05000445/LER-2004-003, Regarding Condition Prohibited by Technical Specifications
| ML042740422 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 09/23/2004 |
| From: | Blevins M, Madden F TXU Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CPSES-200402077, TXX-04142 LER 04-003-00 | |
| Download: ML042740422 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2) |
| 4452004003R00 - NRC Website | |
text
G Pw TXU v'9 Power TXU Power Comanche Peak Steam Electric Station P. O. Box 1002 (EO1)
Glen Rose, TX 76043 Tel: 254 897 5209 Fax: 254 897 6652 mike.blevinsetxu.corn Mike Blevins Senior Vice President &
Chief Nuclear Officer Ref: 10CFR50.73(a)(2)(i)(B)
CPSES-200402077 Log # TXX-04142 September 23, 2004 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-445 CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS LICENSEE EVENT REPORT 445/04-003-00 Gentlemen:
Enclosed is Licensee Event Report (LER) 04-003-00 for Comanche Peak Steam Electric Station Unit 1, "Reactor Coolant System Leakage Detection Instrumentation Inoperable for Intermittent Periods Due to a Design Related Siphoning Condition."
This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2.
TXX-04142 Page 2 of 2 Sincerely, TXU Generation Company LP By:
TXU Generation Management Company LLC, Its General Partner Mike Blevins By: 41 %1')' LL red 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-04142 NRC FORI 366 U.S. NUCLEARREGULATORY COWMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 063012007 (6-2004)
Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOIA'Privacy Service Branch (fT-5F52) U.S. Nuclear Regulatory Commission. Washington. DC 20555-0001, orbyinternet e-mailto inFocollUects~rc.gov and totheDeskOfficer Oficeof LICENSEE EVENT REPORT (LER)
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Docket Number (2)
Page (3)
COMANCHE PEAK STEAM ELECTRIC STATION UNIT I 05000445 1 OF 6 Tak (4)
CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS Event Date 5)
LER Number (6)
Repot Date (7 l
Other Facilities Involved (8)
Month Day Year Year Sovequtiat Revision Month Day Year Facility Name Docket Numbers Number Number N/A 05000 07 26 004 4
003 00 09 23 -
04 05000 Operating Tis repot m-umae pursuant to the requreet 3Of 10 CFR : (Check atl that apoiv) (It1)______________
Mode (9) 1 l 20.2201(b) 20.2203(aX3Xi) 50.73(aX2XiXC) 50.73(aX2Xvii)
Power 100 20.2201(d) 20.2203(aX3Xii) l 50.73(aX)(2Xii)(A) 50.73(aX2)(viii)(A)
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20.2203(aXI) 20.2203(aX4) 50.73(a)(2XiiXB)
S0.73(aX2XviiiXB) 20.2203(aX2Xi)
S0.36(cX2XiXA) 50.73(a)(2)(iii) 50.73(aX2Xix)(A) 20.2203(a)(2)(ii) 50.36(c)(IXiiXA) 50.73(aX2XivXA) 50.72(aX2)(x) 20.2203(aX2Xiii) 50.36(cX2) 50.73(aX2XvXA) 73.71(aX4) 20.2203(aX2)(iv) 50.46(a)(3)(ii)
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73.71 (aXS) 20.2203(a 2Xv) 50.73(aX)(2XiA) 50.73(a)(2)v)(C)
OTHER 20.2203(aX2Xvi)
X 50.73(aX2XiXB) 50.73(a)(2XvD)
Specify in Abstract below or in =
(If morespace is requied. use additonal cops of SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On June 11, 2004, Operations personnel (utility, licensed) observed that the containment sump flow counter [EIIS:(CTR)] did not indicate flow when containment sump pump 4 ran to pump down containment sump 2. At CPSES, containment leakage is collected in containment sump 1, containment sump 2, or the reactor cavity sump [EIIS:(WK)(SUMP)] and is pumped via a common discharge header to a floor drain tank [EIIS:(WK)(TK)] or a waste hold-up tank [EIIS:(WK)(TK)]. The common discharge header contains a flow totalizer [EIIS:(FQI)] that measures flow and facilitates the recording of this total flow in the control room. Additionally, a run time counter [EIIS:(CTR)] records the run time of each pump. When the water level in the sump reaches a low level, the sump pumps [EIIS:(NH)(SUMP)(P)] are designed to shutoff.
