wide Range Temperature Indicators Credited for Remote Shutdown per Technical Specification 3.3.4" 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) 2010-006-00. The attached LER identifies an event which is reportable as a safety system functional failure under 10 CFR 50.73(a)(2)(v). This condition was recorded in the Entergy Corrective Action Program as Condition Report CR-IP2-2010-05446.
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/cbr 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
Abstract
On September 1, 2010, during performance of 2-PT-QO17C (Alternate Safe Shutdown Supply Verification to 23 CCP),
the Reactor Coolant System (RCS)
Wide Range Hot Leg Temperature Instruments TI-5139 (Loop 21) and TI-5141 (Loop 22) test readings were found out of specification.
Technical Specification Basis 3.3.4 (Remote Shutdown),
Table 3.3.4-1, Function 3.b Decay Heat Removal via Steam Generators, RCS Hot Leg (HL)
Temperature requires one operable function.
The RCS HL Temperature is also credited in Technical Requirements Manual (TRM) 3.3.D (Appendix R Alternate Safe Shutdown Instrumentation).
After verification of proper performance of the test, Operations concluded the function for RCS HL Temperature was inoperable and entered TS 3.3.4 Action Statement A.1.
The apparent cause was indeterminate.
A Failure Modes and Effect Analysis identified two possible causes: PC-l) A test process failure.
The test has had historical problems with the test sequence where the instruments are powered prior to start of the 23 CCP and starting currents impacted instrument readout.
Also the instruments and circuit is required to warm up and stabilize after establishing power.
To mitigate these effects the test was revised.
PC-2)
Component failure.
A complete failure of the R/I converter (TM) could cause the condition but a successful re-test and calibration ruled out a complete failure.
Corrective actions include re-performing test 2-PT-QO17C with engineering review, and evaluating re-test results and identifying any additional actions.
The event had no effect on public health and safety.
(if more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)
Past Similar Events A review was performed of the past three years of Licensee Event Reports (LERs) for events that reported a loss of remote shutdown instruments for Indian Point Unit 2.
Two LERs were identified: LER-2009-003 and LER-2009-004.
LER-2009-003 reported a SSFF for an inoperable 21 Pressurizer Backup Heater that is credited in TS 3.3.4.
LER-2009-004 reported a SSFF for an inoperable 23 Charging Pump that is credited in TS 3.3.4.
These LERs were SSFFs as a result of failed components (breaker and internal pump valve) and not remote shutdown instruments.
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 shutdown requiring the use of the remote shutdown panel.
There was no significant potential safety consequences of this event because in accordance with NUREG-0800, Section 7.4, shutdown remote from the CR is not an event analyzed in the USFAR for accident analysis (Chapter 14).
Specific scenarios are not specified on which the adequacy of shutdown capability remote from the CR is evaluated.
A recognized type of event that could force the evacuation of the CR and the need to shut down remote from the CR is smoke from a fire.
Fire damage limits as they impact safe shutdown do not require consideration of an additional random single failure in the capability to safely shut down.
Therefore, application of single failure to remote shutdown is applicable only to other events that could cause the CR to become uninhabitable.
These events would not result in consequential damage or unavailability of systems required for safe shutdown.