05000237/LER-2006-001, Re Isolation Condenser Declared Inoperable Due to Inadequate Backfilling of Instrument Sensing Lines
| ML061010637 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/03/2006 |
| From: | Bost D Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SVPLTR # 06-0018 LER 06-001-00 | |
| Download: ML061010637 (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) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 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 |
| 2372006001R00 - NRC Website | |
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Exelon G mneration Company, LLC www.exeloncorp.com Dresden Nuclear Power Station Nuclear 65oo No -th Dresden Road Morris, IL 60450-9765 10 CFR 50.73 April 3, 2006 SVPILTR # 06-0018 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit No. 2 Renewed Facility Operating License No. DRP-19 NRC Docket No. 50-237
Subject:
Licensee Event Report 237/2006-001-00, "Unit 2 Isolation Condenser Declared Inoperable Due To Inadequate Backfilling Of Instrument Sensing Lines" Enclosed is Licensee Event Report 237/2006-001-00, "Unit 2 Isolation Condenser Declared Inoperable Due To Inadequate Backfilling Of Instrument Sensing Lines," for Dresden Nuclear Power Station, Unit 2. This event is being reported in accordance with 10 CFR 50.73(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 mitigate the consequences of an accident."
Should you have any questions concerning this report, please contact Mr. Pedro Salas, Regulatory Assurance Manager, at (815) 416-2800.
Resp ectfully, Danny G. Bost Site \\Vice President Dresden Nuclear Power Station Enclosure cc:
Regional Administrator - NRC Region IlIl NRC Senior Resident Inspector - Dresden Nuclear Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXP RES: 06/30/2007 (6-2004)
, the NRC may digits/characters for each block) nnot conduct or sponsor, and a person Is not required to respond to, the dgiscaatrfoeahbok informato r~ptinn
- 1. FACILITY NAMI
- 2. DOCKET NUMBER
- 3. PAGE Dresden Nuclear Power Station Unit 2 05000237 1 OF: 3
- 4. TITLE Unit 2 Isolation Condenser Declared Inoperable Due To Inadequate Backfilling Of Instrument Sensing Lines
- 5. EVENT DAXE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEUNTA RVFCILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER RNEOV MONTH DAY YEAR IL NN/A FACILtTY NAME DOCKET NUMBER 02 01
.2006 2006 - 001 -
00 04 03 2006 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORTIS SUBMITTED PURSUANTTO THE REQUIREMENTS OF 10 CFR§: (Check al/thatapply)
O 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1 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)
O 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
El 50.73(a)(2)(;ii)
El 50.73(a)(2)(1x)(A)
- 10. POWER LEVEiL E
20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
[I 50.73(a)(2)(X)
O 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[I 50.73(a)(2)(v)(B)
El 73.71(a)(5) 098 El 20.2203(a)(2)(v)
E 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
E OTHER El 20.2203(a)(2)(vi)
Dl 50.73(a)(2)(i)(B)
Z 50.73(a)(2)(v)(D)
Specify In Abstra.t below or In NRC Fnrm.166A
- 12. LICENSEE CONTACT FOR THIS LER CArlaId klfl**C NAMF cTE aCa 1 a~lMnRF Ia..a A.... Ca.M-Dresden Nuclear Power Station - George Papanic Jr.
~(815) 416. -2815~,,aaicai El YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
ABSTRACT (Limit Io 1400 spaces, i.e., approximately 15 single-spaced typewtitten lines)
On February 1, 2006, at approximately 1943 hours0.0225 days <br />0.54 hours <br />0.00321 weeks <br />7.393115e-4 months <br /> (CST), with Unit 2 at approximately 98 percent power, Dresden Nuclear Power Station technicians were performing a calibration of the Isolation Condenser Steam/Condensate Line High Flow instrumentation when a technician observed an unexpected response during the return to service of the Isolation Condenser Condensate Line High Flow Differential Pressure Switch DPIS 2-1349B. The switch monitors flow in the Isolation Condenser Condensate Return line. The calibration was stopped. The Isolation Condenser was declared inoperable and isolated.
Subsequent investigations determined that the observed unexpected response was the result of voids in the instrument sensing lines of the Isolation Condenser Steam/Condensate Line High Flow Differential Pressure Switch and ti-at the instrumentation was operable with the voids present.
The apparent cause of the voids in the instrument sensing lines of the Isolation Condenser Steam/Condensate Line High Flow Differential Pressure Switch was the failure of Procedure DOP 1300-11, "Unit 2 Isolation Condenser Fill and Vent," to identify that the sensing lines required backfilling after filling of the Isolation Condenser piping. A corrective action was created to revise Procedure DOP 1300-11 to require the backfilling of sensing lines after filling of the Isolation Condenser piping.
NRC ORM 66(-200)
PINTE ON ECYLED APE NRC FORM 366 (6-2004)
PRINTED ON RECYCLED PAPER
U.S. NUCLEAR REGULATORY COMMISSION (1.2001)
LICENSEE EVENT REPORT (LER)
FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6) 1 PAGE (3)
I I
REVISIO SEQUENTIAL N
PYEARen N01 I
MBE Dresden Nuclear Power Station Unit 205000237 2006
-- 001
-- 00 2
OF 3
NARRATIVE
(If irore space is required, use additional copies of (If rrore space is required, use additional copies of NRC Form 366A) (17)
IC Condensate Return Line. The preferred method is to backfill the sensing lines after completion of the filliig of the IC piping.
A review of the performance of the Unit 3 IC Steam/Condensate Line High Flow Differential Pressure Switches DPIS 3-1349A and DPIS 3-1349B indicate that the sensing lines are filled and operating normally.
D.
Safety Analysis
The safety significance of the event is minimal. The IC during this event was in compliance with the requirements of Technical Specification 3.5.3, "IC System," and subsequent investigations deterrrined that the IC Steam/Condensate Line High Flow instrumentation was operable with the voids present. Therefore, the consequences of this event had minimal impact on the health and safety of the public and reactor safety.
E.
Corrective Actions
Unit 2 Procedure DOP 1300-11 will be revised to require the backfilling of DPIS 2-1349A and DPIS 2-1349B sensing lines after filling of the Isolation Condenser piping.
Unit 3 Procedure DOP 1300-10, "Unit 3 Isolation Condenser Fill and Vent," will be revised to require the backfilling of DPIS 3-1349A and DPIS 3-1349B sensing lines after filling of the Isolation Condenser piping.
Unit 2 IC Condensate Line High Flow Differential Pressure Switches DPIS 2-1349A and DPIS 2-1349B sensing lines will be backfilled at the next Unit 2 forced outage of sufficient duration.
F.
Previous Occurrences
A review of DNPS Licensee Event Reports (LERs) for the last three years did not identify any similar events.
G.
Component Failure Data
NA