Subsequent troubleshooting revealed that system elevation differences were causing the drain header to siphon intermittently to the floor drain tank leaving a void in the piping. When the sump pump was subsequently run, the water would fill the piping resulting in minimal flow registering on the flow totalizer. The siphoning condition would occur after the pump was secured from the normal pump run resulting in the flow totalizer continuing to indicate flow.
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Enclosure to TXX-04142 NRC F1R M 366A U.S. NUCLEAR REGULATORY COMUMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
Facility Name (l)
Docket UR Number (6) lage(3)
Sequen l
Revision COMANCHE PEAK STEAM ELECTRIC STATION UNIT I 0
4 11 Number a,
Number 3 050(00445 H5
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003 H 0 3OF 6 NARRATIVE (If more space is requed, ise addiutional eopis of (Ifmore spce is equeduse additional copies of (If more spac required. ue additonal cops of NRC Fonn 366A) (17)
III.
ANALYSIS OF THE EVENT
A.
SAFETY SYSTEM RESPONSES THAT OCCURRED Not applicable - No safety system responses occurred as a result of this event.
B.
DURATION OF SAFETY SYSTEM TRAIN INOPERABILITY The Unit 1 Containment Sump Level and Flow Monitoring system was determined to have been inoperable per TS on December 15, 2003, for approximately 31 hours3.587963e-4 days <br />0.00861 hours <br />5.125661e-5 weeks <br />1.17955e-5 months <br />. The Unit 1 Containment Sump Level and Flow Monitoring system could have also been inoperable at other times in the past due to the siphoning condition which existed since initial Unit 1 licensing in 1990.
C.
SAFETY CONSEQUENCES AND IMPLICATIONS
Section 5.2.5.2.2 of the Final Safety Analysis Report (FSAR) describes the primary detection of unidentified leakage to the Containment atmosphere as being provided by air particulate monitors, containment sump flow monitors, and the condensate flow rate measuring system. These systems provide an early indication of reactor coolant pressure boundary degradation as soon after occurrence as practical to minimize the potential for a gross pressure boundary failure which would result in a loss of coolant accident. The leakage detection system is credited in the CPSES safety analyses for General Design Criteria 4 (GDC-4) Leak Before Break to detect leaks and allow an orderly shutdown prior to a LOCA. This event involved the inoperability of one of the means of Reactor Coolant System leak detection, namely the containment sump flow monitors.
Had all means of detecting unidentified leakage been unavailable, early detection of a pressure boundary breach would have been compromised. However, a loss of coolant accident is fully bounded by Section 15.6.5 of the FSAR. Because the Containment Sump Level and Flow Monitoring system does not perform a nuclear safety function, there were no safety system functional failures associated with this event. Based on this analysis it was concluded that this event did not adversely affect the safe operation of CPSES Unit 1 or the health and safety of the public.
{If mole spac is roqurodu rcadditional copc of NRC Form 366A) (17)
IV.
CAUSE OF THE EVENT
TXU Power has determined that the cause of this event was a siphoning condition that was inherent in the original design of the Unit 1 Containment Sump Level and Flow Monitoring system.
V.
CORRECTIVE ACTIONS
To correct the siphoning condition, vacuum breakers were installed in the Unit 1 sump discharge piping. Unit 2 was not believed to be affected by this condition. However, vacuum breakers were also installed in Unit 2 sump discharge piping as a precautionary measure.
VI.
PREVIOUS SIMILAR EVENTS
There has been one other reportable event in the last three years involving an original design condition (see LER 02-001-00 for Units 1 and 2). However, details/causes are sufficiently different from the event described in this LER such that the previous corrective actions could not have prevented this event.
NRC FORIM 366A(1-2001)