05000446/LER-2004-003, Regarding Containment Pressure Channel Inoperable Due to a Secondary Ground
| ML050330170 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/21/2005 |
| From: | Madden F TXU Generation Co, LP, TXU Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CPSES-200500005, TXX-05002 LER 04-003-00 | |
| Download: ML050330170 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4462004003R00 - NRC Website | |
text
L TXU Power TXU POwa Comanche Peak Steam ectric Station P. 0. Box 1002 (E0U)
Glen Rose. TX 76043 Te: 254 897 5209 Fax 254 897 6652 mikeblevins~txu.com Mike Blevins Senior Vice President &
Chief Nudlear Officer Ref: 10CFR50.73(a)(2)(i)(B)
CPSES-200500005 Log # TXX-05002 January 21, 2005 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-446 CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS LICENSEE EVENT REPORT 446/04-003-00 Gentlemen:
Enclosed is Licensee Event Report (LER) 04-003-00 for Comanche Peak Steam Electric Station Unit 2, "Containment Pressure Channel Inoperable Due to a Secondary Ground."
This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2.
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway Comanche Peak Diablo Canyon
- Palo Verde South Texas Project Wolf Creek
TXX-05002 Page 2 of 2 Sincerely, TXU Generation Company LP By:
TXU Generation Management Company LLC, Its General Partner Mike Blevins Bv:jJ Hi29QLL
/Fred W. Madden Director, Regulatory Affairs GLM Enclosures c -
B. S. Mallett, Region IV W. D. Johnson, Region IV M. C. Thadani, NRR Resident Inspectors, CPSES
Enclosure to TXX-05002 NRC FORbl 366 U.S NUCLEAR REGULATORY COMLMISSION APPROVED BY OblB NO. 3150-0104 EXPIRES 06r3i2007 (6-2004)
, the NRC may not conduct or smonsor, and a pernn snot requird to resond to, the informatin collection Facility Name (I)
Docket Number (2)
Page (3)
COMANCHE PEAK STEAM ELECTRIC STATION UNIT 2 05000446 1 OF 6 Tale (4)
CONTAINMENT PRESSURE CHANNEL INOPERABLE DUE TO A SECONDARY GROUND Event Dte (5)
LER Number 6 Report Doe (7)
Other Facilities Involved (ti Month Day Year Yew Sequential Revisioa Month Dry Y
Facility Name Docket Number I
Number Number N/A 0S000 11 23 04 04 003 00 01 21 05 05000 Opernttg This repo is rubmitted purst to the _ rements of 10 CFR: (Check all that aPpv) (It)
.)
Mode (9) 1 20.2201(b) 20.2203(aX3Xi) 50.73(aX2XiXC) 50.73(aX2Xvii)
Power 20.2201(d) 20.2203(a)X3)(ii) 50.73(aX2XiiXA) 50.73(a)(2XviiiXA)
Level 100 20.2203(aXl) 20.2203(aX4) 50.73(aX2XiiXB)
_ 50.73(aX2XviiiXB) 20.2203(aX2)(i) 50.36(cX2XiXA) 50.73(aX2Xiii) 50.73(aX2XixXA) 20.2203(aX2Xii) 50.36(cX)I)(ii)(A) 50.73(aX2XivXA)
_ 50.72(aX2Xx) 20.2203(aX2Xiii)
I 50.36(cX2) 50.73(aX2XvXA) 73.71(a)(4) 20.2203(aX2Xiv) 50.46(aX3Xii) 50.73(aN2XvXB) 73.71(aX5) 20.2203(aX2)(v) 50.73(a)(2XiXA)
=
50.73(aX2XvXC)
OTHER 20.2203(aX2)(vi)
X 50.73(aX2XiXB)
X 50 73(aX2XvXD)
Specify in Abstract below or in =
(If more space is requied, u ackditional copis Of SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On August 5, 2004, CPSES Unit 2 was in Mode 1, Power Operation, operating at approximately 100 percent power. At 0755 hours0.00874 days <br />0.21 hours <br />0.00125 weeks <br />2.872775e-4 months <br />, Operators in the Unit 2 Control Room received a computer point deviation alarm on one of the four Engineered Safety Feature Actuation System (ESFAS) intermediate range containment pressure channels (channel 2-P-0935) [EIIS:(JE)(CHA)]. At that time, the channel was found to be reading approximately 2.0 psig low with respect to the other channels. Over the next 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />, channel 2-P-0935 acted erratically and failed to track the other three containment pressure channels. The channel deviations during this time ranged from approximately 5.0 psig low to approximately 1.0 psig low.
NRC FIVLM 360A (I-200I)
Enclosure to TXX-05002 (If more space is required use adiioncl eopies of (If more space is required use addioi copies of (If more space is required, use additional copies of (If more spce i rqure4 use additional copies of NRC Form 366A) (17)
IV.
CAUSE OF THE EVENT
TXU Power believes that this event was caused by a secondary ground in the junction box associated with the pressure transmitter. The expansion anchors, securing the junction box to the reactor building wall, were found to be exuding a white, mineral-rich liquid from the concrete. This liquid had over time dripped on the cable shield at the bottom of the junction box. The built up mineral deposits produced a current path to ground, essentially causing the shield for one of the cables to be grounded at both ends. This caused a grounding loop, which lead to the intermittent erroneous indications.
V.
CORRECTIVE ACTIONS
This condition was corrected and the loop was restored to service, with normal containment pressure indications. Per the CPSES Corrective Action Program, Engineering will review other potential locations where this condition may exist and inspect those locations for the existence of this condition as appropriate.
VI.
PREVIOUS SIMILAR EVENTS
There has been one other reportable event in the last three years involving channel 2-P-0935 being inoperable (see Unit 2 LER 2003-004-00). However, the cause of that event (random electronic failure) was sufficiently different from the event described in this LER such that the previous corrective actions could not have prevented this event.
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